1
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Waddell HMM, Mereacre V, Alvarado FJ, Munro ML. Clustering properties of the cardiac ryanodine receptor in health and heart failure. J Mol Cell Cardiol 2023; 185:38-49. [PMID: 37890552 PMCID: PMC10717225 DOI: 10.1016/j.yjmcc.2023.10.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/20/2023] [Revised: 10/09/2023] [Accepted: 10/24/2023] [Indexed: 10/29/2023]
Abstract
The cardiac ryanodine receptor (RyR2) is an intracellular Ca2+ release channel vital for the function of the heart. Physiologically, RyR2 is triggered to release Ca2+ from the sarcoplasmic reticulum (SR) which enables cardiac contraction; however, spontaneous Ca2+ leak from RyR2 has been implicated in the pathophysiology of heart failure (HF). RyR2 channels have been well documented to assemble into clusters within the SR membrane, with the organisation of RyR2 clusters recently gaining interest as a mechanism by which the occurrence of pathological Ca2+ leak is regulated, including in HF. In this review, we explain the terminology relating to key nanoscale RyR2 clustering properties as both single clusters and functionally grouped Ca2+ release units, with a focus on the advancements in super-resolution imaging approaches which have enabled the detailed study of cluster organisation. Further, we discuss proposed mechanisms for modulating RyR2 channel organisation and the debate regarding the potential impact of cluster organisation on Ca2+ leak activity. Finally, recent experimental evidence investigating the nanoscale remodelling and functional alterations of RyR2 clusters in HF is discussed with consideration of the clinical implications.
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Affiliation(s)
- Helen M M Waddell
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Valeria Mereacre
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand
| | - Francisco J Alvarado
- Department of Medicine and Cardiovascular Research Center, University of Wisconsin-Madison School of Medicine and Public Health, Madison, WI, USA
| | - Michelle L Munro
- Department of Physiology and HeartOtago, School of Biomedical Sciences, University of Otago, Dunedin, New Zealand.
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2
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Magyar ZÉ, Bauer J, Bauerová-Hlinková V, Jóna I, Gaburjakova J, Gaburjakova M, Almássy J. Eu 3+ detects two functionally distinct luminal Ca 2+ binding sites in ryanodine receptors. Biophys J 2023; 122:3516-3531. [PMID: 37533257 PMCID: PMC10502479 DOI: 10.1016/j.bpj.2023.07.029] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2023] [Revised: 06/26/2023] [Accepted: 07/31/2023] [Indexed: 08/04/2023] Open
Abstract
Ryanodine receptors (RyRs) are Ca2+ release channels, gated by Ca2+ in the cytosol and the sarcoplasmic reticulum lumen. Their regulation is impaired in certain cardiac and muscle diseases. Although a lot of data is available on the luminal Ca2+ regulation of RyR, its interpretation is complicated by the possibility that the divalent ions used to probe the luminal binding sites may contaminate the cytoplasmic sites by crossing the channel pore. In this study, we used Eu3+, an impermeable agonist of Ca2+ binding sites, as a probe to avoid this complication and to gain more specific information about the function of the luminal Ca2+ sensor. Single-channel currents were measured from skeletal muscle and cardiac RyRs (RyR1 and RyR2) using the lipid bilayer technique. We show that RyR2 is activated by the luminal addition of Ca2+, whereas RyR1 is inhibited. These results were qualitatively reproducible using Eu3+. The luminal regulation of RyR1 carrying a mutation associated with malignant hyperthermia was not different from that of the wild-type. RyR1 inhibition by Eu3+ was extremely voltage dependent, whereas RyR2 activation did not depend on the membrane potential. These results suggest that the RyR1 inhibition site is in the membrane's electric field (channel pore), whereas the RyR2 activation site is outside. Using in silico analysis and previous results, we predicted putative Ca2+ binding site sequences. We propose that RyR2 bears an activation site, which is missing in RyR1, but both isoforms share the same inhibitory Ca2+ binding site near the channel gate.
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Affiliation(s)
- Zsuzsanna É Magyar
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Jacob Bauer
- Institute of Molecular Biology, Slovak Academy of Sciences, Bratislava, Slovakia
| | | | - István Jóna
- Department of Physiology, Faculty of Medicine, University of Debrecen, Debrecen, Hungary
| | - Jana Gaburjakova
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - Marta Gaburjakova
- Institute of Molecular Physiology and Genetics, Centre of Biosciences, Slovak Academy of Sciences, Bratislava, Slovakia
| | - János Almássy
- Department of Physiology, Semmelweis University, Budapest, Hungary.
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3
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Yang JZ, Zhang KK, Shen HW, Liu Y, Li XW, Chen LJ, Liu JL, Li JH, Zhao D, Wang Q, Zhou CS. Sigma-1 receptor knockout disturbs gut microbiota, remodels serum metabolome, and exacerbates isoprenaline-induced heart failure. Front Microbiol 2023; 14:1255971. [PMID: 37720144 PMCID: PMC10501138 DOI: 10.3389/fmicb.2023.1255971] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2023] [Accepted: 08/15/2023] [Indexed: 09/19/2023] Open
Abstract
Introduction Heart failure (HF) is usually the end stage of the continuum of various cardiovascular diseases. However, the mechanism underlying the progression and development of HF remains poorly understood. The sigma-1 receptor (Sigmar1) is a non-opioid transmembrane receptor implicated in many diseases, including HF. However, the role of Sigmar1 in HF has not been fully elucidated. Methods In this study, we used isoproterenol (ISO) to induce HF in wild-type (WT) and Sigmar1 knockout (Sigmar1-/-) mice. Multi-omic analysis, including microbiomics, metabolomics and transcriptomics, was employed to comprehensively evaluate the role of Sigmar1 in HF. Results Compared with the WT-ISO group, Sigmar1-/- aggravated ISO-induced HF, including left ventricular systolic dysfunction and ventricular remodeling. Moreover, Sigmar1-/- exacerbated ISO-induced gut microbiota dysbiosis, which was demonstrated by the lower abundance of probiotics g_Akkermansia and g_norank_f_Muribaculaceae, and higher abundance of pathogenic g_norank_f_Oscillospiraceae and Allobaculum. Furthermore, differential metabolites among WT-Control, WT-ISO and Sigmar-/--ISO groups were mainly enriched in bile secretion, tryptophan metabolism and phenylalanine metabolism, which presented a close association with microbial dysbiosis. Corresponding with the exacerbation of the microbiome, the inflammation-related NOD-like receptor signaling pathway, NF-kappa B signaling pathway and TNF signaling pathway were activated in the heart tissues. Conclusion Taken together, this study provides evidence that a Sigmar1 knockout disturbs the gut microbiota and remodels the serum metabolome, which may exacerbate HF by stimulating heart inflammation.
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Affiliation(s)
- Jian-Zheng Yang
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Kai-Kai Zhang
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Hong-Wu Shen
- Key Laboratory of Evidence Science (China University of Political Science and Law), Ministry of Education, Beijing, China
- Security Department, University of Electronic Science and Technology of China, Chengdu, China
| | - Yi Liu
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Xiu-Wen Li
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Li-Jian Chen
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Jia-Li Liu
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Jia-Hao Li
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Dong Zhao
- Key Laboratory of Evidence Science (China University of Political Science and Law), Ministry of Education, Beijing, China
| | - Qi Wang
- Guangzhou Key Laboratory of Forensic Multi-Omics for Precision Identification, School of Forensic Medicine, Southern Medical University, Guangzhou, China
| | - Chu-Song Zhou
- Department of Spine Surgery, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
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4
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González-Lafuente L, Navarro-García JA, Valero-Almazán Á, Rodríguez-Sánchez E, Vázquez-Sánchez S, Mercado-García E, Pineros P, Poveda J, Fernández-Velasco M, Kuro-O M, Ruilope LM, Ruiz-Hurtado G. Partial Genetic Deletion of Klotho Aggravates Cardiac Calcium Mishandling in Acute Kidney Injury. Int J Mol Sci 2023; 24:ijms24021322. [PMID: 36674838 PMCID: PMC9867237 DOI: 10.3390/ijms24021322] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 01/02/2023] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
Acute kidney injury (AKI) is associated with an elevated risk of cardiovascular major events and mortality. The pathophysiological mechanisms underlying the complex cardiorenal network interaction remain unresolved. It is known that the presence of AKI and its evolution are significantly associated with an alteration in the anti-aging factor klotho expression. However, it is unknown whether a klotho deficiency might aggravate cardiac damage after AKI. We examined intracellular calcium (Ca2+) handling in native ventricular isolated cardiomyocytes from wild-type (+/+) and heterozygous hypomorphic mice for the klotho gene (+/kl) in which an overdose of folic acid was administered to induce AKI. Twenty-four hours after AKI induction, cardiomyocyte contraction was decreased in mice with the partial deletion of klotho expression (heterozygous hypomorphic klotho named +/kl). This was accompanied by alterations in Ca2+ transients during systole and an impairment of sarco/endoplasmic reticulum Ca2+-ATPase (SERCA2a) function in +/kl mice after AKI induction. Moreover, Ca2+ spark frequency and the incidence of Ca2+ pro-arrhythmic events were greater in cardiomyocytes from heterozygous hypomorphic klotho compared to wild-type mice after AKI. A decrease in klotho expression plays a role in cardiorenal damage aggravating cardiac Ca2+ mishandling after an AKI, providing the basis for future targeted approaches directed to control klotho expression as novel therapeutic strategies to reduce the cardiac burden that affects AKI patients.
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Affiliation(s)
- Laura González-Lafuente
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - José Alberto Navarro-García
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Ángela Valero-Almazán
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Elena Rodríguez-Sánchez
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Sara Vázquez-Sánchez
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Elisa Mercado-García
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Patricia Pineros
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - Jonay Poveda
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
| | - María Fernández-Velasco
- IdiPAZ Institute for Health Research/Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares, CIBER-CV, 28046 Madrid, Spain
| | - Makoto Kuro-O
- Division of Anti-Ageing Medicine, Centre for Molecular Medicine, Jichi Medical University, Shimotsuke 329-0498, Japan
| | - Luis M. Ruilope
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBER-CV), Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
- School of Doctoral Studies and Research, European University of Madrid, 28040 Madrid, Spain
| | - Gema Ruiz-Hurtado
- Cardiorenal Translational Laboratory, Institute of Research Imas12, Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
- Centro de Investigación Biomédica en Red de Enfermedades Cardiovasculares (CIBER-CV), Hospital Universitario 12 de Octubre, 28041 Madrid, Spain
- Departamento de Fisiología, Facultad de Medicina, Universidad Autónoma de Madrid, 28029 Madrid, Spain
- Correspondence: ; Tel.: +34-91-3908001
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5
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Tkaczyszyn M, Górniak KM, Lis WH, Ponikowski P, Jankowska EA. Iron Deficiency and Deranged Myocardial Energetics in Heart Failure. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2022; 19:17000. [PMID: 36554881 PMCID: PMC9778731 DOI: 10.3390/ijerph192417000] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 10/05/2022] [Revised: 12/10/2022] [Accepted: 12/12/2022] [Indexed: 06/17/2023]
Abstract
Among different pathomechanisms involved in the development of heart failure, adverse metabolic myocardial remodeling closely related to ineffective energy production, constitutes the fundamental feature of the disease and translates into further progression of both cardiac dysfunction and maladaptations occurring within other organs. Being the component of key enzymatic machineries, iron plays a vital role in energy generation and utilization, hence the interest in whether, by correcting systemic and/or cellular deficiency of this micronutrient, we can influence the energetic efficiency of tissues, including the heart. In this review we summarize current knowledge on disturbed energy metabolism in failing hearts as well as we analyze experimental evidence linking iron deficiency with deranged myocardial energetics.
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Affiliation(s)
- Michał Tkaczyszyn
- Institute of Heart Diseases, Wroclaw Medical University, 50-556 Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, 50-566 Wroclaw, Poland
| | | | - Weronika Hanna Lis
- Institute of Heart Diseases, University Hospital, 50-566 Wroclaw, Poland
| | - Piotr Ponikowski
- Institute of Heart Diseases, Wroclaw Medical University, 50-556 Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, 50-566 Wroclaw, Poland
| | - Ewa Anita Jankowska
- Institute of Heart Diseases, Wroclaw Medical University, 50-556 Wroclaw, Poland
- Institute of Heart Diseases, University Hospital, 50-566 Wroclaw, Poland
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6
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Jin X, Amoni M, Gilbert G, Dries E, Doñate Puertas R, Tomar A, Nagaraju CK, Pradhan A, Yule DI, Martens T, Menten R, Vanden Berghe P, Rega F, Sipido K, Roderick HL. InsP 3R-RyR Ca 2+ channel crosstalk facilitates arrhythmias in the failing human ventricle. Basic Res Cardiol 2022; 117:60. [PMID: 36378362 DOI: 10.1007/s00395-022-00967-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/27/2022] [Revised: 10/13/2022] [Accepted: 10/31/2022] [Indexed: 11/16/2022]
Abstract
Dysregulated intracellular Ca2+ handling involving altered Ca2+ release from intracellular stores via RyR channels underlies both arrhythmias and reduced function in heart failure (HF). Mechanisms linking RyR dysregulation and disease are not fully established. Studies in animals support a role for InsP3 receptor Ca2+ channels (InsP3R) in pathological alterations in cardiomyocyte Ca2+ handling but whether these findings translate to the divergent physiology of human cardiomyocytes during heart failure is not determined. Using electrophysiological and Ca2+ recordings in human ventricular cardiomyocytes, we uncovered that Ca2+ release via InsP3Rs facilitated Ca2+ release from RyR and induced arrhythmogenic delayed after depolarisations and action potentials. InsP3R-RyR crosstalk was particularly increased in HF at RyR clusters isolated from the T-tubular network. Reduced SERCA activity in HF further facilitated the action of InsP3. Nanoscale imaging revealed co-localisation of InsP3Rs with RyRs in the dyad, which was increased in HF, providing a mechanism for augmented Ca2+ channel crosstalk. Notably, arrhythmogenic activity dependent on InsP3Rs was increased in tissue wedges from failing hearts perfused with AngII to promote InsP3 generation. These data indicate a central role for InsP3R-RyR Ca2+ signalling crosstalk in the pro-arrhythmic action of GPCR agonists elevated in HF and the potential for their therapeutic targeting.
