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Pluteanu F, Glaser D, Massing F, Schulte JS, Kirchhefer U. Loss of protein phosphatase 2A regulatory subunit PPP2R5A is associated with increased incidence of stress-induced proarrhythmia. Front Cardiovasc Med 2024; 11:1419597. [PMID: 38863902 PMCID: PMC11165201 DOI: 10.3389/fcvm.2024.1419597] [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: 04/18/2024] [Accepted: 05/16/2024] [Indexed: 06/13/2024] Open
Abstract
Background Protein phosphatase 2A (PP2A) is a serine/threonine-selective holoenzyme that controls Ca2+ homeostasis and contractility of the heart via dephosphorylation of regulatory proteins. In some genetically modified mouse models with increased arrhythmogenicity, a reduced expression of the regulatory subunit B56α of PP2A was found as a concomitant effect. Whether there is a general correlation between the abundance of B56α and the promotion of cardiac arrhythmogenesis remains unclear. Methods The aim of this study was therefore to investigate the role of PP2A-B56α in the propensity for arrhythmic activity in the heart. The experimental analysis of this question has been addressed by using a mouse model with deletion of the PP2A-B56α gene, PPP2R5A (KO), in comparison to wild-type animals (WT). Evidence for arrhythmogenicity was investigated in whole animal, isolated heart and cardiomyocytes by ECG, recording of monophasic action potential (MAP) induced by programmed electrical stimulation (PES), measurement of Ca2+ transients under increased pacing frequencies and determination of total K+ channel currents (I K). Results ECG measurements showed a prolongation of QT time in KO vs. WT. KO mice exhibited a higher rate of premature ventricular contractions in the ECG. MAP measurements in Langendorff-perfused KO hearts showed increased episodes of ventricular tachyarrhythmia induced by PES. However, the KO hearts showed values for MAP duration that were similar to those in WT hearts. In contrast, KO showed more myocardial cells with spontaneous arrhythmogenic Ca2+ transient events compared to WT. The whole-cell patch-clamp technique applied to ventricular cardiomyocytes revealed comparable peak potassium channel current densities between KO and WT. Conclusion These findings support the assumption that a decrease or even the loss of PP2A-B56α leads to an increased propensity of triggered arrhythmias. This could be based on the increased spontaneous Ca2+ tansients observed.
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Affiliation(s)
- Florentina Pluteanu
- Department of Anatomy, Animal Physiology and Biophysics, University of Bucharest, Bucharest, Romania
| | - Dennis Glaser
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Fabian Massing
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Jan S. Schulte
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
| | - Uwe Kirchhefer
- Institut für Pharmakologie und Toxikologie, Universitätsklinikum Münster, Universität Münster, Münster, Germany
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2
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Wang R, Lv X, Xu W, Li X, Tang X, Huang H, Yang M, Ma S, Wang N, Niu Y. Effects of the periodic fasting-mimicking diet on health, lifespan, and multiple diseases: a narrative review and clinical implications. Nutr Rev 2024:nuae003. [PMID: 38287649 DOI: 10.1093/nutrit/nuae003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2024] Open
Abstract
Dietary restriction and fasting have been recognized for their beneficial effects on health and lifespan and their potential application in managing chronic metabolic diseases. However, long-term adherence to strict dietary restrictions and prolonged fasting poses challenges for most individuals and may lead to unhealthy rebound eating habits, negatively affecting overall health. As a result, a periodic fasting-mimicking diet (PFMD), involving cycles of fasting for 2 or more days while ensuring basic nutritional needs are met within a restricted caloric intake, has gained widespread acceptance. Current research indicates that a PFMD can promote stem cell regeneration, suppress inflammation, extend the health span of rodents, and improve metabolic health, among other effects. In various disease populations such as patients with diabetes, cancer, multiple sclerosis, and Alzheimer's disease, a PFMD has shown efficacy in alleviating disease symptoms and improving relevant markers. After conducting an extensive analysis of available research on the PFMD, it is evident that its advantages and potential applications are comparable to other fasting methods. Consequently, it is proposed in this review that a PFMD has the potential to fully replace water-only or very-low-energy fasting regimens and holds promise for application across multiple diseases.
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Affiliation(s)
- Ruohua Wang
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Xinyi Lv
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Wenyu Xu
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Xiaoqing Li
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Xuanfeng Tang
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - He Huang
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Mengxia Yang
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Shuran Ma
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Nan Wang
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
| | - Yucun Niu
- Department of Nutrition and Food Hygiene, College of Public Health, Key Laboratory of Precision Nutrition and Health, Ministry of Education, Harbin Medical University, Heilongjiang, China
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3
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Dias IHK, Shokr H. Oxysterols as Biomarkers of Aging and Disease. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2024; 1440:307-336. [PMID: 38036887 DOI: 10.1007/978-3-031-43883-7_16] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/02/2023]
Abstract
Oxysterols derive from either enzymatic or non-enzymatic oxidation of cholesterol. Even though they are produced as intermediates of bile acid synthesis pathway, they are recognised as bioactive compounds in cellular processes. Therefore, their absence or accumulation have been shown to be associated with disease phenotypes. This chapter discusses the contribution of oxysterol to ageing, age-related diseases such as neurodegeneration and various disorders such as cancer, cardiovascular disease, diabetes, metabolic and ocular disorders. It is clear that oxysterols play a significant role in development and progression of these diseases. As a result, oxysterols are being investigated as suitable markers for disease diagnosis purposes and some drug targets are in development targeting oxysterol pathways. However, further research will be needed to confirm the suitability of these potentials.
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Affiliation(s)
- Irundika H K Dias
- Aston Medical School, College of Health and Life Sciences, Aston University, Birmingham, UK.
| | - Hala Shokr
- Manchester Pharmacy School, Faculty of Biology, Medicine and Health, The University of Manchester, Manchester, UK
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4
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Velliou M, Sanidas E, Diakantonis A, Ventoulis I, Parissis J, Polyzogopoulou E. The Optimal Management of Patients with Atrial Fibrillation and Acute Heart Failure in the Emergency Department. MEDICINA (KAUNAS, LITHUANIA) 2023; 59:2113. [PMID: 38138216 PMCID: PMC10744575 DOI: 10.3390/medicina59122113] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 11/29/2023] [Accepted: 11/30/2023] [Indexed: 12/24/2023]
Abstract
Atrial fibrillation (AF) and acute heart failure (AHF) are two closely interrelated conditions that frequently coexist in a manifold manner, with AF serving either as the causative factor or as the consequence or even as an innocent bystander. The interplay between these two clinical conditions is complex, given that they share common pathophysiological pathways and they can reciprocally exacerbate each other, thus triggering a vicious cycle that worsens the prognosis and increases the thromboembolic risk. The optimal management of AF in the context of AHF in the emergency department remains a challenge depending on the time onset, as well as the nature and the severity of the associated symptoms. Acute rate control, along with early rhythm control, when indicated, and anticoagulation represent the main pillars of the therapeutic intervention. The purpose of this review is to elucidate the pathophysiological link between AF and AHF and accordingly present a stepwise algorithmic approach for the management of AF in AHF patients in the emergency setting.
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Affiliation(s)
- Maria Velliou
- Emergency Medicine Department, Attikon University Hospital, 12462 Athens, Greece; (M.V.); (A.D.); (J.P.)
| | - Elias Sanidas
- Department of Cardiology, Laiko General Hospital, 11527 Athens, Greece;
| | - Antonis Diakantonis
- Emergency Medicine Department, Attikon University Hospital, 12462 Athens, Greece; (M.V.); (A.D.); (J.P.)
| | - Ioannis Ventoulis
- Department of Occupational Therapy, University of Western Macedonia, 50200 Ptolemaida, Greece;
| | - John Parissis
- Emergency Medicine Department, Attikon University Hospital, 12462 Athens, Greece; (M.V.); (A.D.); (J.P.)
| | - Effie Polyzogopoulou
- Emergency Medicine Department, Attikon University Hospital, 12462 Athens, Greece; (M.V.); (A.D.); (J.P.)
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5
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Siu A, Tandanu E, Ma B, Osas EE, Liu H, Liu T, Chou OHI, Huang H, Tse G. Precision medicine in catecholaminergic polymorphic ventricular tachycardia: Recent advances toward personalized care. Ann Pediatr Cardiol 2023; 16:431-446. [PMID: 38817258 PMCID: PMC11135882 DOI: 10.4103/apc.apc_96_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 12/12/2023] [Accepted: 01/14/2024] [Indexed: 06/01/2024] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited cardiac ion channelopathy where the initial disease presentation is during childhood or adolescent stages, leading to increased risks of sudden cardiac death. Despite advances in medical science and technology, several gaps remain in the understanding of the molecular mechanisms, risk prediction, and therapeutic management of patients with CPVT. Recent studies have identified and validated seven sets of genes responsible for various CPVT phenotypes, including RyR2, CASQ-2, TRDN, CALM1, 2, and 3, and TECRL, providing novel insights into the molecular mechanisms. However, more data on atypical CPVT genotypes are required to investigate the underlying mechanisms further. The complexities of the underlying genetics contribute to challenges in risk stratification as well as the uncertainty surrounding nongenetic modifiers. Therapeutically, although medical management involving beta-blockers and flecainide, or insertion of an implantable cardioverter defibrillator remains the mainstay of treatment, animal and stem cell studies on gene therapy for CPVT have shown promising results. However, its clinical applicability remains unclear. Current gene therapy studies have primarily focused on the RyR2 and CASQ-2 variants, which constitute 75% of all CPVT cases. Alternative approaches that target a broader population, such as CaMKII inhibition, could be more feasible for clinical implementation. Together, this review provides an update on recent research on CPVT, highlighting the need for further investigation of the molecular mechanisms, risk stratification, and therapeutic management of this potentially lethal condition.
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Affiliation(s)
- Anthony Siu
- Cardiac Electrophysiology Unit, Cardiovascular Analytics Group, Powerhealth Research Institute, Hong Kong, China
- GKT School of Medical Education, King’s College London, London, United Kingdom
| | - Edelyne Tandanu
- GKT School of Medical Education, King’s College London, London, United Kingdom
| | - Brian Ma
- Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | | | - Haipeng Liu
- Research Centre for Intelligent Healthcare, Coventry University, Coventry, United Kingdom
| | - Tong Liu
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China
| | - Oscar Hou In Chou
- Li Ka Shing Faculty of Medicine, University of Hong Kong, Hong Kong, China
| | - Helen Huang
- University of Medicine and Health Science, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Gary Tse
- Department of Cardiology, Tianjin Key Laboratory of Ionic-Molecular Function of Cardiovascular Disease, Tianjin Institute of Cardiology, Second Hospital of Tianjin Medical University, Tianjin, China
- Kent and Medway Medical School, University of Kent, Canterbury, United Kingdom
- School of Nursing and Health Studies, Hong Kong Metropolitan University, Hong Kong, China
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6
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Richardson SJ, Thekkedam CG, Casarotto MG, Beard NA, Dulhunty AF. FKBP12 binds to the cardiac ryanodine receptor with negative cooperativity: implications for heart muscle physiology in health and disease. Philos Trans R Soc Lond B Biol Sci 2023; 378:20220169. [PMID: 37122219 PMCID: PMC10150220 DOI: 10.1098/rstb.2022.0169] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/02/2023] Open
Abstract
Cardiac ryanodine receptors (RyR2) release the Ca2+ from intracellular stores that is essential for cardiac myocyte contraction. The ion channel opening is tightly regulated by intracellular factors, including the FK506 binding proteins, FKBP12 and FKBP12.6. The impact of these proteins on RyR2 activity and cardiac contraction is debated, with often apparently contradictory experimental results, particularly for FKBP12. The isoform that regulates RyR2 has generally been considered to be FKBP12.6, despite the fact that FKBP12 is the major isoform associated with RyR2 in some species and is bound in similar proportions to FKBP12.6 in others, including sheep and humans. Here, we show time- and concentration-dependent effects of adding FKBP12 to RyR2 channels that were partly depleted of FKBP12/12.6 during isolation. The added FKBP12 displaced most remaining endogenous FKBP12/12.6. The results suggest that FKBP12 activates RyR2 with high affinity and inhibits RyR2 with lower affinity, consistent with a model of negative cooperativity in FKBP12 binding to each of the four subunits in the RyR tetramer. The easy dissociation of some FKBP12/12.6 could dynamically alter RyR2 activity in response to changes in in vivo regulatory factors, indicating a significant role for FKBP12/12.6 in Ca2+ signalling and cardiac function in healthy and diseased hearts. This article is part of the theme issue 'The heartbeat: its molecular basis and physiological mechanisms'.