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Affiliation(s)
- Xin Jin
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium.,Department of Internal Medicine, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Matthew Amoni
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - Guillaume Gilbert
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - Eef Dries
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - Rosa Doñate Puertas
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - Ashutosh Tomar
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - Chandan K Nagaraju
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - Ankit Pradhan
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - David I Yule
- Department of Pharmacology and Physiology, Medical Center School of Medicine and Dentistry, University of Rochester, 601 Elmwood Avenue, Box 711, Rochester, NY, 14642, USA
| | - Tobie Martens
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, 3000, Leuven, Belgium.,Cell and Tissue Imaging Cluster (CIC), KU Leuven, 3000, Leuven, Belgium
| | - Roxane Menten
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - Pieter Vanden Berghe
- Laboratory for Enteric NeuroScience (LENS), Translational Research Center for Gastrointestinal Disorders (TARGID), KU Leuven, 3000, Leuven, Belgium.,Cell and Tissue Imaging Cluster (CIC), KU Leuven, 3000, Leuven, Belgium
| | - Filip Rega
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium.,Department of Cardiology and Department of Cardiac Surgery, University Hospitals Leuven, Leuven, Belgium
| | - Karin Sipido
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium
| | - H Llewelyn Roderick
- Department of Cardiovascular Sciences, Laboratory of Experimental Cardiology, KU Leuven, 3000, Leuven, Belgium.
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7
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Hegner P, Drzymalski M, Biedermann A, Memmel B, Durczok M, Wester M, Floerchinger B, Provaznik Z, Schmid C, Zausig Y, Maier LS, Wagner S. SAR296968, a Novel Selective Na+/Ca2+ Exchanger Inhibitor, Improves Ca2+ Handling and Contractile Function in Human Atrial Cardiomyocytes. Biomedicines 2022; 10:biomedicines10081932. [PMID: 36009478 PMCID: PMC9406204 DOI: 10.3390/biomedicines10081932] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2022] [Revised: 07/30/2022] [Accepted: 08/04/2022] [Indexed: 11/16/2022] Open
Abstract
Background: In reverse-mode, cardiac sodium-calcium exchanger (NCX) can increase the cytoplasmic Ca2+ concentration in response to high intracellular Na+ levels, which may contribute to diastolic contractile dysfunction. Furthermore, increased spontaneous Ca2+ release from intracellular stores can activate forward mode NCX. The resulting transient inward current causes delayed afterdepolarization (DAD)-dependent arrhythmias. Moreover, recently, NCX has been associated with impaired relaxation and reduced cardiac function in heart failure with preserved ejection fraction (HFpEF). Since NCX is upregulated in human chronic atrial fibrillation (AF) as well as heart failure (HF), specific inhibition may have therapeutic potential. Objective: We tested the antiarrhythmic, lusitropic and inotropic effects of a novel selective NCX-inhibitor (SAR296968) in human atrial myocardium. Methods and Results: Right atrial appendage biopsies of 46 patients undergoing elective cardiac surgery in a predominant HFpEF cohort (n = 24/46) were investigated. In isolated human atrial cardiomyocytes, SAR296968 reduced the frequency of spontaneous SR Ca2+ release events and increased caffeine transient amplitude. In accordance, in isolated atrial trabeculae, SAR296968 enhanced the developed tension after a 30 s pause of electrical stimulation consistent with reduced diastolic sarcoplasmic reticulum (SR) Ca2+ leak. Moreover, compared to vehicle, SAR296968 decreased steady-state diastolic tension (at 1 Hz) without impairing developed systolic tension. Importantly, SAR296968 did not affect the safety parameters, such as resting membrane potential or action potential duration as measured by patch clamp. Conclusion: The novel selective NCX-inhibitor SAR296968 inhibits atrial pro-arrhythmic activity and improves diastolic and contractile function in human atrial myocardium, which may have therapeutic implications, especially for treatment of HFpEF.
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Affiliation(s)
- Philipp Hegner
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Marzena Drzymalski
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Alexander Biedermann
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Bernadette Memmel
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Melanie Durczok
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Michael Wester
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Bernhard Floerchinger
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Zdenek Provaznik
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Christof Schmid
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - York Zausig
- Department of Anesthesiology, University Medical Center Regensburg, 93053 Regensburg, Germany
- Department of Anesthesiology and Operative Intensive Care Medicine, Aschaffenburg-Alzenau Hospital, 63739 Aschaffenburg, Germany
| | - Lars S. Maier
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, 93053 Regensburg, Germany
- Correspondence: ; Tel.: +49-941-944-7206
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8
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Jorgensen AN, Abdullah CS, Bhuiyan MS, Watt M, Dominic P, Kolluru GK, Kevil CG, Nam HW. Neurogranin regulates calcium-dependent cardiac hypertrophy. Exp Mol Pathol 2022; 127:104815. [PMID: 35870494 PMCID: PMC11118017 DOI: 10.1016/j.yexmp.2022.104815] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 04/15/2022] [Accepted: 07/16/2022] [Indexed: 11/04/2022]
Abstract
Intracellular Ca2+-calmodulin (CaM) signaling plays an important role in Ca2+-CaM-dependent kinase (CaMKII) and calcineurin (CaN)-mediated cardiac biology. While neurogranin (Ng) is known as a major Ca2+-CaM modulator in the brain, its pathophysiological role in cardiac hypertrophy has never been studied before. In the present study, we report that Ng is expressed in the heart and depletion of Ng dysregulates Ca2+ homeostasis and promotes cardiac failure in mice. 10-month-old Ng null mice demonstrate significantly increased heart-to-body weight ratios compared to wild-type. Using histological approaches, we identified that depletion of Ng increases cardiac hypertrophy, fibrosis, and collagen deposition near perivascular areas in the heart tissue of Ng null mice. Ca2+ spark experiments revealed that cardiac myocytes isolated from Ng null mice have decreased spark frequency and width, while the duration of sparks is significantly increased. We also identified that a lack of Ng increases CaMKIIδ signaling and periostin protein expression in these mouse hearts. Overall, we are the first study to explore how Ng expression in the heart plays an important role in Ca2+ homeostasis in cardiac myocytes as well as the pathophysiology of cardiac hypertrophy and fibrosis.
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Affiliation(s)
- Ashton N Jorgensen
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America
| | - Chowdhury S Abdullah
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America
| | - Md Shenuarin Bhuiyan
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America
| | - Megan Watt
- Devision of Cardiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America
| | - Paari Dominic
- Devision of Cardiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America
| | - Gopi K Kolluru
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America
| | - Christopher G Kevil
- Department of Pathology and Translational Pathobiology, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America
| | - Hyung W Nam
- Department of Pharmacology, Toxicology, and Neuroscience, Louisiana State University Health Sciences Center, Shreveport, LA 71130, United States of America.
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9
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Therapeutic Approaches of Ryanodine Receptor-Associated Heart Diseases. Int J Mol Sci 2022; 23:ijms23084435. [PMID: 35457253 PMCID: PMC9031589 DOI: 10.3390/ijms23084435] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2022] [Revised: 04/11/2022] [Accepted: 04/14/2022] [Indexed: 01/08/2023] Open
Abstract
Cardiac diseases are the leading causes of death, with a growing number of cases worldwide, posing a challenge for both healthcare and research. Therefore, the most relevant aim of cardiac research is to unravel the molecular pathomechanisms and identify new therapeutic targets. Cardiac ryanodine receptor (RyR2), the Ca2+ release channel of the sarcoplasmic reticulum, is believed to be a good therapeutic target in a group of certain heart diseases, collectively called cardiac ryanopathies. Ryanopathies are associated with the impaired function of the RyR, leading to heart diseases such as congestive heart failure (CHF), catecholaminergic polymorphic ventricular tachycardia (CPVT), arrhythmogenic right ventricular dysplasia type 2 (ARVD2), and calcium release deficiency syndrome (CRDS). The aim of the current review is to provide a short insight into the pathological mechanisms of ryanopathies and discuss the pharmacological approaches targeting RyR2.
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10
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Blackwell DJ, Faggioni M, Wleklinski MJ, Gomez-Hurtado N, Venkataraman R, Gibbs CE, Baudenbacher FJ, Gong S, Fishman GI, Boyle PM, Pfeifer K, Knollmann BC. The Purkinje-myocardial junction is the anatomic origin of ventricular arrhythmia in CPVT. JCI Insight 2022; 7:e151893. [PMID: 34990403 PMCID: PMC8855823 DOI: 10.1172/jci.insight.151893] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Accepted: 12/21/2021] [Indexed: 11/17/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an arrhythmia syndrome caused by gene mutations that render RYR2 Ca release channels hyperactive, provoking spontaneous Ca release and delayed afterdepolarizations (DADs). What remains unknown is the cellular source of ventricular arrhythmia triggered by DADs: Purkinje cells in the conduction system or ventricular cardiomyocytes in the working myocardium. To answer this question, we used a genetic approach in mice to knock out cardiac calsequestrin either in Purkinje cells or in ventricular cardiomyocytes. Total loss of calsequestrin in the heart causes a severe CPVT phenotype in mice and humans. We found that loss of calsequestrin only in ventricular myocytes produced a full-blown CPVT phenotype, whereas mice with loss of calsequestrin only in Purkinje cells were comparable to WT mice. Subendocardial chemical ablation or restoration of calsequestrin expression in subendocardial cardiomyocytes neighboring Purkinje cells was sufficient to protect against catecholamine-induced arrhythmias. In silico modeling demonstrated that DADs in ventricular myocardium can trigger full action potentials in the Purkinje fiber, but not vice versa. Hence, ectopic beats in CPVT are likely generated at the Purkinje-myocardial junction via a heretofore unrecognized tissue mechanism, whereby DADs in the ventricular myocardium trigger full action potentials in adjacent Purkinje cells.
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Affiliation(s)
- Daniel J. Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Michela Faggioni
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Matthew J. Wleklinski
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pharmacology and
| | - Nieves Gomez-Hurtado
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
| | - Raghav Venkataraman
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Chelsea E. Gibbs
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
| | - Franz J. Baudenbacher
- Department of Biomedical Engineering, Vanderbilt University, Nashville, Tennessee, USA
| | - Shiaoching Gong
- Laboratory of Molecular Biology, Rockefeller University, New York, New York, USA
| | - Glenn I. Fishman
- Leon H. Charney Division of Cardiology, Department of Medicine, New York University School of Medicine, New York, New York, USA
| | - Patrick M. Boyle
- Department of Bioengineering, University of Washington, Seattle, Washington, USA
- Institute for Stem Cell and Regenerative Medicine and
- Center for Cardiovascular Biology, University of Washington, Seattle, Washington, USA
| | - Karl Pfeifer
- Division of Intramural Research, Eunice Kennedy Shriver National Institute of Child Health and Human Development, NIH, Bethesda, Maryland, USA
| | - Bjorn C. Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, USA
- Department of Pharmacology and
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11
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Iaparov B, Baglaeva I, Zahradník I, Zahradníková A. Magnesium Ions Moderate Calcium-Induced Calcium Release in Cardiac Calcium Release Sites by Binding to Ryanodine Receptor Activation and Inhibition Sites. Front Physiol 2022; 12:805956. [PMID: 35145426 PMCID: PMC8821920 DOI: 10.3389/fphys.2021.805956] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2021] [Accepted: 12/21/2021] [Indexed: 12/13/2022] Open
Abstract
Ryanodine receptor channels at calcium release sites of cardiac myocytes operate on the principle of calcium-induced calcium release. In vitro experiments revealed competition of Ca2+ and Mg2+ in the activation of ryanodine receptors (RyRs) as well as inhibition of RyRs by Mg2+. The impact of RyR modulation by Mg2+ on calcium release is not well understood due to the technical limitations of in situ experiments. We turned instead to an in silico model of a calcium release site (CRS), based on a homotetrameric model of RyR gating with kinetic parameters determined from in vitro measurements. We inspected changes in the activity of the CRS model in response to a random opening of one of 20 realistically distributed RyRs, arising from Ca2+/Mg2+ interactions at RyR channels. Calcium release events (CREs) were simulated at a range of Mg2+-binding parameters at near-physiological Mg2+ and ATP concentrations. Facilitation of Mg2+ binding to the RyR activation site inhibited the formation of sparks and slowed down their activation. Impeding Mg-binding to the RyR activation site enhanced spark formation and speeded up their activation. Varying Mg2+ binding to the RyR inhibition site also dramatically affected calcium release events. Facilitation of Mg2+ binding to the RyR inhibition site reduced the amplitude, relative occurrence, and the time-to-end of sparks, and vice versa. The characteristics of CREs correlated dose-dependently with the effective coupling strength between RyRs, defined as a function of RyR vicinity, single-channel calcium current, and Mg-binding parameters of the RyR channels. These findings postulate the role of Mg2+ in calcium release as a negative modulator of the coupling strength among RyRs in a CRS, translating to damping of the positive feedback of the calcium-induced calcium-release mechanism.
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Affiliation(s)
| | | | | | - Alexandra Zahradníková
- Department of Cellular Cardiology, Institute of Experimental Endocrinology, Biomedical Research Center of the Slovak Academy of Sciences, Bratislava, Slovakia
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12
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Bhullar S, Shah A, Dhalla N. Mechanisms for the development of heart failure and improvement of cardiac function by angiotensin-converting enzyme inhibitors. SCRIPTA MEDICA 2022. [DOI: 10.5937/scriptamed53-36256] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/02/2022] Open
Abstract
Angiotensin-converting enzyme (ACE) inhibitors, which prevent the conversion of angiotensin I to angiotensin II, are well-known for the treatments of cardiovascular diseases, such as heart failure, hypertension and acute coronary syndrome. Several of these inhibitors including captopril, enalapril, ramipril, zofenopril and imidapril attenuate vasoconstriction, cardiac hypertrophy and adverse cardiac remodeling, improve clinical outcomes in patients with cardiac dysfunction and decrease mortality. Extensive experimental and clinical research over the past 35 years has revealed that the beneficial effects of ACE inhibitors in heart failure are associated with full or partial prevention of adverse cardiac remodeling. Since cardiac function is mainly determined by coordinated activities of different subcellular organelles, including sarcolemma, sarcoplasmic reticulum, mitochondria and myofibrils, for regulating the intracellular concentration of Ca2+ and myocardial metabolism, there is ample evidence to suggest that adverse cardiac remodelling and cardiac dysfunction in the failing heart are the consequence of subcellular defects. In fact, the improvement of cardiac function by different ACE inhibitors has been demonstrated to be related to the attenuation of abnormalities in subcellular organelles for Ca2+-handling, metabolic alterations, signal transduction defects and gene expression changes in failing cardiomyocytes. Various ACE inhibitors have also been shown to delay the progression of heart failure by reducing the formation of angiotensin II, the development of oxidative stress, the level of inflammatory cytokines and the occurrence of subcellular defects. These observations support the view that ACE inhibitors improve cardiac function in the failing heart by multiple mechanisms including the reduction of oxidative stress, myocardial inflammation and Ca2+-handling abnormalities in cardiomyocytes.
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13
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Pathophysiology of heart failure and an overview of therapies. Cardiovasc Pathol 2022. [DOI: 10.1016/b978-0-12-822224-9.00025-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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14
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Estimating ectopic beat probability with simplified statistical models that account for experimental uncertainty. PLoS Comput Biol 2021; 17:e1009536. [PMID: 34665814 PMCID: PMC8577785 DOI: 10.1371/journal.pcbi.1009536] [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: 03/16/2021] [Revised: 11/09/2021] [Accepted: 10/06/2021] [Indexed: 11/21/2022] Open
Abstract
Ectopic beats (EBs) are cellular arrhythmias that can trigger lethal arrhythmias. Simulations using biophysically-detailed cardiac myocyte models can reveal how model parameters influence the probability of these cellular arrhythmias, however such analyses can pose a huge computational burden. Here, we develop a simplified approach in which logistic regression models (LRMs) are used to define a mapping between the parameters of complex cell models and the probability of EBs (P(EB)). As an example, in this study, we build an LRM for P(EB) as a function of the initial value of diastolic cytosolic Ca2+ concentration ([Ca2+]iini), the initial state of sarcoplasmic reticulum (SR) Ca2+ load ([Ca2+]SRini), and kinetic parameters of the inward rectifier K+ current (IK1) and ryanodine receptor (RyR). This approach, which we refer to as arrhythmia sensitivity analysis, allows for evaluation of the relationship between these arrhythmic event probabilities and their associated parameters. This LRM is also used to demonstrate how uncertainties in experimentally measured values determine the uncertainty in P(EB). In a study of the role of [Ca2+]SRini uncertainty, we show a special property of the uncertainty in P(EB), where with increasing [Ca2+]SRini uncertainty, P(EB) uncertainty first increases and then decreases. Lastly, we demonstrate that IK1 suppression, at the level that occurs in heart failure myocytes, increases P(EB). An ectopic beat is an abnormal cellular electrical event which can trigger dangerous arrhythmias in the heart. Complex biophysical models of the cardiac myocyte can be used to reveal how cell properties affect the probability of ectopic beats. However, such analyses can pose a huge computational burden. We develop a simplified approach that enables a highly complex biophysical model to be reduced to a rather simple statistical model from which the functional relationship between myocyte model parameters and the probability of an ectopic beat is determined. We refer to this approach as arrhythmia sensitivity analysis. Given the efficiency of our approach, we also use it to demonstrate how uncertainties in experimentally measured myocyte model parameters determine the uncertainty in ectopic beat probability. We find that, with increasing model parameter uncertainty, the uncertainty in probability of ectopic beat first increases and then decreases. In general, our approach can efficiently analyze the relationship between cardiac myocyte parameters and the probability of ectopic beats and can be used to study how uncertainty of these cardiac myocyte parameters influences the ectopic beat probability.
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15
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Hutchings DC, Pearman CM, Madders GWP, Woods LS, Eisner DA, Dibb KM, Trafford AW. PDE5 Inhibition Suppresses Ventricular Arrhythmias by Reducing SR Ca 2+ Content. Circ Res 2021; 129:650-665. [PMID: 34247494 PMCID: PMC8409902 DOI: 10.1161/circresaha.121.318473] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
[Figure: see text].
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Affiliation(s)
- David C Hutchings
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom
| | - Charles M Pearman
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom
| | - George W P Madders
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom
| | - Lori S Woods
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom
| | - David A Eisner
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom
| | - Katharine M Dibb
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom
| | - Andrew W Trafford
- Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Faculty of Biology Medicine and Health, University of Manchester, Manchester Academic Health Sciences Centre, United Kingdom
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16
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Yamasan BE, Mercan T, Erkan O, Ozdemir S. Ellagic Acid Prevents Ca 2+ Dysregulation and Improves Functional Abnormalities of Ventricular Myocytes via Attenuation of Oxidative Stress in Pathological Cardiac Hypertrophy. Cardiovasc Toxicol 2021; 21:630-641. [PMID: 33909254 DOI: 10.1007/s12012-021-09654-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 04/20/2021] [Indexed: 01/25/2023]
Abstract
The aim of this study was to investigate whether ellagic acid (EA) treatment can prevent changes in contractile function and Ca2+ regulation of cardiomyocytes in pathologic cardiac hypertrophy. Groups were assigned as Con group; an ISO group in which the rats received isoproterenol alone (5 mg/kg/day); and an ISO + EA group in which the rats received isoproterenol and EA (20 mg/kg/day) for 4 weeks. Subsequently, fractional shortening, intracellular Ca2+ signals, and L-type Ca2+ currents of isolated ventricular myocytes were recorded. Protein expression levels were also determined by the Western blotting method. The survival rate was increased, and the upregulated cardiac hypertrophy markers were significantly attenuated with the EA treatment. The fractional shortening and relaxation rate of myocytes was decreased in the ISO group, whereas EA significantly improved these changes. Ventricular myocytes of the ISO + EA rats displayed lower diastolic Ca2+ levels, higher Ca2+ transients, shorter Ca2+ decay, and higher L-type Ca2+ currents than those of ISO rats. Protein expression analyses indicated that the upregulated p-PLB and p-CaMKII expressions were restored by EA treatment, suggesting improved calcium handling in the ISO + EA rat heart. Moreover, ISO rats displayed significantly increased expression of p-22phox and p47phox subunits of NOX2 protein. Expression of the p22phox subunit was reduced with EA administration, while the decrease in p47phox did not reach a significant level. The increased ROS impairs Ca2+ homeostasis and contractile activity of cardiac myocytes, whereas chronic EA administration prevents Ca2+ dysregulation and functional abnormalities associated with pathological cardiac hypertrophy via the diminution of oxidative stress.
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Affiliation(s)
- Bilge E Yamasan
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Tanju Mercan
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Orhan Erkan
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya, Turkey
| | - Semir Ozdemir
- Department of Biophysics, Akdeniz University Faculty of Medicine, Antalya, Turkey.
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17
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Medvedev RY, Sanchez-Alonso JL, Mansfield CA, Judina A, Francis AJ, Pagiatakis C, Trayanova N, Glukhov AV, Miragoli M, Faggian G, Gorelik J. Local hyperactivation of L-type Ca 2+ channels increases spontaneous Ca 2+ release activity and cellular hypertrophy in right ventricular myocytes from heart failure rats. Sci Rep 2021; 11:4840. [PMID: 33649357 PMCID: PMC7921450 DOI: 10.1038/s41598-021-84275-w] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Accepted: 01/19/2021] [Indexed: 12/15/2022] Open
Abstract
Right ventricle (RV) dysfunction is an independent predictor of patient survival in heart failure (HF). However, the mechanisms of RV progression towards failing are not well understood. We studied cellular mechanisms of RV remodelling in a rat model of left ventricle myocardial infarction (MI)-caused HF. RV myocytes from HF rats show significant cellular hypertrophy accompanied with a disruption of transverse-axial tubular network and surface flattening. Functionally these cells exhibit higher contractility with lower Ca2+ transients. The structural changes in HF RV myocytes correlate with more frequent spontaneous Ca2+ release activity than in control RV myocytes. This is accompanied by hyperactivated L-type Ca2+ channels (LTCCs) located specifically in the T-tubules of HF RV myocytes. The increased open probability of tubular LTCCs and Ca2+ sparks activation is linked to protein kinase A-mediated channel phosphorylation that occurs locally in T-tubules. Thus, our approach revealed that alterations in RV myocytes in heart failure are specifically localized in microdomains. Our findings may indicate the development of compensatory, though potentially arrhythmogenic, RV remodelling in the setting of LV failure. These data will foster better understanding of mechanisms of heart failure and it could promote an optimized treatment of patients.
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Affiliation(s)
- Roman Y Medvedev
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London, W12 0NN, UK.,Dipartimento Di Cardiochirurgia, Università Degli Studi Di Verona, Ospedale Borgo Trento, P.le Stefani 1, 37126, Verona, Italy.,Department of Medicine, Cardiovascular Medicine, Madison School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
| | - Jose L Sanchez-Alonso
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Catherine A Mansfield
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Aleksandra Judina
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | - Alice J Francis
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London, W12 0NN, UK
| | | | - Natalia Trayanova
- Department of Biomedical Engineering and Alliance for Cardiovascular Diagnostic and Treatment Innovation, Johns Hopkins University, Baltimore, USA
| | - Alexey V Glukhov
- Department of Medicine, Cardiovascular Medicine, Madison School of Medicine and Public Health, University of Wisconsin, Madison, WI, 53705, USA
| | - Michele Miragoli
- Humanitas Clinical and Research Center - IRCCS, Rozzano, MI, Italy.,Dipartimento Di Medicina E Chirurgia, Università Degli Studi di Parma, Via Gramsci 14, 43124, Parma, Italy
| | - Giuseppe Faggian
- Dipartimento Di Cardiochirurgia, Università Degli Studi Di Verona, Ospedale Borgo Trento, P.le Stefani 1, 37126, Verona, Italy
| | - Julia Gorelik
- National Heart and Lung Institute, Imperial College London, Du Cane Road, London, W12 0NN, UK.
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18
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Cortassa S, Juhaszova M, Aon MA, Zorov DB, Sollott SJ. Mitochondrial Ca 2+, redox environment and ROS emission in heart failure: Two sides of the same coin? J Mol Cell Cardiol 2021; 151:113-125. [PMID: 33301801 PMCID: PMC7880885 DOI: 10.1016/j.yjmcc.2020.11.013] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2020] [Revised: 11/05/2020] [Accepted: 11/28/2020] [Indexed: 12/11/2022]
Abstract
Heart failure (HF) is a progressive, debilitating condition characterized, in part, by altered ionic equilibria, increased ROS production and impaired cellular energy metabolism, contributing to variable profiles of systolic and diastolic dysfunction with significant functional limitations and risk of premature death. We summarize current knowledge concerning changes of intracellular Na+ and Ca2+ control mechanisms during the disease progression and their consequences on mitochondrial Ca2+ homeostasis and the shift in redox balance. Absent existing biological data, our computational modeling studies advance a new 'in silico' analysis to reconcile existing opposing views, based on different experimental HF models, regarding variations in mitochondrial Ca2+ concentration that participate in triggering and perpetuating oxidative stress in the failing heart and their impact on cardiac energetics. In agreement with our hypothesis and the literature, model simulations demonstrate the possibility that the heart's redox status together with cytoplasmic Na+ concentrations act as regulators of mitochondrial Ca2+ levels in HF and of the bioenergetics response that will ultimately drive ATP supply and oxidative stress. The resulting model predictions propose future directions to study the evolution of HF as well as other types of heart disease, and to develop novel testable mechanistic hypotheses that may lead to improved therapeutics.