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Affiliation(s)
- S J Richardson
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - C G Thekkedam
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - M G Casarotto
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - N A Beard
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
| | - A F Dulhunty
- John Curtin School of Medical Research, Australian National University, Canberra, Australia, Australian Capital Territory 2601, Australia
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7
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Asaki SY, Kessler D, Nayak A, Kim JJ, Miyake CY. Atrioventricular Nodal Ablation Is Not an Effective Treatment Strategy in Catecholaminergic Polymorphic Ventricular Tachycardia. Tex Heart Inst J 2023; 50:493264. [PMID: 37268281 DOI: 10.14503/thij-22-7974] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
Catecholaminergic polymorphic ventricular tachycardia is a rare but lethal heritable arrhythmia syndrome associated with both atrial and ventricular arrhythmias. Treatment includes antiarrhythmics, sympathetic denervation, and implantable cardioverter-defibrillators. The use of atrioventricular nodal ablation as a treatment strategy to prevent ventricular arrhythmias in catecholaminergic polymorphic ventricular tachycardia was not found in the literature. This report describes a teenager with a presenting rhythm of atrial and ventricular fibrillation and cardiac arrest. Her clinical arrhythmia was predominantly atrial dysrhythmias, which delayed her diagnosis of catecholaminergic polymorphic ventricular tachycardia. Before her diagnosis, she underwent atrioventricular nodal ablation in an effort to prevent ventricular arrhythmias, which was ultimately ineffective. This report highlights the importance of recognizing atrial arrhythmias in catecholaminergic polymorphic ventricular tachycardia and provides evidence that atrioventricular nodal ablation is not an effective treatment strategy for this disease.
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Affiliation(s)
- S Yukiko Asaki
- Division of Cardiology, Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
| | | | - Aarushi Nayak
- Division of Cardiology, Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
| | - Jeffrey J Kim
- Division of Cardiology, Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
| | - Christina Y Miyake
- Division of Cardiology, Department of Pediatrics, Texas Children's Hospital, Baylor College of Medicine, Houston, Texas
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas
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8
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Teles MC, Oliveira Portes AM, Campos Coelho BI, Resende LT, Isoldi MC. Cardiac changes in spontaneously hypertensive rats: Modulation by aerobic exercise. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2023; 177:109-124. [PMID: 36347337 DOI: 10.1016/j.pbiomolbio.2022.11.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/10/2022] [Accepted: 11/01/2022] [Indexed: 11/08/2022]
Abstract
Systemic arterial hypertension is a multifactorial clinical condition characterized by high and sustained levels of blood pressure. For a better understanding of the pathophysiology of hypertension, studies are conducted with spontaneously hypertensive animals, which allow the investigation of physiological changes that in most cases cannot be studied in humans. In these animals, myocardial remodeling, increased pro-inflammatory markers, redox imbalance and contractile dysfunctions that lead to changes in cardiac function can be observed. However, it can be inferring that aerobic training improves cardiac function and cardiomyocyte contractility, in addition to controlling inflammation and reducing oxidative stress in cardiac muscle, despite this, the precise mechanisms by which physical exercise improves cardiovascular control are not fully understood. In this review, we provide an overview of the pathophysiological changes that affect the heart of spontaneously hypertensive animals and their modulation by aerobic exercise.
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Affiliation(s)
- Maria Cecília Teles
- Laboratory of Cell Signaling, Department Pharmacy, Federal University of Ouro Preto, Ouro Preto, 35400-000, MG, Brazil.
| | | | - Bianca Iara Campos Coelho
- Laboratory of Cell Signaling, Department Nutrition, Federal University of Ouro Preto, Ouro Preto, 35400-000, MG, Brazil
| | - Letícia Teresinha Resende
- Laboratory of Cell Signaling, Department of General Biology, Federal University of Ouro Preto, Ouro Preto, 35400-000, MG, Brazil
| | - Mauro Cesar Isoldi
- Laboratory of Cell Signaling, Department of General Biology, Federal University of Ouro Preto, Ouro Preto, 35400-000, MG, Brazil
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9
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Giordanino EF. IMPROVING PATIENT SELECTION FOR CARDIAC RESYNCHRONIZATION THERAPY: THE ROLE OF PATHOPHYSIOLOGICAL BIOMARKERS. J Heart Lung Transplant 2022; 41:442-444. [DOI: 10.1016/j.healun.2022.01.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/08/2022] [Accepted: 01/12/2022] [Indexed: 11/30/2022] Open
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10
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Dynamic Regulation of Cysteine Oxidation and Phosphorylation in Myocardial Ischemia-Reperfusion Injury. Cells 2021; 10:cells10092388. [PMID: 34572037 PMCID: PMC8469016 DOI: 10.3390/cells10092388] [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] [Subscribe] [Scholar Register] [Received: 08/16/2021] [Revised: 09/06/2021] [Accepted: 09/07/2021] [Indexed: 02/02/2023] Open
Abstract
Myocardial ischemia-reperfusion (I/R) injury significantly alters heart function following infarct and increases the risk of heart failure. Many studies have sought to preserve irreplaceable myocardium, termed cardioprotection, but few, if any, treatments have yielded a substantial reduction in clinical I/R injury. More research is needed to fully understand the molecular pathways that govern cardioprotection. Redox mechanisms, specifically cysteine oxidations, are acute and key regulators of molecular signaling cascades mediated by kinases. Here, we review the role of reactive oxygen species in modifying cysteine residues and how these modifications affect kinase function to impact cardioprotection. This exciting area of research may provide novel insight into mechanisms and likely lead to new treatments for I/R injury.
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11
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Word TA, Quick AP, Miyake CY, Shak MK, Pan X, Kim JJ, Allen HD, Sibrian‐Vazquez M, Strongin RM, Landstrom AP, Wehrens XHT. Efficacy of RyR2 inhibitor EL20 in induced pluripotent stem cell-derived cardiomyocytes from a patient with catecholaminergic polymorphic ventricular tachycardia. J Cell Mol Med 2021; 25:6115-6124. [PMID: 34110090 PMCID: PMC8366453 DOI: 10.1111/jcmm.16521] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Revised: 03/19/2021] [Accepted: 03/24/2021] [Indexed: 02/04/2023] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited cardiac arrhythmia syndrome that often leads to sudden cardiac death. The most common form of CPVT is caused by autosomal-dominant variants in the cardiac ryanodine receptor type-2 (RYR2) gene. Mutations in RYR2 promote calcium (Ca2+ ) leak from the sarcoplasmic reticulum (SR), triggering lethal arrhythmias. Recently, it was demonstrated that tetracaine derivative EL20 specifically inhibits mutant RyR2, normalizes Ca2+ handling and suppresses arrhythmias in a CPVT mouse model. The objective of this study was to determine whether EL20 normalizes SR Ca2+ handling and arrhythmic events in induced pluripotent stem cell-derived cardiomyocytes (iPSC-CMs) from a CPVT patient. Blood samples from a child carrying RyR2 variant RyR2 variant Arg-176-Glu (R176Q) and a mutation-negative relative were reprogrammed into iPSCs using a Sendai virus system. iPSC-CMs were derived using the StemdiffTM kit. Confocal Ca2+ imaging was used to quantify RyR2 activity in the absence and presence of EL20. iPSC-CMs harbouring the R176Q variant demonstrated spontaneous SR Ca2+ release events, whereas administration of EL20 diminished these abnormal events at low nanomolar concentrations (IC50 = 82 nM). Importantly, treatment with EL20 did not have any adverse effects on systolic Ca2+ handling in control iPSC-CMs. Our results show for the first time that tetracaine derivative EL20 normalized SR Ca2+ handling and suppresses arrhythmogenic activity in iPSC-CMs derived from a CPVT patient. Hence, this study confirms that this RyR2-inhibitor represents a promising therapeutic candidate for treatment of CPVT.
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Affiliation(s)
- Tarah A. Word
- Department of Molecular Physiology & BiophysicsCardiovascular Research InstituteBaylor College of MedicineHoustonTXUSA
| | - Ann P. Quick
- Section of CardiologyDepartment of PediatricsBaylor College of MedicineHoustonTXUSA
| | - Christina Y. Miyake
- Department of Molecular Physiology & BiophysicsCardiovascular Research InstituteBaylor College of MedicineHoustonTXUSA
- Section of CardiologyDepartment of PediatricsBaylor College of MedicineHoustonTXUSA
| | - Mayra K. Shak
- Department of Molecular Physiology & BiophysicsCardiovascular Research InstituteBaylor College of MedicineHoustonTXUSA
| | - Xiaolu Pan
- Department of Molecular Physiology & BiophysicsCardiovascular Research InstituteBaylor College of MedicineHoustonTXUSA
| | - Jean J. Kim
- Department of Molecular & Cellular BiologyStem Cells and Regenerative Medicine CenterBaylor College of MedicineHoustonTXUSA
| | - Hugh D. Allen
- Department of Molecular & Cellular BiologyStem Cells and Regenerative Medicine CenterBaylor College of MedicineHoustonTXUSA
| | | | | | - Andrew P. Landstrom
- Department of PediatricsDivision of CardiologyDuke University School of MedicineDurhamNCUSA
- Department of Cell BiologyDuke University School of MedicineDurhamNCUSA
| | - Xander H. T. Wehrens
- Department of Molecular Physiology & BiophysicsCardiovascular Research InstituteBaylor College of MedicineHoustonTXUSA
- Section of CardiologyDepartment of PediatricsBaylor College of MedicineHoustonTXUSA
- Department of MedicineSection of CardiologyBaylor College of MedicineHoustonTXUSA
- Department of NeuroscienceSection of CardiologyBaylor College of MedicineHoustonTXUSA
- Center for Space MedicineBaylor College of MedicineHoustonTXUSA
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12
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Negri S, Faris P, Moccia F. Endolysosomal Ca 2+ signaling in cardiovascular health and disease. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2021; 363:203-269. [PMID: 34392930 DOI: 10.1016/bs.ircmb.2021.03.001] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
An increase in intracellular Ca2+ concentration ([Ca2+]i) regulates a plethora of functions in the cardiovascular (CV) system, including contraction in cardiomyocytes and vascular smooth muscle cells (VSMCs), and angiogenesis in vascular endothelial cells and endothelial colony forming cells. The sarco/endoplasmic reticulum (SR/ER) represents the largest endogenous Ca2+ store, which releases Ca2+ through ryanodine receptors (RyRs) and/or inositol-1,4,5-trisphosphate receptors (InsP3Rs) upon extracellular stimulation. The acidic vesicles of the endolysosomal (EL) compartment represent an additional endogenous Ca2+ store, which is targeted by several second messengers, including nicotinic acid adenine dinucleotide phosphate (NAADP) and phosphatidylinositol 3,5-bisphosphate [PI(3,5)P2], and may release intraluminal Ca2+ through multiple Ca2+ permeable channels, including two-pore channels 1 and 2 (TPC1-2) and Transient Receptor Potential Mucolipin 1 (TRPML1). Herein, we discuss the emerging, pathophysiological role of EL Ca2+ signaling in the CV system. We describe the role of cardiac TPCs in β-adrenoceptor stimulation, arrhythmia, hypertrophy, and ischemia-reperfusion injury. We then illustrate the role of EL Ca2+ signaling in VSMCs, where TPCs promote vasoconstriction and contribute to pulmonary artery hypertension and atherosclerosis, whereas TRPML1 sustains vasodilation and is also involved in atherosclerosis. Subsequently, we describe the mechanisms whereby endothelial TPCs promote vasodilation, contribute to neurovascular coupling in the brain and stimulate angiogenesis and vasculogenesis. Finally, we discuss about the possibility to target TPCs, which are likely to mediate CV cell infection by the Severe Acute Respiratory Disease-Coronavirus-2, with Food and Drug Administration-approved drugs to alleviate the detrimental effects of Coronavirus Disease-19 on the CV system.
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Affiliation(s)
- Sharon Negri
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Pawan Faris
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy
| | - Francesco Moccia
- Laboratory of Physiology, Department of Biology and Biotechnology "Lazzaro Spallanzani", University of Pavia, Pavia, Italy.
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13
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Mechanisms underlying pathological Ca 2+ handling in diseases of the heart. Pflugers Arch 2021; 473:331-347. [PMID: 33399957 PMCID: PMC10070045 DOI: 10.1007/s00424-020-02504-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Revised: 12/01/2020] [Accepted: 12/09/2020] [Indexed: 02/07/2023]
Abstract
Cardiomyocyte contraction relies on precisely regulated intracellular Ca2+ signaling through various Ca2+ channels and transporters. In this article, we will review the physiological regulation of Ca2+ handling and its role in maintaining normal cardiac rhythm and contractility. We discuss how inherited variants or acquired defects in Ca2+ channel subunits contribute to the development or progression of diseases of the heart. Moreover, we highlight recent insights into the role of protein phosphatase subunits and striated muscle preferentially expressed protein kinase (SPEG) in atrial fibrillation, heart failure, and cardiomyopathies. Finally, this review summarizes current drug therapies and new advances in genome editing as therapeutic strategies for the cardiac diseases caused by aberrant intracellular Ca2+ signaling.
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14
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The molecular mechanisms associated with the physiological responses to inflammation and oxidative stress in cardiovascular diseases. Biophys Rev 2020; 12:947-968. [PMID: 32691301 PMCID: PMC7429613 DOI: 10.1007/s12551-020-00742-0] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2020] [Accepted: 07/13/2020] [Indexed: 02/07/2023] Open
Abstract
The complex physiological signal transduction networks that respond to the dual challenges of inflammatory and oxidative stress are major factors that promote the development of cardiovascular pathologies. These signaling networks contribute to the development of age-related diseases, suggesting crosstalk between the development of aging and cardiovascular disease. Inhibition and/or attenuation of these signaling networks also delays the onset of disease. Therefore, a concept of targeting the signaling networks that are involved in inflammation and oxidative stress may represent a novel treatment paradigm for many types of heart disease. In this review, we discuss the molecular mechanisms associated with the physiological responses to inflammation and oxidative stress especially in heart failure with preserved ejection fraction and emphasize the nature of the crosstalk of these signaling processes as well as possible therapeutic implications for cardiovascular medicine.
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15
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Xie J, Yan X, Xu G, Tian X, Dong N, Feng J, Liu P, Li M, Zhao Y, Wei C, Lyu Y, Ma G, Song G, Wang T, Yan X. ITRAQ-based proteomics reveals the potential mechanism of fluoride-induced myocardial contraction function damage. ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2020; 197:110605. [PMID: 32311614 DOI: 10.1016/j.ecoenv.2020.110605] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Revised: 04/03/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
Fluorosis is a worldwide public health problem, and its adverse effects on the heart have been confirmed by many studies. Abnormal myocardial contractions are often associated with impairment of cardiac function as a cause or consequence. We designed two-part experiments to search for biomarkers and clarify the underlying molecular mechanism of fluoride on myocardial contraction. First, we used Pressure-volume Loop analysis to evaluate changes in myocardial function indexes with multiple fluoride exposure levels in mice (0, 30, 70, and 150 mg/L) exposed for 4 weeks. The results showed that fluoride exposure affects the heart pump function and reduces cardiac contractility. Then, we established a rat model of fluoride exposure (0, 30, 60, and 90 mg/L) for 6 months to carry out proteomic analysis of fluoride-induced myocardial contractile injury. Hematoxylin-eosin (H&E) staining was used to determine the severity of myocardial injury, and myocardial tissue samples were submitted for isobaric tags for relative and absolute quantitation (ITRAQ) analysis. A total of 1607 proteins were successfully identified with 294 differentially expressed proteins (DEPs) in fluoride treated groups. According to Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analysis, 12 DEPs were confirmed to be involved in pathways related to myocardial contraction. Furthermore, we constructed a protein-protein interaction (PPI) network for these 12 core DEPs to illustrate the role and location of each DEP in the myocardial contraction pathway. The results of this study are helpful for identify a potential mechanism and biomarkers of fluoride-induced myocardial contraction function damage, moreover, which can provide a new insight into the heart toxicity of fluoride in animals at the proteomics level.
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Affiliation(s)
- Jiaxin Xie
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Xiaoting Yan
- Department of Urology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Guoqiang Xu
- Shanxi Key Laboratory of Experimental Animal and Human Disease Animal Models, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Xiaolin Tian
- Shanxi Key Laboratory of Ecological Animal Science and Environmental Veterinary Medicine, Shanxi Agricultural University, Taigu, Shanxi, 030801, China; School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Nisha Dong
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Jing Feng
- Shanxi Key Laboratory of Experimental Animal and Human Disease Animal Models, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Penghui Liu
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Meng Li
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Yannan Zhao
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Cailing Wei
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Yi Lyu
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Guijin Ma
- Department of Cardiology, The First Hospital of Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Guohua Song
- Shanxi Key Laboratory of Experimental Animal and Human Disease Animal Models, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Tong Wang
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China
| | - Xiaoyan Yan
- School of Public Health, Shanxi Medical University, Taiyuan, Shanxi, 030001, China.
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16
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Kushnir A, Santulli G, Reiken SR, Coromilas E, Godfrey SJ, Brunjes DL, Colombo PC, Yuzefpolskaya M, Sokol SI, Kitsis RN, Marks AR. Ryanodine Receptor Calcium Leak in Circulating B-Lymphocytes as a Biomarker in Heart Failure. Circulation 2019; 138:1144-1154. [PMID: 29593014 DOI: 10.1161/circulationaha.117.032703] [Citation(s) in RCA: 32] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
BACKGROUND Advances in congestive heart failure (CHF) management depend on biomarkers for monitoring disease progression and therapeutic response. During systole, intracellular Ca2+ is released from the sarcoplasmic reticulum into the cytoplasm through type-2 ryanodine receptor/Ca2+ release channels. In CHF, chronically elevated circulating catecholamine levels cause pathological remodeling of type-2 ryanodine receptor/Ca2+ release channels resulting in diastolic sarcoplasmic reticulum Ca2+ leak and decreased myocardial contractility. Similarly, skeletal muscle contraction requires sarcoplasmic reticulum Ca2+ release through type-1 ryanodine receptors (RyR1), and chronically elevated catecholamine levels in CHF cause RyR1-mediated sarcoplasmic reticulum Ca2+ leak, contributing to myopathy and weakness. Circulating B-lymphocytes express RyR1 and catecholamine-responsive signaling cascades, making them a potential surrogate for defects in intracellular Ca2+ handling because of leaky RyR channels in CHF. METHODS Whole blood was collected from patients with CHF, CHF following left-ventricular assist device implant, and controls. Blood was also collected from mice with ischemic CHF, ischemic CHF+S107 (a drug that specifically reduces RyR channel Ca2+ leak), and wild-type controls. Channel macromolecular complex was assessed by immunostaining RyR1 immunoprecipitated from lymphocyte-enriched preparations. RyR1 Ca2+ leak was assessed using flow cytometry to measure Ca2+ fluorescence in B-lymphocytes in the absence and presence of RyR1 agonists that empty RyR1 Ca2+ stores within the endoplasmic reticulum. RESULTS Circulating B-lymphocytes from humans and mice with CHF exhibited remodeled RyR1 and decreased endoplasmic reticulum Ca2+ stores, consistent with chronic intracellular Ca2+ leak. This Ca2+ leak correlated with circulating catecholamine levels. The intracellular Ca2+ leak was significantly reduced in mice treated with the Rycal S107. Patients with CHF treated with left-ventricular assist devices exhibited a heterogeneous response. CONCLUSIONS In CHF, B-lymphocytes exhibit remodeled leaky RyR1 channels and decreased endoplasmic reticulum Ca2+ stores consistent with chronic intracellular Ca2+ leak. RyR1-mediated Ca2+ leak in B-lymphocytes assessed using flow cytometry provides a surrogate measure of intracellular Ca2+ handling and systemic sympathetic burden, presenting a novel biomarker for monitoring response to pharmacological and mechanical CHF therapy.
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Affiliation(s)
- Alexander Kushnir
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.).,Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Gaetano Santulli
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.)
| | - Steven R Reiken
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.)
| | - Ellie Coromilas
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Sarah J Godfrey
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Danielle L Brunjes
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Paolo C Colombo
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Melana Yuzefpolskaya
- Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
| | - Seth I Sokol
- Department of Medicine, Division of Cardiology, Jacobi Medical Center, Bronx, NY (S.I.S.)
| | - Richard N Kitsis
- Departments of Medicine and Cell Biology, Wilf Family Cardiovascular Research Institute, Albert Einstein Cancer Center, Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY (R.N.K.)
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York (A.K., G.S., S.R.R., A.R.M.).,Department of Medicine, Division of Cardiology, Columbia University Medical Center, New York (A.K., E.C., S.J.G., D.L.B., P.C.C., M.Y., A.R.M.)
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17
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Ivarsson N, Mattsson CM, Cheng AJ, Bruton JD, Ekblom B, Lanner JT, Westerblad H. SR Ca 2+ leak in skeletal muscle fibers acts as an intracellular signal to increase fatigue resistance. J Gen Physiol 2019; 151:567-577. [PMID: 30635368 PMCID: PMC6445590 DOI: 10.1085/jgp.201812152] [Citation(s) in RCA: 31] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2018] [Accepted: 11/16/2018] [Indexed: 01/14/2023] Open
Abstract
Skeletal muscle oxidative capacity and fatigue resistance can be improved with endurance training, but the mechanism is not fully understood. Ivarsson et al. find that the signaling pathway that increases fatigue resistance in muscle is triggered by a mild Ca2+ leak from the sarcoplasmic reticulum. Effective practices to improve skeletal muscle fatigue resistance are crucial for athletes as well as patients with dysfunctional muscles. To this end, it is important to identify the cellular signaling pathway that triggers mitochondrial biogenesis and thereby increases oxidative capacity and fatigue resistance in skeletal muscle fibers. Here, we test the hypothesis that the stress induced in skeletal muscle fibers by endurance exercise causes a reduction in the association of FK506-binding protein 12 (FKBP12) with ryanodine receptor 1 (RYR1). This will result in a mild Ca2+ leak from the sarcoplasmic reticulum (SR), which could trigger mitochondrial biogenesis and improved fatigue resistance. After giving mice access to an in-cage running wheel for three weeks, we observed decreased FKBP12 association to RYR1, increased baseline [Ca2+]i, and signaling associated with greater mitochondrial biogenesis in muscle, including PGC1α1. After six weeks of voluntary running, FKBP12 association is normalized, baseline [Ca2+]i returned to values below that of nonrunning controls, and signaling for increased mitochondrial biogenesis was no longer present. The adaptations toward improved endurance exercise performance that were observed with training could be mimicked by pharmacological agents that destabilize RYR1 and thereby induce a modest Ca2+ leak. We conclude that a mild RYR1 SR Ca2+ leak is a key trigger for the signaling pathway that increases muscle fatigue resistance.