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Affiliation(s)
- Sonia Cortassa
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States.
| | - Magdalena Juhaszova
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States.
| | - Miguel A Aon
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States; Translational Gerontology Branch, National Institute on Aging, NIH, Baltimore, MD, United States.
| | - Dmitry B Zorov
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States; Belozersky Institute of Physico-Chemical Biology, Lomonosov Moscow State University, Moscow, Russia.
| | - Steven J Sollott
- Laboratory of Cardiovascular Science, National Institute on Aging, NIH, Baltimore, MD, United States.
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19
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Liu R, Li D, Sun F, Rampoldi A, Maxwell JT, Wu R, Fischbach P, Castellino SM, Du Y, Fu H, Mandawat A, Xu C. Melphalan induces cardiotoxicity through oxidative stress in cardiomyocytes derived from human induced pluripotent stem cells. Stem Cell Res Ther 2020; 11:470. [PMID: 33153480 PMCID: PMC7643439 DOI: 10.1186/s13287-020-01984-1] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2020] [Accepted: 10/20/2020] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Treatment-induced cardiotoxicity is a leading noncancer-related cause of acute and late onset morbidity and mortality in cancer patients on antineoplastic drugs such as melphalan-increasing clinical case reports have documented that it could induce cardiotoxicity including severe arrhythmias and heart failure. As the mechanism by which melphalan impairs cardiac cells remains poorly understood, here, we aimed to use cardiomyocytes derived from human induced pluripotent stem cells (hiPSC-CMs) to investigate the cellular and molecular mechanisms of melphalan-induced cardiotoxicity. METHODS hiPSC-CMs were generated and treated with clinically relevant doses of melphalan. To characterize melphalan-induced cardiotoxicity, cell viability and apoptosis were quantified at various treatment durations. Ca2+ transient and contractility analyses were used to examine the alterations of hiPSC-CM function. Proteomic analysis, reactive oxygen species detection, and RNA-Sequencing were conducted to investigate underlying mechanisms. RESULTS Melphalan treatment of hiPSC-CMs induced oxidative stress, caused Ca2+ handling defects and dysfunctional contractility, altered global transcriptomic and proteomic profiles, and resulted in apoptosis and cell death. The antioxidant N-acetyl-L-cysteine attenuated these genomic, cellular, and functional alterations. In addition, several other signaling pathways including the p53 and transforming growth factor-β signaling pathways were also implicated in melphalan-induced cardiotoxicity according to the proteomic and transcriptomic analyses. CONCLUSIONS Melphalan induces cardiotoxicity through the oxidative stress pathway. This study provides a unique resource of the global transcriptomic and proteomic datasets for melphalan-induced cardiotoxicity and can potentially open up new clinical mechanism-based targets to prevent and treat melphalan-induced cardiotoxicity.
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Affiliation(s)
- Rui Liu
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
- Department of Pediatrics, The Third Xiangya Hospital of Central South University, Changsha, 410013, Hunan, China
| | - Dong Li
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - Fangxu Sun
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Antonio Rampoldi
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - Joshua T Maxwell
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - Ronghu Wu
- School of Chemistry and Biochemistry and the Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, Atlanta, GA, 30332, USA
| | - Peter Fischbach
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - Sharon M Castellino
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA
| | - Yuhong Du
- Emory Chemical Biology Discovery Center and the Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Haian Fu
- Emory Chemical Biology Discovery Center and the Department of Pharmacology and Chemical Biology, Emory University School of Medicine, Atlanta, GA, 30322, USA
| | - Anant Mandawat
- Department of Medicine, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Department of Hematology and Medical Oncology, Emory University School of Medicine, Atlanta, GA, 30322, USA
- Cardio-Oncology Program, Winship Cancer Institute of Emory University, Atlanta, GA, 30322, USA
| | - Chunhui Xu
- Department of Pediatrics, Emory University School of Medicine and Children's Healthcare of Atlanta, 2015 Uppergate Drive, Atlanta, GA, 30322, USA.
- Wallace H. Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, GA, 30322, USA.
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20
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Sarcoplasmic reticulum calcium mishandling: central tenet in heart failure? Biophys Rev 2020; 12:865-878. [PMID: 32696300 DOI: 10.1007/s12551-020-00736-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 07/08/2020] [Indexed: 12/17/2022] Open
Abstract
Excitation-contraction coupling links excitation of the sarcolemmal surface membrane to mechanical contraction. In the heart this link is established via a Ca2+-induced Ca2+ release process, which, following sarcolemmal depolarisation, prompts Ca2+ release from the sarcoplasmic reticulum (SR) though the ryanodine receptor (RyR2). This substantially raises the cytoplasmic Ca2+ concentration to trigger systole. In diastole, Ca2+ is removed from the cytoplasm, primarily via the sarcoplasmic-endoplasmic reticulum Ca2+-dependent ATPase (SERCA) pump on the SR membrane, returning Ca2+ to the SR store. Ca2+ movement across the SR is thus fundamental to the systole/diastole cycle and plays an essential role in maintaining cardiac contractile function. Altered SR Ca2+ homeostasis (due to disrupted Ca2+ release, storage, and reuptake pathways) is a central tenet of heart failure and contributes to depressed contractility, impaired relaxation, and propensity to arrhythmia. This review will focus on the molecular mechanisms that underlie asynchronous Ca2+ cycling around the SR in the failing heart. Further, this review will illustrate that the combined effects of expression changes and disruptions to RyR2 and SERCA2a regulatory pathways are critical to the pathogenesis of heart failure.
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21
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Intracellular calcium leak in heart failure and atrial fibrillation: a unifying mechanism and therapeutic target. Nat Rev Cardiol 2020; 17:732-747. [PMID: 32555383 DOI: 10.1038/s41569-020-0394-8] [Citation(s) in RCA: 83] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/06/2020] [Indexed: 12/14/2022]
Abstract
Ca2+ is a fundamental second messenger in all cell types and is required for numerous essential cellular functions, including cardiac and skeletal muscle contraction. The intracellular concentration of free Ca2+ ([Ca2+]) is regulated primarily by ion channels, pumps (ATPases), exchangers and Ca2+-binding proteins. Defective regulation of [Ca2+] is found in a diverse spectrum of pathological states that affect all the major organs. In the heart, abnormalities in the regulation of cytosolic and mitochondrial [Ca2+] occur in heart failure (HF) and atrial fibrillation (AF), two common forms of heart disease and leading contributors to morbidity and mortality. In this Review, we focus on the mechanisms that regulate ryanodine receptor 2 (RYR2), the major sarcoplasmic reticulum (SR) Ca2+-release channel in the heart, how RYR2 becomes dysfunctional in HF and AF, and its potential as a therapeutic target. Inherited RYR2 mutations and/or stress-induced phosphorylation and oxidation of the protein destabilize the closed state of the channel, resulting in a pathological diastolic Ca2+ leak from the SR that both triggers arrhythmias and impairs contractility. On the basis of our increased understanding of SR Ca2+ leak as a shared Ca2+-dependent pathological mechanism in HF and AF, a new class of drugs developed in our laboratory, known as rycals, which stabilize RYR2 channels and prevent Ca2+ leak from the SR, are undergoing investigation in clinical trials.
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22
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Gilbert G, Demydenko K, Dries E, Puertas RD, Jin X, Sipido K, Roderick HL. Calcium Signaling in Cardiomyocyte Function. Cold Spring Harb Perspect Biol 2020; 12:cshperspect.a035428. [PMID: 31308143 DOI: 10.1101/cshperspect.a035428] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Rhythmic increases in intracellular Ca2+ concentration underlie the contractile function of the heart. These heart muscle-wide changes in intracellular Ca2+ are induced and coordinated by electrical depolarization of the cardiomyocyte sarcolemma by the action potential. Originating at the sinoatrial node, conduction of this electrical signal throughout the heart ensures synchronization of individual myocytes into an effective cardiac pump. Ca2+ signaling pathways also regulate gene expression and cardiomyocyte growth during development and in pathology. These fundamental roles of Ca2+ in the heart are illustrated by the prevalence of altered Ca2+ homeostasis in cardiovascular diseases. Indeed, heart failure (an inability of the heart to support hemodynamic needs), rhythmic disturbances, and inappropriate cardiac growth all share an involvement of altered Ca2+ handling. The prevalence of these pathologies, contributing to a third of all deaths in the developed world as well as to substantial morbidity makes understanding the mechanisms of Ca2+ handling and dysregulation in cardiomyocytes of great importance.
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Affiliation(s)
- Guillaume Gilbert
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Kateryna Demydenko
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Eef Dries
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Rosa Doñate Puertas
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Xin Jin
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - Karin Sipido
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
| | - H Llewelyn Roderick
- Laboratory of Experimental Cardiology, Department of Cardiovascular Sciences, KU Leuven, BE3000 Leuven, Belgium
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23
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Shiferaw Y, Aistrup GL, Louch WE, Wasserstrom JA. Remodeling Promotes Proarrhythmic Disruption of Calcium Homeostasis in Failing Atrial Myocytes. Biophys J 2019; 118:476-491. [PMID: 31889516 DOI: 10.1016/j.bpj.2019.12.012] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2019] [Revised: 11/19/2019] [Accepted: 12/09/2019] [Indexed: 01/31/2023] Open
Abstract
It is well known that heart failure (HF) typically coexists with atrial fibrillation (AF). However, until now, no clear mechanism has been established that relates HF to AF. In this study, we apply a multiscale computational framework to establish a mechanistic link between atrial myocyte structural remodeling in HF and AF. Using a spatially distributed model of calcium (Ca) signaling, we show that disruption of the spatial relationship between L-type Ca channels (LCCs) and ryanodine receptors results in markedly increased Ca content of the sarcoplasmic reticulum (SR). This increase in SR load is due to changes in the balance between Ca entry via LCCs and Ca extrusion due to the sodium-calcium exchanger after an altered spatial relationship between these signaling proteins. Next, we show that the increased SR load in atrial myocytes predisposes these cells to subcellular Ca waves that occur during the action potential (AP) and are triggered by LCC openings. These waves are common in atrial cells because of the absence of a well-developed t-tubule system in most of these cells. This distinct spatial architecture allows for the presence of a large pool of orphaned ryanodine receptors, which can fire and sustain Ca waves during the AP. Finally, we incorporate our atrial cell model in two-dimensional tissue simulations and demonstrate that triggered wave generation in cells leads to electrical waves in tissue that tend to fractionate to form wavelets of excitation. This fractionation is driven by the underlying stochasticity of subcellular Ca waves, which perturbs AP repolarization and consequently induces localized conduction block in tissue. We outline the mechanism for this effect and argue that it may explain the propensity for atrial arrhythmias in HF.
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Affiliation(s)
- Yohannes Shiferaw
- Department of Physics, California State University, Northridge, California.
| | - Gary L Aistrup
- Department of Experimental Cardiology, Masonic Medical Research Institute, Utica, New York
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway; KG Jebsen Center for Cardiac Research, University of Oslo, Oslo, Norway
| | - J A Wasserstrom
- Department of Medicine (Cardiology) and The Feinberg Cardiovascular and Renal Institute, Northwestern University Feinberg School of Medicine, Chicago, Illinois
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24
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Pérez-Treviño P, Sepúlveda-Leal J, Altamirano J. Simultaneous assessment of calcium handling and contractility dynamics in isolated ventricular myocytes of a rat model of post-acute isoproterenol-induced cardiomyopathy. Cell Calcium 2019; 86:102138. [PMID: 31838436 DOI: 10.1016/j.ceca.2019.102138] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2019] [Revised: 12/02/2019] [Accepted: 12/02/2019] [Indexed: 12/21/2022]
Abstract
Stress-induced cardiomyopathy (SIC) results from a profound catecholaminergic surge during strong emotional or physical stress. SIC is characterized by acute left ventricular apex hypokinesia, in the absence of coronary arteries occlusion, and can lead to arrhythmias and acute heart failure. Although, most SIC patients recover, the process could be slow, and recurrence or death may occur. Despite that the SIC common denominator is a large catecholamine discharge, the pathophysiological mechanism is incompletely understood. It is thought that catecholamines have direct cytotoxicity on apical ventricular myocytes (VM), which have the highest β-adrenergic receptors density, and whose overstimulation might cause acute Ca2+ overload and oxidative stress, causing death in some VM and stunning others. Rodents receiving acute isoproterenol (ISO) overdose (OV) mimic SIC development, however, they have not been used to simultaneously assess Ca2+ handling and contractility status in isolated VM, which might explain ventricular hypokinesia. Therefore, treating rats with a single ISO-OV (67 mg/kg body weight), we sought out to characterize, with confocal imaging, Ca2+ and shortening dynamics in Fluo-4-loaded VM, during the early (1-5 days) and late post-acute phases (15 days). We found that ISO-OV VM showed contractile dysfunction; blunted shortening with slower force development and relaxation. These correlated with Ca2+ mishandling; blunted Ca2+ transient, with slower time to peak and SR Ca2+ recovery. SR Ca2+ content was low, nevertheless, diastolic Ca2+ sparks were more frequent, and their duration increased. Contractility and Ca2+ dysfunction aggravated or remained altered over time, explaining slow recovery. We conclude that diminished VM contractility is the main determinant of ISO-OV hypokinesia and is mostly related to Ca2+ mishandling.
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Affiliation(s)
- Perla Pérez-Treviño
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Av. Morones Prieto No. 3000 Pte., Monterrey, N.L., 64710, Mexico
| | - José Sepúlveda-Leal
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Av. Morones Prieto No. 3000 Pte., Monterrey, N.L., 64710, Mexico
| | - Julio Altamirano
- Tecnologico de Monterrey, Escuela de Medicina y Ciencias de la Salud, Av. Morones Prieto No. 3000 Pte., Monterrey, N.L., 64710, Mexico.