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Affiliation(s)
- Niklas Ivarsson
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Stockholm, Sweden
| | - C Mikael Mattsson
- Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Arthur J Cheng
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Stockholm, Sweden
| | - Joseph D Bruton
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Stockholm, Sweden
| | - Björn Ekblom
- Åstrand Laboratory of Work Physiology, The Swedish School of Sport and Health Sciences, Stockholm, Sweden
| | - Johanna T Lanner
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Stockholm, Sweden
| | - Håkan Westerblad
- Department of Physiology and Pharmacology, Biomedicum C5, Karolinska Institutet, Stockholm, Sweden
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18
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Blaychfeld‐Magnazi M, Knobler H, Voet H, Reshef N, Weitzman S, Sumner AE, Zornitzki T. Ethnic Variation in the Association of Hypertension With Type 2 Diabetes. J Clin Hypertens (Greenwich) 2017; 19:184-189. [PMID: 27481649 PMCID: PMC5290254 DOI: 10.1111/jch.12883] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2016] [Revised: 06/02/2016] [Accepted: 06/09/2016] [Indexed: 11/28/2022]
Abstract
Lifestyle changes occurring with urbanization increase the prevalence of both type 2 diabetes mellitus (T2DM) and hypertension (HTN). Yemenites who have immigrated to Israel have demonstrated a dramatic increase in T2DM but the prevalence of HTN in diabetic Yemenites is unclear. In a cross-sectional study, the authors evaluated the prevalence of HTN and lifestyle patterns in Israelis with T2DM of Yemenite (Y-DM) and non-Yemenite (NY-DM) origin. Y-DM (n=63) and NY-DM (n=120) had similar age (63±7 vs 64±7 years, P=.5), diabetes duration, diet adherence, and exercise patterns. Y-DM had a lower prevalence of HTN (63%) than NY-DM (83%) (P<.01). Furthermore, Yemenite origin was independently associated with lower prevalence of HTN (odds ratio, 0.3; 95% confidence interval, 0.12-0.71). Blood pressure was well controlled with fewer antihypertensive medications in Y-DM than NY-DM (P<.01). Even though lifestyle patterns were similar in the two groups, Y-DM had a lower prevalence of HTN compared with NY-DM and required fewer antihypertensive medications.
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Affiliation(s)
- Moran Blaychfeld‐Magnazi
- Diabetes, Endocrinology and Metabolic Disease InstituteKaplan Medical CenterHebrew University Medical School of JerusalemRehovotIsrael
- Institute of Biochemistry Food Science and NutritionRobert H. Smith Faculty of Agriculture, Food and EnvironmentHebrew University of JerusalemRehovotIsrael
| | - Hilla Knobler
- Diabetes, Endocrinology and Metabolic Disease InstituteKaplan Medical CenterHebrew University Medical School of JerusalemRehovotIsrael
| | - Hillary Voet
- Department of Environmental Economics and ManagementRobert H. Smith Faculty of Agriculture, Food and EnvironmentHebrew University of JerusalemRehovotIsrael
| | - Naama Reshef
- Diabetes, Endocrinology and Metabolic Disease InstituteKaplan Medical CenterHebrew University Medical School of JerusalemRehovotIsrael
| | - Shimon Weitzman
- Department of EpidemiologyBen‐Gurion University of the NegevBeer‐ShevaIsrael
| | - Anne E. Sumner
- National Institute of Diabetes, Digestive and Kidney Diseases and the National Institute of Minority Health and Health DisparitiesNational Institutes of HealthBethesdaMD
| | - Taiba Zornitzki
- Diabetes, Endocrinology and Metabolic Disease InstituteKaplan Medical CenterHebrew University Medical School of JerusalemRehovotIsrael
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19
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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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20
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Afanasiev SA, Kondratieva DS, Rebrova TY, Batalov RE, Popov SV. Coupling of the Functional Stability of Rat Myocardium and Activity of Lipid Peroxidation in Combined Development of Postinfarction Remodeling and Diabetes Mellitus. J Diabetes Res 2016; 2016:2548689. [PMID: 26844230 PMCID: PMC4710906 DOI: 10.1155/2016/2548689] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 09/28/2015] [Accepted: 10/21/2015] [Indexed: 11/18/2022] Open
Abstract
Coupling of the functional stability of rat myocardium and activity of lipid peroxidation processes in combined development of postinfarction remodeling and diabetes mellitus has been studied. The functional stability of myocardium was studied by means of the analysis of inotropic reaction on extrasystolic stimulus, the degree of left ventricular hypertrophy, and the size of scar zone. It was shown that in combined development of postinfarction cardiac remodeling of heart (PICR) with diabetes mellitus (DM) animal body weight decreased in less degree than in diabetic rats. Animals with combined pathology had no heart hypertrophy. The amplitude of extrasystolic contractions in rats with PICR combined with DM had no differences compared to the control group. In myocardium of rats with PICR combined with DM postextrasystolic potentiation was observed in contrast with the rats with PICR alone. The rats with combined pathology had the decreased value of TBA-active products. Thus, the results of study showed that induction of DM on the stage of the development of postinfarction remodeling increases adaptive ability of myocardium. It is manifested in inhibition of increase of LPO processes activity and maintaining of force-interval reactions of myocardium connected with calcium transport systems of sarcoplasmic reticulum of cardiomyocytes.
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Affiliation(s)
- S. A. Afanasiev
- Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, 111a Kievskaya Street, Tomsk 634012, Russia
| | - D. S. Kondratieva
- Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, 111a Kievskaya Street, Tomsk 634012, Russia
- *D. S. Kondratieva:
| | - T. Yu. Rebrova
- Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, 111a Kievskaya Street, Tomsk 634012, Russia
| | - R. E. Batalov
- Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, 111a Kievskaya Street, Tomsk 634012, Russia
| | - S. V. Popov
- Federal State Budgetary Scientific Institution “Research Institute for Cardiology”, 111a Kievskaya Street, Tomsk 634012, Russia
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21
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Carneiro-Júnior MA, Quintão-Júnior JF, Drummond LR, Lavorato VN, Drummond FR, Amadeu MA, Oliveira EM, Felix LB, Cruz JS, Mill JG, Natali AJ, Prímola-Gomes TN. Effect of exercise training on Ca²⁺ release units of left ventricular myocytes of spontaneously hypertensive rats. ACTA ACUST UNITED AC 2014. [PMID: 25296357 PMCID: PMC4230285 DOI: 10.1590/1414-431x20144063] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
In cardiomyocytes, calcium (Ca2+) release units comprise clusters of
intracellular Ca2+ release channels located on the sarcoplasmic reticulum,
and hypertension is well established as a cause of defects in calcium release unit
function. Our objective was to determine whether endurance exercise training could
attenuate the deleterious effects of hypertension on calcium release unit components
and Ca2+ sparks in left ventricular myocytes of spontaneously hypertensive
rats. Male Wistar and spontaneously hypertensive rats (4 months of age) were divided
into 4 groups: normotensive (NC) and hypertensive control (HC), and normotensive (NT)
and hypertensive trained (HT) animals (7 rats per group). NC and HC rats were
submitted to a low-intensity treadmill running protocol (5 days/week, 1 h/day, 0%
grade, and 50-60% of maximal running speed) for 8 weeks. Gene expression of the
ryanodine receptor type 2 (RyR2) and
FK506 binding protein (FKBP12.6) increased
(270%) and decreased (88%), respectively, in HC compared to NC rats. Endurance
exercise training reversed these changes by reducing RyR2 (230%) and
normalizing FKBP12.6 gene expression (112%). Hypertension also
increased the frequency of Ca2+ sparks (HC=7.61±0.26 vs
NC=4.79±0.19 per 100 µm/s) and decreased its amplitude (HC=0.260±0.08
vs NC=0.324±0.10 ΔF/F0), full width at half-maximum
amplitude (HC=1.05±0.08 vs NC=1.26±0.01 µm), total duration
(HC=11.51±0.12 vs NC=14.97±0.24 ms), time to peak (HC=4.84±0.06
vs NC=6.31±0.14 ms), and time constant of decay (HC=8.68±0.12
vs NC=10.21±0.22 ms). These changes were partially reversed in HT
rats (frequency of Ca2+ sparks=6.26±0.19 µm/s, amplitude=0.282±0.10
ΔF/F0, full width at half-maximum amplitude=1.14±0.01 µm, total
duration=13.34±0.17 ms, time to peak=5.43±0.08 ms, and time constant of
decay=9.43±0.15 ms). Endurance exercise training attenuated the deleterious effects
of hypertension on calcium release units of left ventricular myocytes.
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Affiliation(s)
- M A Carneiro-Júnior
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, Brasil
| | - J F Quintão-Júnior
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - L R Drummond
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - V N Lavorato
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - F R Drummond
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - M A Amadeu
- Laboratório de Bioquímica e Biologia Molecular do Exercício, Escola de Educação Física e Esportes, Universidade de São Paulo, São Paulo, SP, Brasil
| | - E M Oliveira
- Laboratório de Bioquímica e Biologia Molecular do Exercício, Escola de Educação Física e Esportes, Universidade de São Paulo, São Paulo, SP, Brasil
| | - L B Felix
- Departamento de Engenharia Elétrica, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - J S Cruz
- Laboratório de Membranas Excitáveis e Biologia Cardiovascular, Departamento de Bioquímica e Imunologia, Universidade Federal de Minas Gerais, Belo Horizonte, MG, Brasil
| | - J G Mill
- Departamento de Ciências Fisiológicas, Universidade Federal do Espírito Santo, Vitória, ES, Brasil
| | - A J Natali
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
| | - T N Prímola-Gomes
- Laboratório de Biologia do Exercício, Departamento de Educação Física, Universidade Federal de Viçosa, Viçosa, MG, Brasil
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22
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Tian C, Alomar F, Moore CJ, Shao CH, Kutty S, Singh J, Bidasee KR. Reactive carbonyl species and their roles in sarcoplasmic reticulum Ca2+ cycling defect in the diabetic heart. Heart Fail Rev 2014; 19:101-12. [PMID: 23430128 PMCID: PMC4732283 DOI: 10.1007/s10741-013-9384-9] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Efficient and rhythmic cardiac contractions depend critically on the adequate and synchronized release of Ca(2+) from the sarcoplasmic reticulum (SR) via ryanodine receptor Ca(2+) release channels (RyR2) and its reuptake via sarco(endo)plasmic reticulum Ca(2+)-ATPase (SERCA2a). It is well established that this orchestrated process becomes compromised in diabetes. What remain incompletely defined are the molecular mechanisms responsible for the dysregulation of RyR2 and SERCA2a in diabetes. Earlier, we found elevated levels of carbonyl adducts on RyR2 and SERCA2a isolated from hearts of type 1 diabetic rats and showed the presence of these posttranslational modifications compromised their functions. We also showed that these mono- and di-carbonyl reactive carbonyl species (RCS) do not indiscriminately react with all basic amino acid residues on RyR2 and SERCA2a; some residues are more susceptible to carbonylation (modification by RCS) than others. A key unresolved question in the field is which of the many RCS that are upregulated in the heart in diabetes chemically react with RyR2 and SERCA2a? This brief review introduces readers to the field of RCS and their roles in perturbing SR Ca(2+) cycling in diabetes. It also provides new experimental evidence that not all RCS that are upregulated in the heart in diabetes chemically react with RyR2 and SERCA2a, methylglyoxal and glyoxal preferentially do.
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Affiliation(s)
- Chengju Tian
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Fadhel Alomar
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
- Department of Pharmacology, University of Dammam, Kingdom of Saudi Arabia
| | - Caronda J Moore
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Chun Hong Shao
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
| | - Shelby Kutty
- Joint Division of Pediatric Cardiology, University of Nebraska/Creighton University and Children's Hospital and Medical Center, Omaha, Nebraska
| | - Jaipaul Singh
- School of Forensic and Investigative Sciences and School of Pharmacy and Biomedical Sciences, University of Central Lancashire, Preston, UK
| | - Keshore R. Bidasee
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, NE 68198
- Department of Environmental, Agricultural and Occupational Health, University of Nebraska Medical Center, Omaha, NE 68198
- Nebraska Center for Redox Biology, N146 Beadle Center, Lincoln NE 68588-0662
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23
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Bombardier E, Smith IC, Gamu D, Fajardo VA, Vigna C, Sayer RA, Gupta SC, Bal NC, Periasamy M, Tupling AR. Sarcolipin trumps β-adrenergic receptor signaling as the favored mechanism for muscle-based diet-induced thermogenesis. FASEB J 2013; 27:3871-8. [PMID: 23752204 DOI: 10.1096/fj.13-230631] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Sarcolipin (SLN) regulates muscle-based nonshivering thermogenesis and is up-regulated with high-fat feeding (HFF). To investigate whether other muscle-based thermogenic systems compensate for a lack of Sln and to firmly establish SLN as a mediator of diet-induced thermogenesis (DIT), we measured muscle and whole-body energy expenditure in chow- and high-fat-fed Sln(-/-) and wild-type (WT) mice. Following HFF, resting muscle metabolic rate (VO2, μl/g/s) was increased similarly in WT (0.28±0.02 vs. 0.31±0.03) and Sln(-/-) (0.23±0.03 vs. 0.35±0.02) mice due to increased sympathetic nervous system activation in Sln(-/-) mice; however, whole-body metabolic rate (VO2, ml/kg/h) was lower in Sln(-/-) compared with WT mice following HFF but only during periods when the mice were active in their cages (WT, 2894±87 vs. Sln(-/-), 2708±61). Treatment with the β-adrenergic receptor (β-AR) antagonist propranolol during HFF completely prevented muscle-based DIT in Sln(-/-) mice; however, it had no effect in WT mice, resulting in greater differences in whole-body metabolic rate and diet-induced weight gain. Our results suggest that β-AR signaling partially compensates for a lack of SLN to activate muscle-based DIT, but SLN is the primary and more effective mediator.
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Affiliation(s)
- Eric Bombardier
- University of Waterloo, Department of Kinesiology, 200 University Ave. W., ON, Canada N2L 3G1
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Liu X, Betzenhauser MJ, Reiken S, Meli AC, Xie W, Chen BX, Arancio O, Marks AR. Role of leaky neuronal ryanodine receptors in stress-induced cognitive dysfunction. Cell 2012; 150:1055-67. [PMID: 22939628 DOI: 10.1016/j.cell.2012.06.052] [Citation(s) in RCA: 114] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2011] [Revised: 06/01/2012] [Accepted: 06/29/2012] [Indexed: 12/13/2022]
Abstract
The type 2 ryanodine receptor/calcium release channel (RyR2), required for excitation-contraction coupling in the heart, is abundant in the brain. Chronic stress induces catecholamine biosynthesis and release, stimulating β-adrenergic receptors and activating cAMP signaling pathways in neurons. In a murine chronic restraint stress model, neuronal RyR2 were phosphorylated by protein kinase A (PKA), oxidized, and nitrosylated, resulting in depletion of the stabilizing subunit calstabin2 (FKBP12.6) from the channel complex and intracellular calcium leak. Stress-induced cognitive dysfunction, including deficits in learning and memory, and reduced long-term potentiation (LTP) at the hippocampal CA3-CA1 connection were rescued by oral administration of S107, a compound developed in our laboratory that stabilizes RyR2-calstabin2 interaction, or by genetic ablation of the RyR2 PKA phosphorylation site at serine 2808. Thus, neuronal RyR2 remodeling contributes to stress-induced cognitive dysfunction. Leaky RyR2 could be a therapeutic target for treatment of stress-induced cognitive dysfunction.
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Affiliation(s)
- Xiaoping Liu
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA
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Ryanodine receptor phosphorylation, calcium/calmodulin-dependent protein kinase II, and life-threatening ventricular arrhythmias. Trends Cardiovasc Med 2012; 21:48-51. [PMID: 22578240 DOI: 10.1016/j.tcm.2012.02.004] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Ryanodine receptor (RyR2) dysfunction, which may result from a variety of mechanisms, has been implicated in the pathogenesis of cardiac arrhythmias and heart failure. In this review, we discuss the important role of Ca(2+)/calmodulin-dependent protein kinase II (CaMKII) in the regulation of RyR2-mediated Ca(2+) release. In particular, we examine how pathological activation of CaMKII can lead to an increased risk of sudden arrhythmic death. Finally, we discuss how reduction of CaMKII-mediated RyR2 hyperactivity might reduce the risk of arrhythmias and may serve as a rationale for future pharmacotherapeutic approaches.
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Niggli E, Ullrich ND, Gutierrez D, Kyrychenko S, Poláková E, Shirokova N. Posttranslational modifications of cardiac ryanodine receptors: Ca(2+) signaling and EC-coupling. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2012; 1833:866-75. [PMID: 22960642 DOI: 10.1016/j.bbamcr.2012.08.016] [Citation(s) in RCA: 65] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/09/2012] [Revised: 08/18/2012] [Accepted: 08/22/2012] [Indexed: 10/27/2022]
Abstract
In cardiac muscle, a number of posttranslational protein modifications can alter the function of the Ca(2+) release channel of the sarcoplasmic reticulum (SR), also known as the ryanodine receptor (RyR). During every heartbeat RyRs are activated by the Ca(2+)-induced Ca(2+) release mechanism and contribute a large fraction of the Ca(2+) required for contraction. Some of the posttranslational modifications of the RyR are known to affect its gating and Ca(2+) sensitivity. Presently, research in a number of laboratories is focused on RyR phosphorylation, both by PKA and CaMKII, or on RyR modifications caused by reactive oxygen and nitrogen species (ROS/RNS). Both classes of posttranslational modifications are thought to play important roles in the physiological regulation of channel activity, but are also known to provoke abnormal alterations during various diseases. Only recently it was realized that several types of posttranslational modifications are tightly connected and form synergistic (or antagonistic) feed-back loops resulting in additive and potentially detrimental downstream effects. This review summarizes recent findings on such posttranslational modifications, attempts to bridge molecular with cellular findings, and opens a perspective for future work trying to understand the ramifications of crosstalk in these multiple signaling pathways. Clarifying these complex interactions will be important in the development of novel therapeutic approaches, since this may form the foundation for the implementation of multi-pronged treatment regimes in the future. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Cardiac Pathways of Differentiation, Metabolism and Contraction.
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Affiliation(s)
- Ernst Niggli
- Department of Physiology, University of Bern, Bern, Switzerland.
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Novak A, Barad L, Lorber A, Itskovitz-Eldor J, Binah O. Modeling Catecholaminergic Polymorphic Ventricular Tachycardia using Induced Pluripotent Stem Cell-derived Cardiomyocytes. Rambam Maimonides Med J 2012; 3:e0015. [PMID: 23908839 PMCID: PMC3678817 DOI: 10.5041/rmmj.10086] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is an inherited arrhythmogenic cardiac disorder characterized by life-threatening arrhythmias induced by physical or emotional stress, in the absence structural heart abnormalities. The arrhythmias may cause syncope or degenerate into cardiac arrest and sudden death which usually occurs during childhood. Recent studies have shown that CPVT is caused by mutations in the cardiac ryanodine receptor type 2 (RyR2) or calsequestrin 2 (CASQ2) genes. Both proteins are key contributors to the intracellular Ca(2+) handling process and play a pivotal role in Ca(2+) release from the sarcoplasmic reticulum to the cytosol during systole. Although the molecular pathogenesis of CPVT is not entirely clear, it was suggested that the CPVT mutations promote excessive sarcoplasmic reticulum Ca(2+) leak, which initiates delayed afterdepolarizations (DADs) and triggered arrhythmias in cardiac myocytes. The recent breakthrough discovery of induced pluripotent stem cells (iPSC) generated from somatic cells (e.g. fibroblasts, keratinocytes) now enables researches to investigate mutated cardiomyocytes generated from the patient's iPSC. To this end, in the present article we review recent studies on CPVT iPSC-derived cardiomyocytes, thus demonstrating in the mutated cells catecholamine-induced DADs and triggered arrhythmias.
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Affiliation(s)
- Atara Novak
- The Sohnis Family Stem Cells Center, Technion - Israel Institute of Technology, Haifa, Israel
- The Rappaport Family Institute for Research in the Medical Sciences, Technion - Israel Institute of Technology, Haifa, Israel
- Ruth & Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Lili Barad
- The Sohnis Family Stem Cells Center, Technion - Israel Institute of Technology, Haifa, Israel
- The Rappaport Family Institute for Research in the Medical Sciences, Technion - Israel Institute of Technology, Haifa, Israel
- Ruth & Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Avraham Lorber
- Ruth & Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
- Department of Pediatric Cardiology, Rambam Health Care Campus, Haifa, Israel; and
| | - Joseph Itskovitz-Eldor
- The Sohnis Family Stem Cells Center, Technion - Israel Institute of Technology, Haifa, Israel
- Ruth & Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
- Department of Obstetrics and Gynecology, Rambam Health Care Campus, Haifa, Israel
| | - Ofer Binah
- The Sohnis Family Stem Cells Center, Technion - Israel Institute of Technology, Haifa, Israel
- The Rappaport Family Institute for Research in the Medical Sciences, Technion - Israel Institute of Technology, Haifa, Israel
- Ruth & Bruce Rappaport Faculty of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
- To whom correspondence should be addressed., E-mail:
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Vandenberg JI, Perry MD, Perrin MJ, Mann SA, Ke Y, Hill AP. hERG K+ Channels: Structure, Function, and Clinical Significance. Physiol Rev 2012; 92:1393-478. [DOI: 10.1152/physrev.00036.2011] [Citation(s) in RCA: 463] [Impact Index Per Article: 38.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The human ether-a-go-go related gene (hERG) encodes the pore-forming subunit of the rapid component of the delayed rectifier K+ channel, Kv11.1, which are expressed in the heart, various brain regions, smooth muscle cells, endocrine cells, and a wide range of tumor cell lines. However, it is the role that Kv11.1 channels play in the heart that has been best characterized, for two main reasons. First, it is the gene product involved in chromosome 7-associated long QT syndrome (LQTS), an inherited disorder associated with a markedly increased risk of ventricular arrhythmias and sudden cardiac death. Second, blockade of Kv11.1, by a wide range of prescription medications, causes drug-induced QT prolongation with an increase in risk of sudden cardiac arrest. In the first part of this review, the properties of Kv11.1 channels, including biogenesis, trafficking, gating, and pharmacology are discussed, while the second part focuses on the pathophysiology of Kv11.1 channels.