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25
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Gillespie D. Recruiting RyRs to Open in a Ca 2+ Release Unit: Single-RyR Gating Properties Make RyR Group Dynamics. Biophys J 2019; 118:232-242. [PMID: 31839264 DOI: 10.1016/j.bpj.2019.11.021] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2019] [Revised: 11/01/2019] [Accepted: 11/19/2019] [Indexed: 01/01/2023] Open
Abstract
In cardiac myocytes, clusters of type-2 ryanodine receptors (RyR2s) release Ca2+ from the sarcoplasmic reticulum (SR) via a positive feedback mechanism in which fluxed Ca2+ activates nearby RyRs. Although the general principles of this are understood, less is known about how single-RyR gating properties define the RyR group dynamics in an array of many channels. Here, we examine this using simulations with three models of RyR gating that have identical open probabilities: the commonly used two-state Markov gating model, one that utilizes multiple exponentials to fit single-channel open time (OT) and closed time (CT) distributions, and an extension of this multiexponential model that also includes experimentally measured correlations between single-channel OTs and CTs. The simulations of RyR clusters that utilize the multiexponential gating model produce infrequent Ca2+ release events with relatively few open RyRs. Ca2+ release events become even smaller when OT/CT correlations are included. This occurs because the correlations produce a small but consistent bias against recruiting more RyRs to open during the middle of a Ca2+ release event, between the initiation and termination phases (which are unaltered compared to the uncorrelated simulations). In comparison, the two-state model produces frequent, large, and long Ca2+ release events because it had a recruitment bias in favor of opening more RyRs. This difference stems from the two-state model's single-RyR OT and CT distributions being qualitatively different from the experimental ones. Thus, the details of single-RyR gating can profoundly affect SR Ca2+ release even if open probability and mean OTs and CTs are identical. We also show that Ca2+ release events can terminate spontaneously without any reduction in SR [Ca2+], luminal regulation, Ca2+-dependent inactivation, or physical coupling between RyRs when Ca2+ flux is below a threshold value. This supports and extends the pernicious attrition/induction decay hypothesis that SR Ca2+ release events terminate below a threshold Ca2+ flux.
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Affiliation(s)
- Dirk Gillespie
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, Illinois.
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26
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Chu L, Greenstein JL, Winslow RL. Na + microdomains and sparks: Role in cardiac excitation-contraction coupling and arrhythmias in ankyrin-B deficiency. J Mol Cell Cardiol 2019; 128:145-157. [PMID: 30731085 DOI: 10.1016/j.yjmcc.2019.02.001] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Revised: 02/01/2019] [Accepted: 02/02/2019] [Indexed: 01/25/2023]
Abstract
Cardiac sodium (Na+) potassium ATPase (NaK) pumps, neuronal sodium channels (INa), and sodium calcium (Ca2+) exchangers (NCX1) may co-localize to form a Na+ microdomain. It remains controversial as to whether neuronal INa contributes to local Na+ accumulation, resulting in reversal of nearby NCX1 and influx of Ca2+ into the cell. Therefore, there has been great interest in the possible roles of a Na+ microdomain in cardiac Ca2+-induced Ca2+ release (CICR). In addition, the important role of co-localization of NaK and NCX1 in regulating localized Na+ and Ca2+ levels and CICR in ankyrin-B deficient (ankyrin-B+/-) cardiomyocytes has been examined in many recent studies. Altered Na+ dynamics may contribute to the appearance of arrhythmias, but the mechanisms underlying this relationship remain unclear. In order to investigate this, we present a mechanistic canine cardiomyocyte model which reproduces independent local dyadic junctional SR (JSR) Ca2+ release events underlying cell-wide excitation-contraction coupling, as well as a three-dimensional super-resolution model of the Ca2+ spark that describes local Na+ dynamics as governed by NaK pumps, neuronal INa, and NCX1. The model predicts the existence of Na+ sparks, which are generated by NCX1 and exhibit significantly slower dynamics as compared to Ca2+ sparks. Moreover, whole-cell simulations indicate that neuronal INa in the cardiac dyad plays a key role during the systolic phase. Rapid inward neuronal INa can elevate dyadic [Na+] to 35-40 mM, which drives reverse-mode NCX1 transport, and therefore promotes Ca2+ entry into the dyad, enhancing the trigger for JSR Ca2+ release. The specific role of decreased co-localization of NaK and NCX1 in ankyrin-B+/- cardiomyocytes was examined. Model results demonstrate that a reduction in the local NCX1- and NaK-mediated regulation of dyadic [Ca2+] and [Na+] results in an increase in Ca2+ spark activity during isoproterenol stimulation, which in turn stochastically activates NCX1 in the dyad. This alteration in NCX1/NaK co-localization interrupts the balance between NCX1 and NaK currents in a way that leads to enhanced depolarizing inward current during the action potential plateau, which ultimately leads to a higher probability of L-type Ca2+ channel reopening and arrhythmogenic early-afterdepolarizations.
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Affiliation(s)
- Lulu Chu
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD 21218, USA.
| | - Joseph L Greenstein
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD 21218, USA.
| | - Raimond L Winslow
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD 21218, USA.
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27
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Simultaneous Recording of Subcellular Ca 2+ Signals from the Cytosol and Sarco/Endoplasmic Reticulum: Compartmentalized Dye Loading, Imaging, and Analysis. Methods Mol Biol 2019. [PMID: 30710267 DOI: 10.1007/978-1-4939-9030-6_5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
Abstract
An increase in the cytosolic Ca2+ concentration triggers the contraction in cardiomyocytes. In these cells sarcoplasmic reticulum (SR) is the major source of Ca2+, and the release from this store is mediated by the ryanodine receptors (RyRs). These receptors are regulated by cytosolic and intra-SR [Ca2+]. The cytosolic Ca2+ regulation is well established, but there are some limitations to determine indirectly the intra-SR Ca2+ concentration and understand its role in the RyRs regulation. Therefore, the interest to directly measure the free intra-SR Ca2+ concentration ([Ca2+]SR) has led to the application of a low-affinity Ca2+ indicator (Fluo-5N AM) to follow changes of [Ca2+]SR in cardiomyocytes. However the loading of this AM-ester dye into the SR has remained a challenge in freshly isolated mouse cardiomyocytes. Here, we describe an optimized protocol to measure changes of [Ca2+]SR in mouse cardiomyocytes using fluorescent Ca2+ indicators and confocal microscopy. The application of this protocol allows to evaluate directly intra-SR Ca2+ in real time in various mouse models of cardiac disease, including transgenic animals harboring mutants of RyRs or other Ca2+ signaling proteins.
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28
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Nikolaienko R, Bovo E, Zima AV. Redox Dependent Modifications of Ryanodine Receptor: Basic Mechanisms and Implications in Heart Diseases. Front Physiol 2018; 9:1775. [PMID: 30574097 PMCID: PMC6291498 DOI: 10.3389/fphys.2018.01775] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/23/2018] [Indexed: 12/12/2022] Open
Abstract
Heart contraction vitally depends on tightly controlled intracellular Ca regulation. Because contraction is mainly driven by Ca released from the sarcoplasmic reticulum (SR), this organelle plays a particularly important role in Ca regulation. The type two ryanodine receptor (RyR2) is the major SR Ca release channel in ventricular myocytes. Several cardiac pathologies, including myocardial infarction and heart failure, are associated with increased RyR2 activity and diastolic SR Ca leak. It has been suggested that the increased RyR2 activity plays an important role in arrhythmias and contractile dysfunction. Several studies have linked increased SR Ca leak during myocardial infarction and heart failure to the activation of RyR2 in response to oxidative stress. This activation might include direct oxidation of RyR2 as well as indirect activation via phosphorylation or altered interactions with regulatory proteins. Out of ninety cysteine residues per RyR2 subunit, twenty one were reported to be in reduced state that could be potential targets for redox modifications that include S-nitrosylation, S-glutathionylation, and disulfide cross-linking. Despite its clinical significance, molecular mechanisms of RyR dysfunction during oxidative stress are not fully understood. Herein we review the most recent insights into redox-dependent modulation of RyR2 during oxidative stress and heart diseases.
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Affiliation(s)
- Roman Nikolaienko
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
| | - Elisa Bovo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, United States
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29
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Liu G, Li SQ, Hu PP, Tong XY. Altered sarco(endo)plasmic reticulum calcium adenosine triphosphatase 2a content: Targets for heart failure therapy. Diab Vasc Dis Res 2018; 15:322-335. [PMID: 29762054 DOI: 10.1177/1479164118774313] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is responsible for transporting cytosolic calcium into the sarcoplasmic reticulum and endoplasmic reticulum to maintain calcium homeostasis. Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is the dominant isoform expressed in cardiac tissue, which is regulated by endogenous protein inhibitors, post-translational modifications, hormones as well as microRNAs. Dysfunction of sarco(endo)plasmic reticulum calcium adenosine triphosphatase is associated with heart failure, which makes sarco(endo)plasmic reticulum calcium adenosine triphosphatase a promising target for heart failure therapy. This review summarizes current approaches to ameliorate sarco(endo)plasmic reticulum calcium adenosine triphosphatase function and focuses on phospholamban, an endogenous inhibitor of sarco(endo)plasmic reticulum calcium adenosine triphosphatase, pharmacological tools and gene therapies.
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Affiliation(s)
- Gang Liu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Si Qi Li
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Ping Ping Hu
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
| | - Xiao Yong Tong
- Chongqing Key Laboratory of Natural Product Synthesis and Drug Research, School of Pharmaceutical Sciences, Chongqing University, Chongqing, China
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30
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Rodrigues AC, Natali AJ, Cunha DNQD, Costa AJLD, Moura AGD, Araújo Carneiro-Júnior M, Félix LB, Brum PC, Prímola-Gomes TN. Moderate Continuous Aerobic Exercise Training Improves Cardiomyocyte Contractility in Β1 Adrenergic Receptor Knockout Mice. Arq Bras Cardiol 2018; 110:256-262. [PMID: 29466489 PMCID: PMC5898776 DOI: 10.5935/abc.20180025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/14/2017] [Accepted: 09/22/2017] [Indexed: 12/14/2022] Open
Abstract
Background The lack of cardiac β1-adrenergic receptors
(β1-AR) negatively affects the regulation of both
cardiac inotropy and lusitropy, leading, in the long term, to heart failure
(HF). Moderate-intensity aerobic exercise (MCAE) is recommended as an
adjunctive therapy for patients with HF. Objective We tested the effects of MCAE on the contractile properties of left
ventricular (LV) myocytes from β1 adrenergic receptor
knockout (β1ARKO) mice. Methods Four- to five-month-old male wild type (WT) and β1ARKO mice
were divided into groups: WT control (WTc) and trained (WTt); and
β1ARKO control (β1ARKOc) and trained
(β1ARKOt). Animals from trained groups were submitted
to a MCAE regimen (60 min/day; 60% of maximal speed, 5 days/week) on a
treadmill, for 8 weeks. P ≤ 0.05 was considered significant in all
comparisons. Results The β1ARKO and exercised mice exhibited a higher (p <
0.05) running capacity than WT and sedentary ones, respectively. The
β1ARKO mice showed higher body (BW), heart (HW) and
left ventricle (LVW) weights, as well as the HW/BW and LVW/BW than WT mice.
However, the MCAE did not affect these parameters. Left ventricular myocytes
from β1ARKO mice showed increased (p < 0.05) amplitude
and velocities of contraction and relaxation than those from WT. In
addition, MCAE increased (p < 0.05) amplitude and velocities of
contraction and relaxation in β1ARKO mice. Conclusion MCAE improves myocyte contractility in the left ventricle of
β1ARKO mice. This is evidence to support the
therapeutic value of this type of exercise training in the treatment of
heart diseases involving β1-AR desensitization or
reduction.
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31
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Yang J, Zhang R, Jiang X, Lv J, Li Y, Ye H, Liu W, Wang G, Zhang C, Zheng N, Dong M, Wang Y, Chen P, Santosh K, Jiang Y, Liu J. Toll-like receptor 4-induced ryanodine receptor 2 oxidation and sarcoplasmic reticulum Ca 2+ leakage promote cardiac contractile dysfunction in sepsis. J Biol Chem 2017; 293:794-807. [PMID: 29150444 DOI: 10.1074/jbc.m117.812289] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 11/03/2017] [Indexed: 12/22/2022] Open
Abstract
Studies suggest the potential role of a sarcoplasmic reticulum (SR) Ca2+ leak in cardiac contractile dysfunction in sepsis. However, direct supporting evidence is lacking, and the mechanisms underlying this SR leak are poorly understood. Here, we investigated the changes in cardiac Ca2+ handling and contraction in LPS-treated rat cardiomyocytes and a mouse model of polymicrobial sepsis produced by cecal ligation and puncture (CLP). LPS decreased the systolic Ca2+ transient and myocyte contraction as well as SR Ca2+ content. Meanwhile, LPS increased Ca2+ spark-mediated SR Ca2+ leak. Preventing the SR leak with ryanodine receptor (RyR) blocker tetracaine restored SR load and increased myocyte contraction. Similar alterations in Ca2+ handling were observed in cardiomyocytes from CLP mice. Treatment with JTV-519, an anti-SR leak drug, restored Ca2+ handling and improved cardiac function. In the LPS-treated cardiomyocytes, mitochondrial reactive oxygen species and oxidative stress in RyR2 were increased, whereas the levels of the RyR2-associated FK506-binding protein 1B (FKBP12.6) were decreased. The Toll-like receptor 4 (TLR4)-specific inhibitor TAK-242 reduced the oxidative stress in LPS-treated cells, decreased the SR leak, and normalized Ca2+ handling and myocyte contraction. Consistently, TLR4 deletion significantly improved cardiac function and corrected abnormal Ca2+ handling in the CLP mice. This study provides evidence for the critical role of the SR Ca2+ leak in the development of septic cardiomyopathy and highlights the therapeutic potential of JTV-519 by preventing SR leak. Furthermore, it reveals that TLR4 activation-induced mitochondrial reactive oxygen species production and the resulting oxidative stress in RyR2 contribute to the SR Ca2+ leak.