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Affiliation(s)
- Jamie I. Vandenberg
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Matthew D. Perry
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Mark J. Perrin
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Stefan A. Mann
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Ying Ke
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
| | - Adam P. Hill
- Mark Cowley Lidwill Research Programme in Cardiac Electrophysiology, Victor Chang Cardiac Research Institute, Sydney, New South Wales, Australia; St Vincent's Clinical School, University of New South Wales, New South Wales, Australia; and University of Ottawa Heart Institute, Ottawa, Canada
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Abstract
RATIONALE In cardiac muscle, Ca(2+)-induced Ca(2+) release (CICR) from the sarcoplasmic reticulum (SR) is mediated by ryanodine receptor (RyR) Ca(2+) release channels. The inherent positive feedback of CICR is normally well-controlled. Understanding this control mechanism is a priority because its malfunction has life-threatening consequences. OBJECTIVE We show that CICR local control is governed by SR Ca(2+) load, largely because load determines the single RyR current amplitude that drives inter-RyR CICR. METHODS AND RESULTS We differentially manipulated single RyR Ca(2+) flux amplitude and SR Ca(2+) load in permeabilized ventricular myocytes as an endogenous cell biology model of the heart. Large RyR-permeable organic cations were used to interfere with Ca(2+) conductance through the open RyR pore. Single-channel studies show this attenuates current amplitude without altering other aspects of RyR function. In cells, the same experimental maneuver increased resting SR Ca(2+) load. Despite the increased load, Ca(2+) spark (inter-RyR CICR events) frequency decreased and sparks terminated earlier. CONCLUSIONS Spark local control follows single RyR current amplitude, not simply SR Ca(2+) load. Spark frequency increases with load because spontaneous RyR openings at high loads produce larger currents (ie, a larger CICR trigger signal). Sparks terminate when load falls to the point at which single RyR current amplitude is no longer sufficient to sustain inter-RyR CICR. Thus, RyRs that spontaneously close no longer reopen and local Ca(2+) release ends.
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Affiliation(s)
- Tao Guo
- Department of Molecular Biophysics and Physiology, Section of Cellular Signaling, Rush University Medical Center, Chicago, IL 60112, USA
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Abstract
Metabolic syndrome is characterized by a combination of obesity, hypertension, insulin resistance, dyslipidemia, and impaired glucose tolerance. This multifaceted syndrome is often accompanied by a hyperdynamic circulatory state characterized by increased blood pressure, total blood volume, cardiac output, and metabolic tissue demand. Experimental, epidemiological, and clinical studies have demonstrated that patients with metabolic syndrome have significantly elevated cardiovascular morbidity and mortality rates. One of the main and frequent complications seen in metabolic syndrome is cardiovascular disease. The primary endpoints of cardiometabolic risk are coronary and peripheral arterial disease, myocardial infarction, congestive heart failure, arrhythmia, and stroke. Alterations in expression and/or functioning of several key proteins involved in regulating and maintaining ionic homeostasis can cause cardiac disturbances. One such group of proteins is known as ryanodine receptors (intracellular calcium release channels), which are the major channels through which Ca(2+) ions leave the sarcoplasmic reticulum, leading to cardiac muscle contraction. The economic cost of metabolic syndrome and its associated complications has a significant effect on health care budgets. Improvements in body weight, blood lipid profile, and hyperglycemia can reduce cardiometabolic risk. However, constant hyperadrenergic stimulation still contributes to the burden of disease. Normalization of the hyperdynamic circulatory state with conventional therapies is the most reasonable therapeutic strategy to date. JTV519 (K201) is a newly developed 1,4-benzothiazepine drug with antiarrhythmic and cardioprotective properties. It appears to be very effective in not only preventing but also in reversing the characteristic myocardial changes and preventing lethal arrhythmias. It is also a unique candidate to improve diastolic heart failure in metabolic syndrome.
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Affiliation(s)
- U Deniz Dincer
- Department of Pharmacology, Ufuk University School of Medicine. Mevlana Bulvari, Balgat, Ankara, Turkey
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Ullrich ND, Valdivia HH, Niggli E. PKA phosphorylation of cardiac ryanodine receptor modulates SR luminal Ca2+ sensitivity. J Mol Cell Cardiol 2012; 53:33-42. [PMID: 22487381 DOI: 10.1016/j.yjmcc.2012.03.015] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2011] [Revised: 03/21/2012] [Accepted: 03/23/2012] [Indexed: 11/26/2022]
Abstract
During physical exercise and stress, the sympathetic system stimulates cardiac contractility via β-adrenergic receptor activation, resulting in protein kinase A (PKA)-mediated phosphorylation of the cardiac ryanodine receptor, RyR2, at Ser2808. Hyperphosphorylation of RyR2-S2808 has been proposed as a mechanism contributing to arrhythmogenesis and heart failure. However, the role of RyR2 phosphorylation during β-adrenergic stimulation remains controversial. We examined the contribution of RyR2-S2808 phosphorylation to altered excitation-contraction coupling and Ca(2+) signaling using an experimental approach at the interface of molecular and cellular levels and a transgenic mouse with ablation of the RyR2-S2808 phosphorylation site (RyR2-S2808A). Experimentally challenging the communication between L-type Ca(2+) channels and RyR2 led to a spatiotemporal de-synchronization of RyR2 openings, as visualized using confocal Ca(2+) imaging. β-Adrenergic stimulation re-synchronized RyR2s, but less efficiently in RyR2-S2808A than in control cardiomyocytes, as indicated by comprehensive analysis of RyR2 activation. In addition, spontaneous Ca(2+) waves in RyR2-S2808A myocytes showed significantly slowed propagation and complete absence of acceleration during β-adrenergic stress, unlike wild type cells. Single channel recordings revealed an attenuation of luminal Ca(2+) sensitivity in RyR2-S2808A channels upon addition of PKA. This suggests that phosphorylation of RyR2-S2808 may be involved in RyR2 modulation by luminal (intra-SR) Ca(2+) ([Ca(2+)](SR)). We show here by three independent experimental approaches that PKA-dependent RyR2-S2808 phosphorylation plays significant functional roles at the subcellular level, namely, Ca(2+) release synchronization, Ca(2+) wave propagation and functional adaptation of RyR2 to variable [Ca(2+)](SR). These results indicate a direct mechanistic link between RyR2 phosphorylation and SR luminal Ca(2+) sensing.
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Affiliation(s)
- Nina D Ullrich
- Department of Physiology, University of Bern, Bühlplatz 5, CH-3012 Bern, Switzerland
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Fatima A, Xu G, Shao K, Papadopoulos S, Lehmann M, Arnáiz-Cot JJ, Rosa AO, Nguemo F, Matzkies M, Dittmann S, Stone SL, Linke M, Zechner U, Beyer V, Hennies HC, Rosenkranz S, Klauke B, Parwani AS, Haverkamp W, Pfitzer G, Farr M, Cleemann L, Morad M, Milting H, Hescheler J, Saric T. In vitro modeling of ryanodine receptor 2 dysfunction using human induced pluripotent stem cells. Cell Physiol Biochem 2011; 28:579-92. [PMID: 22178870 DOI: 10.1159/000335753] [Citation(s) in RCA: 157] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/14/2011] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND/AIMS Induced pluripotent stem (iPS) cells generated from accessible adult cells of patients with genetic diseases open unprecedented opportunities for exploring the pathophysiology of human diseases in vitro. Catecholaminergic polymorphic ventricular tachycardia type 1 (CPVT1) is an inherited cardiac disorder that is caused by mutations in the cardiac ryanodine receptor type 2 gene (RYR2) and is characterized by stress-induced ventricular arrhythmia that can lead to sudden cardiac death in young individuals. The aim of this study was to generate iPS cells from a patient with CPVT1 and determine whether iPS cell-derived cardiomyocytes carrying patient specific RYR2 mutation recapitulate the disease phenotype in vitro. METHODS iPS cells were derived from dermal fibroblasts of healthy donors and a patient with CPVT1 carrying the novel heterozygous autosomal dominant mutation p.F2483I in the RYR2. Functional properties of iPS cell derived-cardiomyocytes were analyzed by using whole-cell current and voltage clamp and calcium imaging techniques. RESULTS Patch-clamp recordings revealed arrhythmias and delayed afterdepolarizations (DADs) after catecholaminergic stimulation of CPVT1-iPS cell-derived cardiomyocytes. Calcium imaging studies showed that, compared to healthy cardiomyocytes, CPVT1-cardiomyocytes exhibit higher amplitudes and longer durations of spontaneous Ca(2+) release events at basal state. In addition, in CPVT1-cardiomyocytes the Ca(2+)-induced Ca(2+)-release events continued after repolarization and were abolished by increasing the cytosolic cAMP levels with forskolin. CONCLUSION This study demonstrates the suitability of iPS cells in modeling RYR2-related cardiac disorders in vitro and opens new opportunities for investigating the disease mechanism in vitro, developing new drugs, predicting their toxicity, and optimizing current treatment strategies.
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Affiliation(s)
- Azra Fatima
- Institute for Neurophysiology, University of Cologne, Robert Koch Strasse 39, Cologne, Germany
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Kooij V, Stienen GJM, van der Velden J. The role of protein kinase C-mediated phosphorylation of sarcomeric proteins in the heart-detrimental or beneficial? Biophys Rev 2011; 3:107. [PMID: 28510060 DOI: 10.1007/s12551-011-0050-y] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2011] [Accepted: 06/08/2011] [Indexed: 10/18/2022] Open
Abstract
Protein kinase C (PKC) is a family of serine/threonine protein kinases, and alterations have been found in PKC isoform expression and localization in the failing heart. These alterations in PKC activation levels influence the PKC-mediated phosphorylation status of cellular target proteins involved in Ca2+-handling and sarcomeric contraction. The differences observed in the effects due to PKC-mediated phosphorylation may underlie part of the contractile dysfunction observed in the failing heart. It is therefore important to establish the beneficial and detrimental effects of this kinase in the healthy and failing heart. The function of PKC has been studied intensively; however, the complexity of the regulation of this kinase makes the interpretation of the different effects difficult. The main focus of this review is the (patho)physiological impact of phosphorylation of sarcomeric proteins, myosin light chain-2, troponin I and T, desmin, myosin binding protein-C, and titin by PKC.
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Affiliation(s)
- Viola Kooij
- Division of Cardiology, Johns Hopkins Bayview Proteomics Center, Johns Hopkins University, 5200 Eastern Avenue, MFL Bldg, Center Tower, Rm 601, Baltimore, MD, 21224, USA.
| | - Ger J M Stienen
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
| | - Jolanda van der Velden
- Laboratory for Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
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Thireau J, Pasquié JL, Martel E, Le Guennec JY, Richard S. New drugs vs. old concepts: a fresh look at antiarrhythmics. Pharmacol Ther 2011; 132:125-45. [PMID: 21420430 DOI: 10.1016/j.pharmthera.2011.03.003] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2011] [Accepted: 03/01/2011] [Indexed: 01/10/2023]
Abstract
Common arrhythmias, particularly atrial fibrillation (AF) and ventricular tachycardia/fibrillation (VT/VF) are a major public health concern. Classic antiarrhythmic (AA) drugs for AF are of limited effectiveness, and pose the risk of life-threatening VT/VF. For VT/VF, implantable cardiac defibrillators appear to be the unique, yet unsatisfactory, solution. Very few AA drugs have been successful in the last few decades, due to safety concerns or limited benefits in comparison to existing therapy. The Vaughan-Williams classification (one drug for one molecular target) appears too restrictive in light of current knowledge of molecular and cellular mechanisms. New AA drugs such as atrial-specific and/or multichannel blockers, upstream therapy and anti-remodeling drugs, are emerging. We focus on the cellular mechanisms related to abnormal Na⁺ and Ca²⁺ handling in AF, heart failure, and inherited arrhythmias, and on novel strategies aimed at normalizing ionic homeostasis. Drugs that prevent excessive Na⁺ entry (ranolazine) and aberrant diastolic Ca²⁺ release via the ryanodine receptor RyR2 (rycals, dantrolene, and flecainide) exhibit very interesting antiarrhythmic properties. These drugs act by normalizing, rather than blocking, channel activity. Ranolazine preferentially blocks abnormal persistent (vs. normal peak) Na⁺ currents, with minimal effects on normal channel function (cell excitability, and conduction). A similar "normalization" concept also applies to RyR2 stabilizers, which only prevent aberrant opening and diastolic Ca²⁺ leakage in diseased tissues, with no effect on normal function during systole. The different mechanisms of action of AA drugs may increase the therapeutic options available for the safe treatment of arrhythmias in a wide variety of pathophysiological situations.