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Affiliation(s)
- Jie Yang
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China.,the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Rui Zhang
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China
| | - Xin Jiang
- the Department of Cardiology, Second Affiliated Hospital of Jinan University (Shenzhen People's Hospital), Shenzhen 518000, China
| | - Jingzhang Lv
- the Shenzhen Entry-Exit Inspection and Quarantine Bureau, Shenzhen 518045, China, and
| | - Ying Li
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Hongyu Ye
- the Department of Cardiothoracic Surgery, Zhongshan People's Hospital, Zhongshan 528415, China
| | - Wenjuan Liu
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Gang Wang
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Cuicui Zhang
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Na Zheng
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Ming Dong
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Yan Wang
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Peiya Chen
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Kumar Santosh
- the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
| | - Yong Jiang
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China,
| | - Jie Liu
- From the Department of Pathophysiology, Southern Medical University, Guangzhou 510515, China, .,the Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen 518060, China
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32
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Olgar Y, Celen MC, Yamasan BE, Ozturk N, Turan B, Ozdemir S. Rho-kinase inhibition reverses impaired Ca 2+ handling and associated left ventricular dysfunction in pressure overload-induced cardiac hypertrophy. Cell Calcium 2017; 67:81-90. [DOI: 10.1016/j.ceca.2017.09.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2017] [Revised: 08/24/2017] [Accepted: 09/09/2017] [Indexed: 10/18/2022]
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33
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Hanna AD, Lam A, Thekkedam C, Willemse H, Dulhunty AF, Beard NA. The Anthracycline Metabolite Doxorubicinol Abolishes RyR2 Sensitivity to Physiological Changes in Luminal Ca2+ through an Interaction with Calsequestrin. Mol Pharmacol 2017; 92:576-587. [DOI: 10.1124/mol.117.108183] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2017] [Accepted: 09/07/2017] [Indexed: 12/31/2022] Open
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34
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Estrada-Avilés R, Rodríguez G, Zarain-Herzberg A. The cardiac calsequestrin gene transcription is modulated at the promoter by NFAT and MEF-2 transcription factors. PLoS One 2017; 12:e0184724. [PMID: 28886186 PMCID: PMC5590987 DOI: 10.1371/journal.pone.0184724] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Accepted: 08/08/2017] [Indexed: 12/13/2022] Open
Abstract
Calsequestrin-2 (CASQ2) is the main Ca2+-binding protein inside the sarcoplasmic reticulum of cardiomyocytes. Previously, we demonstrated that MEF-2 and SRF binding sites within the human CASQ2 gene (hCASQ2) promoter region are functional in neonatal cardiomyocytes. In this work, we investigated if the calcineurin/NFAT pathway regulates hCASQ2 expression in neonatal cardiomyocytes. The inhibition of NFAT dephosphorylation with CsA or INCA-6, reduced both the luciferase activity of hCASQ2 promoter constructs (-3102/+176 bp and -288/+176 bp) and the CASQ2 mRNA levels in neonatal rat cardiomyocytes. Additionally, NFATc1 and NFATc3 over-expressing neonatal cardiomyocytes showed a 2-3-fold increase in luciferase activity of both hCASQ2 promoter constructs, which was prevented by CsA treatment. Site-directed mutagenesis of the -133 bp MEF-2 binding site prevented trans-activation of hCASQ2 promoter constructs induced by NFAT overexpression. Chromatin Immunoprecipitation (ChIP) assays revealed NFAT and MEF-2 enrichment within the -288 bp to +76 bp of the hCASQ2 gene promoter. Besides, a direct interaction between NFAT and MEF-2 proteins was demonstrated by protein co-immunoprecipitation experiments. Taken together, these data demonstrate that NFAT interacts with MEF-2 bound to the -133 bp binding site at the hCASQ2 gene promoter. In conclusion, in this work, we demonstrate that the Ca2+-calcineurin/NFAT pathway modulates the transcription of the hCASQ2 gene in neonatal cardiomyocytes.
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Affiliation(s)
- Rafael Estrada-Avilés
- Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Gabriela Rodríguez
- Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
| | - Angel Zarain-Herzberg
- Department of Biochemistry, School of Medicine, National Autonomous University of Mexico, Mexico City, Mexico
- * E-mail:
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35
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Abstract
Cardiac contractility is regulated by changes in intracellular Ca concentration ([Ca2+]i). Normal function requires that [Ca2+]i be sufficiently high in systole and low in diastole. Much of the Ca needed for contraction comes from the sarcoplasmic reticulum and is released by the process of calcium-induced calcium release. The factors that regulate and fine-tune the initiation and termination of release are reviewed. The precise control of intracellular Ca cycling depends on the relationships between the various channels and pumps that are involved. We consider 2 aspects: (1) structural coupling: the transporters are organized within the dyad, linking the transverse tubule and sarcoplasmic reticulum and ensuring close proximity of Ca entry to sites of release. (2) Functional coupling: where the fluxes across all membranes must be balanced such that, in the steady state, Ca influx equals Ca efflux on every beat. The remainder of the review considers specific aspects of Ca signaling, including the role of Ca buffers, mitochondria, Ca leak, and regulation of diastolic [Ca2+]i.
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Affiliation(s)
- David A Eisner
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom.
| | - Jessica L Caldwell
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom
| | - Kornél Kistamás
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom
| | - Andrew W Trafford
- From the Unit of Cardiac Physiology, Division of Cardiovascular Sciences, Manchester Academic Health Sciences Centre, University of Manchester, United Kingdom
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36
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Györke S, Belevych AE, Liu B, Kubasov IV, Carnes CA, Radwański PB. The role of luminal Ca regulation in Ca signaling refractoriness and cardiac arrhythmogenesis. J Gen Physiol 2017; 149:877-888. [PMID: 28798279 PMCID: PMC5583712 DOI: 10.1085/jgp.201711808] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2017] [Revised: 06/19/2017] [Accepted: 07/12/2017] [Indexed: 01/05/2023] Open
Abstract
Györke et al. discuss the role of sarcoplasmic reticulum Ca2+ in cardiac refractoriness and pathological implications.
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Affiliation(s)
- Sándor Györke
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH .,Davis Heart and Lung Research Institute, Columbus, OH
| | - Andriy E Belevych
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH.,Davis Heart and Lung Research Institute, Columbus, OH
| | - Bin Liu
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH.,Davis Heart and Lung Research Institute, Columbus, OH
| | - Igor V Kubasov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Cynthia A Carnes
- College of Pharmacy, The Ohio State University, Columbus, OH.,Davis Heart and Lung Research Institute, Columbus, OH
| | - Przemysław B Radwański
- College of Pharmacy, The Ohio State University, Columbus, OH.,Davis Heart and Lung Research Institute, Columbus, OH
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37
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Liu W, Chen P, Deng J, Lv J, Liu J. Resveratrol and polydatin as modulators of Ca 2+ mobilization in the cardiovascular system. Ann N Y Acad Sci 2017; 1403:82-91. [PMID: 28665033 DOI: 10.1111/nyas.13386] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/27/2017] [Revised: 04/20/2017] [Accepted: 04/21/2017] [Indexed: 12/29/2022]
Abstract
In the cardiovascular system, Ca2+ controls cardiac excitation-contraction coupling and vascular contraction and dilation. Disturbances in intracellular Ca2+ homeostasis induce malfunctions of the cardiovascular system, including cardiac pump dysfunction, arrhythmia, remodeling, and apoptosis, as well as hypertension and impairment of vascular reactivity. Therefore, developing drugs and strategies manipulating Ca2+ handling are highly valued in the treatment of cardiovascular disease. Resveratrol (Res) and polydatin (PD), a Res glucoside, have been well established to have beneficial effects on improving cardiovascular function. Studies from our laboratory and others have demonstrated that they exhibit inotropic effects on normal heart and therapeutic effects on hypertension, cardiac ischemia/reperfusion injury, hypertrophy, and heart failure by manipulating Ca2+ mobilization. The actions of Res and PD on Ca2+ signals delicately manipulated by multiple Ca2+ -handling proteins are pleiotropic and somewhat controversial, depending on cellular species and intracellular oxidative status. Here, we focus on the effects of Res and PD on controlling Ca2+ homeostasis in the heart and vasculature under normal and diseased conditions and highlight the key direct and indirect molecules mediating these effects.
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Affiliation(s)
- Wenjuan Liu
- Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen, China
| | - Peiya Chen
- Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen, China
| | - Jianxin Deng
- Department of Endocrinology, the First Affiliated Hospital of Shenzhen University, Shenzhen University, Shenzhen, China.,Department of Endocrinology, Shenzhen No. 2 People's Hospital, Shenzhen, China
| | - Jingzhang Lv
- Shenzhen Entry-Exit Inspection and Quarantine Bureau, Shenzhen, China
| | - Jie Liu
- Department of Pathophysiology, School of Medicine, Shenzhen University, Shenzhen, China
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38
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Reilly-O'Donnell B, Robertson GB, Karumbi A, McIntyre C, Bal W, Nishi M, Takeshima H, Stewart AJ, Pitt SJ. Dysregulated Zn 2+ homeostasis impairs cardiac type-2 ryanodine receptor and mitsugumin 23 functions, leading to sarcoplasmic reticulum Ca 2+ leakage. J Biol Chem 2017. [PMID: 28630041 PMCID: PMC5555195 DOI: 10.1074/jbc.m117.781708] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Aberrant Zn2+ homeostasis is associated with dysregulated intracellular Ca2+ release, resulting in chronic heart failure. In the failing heart a small population of cardiac ryanodine receptors (RyR2) displays sub-conductance-state gating leading to Ca2+ leakage from sarcoplasmic reticulum (SR) stores, which impairs cardiac contractility. Previous evidence suggests contribution of RyR2-independent Ca2+ leakage through an uncharacterized mechanism. We sought to examine the role of Zn2+ in shaping intracellular Ca2+ release in cardiac muscle. Cardiac SR vesicles prepared from sheep or mouse ventricular tissue were incorporated into phospholipid bilayers under voltage-clamp conditions, and the direct action of Zn2+ on RyR2 channel function was examined. Under diastolic conditions, the addition of pathophysiological concentrations of Zn2+ (≥2 nm) caused dysregulated RyR2-channel openings. Our data also revealed that RyR2 channels are not the only SR Ca2+-permeable channels regulated by Zn2+. Elevating the cytosolic Zn2+ concentration to 1 nm increased the activity of the transmembrane protein mitsugumin 23 (MG23). The current amplitude of the MG23 full-open state was consistent with that previously reported for RyR2 sub-conductance gating, suggesting that in heart failure in which Zn2+ levels are elevated, RyR2 channels do not gate in a sub-conductance state, but rather MG23-gating becomes more apparent. We also show that in H9C2 cells exposed to ischemic conditions, intracellular Zn2+ levels are elevated, coinciding with increased MG23 expression. In conclusion, these data suggest that dysregulated Zn2+ homeostasis alters the function of both RyR2 and MG23 and that both ion channels play a key role in diastolic SR Ca2+ leakage.
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Affiliation(s)
- Benedict Reilly-O'Donnell
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Gavin B Robertson
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Angela Karumbi
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Connor McIntyre
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Wojciech Bal
- Department of Biophysics, Institute of Biochemistry and Biophysics, Polish Academy of Science, Warsaw, 02-106 Poland, and
| | - Miyuki Nishi
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Hiroshi Takeshima
- Graduate School of Pharmaceutical Sciences, Kyoto University, Kyoto 606-8501, Japan
| | - Alan J Stewart
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom
| | - Samantha J Pitt
- From the School of Medicine, University of St. Andrews, St. Andrews, KY16 9TF, Scotland, United Kingdom,
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39
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Belevych AE, Ho HT, Bonilla IM, Terentyeva R, Schober KE, Terentyev D, Carnes CA, Györke S. The role of spatial organization of Ca 2+ release sites in the generation of arrhythmogenic diastolic Ca 2+ release in myocytes from failing hearts. Basic Res Cardiol 2017; 112:44. [PMID: 28612155 DOI: 10.1007/s00395-017-0633-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/03/2017] [Accepted: 06/06/2017] [Indexed: 01/20/2023]
Abstract
In heart failure (HF), dysregulated cardiac ryanodine receptors (RyR2) contribute to the generation of diastolic Ca2+ waves (DCWs), thereby predisposing adrenergically stressed failing hearts to life-threatening arrhythmias. However, the specific cellular, subcellular, and molecular defects that account for cardiac arrhythmia in HF remain to be elucidated. Patch-clamp techniques and confocal Ca2+ imaging were applied to study spatially defined Ca2+ handling in ventricular myocytes isolated from normal (control) and failing canine hearts. Based on their activation time upon electrical stimulation, Ca2+ release sites were categorized as coupled, located in close proximity to the sarcolemmal Ca2+ channels, and uncoupled, the Ca2+ channel-free non-junctional Ca2+ release units. In control myocytes, stimulation of β-adrenergic receptors with isoproterenol (Iso) resulted in a preferential increase in Ca2+ spark rate at uncoupled sites. This site-specific effect of Iso was eliminated by the phosphatase inhibitor okadaic acid, which caused similar facilitation of Ca2+ sparks at coupled and uncoupled sites. Iso-challenged HF myocytes exhibited increased predisposition to DCWs compared to control myocytes. In addition, the overall frequency of Ca2+ sparks was increased in HF cells due to preferential stimulation of coupled sites. Furthermore, coupled sites exhibited accelerated recovery from functional refractoriness in HF myocytes compared to control myocytes. Spatially resolved subcellular Ca2+ mapping revealed that DCWs predominantly originated from coupled sites. Inhibition of CaMKII suppressed DCWs and prevented preferential stimulation of coupled sites in Iso-challenged HF myocytes. These results suggest that CaMKII- (and phosphatase)-dependent dysregulation of junctional Ca2+ release sites contributes to Ca2+-dependent arrhythmogenesis in HF.