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Affiliation(s)
- Jérôme Thireau
- Inserm U1046 Physiologie & Médecine Expérimentale du Cœur et des Muscles, Université Montpellier-1, Université Montpellier-2, 34295 Montpellier Cedex 5, France
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Shanmugam M, Gao S, Hong C, Fefelova N, Nowycky MC, Xie LH, Periasamy M, Babu GJ. Ablation of phospholamban and sarcolipin results in cardiac hypertrophy and decreased cardiac contractility. Cardiovasc Res 2010; 89:353-61. [PMID: 20833651 DOI: 10.1093/cvr/cvq294] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
AIMS Improving the sarco(endo)plasmic reticulum (SR) Ca(2+)-ATPase (SERCA) function has clinical implications in treating heart failure. The present study aimed to determine the effect of constitutive activation of the SERCA pump on cardiac contractility in normal mice and during pressure-overload-induced cardiac hypertrophy. METHODS AND RESULTS The SERCA pump was constitutively activated in both atrial and ventricular chambers of the mouse heart by ablating its key regulators, phospholamban (PLN) and sarcolipin (SLN). The double-knockout (dKO) mice for PLN and SLN showed increased SERCA pump activity, Ca(2+) transients and SR Ca(2+) load, and developed cardiac hypertrophy. Echocardiographic measurements showed that the basal cardiac function was not affected in the young dKO mice. However, the cardiac function worsened upon ageing and when subjected to pressure overload. CONCLUSION Our studies suggest that the constitutive activation of the SERCA pump is detrimental to cardiac function. Our findings also emphasize the need for dynamic regulation of the SERCA pump by PLN and/or SLN to maintain cardiac contractility in normal conditions and during pathophysiological states.
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Affiliation(s)
- Mayilvahanan Shanmugam
- Department of Cell Biology and Molecular Medicine, University of Medicine and Dentistry of New Jersey-New Jersey Medical School, 185 South Orange Avenue, MSB, G609, Newark, NJ 07103, USA
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Wei L, Dirksen RT. Ryanodinopathies: RyR-Linked Muscle Diseases. CURRENT TOPICS IN MEMBRANES 2010; 66:139-67. [PMID: 22353479 DOI: 10.1016/s1063-5823(10)66007-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 03/24/2023]
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Nicholl PA, Howlett SE. Sarcoplasmic Reticulum Calcium Release Channels in Ventricles of Older Adult Hamsters. Can J Aging 2010; 25:107-13. [PMID: 16770752 DOI: 10.1353/cja.2006.0026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
ABSTRACTWhether the density of sarcoplasmic reticulum (SR) calcium release channels / ryanodine receptors in the heart declines with age is not clear. We investigated age-related changes in the density of «3H»-ryanodine receptors in crude ventricular homogenates, which contained all ligand binding sites in heart and in isolated junctional SR membranes. Experiments utilized young (120 days) and older adult (300 days) hamsters. «3H»-ryanodine binding site density did not change with age in crude homogenate preparations, although total heart protein concentration increased significantly with age. In contrast, the density of «3H»-ryanodine binding sites decreased markedly in heavy SR membranes purified from older hearts. These results show that demonstration of age-related changes in cardiac ryanodine receptor density depends upon the preparation used. Furthermore, the increase in total ventricular protein with age suggests that normalization of data by membrane protein should be used with caution in studies of aging heart.
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Affiliation(s)
- Peter A Nicholl
- Department of Pharmacology, Dalhousie University, Halifax, NS, B3H 1X5, Canada
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Qi MY, Feng Y, Dai DZ, Li N, Cheng YS, Dai Y. CPU86017, a berberine derivative, attenuates cardiac failure through normalizing calcium leakage and downregulated phospholamban and exerting antioxidant activity. Acta Pharmacol Sin 2010; 31:165-74. [PMID: 20139899 DOI: 10.1038/aps.2009.180] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
AIM To investigate whether CPU86017, a berberine derivative, attenuates heart failure by blocking calcium influx and exerting its antioxidant activity. METHODS Myocardial infarction was induced in male Sprague-Dawley rats for 17 d followed by isoproterenol (ISO) (5 mg/kg, sc) treatment for 5 d to reduce cardiac function. The rats were divided into 5 groups: sham operation, myocardial infarction (MI), MI plus ISO, and co-treated (in mg/kg, po) with either propranolol (PRO, 10) or CPU86017 (80). Hemodynamic measurements were conducted, and measurements of the redox system, calcium handling proteins and endothelin (ET) system in vivo were done. Furthermore, calcium flux studies and PLB immunocytochemistry were conducted in vitro. RESULTS Compared to sham operation, HF was evident following MI and further worsened by ISO treatment. This occurred in parallel with downregulated mRNA and protein production of SERCA2a, PLB, and FKBP12.6, and was associated with upregulation of preproET-1, endothelin converting enzyme, and PKA mRNA production in the myocardium in vivo. Calcium leakage was induced by ISO treatment of isolated beating myocytes in vitro. These changes were attenuated by treatment with either PRO or CPU86017. PLB fluorescence in myocytes was downregulated by ISO treatment, and was relieved significantly by treatment with antioxidant aminoguanidine, ascorbic acid or CPU86017 in vitro. CONCLUSION HF, calcium leakage, downregulated PLB, FKBP12.6, SERCA2a production, and upregulated PKA were caused by ISO treatment, and were abolished by CPU86017 treatment. The beneficial effects of CPU86017 are attributable to its antioxidant and calcium influx blocking effects.
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Lompré AM, Hajjar RJ, Harding SE, Kranias EG, Lohse MJ, Marks AR. Ca2+ cycling and new therapeutic approaches for heart failure. Circulation 2010; 121:822-30. [PMID: 20124124 DOI: 10.1161/circulationaha.109.890954] [Citation(s) in RCA: 91] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Anne-Marie Lompré
- INSERM UMRS956/Université Pierre et Marie Curie, Faculté de Médecine, 91 Boulevard de l'Hôpital, 75013 Paris, France.
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Kondtratieva DS, Afanasiev SA, Rebrova TY, Tsapko LP, Karpov RS. Rhythmoinotropic myocardial reactions in rats with postinfarction cardiosclerosis against the background of streptozotocin-induced diabetes. Bull Exp Biol Med 2009; 148:181-3. [PMID: 20027322 DOI: 10.1007/s10517-009-0675-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
We studied rhythmoinotropic reactions of the myocardium in rats with postinfarction cardiosclerosis and in rats with postinfarction cardiosclerosis against the background of streptozotocin-induced diabetes. Inotropic myocardial response in rats with postinfarction cardiosclerosis was significantly inhibited after rest periods, while in streptozotocin diabetic rats the rhythmoinotropic myocardial reaction was comparable with the reaction of intact myocardium. The combination of postinfarction cardiosclerosis and diabetes paradoxically contributed to preservation of contractile function of the myocardium in rats.
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Affiliation(s)
- D S Kondtratieva
- Institute of Cardiology, Tomsk Research Center, Siberian Division of Russian Academy of Medical Sciences, Russia.
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Oyama MA, Chittur SV, Reynolds CA. Decreased triadin and increased calstabin2 expression in Great Danes with dilated cardiomyopathy. J Vet Intern Med 2009; 23:1014-9. [PMID: 19674278 DOI: 10.1111/j.1939-1676.2009.0360.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Dilated cardiomyopathy (DCM) is a common cardiac disease of Great Dane dogs, yet very little is known about the underlying molecular abnormalities that contribute to disease. OBJECTIVE Discover a set of genes that are differentially expressed in Great Dane dogs with DCM as a way to identify candidate genes for further study as well as to better understand the molecular abnormalities that underlie the disease. ANIMALS Three Great Dane dogs with end-stage DCM and 3 large breed control dogs. METHODS Prospective study. Transcriptional activity of 42,869 canine DNA sequences was determined with a canine-specific oligonucleotide microarray. Genome expression patterns of left ventricular tissue samples from affected Great Dane dogs were evaluated by measuring the relative amount of complementary RNA hybridization to the microarray probes and comparing it with expression from large breed dogs with noncardiac disease. RESULTS Three hundred and twenty-three transcripts were differentially expressed (> or = 2-fold change). The transcript with the greatest degree of upregulation (+61.3-fold) was calstabin2 (FKBP12.6), whereas the transcript with the greatest degree of downregulation (-9.07-fold) was triadin. Calstabin2 and triadin are both regulatory components of the cardiac ryanodine receptor (RyR2) and are critical to normal intracellular Ca2+ release and excitation-contraction coupling. CONCLUSION AND CLINICAL IMPORTANCE Great Dane dogs with DCM demonstrate abnormal calstabin2 and triadin expression. These changes likely affect Ca2+ flux within cardiac cells and may contribute to the pathophysiology of disease. Microarray-based analysis identifies calstabin2, triadin, and RyR2 function as targets of future study.
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Affiliation(s)
- M A Oyama
- Department of Clinical Studies, School of Veterinary Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA.
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Beery TA, Shah MJ, Benson DW. Genetic characterization of familial CPVT after 30 years. Biol Res Nurs 2009; 11:66-72. [PMID: 19398417 DOI: 10.1177/1099800409333369] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a stress-related, bidirectional ventricular tachycardia and atrial tachyarrhythmia in the absence of either structural heart disease or prolonged QT interval. Autosomal dominant and recessive forms of CPVT because of mutations in the cardiac ryanodine receptor (RyR2) or calsequestrin 2 (CASQ2) have been reported. The objective of this study was the clinical and genetic characterization of the family of an individual initially diagnosed as a child in 1978. METHOD We collected family medical history and recorded a four-generation pedigree. We performed mutation analysis of RyR2 "critical regions'' in the N-terminus, FKBP12.6 binding domain, Ca2+ binding domain, and transmembrane domains of the C-terminus by direct sequencing. RESULTS CPVT was diagnosed in two of the nine family members evaluated. Pedigree analysis suggested autosomal dominant disease transmission. There were no additional reports of seizures, pregnancy loss, neonatal death, or sudden cardiac death in family members. A novel RyR2 gene variant (W4645R) was found in four family members including two without symptoms. RyR2-W4645R segregates with disease in this family with incomplete penetrance. The W4645 residue is evolutionarily conserved in the transmembrane region adjacent to previously reported disease-causing mutations. Based on sorting intolerant from tolerant analysis of protein structure, RyR2-W4645R is predicted to be deleterious. CONCLUSIONS All current evidence supports RyR2-W4645R as a disease-causing variant, which was silent in persons for two generations before causing symptoms in persons for the next two generations, beginning in 1978.
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Affiliation(s)
- Theresa A Beery
- University of Cincinnati, and Cincinnati Children's Hospital Medical Center, Cincinnati, Ohio 45221-0038, USA.
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Davis J, Westfall MV, Townsend D, Blankinship M, Herron TJ, Guerrero-Serna G, Wang W, Devaney E, Metzger JM. Designing heart performance by gene transfer. Physiol Rev 2008; 88:1567-651. [PMID: 18923190 DOI: 10.1152/physrev.00039.2007] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The birth of molecular cardiology can be traced to the development and implementation of high-fidelity genetic approaches for manipulating the heart. Recombinant viral vector-based technology offers a highly effective approach to genetically engineer cardiac muscle in vitro and in vivo. This review highlights discoveries made in cardiac muscle physiology through the use of targeted viral-mediated genetic modification. Here the history of cardiac gene transfer technology and the strengths and limitations of viral and nonviral vectors for gene delivery are reviewed. A comprehensive account is given of the application of gene transfer technology for studying key cardiac muscle targets including Ca(2+) handling, the sarcomere, the cytoskeleton, and signaling molecules and their posttranslational modifications. The primary objective of this review is to provide a thorough analysis of gene transfer studies for understanding cardiac physiology in health and disease. By comparing results obtained from gene transfer with those obtained from transgenesis and biophysical and biochemical methodologies, this review provides a global view of cardiac structure-function with an eye towards future areas of research. The data presented here serve as a basis for discovery of new therapeutic targets for remediation of acquired and inherited cardiac diseases.