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Affiliation(s)
- Andriy E Belevych
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210, USA. .,Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA.
| | - Hsiang-Ting Ho
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210, USA.,Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA
| | - Ingrid M Bonilla
- Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA.,College of Pharmacy, The Ohio State University, Columbus, OH, 43210, USA
| | - Radmila Terentyeva
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | - Karsten E Schober
- College of Veterinary Medicine, The Ohio State University, Columbus, OH, 43210, USA
| | - Dmitry Terentyev
- Department of Medicine, Division of Cardiology, Cardiovascular Research Center, Rhode Island Hospital, The Warren Alpert Medical School of Brown University, Providence, RI, 02903, USA
| | - Cynthia A Carnes
- Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA.,College of Pharmacy, The Ohio State University, Columbus, OH, 43210, USA
| | - Sándor Györke
- Department of Physiology and Cell Biology, The Ohio State University, Columbus, OH, 43210, USA. .,Davis Heart and Lung Research Institute, The Ohio State University Medical Center, Columbus, OH, 43210, USA.
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40
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Sato D, Shannon TR, Bers DM. Sarcoplasmic Reticulum Structure and Functional Properties that Promote Long-Lasting Calcium Sparks. Biophys J 2016; 110:382-390. [PMID: 26789761 DOI: 10.1016/j.bpj.2015.12.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 12/07/2015] [Accepted: 12/09/2015] [Indexed: 11/18/2022] Open
Abstract
Calcium (Ca) sparks are the fundamental sarcoplasmic reticulum (SR) Ca release events in cardiac myocytes, and they have a typical duration of 20-40 ms. However, when a fraction of ryanodine receptors (RyRs) are blocked by tetracaine or ruthenium red, Ca sparks lasting hundreds of milliseconds have been observed experimentally. The fundamental mechanism underlying these extremely prolonged Ca sparks is not understood. In this study, we use a physiologically detailed mathematical model of subcellular Ca cycling to examine how Ca spark duration is influenced by the number of functional RyRs in a junctional cluster (which is reduced by tetracaine or ruthenium red) and other SR Ca handling properties. One RyR cluster contains a few to several hundred RyRs, and we use a four-state Markov RyR gating model. Each RyR opens stochastically and is regulated by cytosolic and luminal Ca. We varied the number of functional RyRs in the single cluster, diffusion within the SR network, diffusion between network and junctional SR, cytosolic Ca diffusion, SERCA uptake activity, and RyR open probability. For long-lasting Ca release events, opening events within the cluster must occur continuously because the typical open time of the RyR is only a few milliseconds. We found the following: 1) if the number of RyRs is too small, it is difficult to maintain consecutive openings and stochastic attrition terminates the release; 2) if the number of RyRs is too large, the depletion of Ca from the junctional SR terminates the release; and 3) very long release events require relatively small-sized RyR clusters (reducing flux as seen experimentally with tetracaine) and sufficiently rapid intra-SR Ca diffusion, such that local junctional intra-SR [Ca] can be maintained by intra-SR diffusion and overall SR Ca reuptake.
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Affiliation(s)
- Daisuke Sato
- Department of Pharmacology, University of California, Davis, Davis, California.
| | - Thomas R Shannon
- Molecular Biophysics and Physiology, Rush University, Chicago, Illinois
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, Davis, California
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41
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Ho HT, Belevych AE, Liu B, Bonilla IM, Radwański PB, Kubasov IV, Valdivia HH, Schober K, Carnes CA, Györke S. Muscarinic Stimulation Facilitates Sarcoplasmic Reticulum Ca Release by Modulating Ryanodine Receptor 2 Phosphorylation Through Protein Kinase G and Ca/Calmodulin-Dependent Protein Kinase II. Hypertension 2016; 68:1171-1178. [PMID: 27647848 DOI: 10.1161/hypertensionaha.116.07666] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Accepted: 08/21/2016] [Indexed: 01/01/2023]
Abstract
Although the effects and the underlying mechanism of sympathetic stimulation on cardiac Ca handling are relatively well established both in health and disease, the modes of action and mechanisms of parasympathetic modulation are poorly defined. Here, we demonstrate that parasympathetic stimulation initiates a novel mode of excitation-contraction coupling that enhances the efficiency of cardiac sarcoplasmic reticulum Ca store utilization. This efficient mode of excitation-contraction coupling involves reciprocal changes in the phosphorylation of ryanodine receptor 2 at Ser-2808 and Ser-2814. Specifically, Ser-2808 phosphorylation was mediated by muscarinic receptor subtype 2 and activation of PKG (protein kinase G), whereas dephosphorylation of Ser-2814 involved activation of muscarinic receptor subtype 3 and decreased reactive oxygen species-dependent activation of CaMKII (Ca/calmodulin-dependent protein kinase II). The overall effect of these changes in phosphorylation of ryanodine receptor 2 is an increase in systolic Ca release at the low sarcoplasmic reticulum Ca content and a paradoxical reduction in aberrant Ca leak. Accordingly, cholinergic stimulation of cardiomyocytes isolated from failing hearts improved Ca cycling efficiency by restoring altered ryanodine receptor 2 phosphorylation balance.
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Affiliation(s)
- Hsiang-Ting Ho
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Andriy E Belevych
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Bin Liu
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Ingrid M Bonilla
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Przemysław B Radwański
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Igor V Kubasov
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Héctor H Valdivia
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Karsten Schober
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Cynthia A Carnes
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.)
| | - Sándor Györke
- From the Department of Physiology and Cell Biology (H.-T.H., A.E.B., B.L., P.B.R., S.G.), College of Pharmacy (I.M.B., P.B.R., C.A.C.), and College of Veterinary Medicine (K.S.), The Ohio State University, Columbus; Davis Heart and Lung Research Institute, Columbus, OH (H.-T.H., A.E.B., B.L., I.M.B., P.B.R., C.A.C., S.G.); Department of Medicine, Duke University, Durham, NC (H.-T.H.); Laboratory of Neuromuscular Physiology, I.M. Sechenov Institute of Evolutionary Physiology and Biochemistry, Petersburg, Russia (I.V.K.); and Center for Arrhythmia Research, Cardiovascular Division of the Department of Internal Medicine, University of Michigan, Ann Arbor (H.H.V.).
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42
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Sprenkeler DJ, Vos MA. Post-extrasystolic Potentiation: Link between Ca(2+) Homeostasis and Heart Failure? Arrhythm Electrophysiol Rev 2016; 5:20-6. [PMID: 27403289 DOI: 10.15420/aer.2015.29.2] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
Abstract
Post-extrasystolic potentiation (PESP) describes the phenomenon of increased contractility of the beat following an extrasystole and has been attributed to changes in Ca(2+) homeostasis. While this effect has long been regarded to be a normal physiological phenomenon, a number of reports describe an enhanced potentiation of the post-extrasystolic beat in heart failure patients. The exact mechanism of this increased PESP is unknown, but disruption of normal Ca(2+) handling in heart failure may be the underlying cause. The use of PESP as a prognostic marker or therapeutic intervention have recently regained new attention, however, the value of the application of PESP in the clinic is still under debate. In this review, the mechanism of PESP with regard to Ca(2+) in the normal and failing heart will be discussed and the possible diagnostic and therapeutic role of this phenomenon will be explored.
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Affiliation(s)
| | - Marc A Vos
- University Medical Center Utrecht, Utrecht, The Netherlands
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43
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Fernandez-Tenorio M, Niggli E. Real-time intra-store confocal Ca 2+ imaging in isolated mouse cardiomyocytes. Cell Calcium 2016; 60:331-340. [PMID: 27431464 DOI: 10.1016/j.ceca.2016.07.002] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Revised: 07/07/2016] [Accepted: 07/07/2016] [Indexed: 11/26/2022]
Abstract
To initiate the contraction of cardiomyocytes, Ca2+ is released from the SR to the cytosol via ryanodine receptors (RyRs), which are activated by the Ca2+-induced Ca2+ release mechanism (CICR). The activity of RyRs is regulated by both, cytosolic and SR luminal Ca2+. Deregulation of the CICR, by dysfunctional SR Ca2+ release or uptake, is frequently associated with cardiac pathologies (e.g. arrhythmias, CPVT, heart failure). Recently, the interest to directly measure changes of the free Ca2+ concentration within the SR ([Ca2+]SR) has led to the application of low affinity Ca2+ indicators (mag-fluo-4, Fluo-5N) to follow changes of [Ca2+]SR in cardiomyocytes from some species. However, direct measurement of Ca2+ signals from the SR have not been possible in freshly isolated mouse cardiomyocytes. Here, we show a new protocol optimized to measure changes of [Ca2+]SR in mouse cardiomyocytes using fluorescent Ca2+ indicators and confocal microscopy. The application of this protocol permits the design of experimental studies with direct evaluation of SR Ca2+ in real time in various mouse models of cardiac disease, including transgenic animals harboring mutants of RyRs or other Ca2+ signaling proteins. The technique, in combination with these models, will help to understand how these diseases and mutations affect Ca2+ signals within the SR and the Ca2+ sensitivity of the RyRs for cytosolic and SR luminal Ca2+, thereby contributing to arrhythmias or weak heart beat.
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Affiliation(s)
| | - Ernst Niggli
- Department of Physiology, University of Bern, 3012 Bern, Switzerland.
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44
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Mason FE, Sossalla S. The Significance of the Late Na+ Current for Arrhythmia Induction and the Therapeutic Antiarrhythmic Potential of Ranolazine. J Cardiovasc Pharmacol Ther 2016; 22:40-50. [DOI: 10.1177/1074248416644989] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The purpose of this article is to review the basis of arrhythmogenesis, the functional and clinical role of the late Na current, and its therapeutic inhibition. Under pathological conditions such as ischemia and heart failure this current is abnormally enhanced and influences cellular electrophysiology as a proarrhythmic substrate in myocardial pathology. Ranolazine the only approved late Na current blocker has been demonstrated to produce antiarrhythmic effects in the atria and the ventricle. We summarize recent experimental and clinical studies of ranolazine and other experimental late Na current blockers and discuss the significance of the available data.
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Affiliation(s)
- Fleur E. Mason
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
| | - Samuel Sossalla
- Department of Cardiology and Pneumology, Georg-August-University Göttingen, Göttingen, Germany
- Department of Internal Medicine III (Cardiology and Angiology), University Hospital Schleswig-Holstein, Kiel, Germany
- German Centre for Cardiovascular Research (DZHK), Göttingen & Kiel, Germany
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45
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Chu L, Greenstein JL, Winslow RL. Modeling Na +-Ca 2+ exchange in the heart: Allosteric activation, spatial localization, sparks and excitation-contraction coupling. J Mol Cell Cardiol 2016; 99:174-187. [PMID: 27377851 DOI: 10.1016/j.yjmcc.2016.06.068] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2016] [Revised: 06/14/2016] [Accepted: 06/30/2016] [Indexed: 01/19/2023]
Abstract
The cardiac sodium (Na+)/calcium (Ca2+) exchanger (NCX1) is an electrogenic membrane transporter that regulates Ca2+ homeostasis in cardiomyocytes, serving mainly to extrude Ca2+ during diastole. The direction of Ca2+ transport reverses at membrane potentials near that of the action potential plateau, generating an influx of Ca2+ into the cell. Therefore, there has been great interest in the possible roles of NCX1 in cardiac Ca2+-induced Ca2+ release (CICR). Interest has been reinvigorated by a recent super-resolution optical imaging study suggesting that ~18% of NCX1 co-localize with ryanodine receptor (RyR2) clusters, and ~30% of additional NCX1 are localized to within ~120nm of the nearest RyR2. NCX1 may therefore occupy a privileged position in which to modulate CICR. To examine this question, we have developed a mechanistic biophysically-detailed model of NCX1 that describes both NCX1 transport kinetics and Ca2+-dependent allosteric regulation. This NCX1 model was incorporated into a previously developed super-resolution model of the Ca2+ spark as well as a computational model of the cardiac ventricular myocyte that includes a detailed description of CICR with stochastic gating of L-type Ca2+ channels and RyR2s, and that accounts for local Ca2+ gradients near the dyad via inclusion of a peri-dyadic (PD) compartment. Both models predict that increasing the fraction of NCX1 in the dyad and PD decreases spark frequency, fidelity, and diastolic Ca2+ levels. Spark amplitude and duration are less sensitive to NCX1 spatial redistribution. On the other hand, NCX1 plays an important role in promoting Ca2+ entry into the dyad, and hence contributing to the trigger for RyR2 release at depolarized membrane potentials and in the presence of elevated local Na+ concentration. Whole-cell simulation of NCX1 tail currents are consistent with the finding that a relatively high fraction of NCX1 (~45%) resides in the dyadic and PD spaces, with a dyad-to-PD ratio of roughly 1:2. Allosteric Ca2+ activation of NCX1 helps to "functionally localize" exchanger activity to the dyad and PD by reducing exchanger activity in the cytosol thereby protecting the cell from excessive loss of Ca2+ during diastole.
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Affiliation(s)
- Lulu Chu
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD, 21218, USA.
| | - Joseph L Greenstein
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD, 21218, USA.
| | - Raimond L Winslow
- Department of Biomedical Engineering and the Institute for Computational Medicine, The Johns Hopkins University School of Medicine and Whiting School of Engineering, 3400 N Charles Street, Baltimore, MD, 21218, USA.
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46
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Bovo E, Martin JL, Tyryfter J, de Tombe PP, Zima AV. R-CEPIA1er as a new tool to directly measure sarcoplasmic reticulum [Ca] in ventricular myocytes. Am J Physiol Heart Circ Physiol 2016; 311:H268-75. [PMID: 27233762 PMCID: PMC4967208 DOI: 10.1152/ajpheart.00175.2016] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2016] [Accepted: 05/24/2016] [Indexed: 11/22/2022]
Abstract
In cardiomyocytes, [Ca] within the sarcoplasmic reticulum (SR; [Ca]SR) partially determines the amplitude of cytosolic Ca transient that, in turn, governs myocardial contraction. Therefore, it is critical to understand the molecular mechanisms that regulate [Ca]SR handling. Until recently, the best approach available to directly measure [Ca]SR was to use low-affinity Ca indicators (e.g., Fluo-5N). However, this approach presents several limitations, including nonspecific cellular localization, dye extrusion, and species limitation. Recently a new genetically encoded family of Ca indicators has been generated, named Ca-measuring organelle-entrapped protein indicators (CEPIA). Here, we tested the red fluorescence SR-targeted Ca sensor (R-CEPIA1er) as a tool to directly measure [Ca]SR dynamics in ventricular myocytes. Infection of rabbit and rat ventricular myocytes with an adenovirus expressing the R-CEPIA1er gene displayed prominent localization in the SR and nuclear envelope. Calibration of R-CEPIA1er in myocytes resulted in a Kd of 609 μM, suggesting that this sensor is sensitive in the whole physiological range of [Ca]SR [Ca]SR dynamics measured with R-CEPIA1er were compared with [Ca]SR measured with Fluo5-N. We found that both the time course of the [Ca]SR depletion and fractional SR Ca release induced by an action potential were similar between these two Ca sensors. R-CEPIA1er fluorescence did not decline during experiments, indicating lack of dye extrusion or photobleaching. Furthermore, measurement of [Ca]SR with R-CEPIA1er can be combined with cytosolic [Ca] measurements (with Fluo-4) to obtain more detailed information regarding Ca handling in cardiac myocytes. In conclusion, R-CEPIA1er is a promising tool that can be used to measure [Ca]SR dynamics in myocytes from different animal species.
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Affiliation(s)
- Elisa Bovo
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois
| | - Jody L Martin
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois
| | - Jollyn Tyryfter
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois
| | - Pieter P de Tombe
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois
| | - Aleksey V Zima
- Department of Cell and Molecular Physiology, Loyola University Chicago, Stritch School of Medicine, Maywood, Illinois
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47
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Weinberg SH. Impaired Sarcoplasmic Reticulum Calcium Uptake and Release Promote Electromechanically and Spatially Discordant Alternans: A Computational Study. CLINICAL MEDICINE INSIGHTS-CARDIOLOGY 2016; 10:1-15. [PMID: 27385917 PMCID: PMC4920205 DOI: 10.4137/cmc.s39709] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/01/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 02/01/2023]
Abstract
Cardiac electrical dynamics are governed by cellular-level properties, such as action potential duration (APD) restitution and intracellular calcium (Ca) handling, and tissue-level properties, including conduction velocity restitution and cell-cell coupling. Irregular dynamics at the cellular level can lead to instabilities in cardiac tissue, including alternans, a beat-to-beat alternation in the action potential and/or the intracellular Ca transient. In this study, we incorporate a detailed single cell coupled map model of Ca cycling and bidirectional APD-Ca coupling into a spatially extended tissue model to investigate the influence of sarcoplasmic reticulum (SR) Ca uptake and release properties on alternans and conduction block. We find that an intermediate SR Ca uptake rate and larger SR Ca release resulted in the widest range of stimulus periods that promoted alternans. However, both reduced SR Ca uptake and release promote arrhythmogenic spatially and electromechanically discordant alternans, suggesting a complex interaction between SR Ca handling and alternans characteristics at the cellular and tissue level.
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Affiliation(s)
- Seth H Weinberg
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA, USA
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48
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Beta-Adrenoceptor Stimulation Reveals Ca2+ Waves and Sarcoplasmic Reticulum Ca2+ Depletion in Left Ventricular Cardiomyocytes from Post-Infarction Rats with and without Heart Failure. PLoS One 2016; 11:e0153887. [PMID: 27096943 PMCID: PMC4838269 DOI: 10.1371/journal.pone.0153887] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2015] [Accepted: 04/05/2016] [Indexed: 11/25/2022] Open
Abstract
Abnormal cellular Ca2+ handling contributes to both contractile dysfunction and arrhythmias in heart failure. Reduced Ca2+ transient amplitude due to decreased sarcoplasmic reticulum Ca2+ content is a common finding in heart failure models. However, heart failure models also show increased propensity for diastolic Ca2+ release events which occur when sarcoplasmic reticulum Ca2+ content exceeds a certain threshold level. Such Ca2+ release events can initiate arrhythmias. In this study we aimed to investigate if both of these aspects of altered Ca2+ homeostasis could be found in left ventricular cardiomyocytes from rats with different states of cardiac function six weeks after myocardial infarction when compared to sham-operated controls. Video edge-detection, whole-cell Ca2+ imaging and confocal line-scan imaging were used to investigate cardiomyocyte contractile properties, Ca2+ transients and Ca2+ waves. In baseline conditions, i.e. without beta-adrenoceptor stimulation, cardiomyocytes from rats with large myocardial infarction, but without heart failure, did not differ from sham-operated animals in any of these aspects of cellular function. However, when exposed to beta-adrenoceptor stimulation, cardiomyocytes from both non-failing and failing rat hearts showed decreased sarcoplasmic reticulum Ca2+ content, decreased Ca2+ transient amplitude, and increased frequency of Ca2+ waves. These results are in line with a decreased threshold for diastolic Ca2+ release established by other studies. In the present study, factors that might contribute to a lower threshold for diastolic Ca2+ release were increased THR286 phosphorylation of Ca2+/calmodulin-dependent protein kinase II and increased protein phosphatase 1 abundance. In conclusion, this study demonstrates both decreased sarcoplasmic reticulum Ca2+ content and increased propensity for diastolic Ca2+ release events in ventricular cardiomyocytes from rats with heart failure after myocardial infarction, and that these phenomena are also found in rats with large myocardial infarctions without heart failure development. Importantly, beta-adrenoceptor stimulation is necessary to reveal these perturbations in Ca2+ handling after a myocardial infarction.
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49
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Petrovič P, Valent I, Cocherová E, Pavelková J, Zahradníková A. Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes. ACTA ACUST UNITED AC 2016; 145:489-511. [PMID: 26009544 PMCID: PMC4442793 DOI: 10.1085/jgp.201411281] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Calcium waves can form and propagate at low frequencies of spontaneous calcium sparks if the calcium dependence of spark frequency is sufficiently steep, or the number of open RyRs is sufficiently large. The role of cardiac ryanodine receptor (RyR) gating in the initiation and propagation of calcium waves was investigated using a mathematical model comprising a stochastic description of RyR gating and a deterministic description of calcium diffusion and sequestration. We used a one-dimensional array of equidistantly spaced RyR clusters, representing the confocal scanning line, to simulate the formation of calcium sparks. Our model provided an excellent description of the calcium dependence of the frequency of diastolic calcium sparks and of the increased tendency for the production of calcium waves after a decrease in cytosolic calcium buffering. We developed a hypothesis relating changes in the propensity to form calcium waves to changes of RyR gating and tested it by simulation. With a realistic RyR gating model, increased ability of RyR to be activated by Ca2+ strongly increased the propensity for generation of calcium waves at low (0.05–0.1-µM) calcium concentrations but only slightly at high (0.2–0.4-µM) calcium concentrations. Changes in RyR gating altered calcium wave formation by changing the calcium sensitivity of spontaneous calcium spark activation and/or the average number of open RyRs in spontaneous calcium sparks. Gating changes that did not affect RyR activation by Ca2+ had only a weak effect on the propensity to form calcium waves, even if they strongly increased calcium spark frequency. Calcium waves induced by modulating the properties of the RyR activation site could be suppressed by inhibiting the spontaneous opening of the RyR. These data can explain the increased tendency for production of calcium waves under conditions when RyR gating is altered in cardiac diseases.
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Affiliation(s)
- Pavol Petrovič
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovak Republic
| | - Ivan Valent
- Department of Physical and Theoretical Chemistry, Faculty of Natural Sciences, Comenius University, 842 15 Bratislava, Slovak Republic Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic
| | - Elena Cocherová
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic Institute of Electronics and Photonics, Faculty of Electrical Engineering and Information Technology, Slovak University of Technology, 812 19 Bratislava, Slovak Republic
| | - Jana Pavelková
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic
| | - Alexandra Zahradníková
- Department of Muscle Cell Research, Institute of Molecular Physiology and Genetics, Slovak Academy of Sciences, 833 34 Bratislava, Slovak Republic
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50
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Sankaranarayanan R, Li Y, Greensmith DJ, Eisner DA, Venetucci L. Biphasic decay of the Ca transient results from increased sarcoplasmic reticulum Ca leak. J Physiol 2016; 594:611-23. [PMID: 26537441 PMCID: PMC4785612 DOI: 10.1113/jp271473] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/21/2015] [Accepted: 10/30/2015] [Indexed: 01/25/2023] Open
Abstract
Key points Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay. In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase. Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient. Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine. Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient.
Abstract In heart failure, a reduction in Ca transient amplitude and contractile dysfunction can by caused by Ca leak through the sarcoplasmic reticulum (SR) Ca channel (ryanodine receptor, RyR) and/or decreased activity of the SR Ca ATPase (SERCA). We have characterised the effects of two forms of Ca leak (Ca‐sensitising and non‐sensitising) on calcium cycling and compared with those of SERCA inhibition. We measured [Ca2+]i with fluo‐3 in voltage‐clamped rat ventricular myocytes. Increasing SR leak with either caffeine (to sensitise the RyR to Ca activation) or ryanodine (non‐sensitising) had similar effects to SERCA inhibition: decreased systolic [Ca2+]i, increased diastolic [Ca2+]i and slowed decay. However, in the presence of isoproterenol, leak produced a biphasic decay of the Ca transient in the majority of cells while SERCA inhibition produced monophasic decay. Tetracaine reversed the effects of caffeine but not of ryanodine. When caffeine (1 mmol l−1) was added to a cell which displayed Ca waves, the wave frequency initially increased before waves disappeared and biphasic decay developed. Eventually (at higher caffeine concentrations), the biphasic decay was replaced by slow decay. We conclude that, in the presence of adrenergic stimulation, Ca leak can produce biphasic decay; the slow phase results from the leak opposing Ca uptake by SERCA. The degree of leak determines whether decay of Ca waves, biphasic or monophasic, occurs. Ca leak from the sarcoplasmic reticulum through the ryanodine receptor (RyR) reduces the amplitude of the Ca transient and slows its rate of decay. In the presence of β‐adrenergic stimulation, RyR‐mediated Ca leak produces a biphasic decay of the Ca transient with a fast early phase and a slow late phase. Two forms of Ca leak have been studied, Ca‐sensitising (induced by caffeine) and non‐sensitising (induced by ryanodine) and both induce biphasic decay of the Ca transient. Only Ca‐sensitising leak can be reversed by traditional RyR inhibitors such as tetracaine. Ca leak can also induce Ca waves. At low levels of leak, waves occur. As leak is increased, first biphasic decay and then slowed monophasic decay is seen. The level of leak has major effects on the shape of the Ca transient.
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Affiliation(s)
- Rajiv Sankaranarayanan
- Unit of Cardiac Physiology, Institute of Cardiovascular Sciences University of Manchester, Manchester, UK
| | - Yatong Li
- Unit of Cardiac Physiology, Institute of Cardiovascular Sciences University of Manchester, Manchester, UK
| | - David J Greensmith
- Biomedical Research Centre, School of Environment & Life Sciences, University of Salford, Salford, UK
| | - David A Eisner
- Unit of Cardiac Physiology, Institute of Cardiovascular Sciences University of Manchester, Manchester, UK
| | - Luigi Venetucci
- Unit of Cardiac Physiology, Institute of Cardiovascular Sciences University of Manchester, Manchester, UK.,Manchester Heart Centre, Manchester Royal Infirmary, Central Manchester Foundation Trust, Manchester, UK
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