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Affiliation(s)
- Jennifer Davis
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota 55455, USA
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Caldwell PT, Thorne PA, Johnson PD, Boitano S, Runyan RB, Selmin O. Trichloroethylene disrupts cardiac gene expression and calcium homeostasis in rat myocytes. Toxicol Sci 2008; 104:135-43. [PMID: 18411232 DOI: 10.1093/toxsci/kfn078] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We have been investigating the molecular mechanisms by which trichloroethylene (TCE) might induce cardiac malformations in the embryonic heart. Previous results indicated that TCE disrupted expression of genes encoding proteins involved in regulation of intracellular Ca2+, [Ca2+](i), in cardiac cells, including ryanodine receptor isoform 2 (Ryr2), and sarcoendoplasmatic reticulum Ca2+ ATPase, Serca2a. These observations are important in light of the notion that altered cardiac contractility can produce morphological defects. The hypothesis tested in this study is that the TCE-induced changes in gene expression of Ca2+-associated proteins resulted in altered Ca2+ flux regulation. We used real-time PCR and digital imaging microscopy to characterize effects of various doses of TCE on gene expression and Ca2+ response to vasopressin (VP) in rat cardiac H9c2 myocytes. We observed a reduction in Serca2a and Ryr2 expression at 12 and 48 h after exposure to TCE. In addition, we found significant differences in Ca2+ response to VP in cells treated with TCE doses as low as 10 parts per billion. Taken all together, our data strongly indicate that exposure to TCE disrupts the ability of myocytes to regulate cellular Ca2+ fluxes. Perturbation of calcium signaling alters cardiac cell physiology and signal transduction and may hint to morphogenetic consequences in the context of heart development. These results point to a novel area of TCE biology and, if confirmed in vivo, may help to explain the apparent cardio-specific toxicity of TCE exposure in the rodent embryo.
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Affiliation(s)
- Patricia T Caldwell
- Department of Veterinary Science & Microbiology, University of Arizona, Tucson, Arizona 85721, USA
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Abstract
Puffs and sparks are localized intracellular Ca(2+) elevations that arise from the cooperative activity of Ca(2+)-regulated inositol 1,4,5-trisphosphate receptors and ryanodine receptors clustered at Ca(2+) release sites on the surface of the endoplasmic reticulum or the sarcoplasmic reticulum. While the synchronous gating of Ca(2+)-regulated Ca(2+) channels can be mediated entirely though the buffered diffusion of intracellular Ca(2+), interprotein allosteric interactions also contribute to the dynamics of ryanodine receptor (RyR) gating and Ca(2+) sparks. In this article, Markov chain models of Ca(2+) release sites are used to investigate how the statistics of Ca(2+) spark generation and termination are related to the coupling of RyRs via local [Ca(2+)] changes and allosteric interactions. Allosteric interactions are included in a manner that promotes the synchronous gating of channels by stabilizing neighboring closed-closed and/or open-open channel pairs. When the strength of Ca(2+)-mediated channel coupling is systematically varied (e.g., by changing the Ca(2+) buffer concentration), simulations that include synchronizing allosteric interactions often exhibit more robust Ca(2+) sparks; however, for some Ca(2+) coupling strengths the sparks are less robust. We find no evidence that the distribution of spark durations can be used to distinguish between allosteric interactions that stabilize closed channel pairs, open channel pairs, or both in a balanced fashion. On the other hand, the changes in spark duration, interspark interval, and frequency observed when allosteric interactions that stabilize closed channel pairs are gradually removed from simulations are qualitatively different than the changes observed when open or both closed and open channel pairs are stabilized. Thus, our simulations clarify how changes in spark statistics due to pharmacological washout of the accessory proteins mediating allosteric coupling may indicate the type of synchronizing allosteric interactions exhibited by physically coupled RyRs. We also investigate the validity of a mean-field reduction applicable to the dynamics of a ryanodine receptor cluster coupled via local [Ca(2+)] and allosteric interactions. In addition to facilitating parameter studies of the effect of allosteric coupling on spark statistics, the derivation of the mean-field model establishes the correct functional form for cooperativity factors representing the coupled gating of RyRs. This mean-field formulation is well suited for use in computationally efficient whole cell simulations of excitation-contraction coupling.
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Cardiac cell: a biological laser? Biosystems 2008; 92:49-60. [PMID: 18191016 DOI: 10.1016/j.biosystems.2007.11.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2007] [Revised: 10/30/2007] [Accepted: 11/26/2007] [Indexed: 11/23/2022]
Abstract
We present a new concept of cardiac cells based on an analogy with lasers, practical implementations of quantum resonators. In this concept, each cardiac cell comprises a network of independent nodes, characterised by a set of discrete energy levels and certain transition probabilities between them. Interaction between the nodes is given by threshold-limited energy transfer, leading to quantum-like behaviour of the whole network. We propose that in cardiomyocytes, during each excitation-contraction coupling cycle, stochastic calcium release and the unitary properties of ionic channels constitute an analogue to laser active medium prone to "population inversion" and "spontaneous emission" phenomena. This medium, when powered by an incoming threshold-reaching voltage discharge in the form of an action potential, responds to the calcium influx through L-type calcium channels by stimulated emission of Ca2+ ions in a coherent, synchronised and amplified release process known as calcium-induced calcium release. In parallel, phosphorylation-stimulated molecular amplification in protein cascades adds tuneable features to the cells. In this framework, the heart can be viewed as a coherent network of synchronously firing cardiomyocytes behaving as pulsed laser-like amplifiers, coupled to pulse-generating pacemaker master-oscillators. The concept brings a new viewpoint on cardiac diseases as possible alterations of "cell lasing" properties.
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von Lewinski D, Bisping E, Elgner A, Kockskämper J, Pieske B. Mechanistic insight into the functional and toxic effects of Strophanthidin in the failing human myocardium. Eur J Heart Fail 2007; 9:1086-94. [DOI: 10.1016/j.ejheart.2007.08.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2007] [Accepted: 08/22/2007] [Indexed: 11/30/2022] Open
Affiliation(s)
- Dirk von Lewinski
- Abteilung Kardiologie und Pneumologie, Georg-August-Universität Göttingen; Robert-Koch-Str. 40 37075 Göttingen Germany
- Abteilung Kardiologie, Medizinische Universität Graz; Auenbruggerplatz 15 8036 Graz Austria
| | - Egbert Bisping
- Abteilung Kardiologie und Pneumologie, Georg-August-Universität Göttingen; Robert-Koch-Str. 40 37075 Göttingen Germany
- Abteilung Kardiologie, Medizinische Universität Graz; Auenbruggerplatz 15 8036 Graz Austria
| | - Andreas Elgner
- Abteilung Kardiologie und Pneumologie, Georg-August-Universität Göttingen; Robert-Koch-Str. 40 37075 Göttingen Germany
| | - Jens Kockskämper
- Abteilung Kardiologie und Pneumologie, Georg-August-Universität Göttingen; Robert-Koch-Str. 40 37075 Göttingen Germany
- Abteilung Kardiologie, Medizinische Universität Graz; Auenbruggerplatz 15 8036 Graz Austria
| | - Burkert Pieske
- Abteilung Kardiologie, Medizinische Universität Graz; Auenbruggerplatz 15 8036 Graz Austria
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Cerrone M, Noujaim SF, Tolkacheva EG, Talkachou A, O'Connell R, Berenfeld O, Anumonwo J, Pandit SV, Vikstrom K, Napolitano C, Priori SG, Jalife J. Arrhythmogenic mechanisms in a mouse model of catecholaminergic polymorphic ventricular tachycardia. Circ Res 2007; 101:1039-48. [PMID: 17872467 PMCID: PMC2515360 DOI: 10.1161/circresaha.107.148064] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Catecholaminergic polymorphic ventricular tachycardia (VT) is a lethal familial disease characterized by bidirectional VT, polymorphic VT, and ventricular fibrillation. Catecholaminergic polymorphic VT is caused by enhanced Ca2+ release through defective ryanodine receptor (RyR2) channels. We used epicardial and endocardial optical mapping, chemical subendocardial ablation with Lugol's solution, and patch clamping in a knockin (RyR2/RyR2(R4496C)) mouse model to investigate the arrhythmogenic mechanisms in catecholaminergic polymorphic VT. In isolated hearts, spontaneous ventricular arrhythmias occurred in 54% of 13 RyR2/RyR2(R4496C) and in 9% of 11 wild-type (P=0.03) littermates perfused with Ca2+and isoproterenol; 66% of 12 RyR2/RyR2(R4496C) and 20% of 10 wild-type hearts perfused with caffeine and epinephrine showed arrhythmias (P=0.04). Epicardial mapping showed that monomorphic VT, bidirectional VT, and polymorphic VT manifested as concentric epicardial breakthrough patterns, suggesting a focal origin in the His-Purkinje networks of either or both ventricles. Monomorphic VT was clearly unifocal, whereas bidirectional VT was bifocal. Polymorphic VT was initially multifocal but eventually became reentrant and degenerated into ventricular fibrillation. Endocardial mapping confirmed the Purkinje fiber origin of the focal arrhythmias. Chemical ablation of the right ventricular endocardial cavity with Lugol's solution induced complete right bundle branch block and converted the bidirectional VT into monomorphic VT in 4 anesthetized RyR2/RyR2(R4496C) mice. Under current clamp, single Purkinje cells from RyR2/RyR2(R4496C) mouse hearts generated delayed afterdepolarization-induced triggered activity at lower frequencies and level of adrenergic stimulation than wild-type. Overall, the data demonstrate that the His-Purkinje system is an important source of focal arrhythmias in catecholaminergic polymorphic VT.
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Affiliation(s)
- Marina Cerrone
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
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Rosso R, Kalman JM, Rogowski O, Diamant S, Birger A, Biner S, Belhassen B, Viskin S. Calcium channel blockers and beta-blockers versus beta-blockers alone for preventing exercise-induced arrhythmias in catecholaminergic polymorphic ventricular tachycardia. Heart Rhythm 2007; 4:1149-54. [PMID: 17765612 DOI: 10.1016/j.hrthm.2007.05.017] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2007] [Accepted: 05/19/2007] [Indexed: 01/18/2023]
Abstract
BACKGROUND The mainstay of therapy for catecholaminergic polymorphic ventricular tachycardia (CPVT) is maximal doses of beta-blockers. However, although beta-blockers prevent exercise-induced ventricular tachycardia (VT), most patients continue to have ventricular ectopy during exercise, and some studies report high mortality rates despite beta-blockade. OBJECTIVE The purpose of this study was to investigate whether combining a calcium channel blocker with beta-blockers would prevent ventricular arrhythmias during exercise better than beta-blockers alone since the mutations causing CPVT lead to intracellular calcium overload. METHODS Five patients with CPVT and one with polymorphic VT (PVT) and hypertrophic cardiomyopathy who had exercise-induced ventricular ectopy despite beta-blocker therapy were studied. Symptom-limited exercise was first performed during maximal beta-blocker therapy and repeated after addition of oral verapamil. RESULTS When comparing exercise during beta-blockers with exercise during beta-blockers + verapamil, exercise-induced arrhythmias were reduced: (1) Three patients had nonsustained VT on beta-blockers, and none of them had VT on combination therapy. (2) The number of ventricular ectopics during the whole exercise test went down from 78 +/- 59 beats to 6 +/- 8 beats; the ratio of ventricular ectopic to sinus beats during the 10-second period recorded at the time of the worst ventricular arrhythmia went down from 0.9 +/- 0.4 to 0.2 +/- 0.2. One patient with recurrent spontaneous VT leading to multiple shocks from her implanted cardioverter-defibrillator (ICD) despite maximal beta-blocker therapy (14 ICD shocks over 6 months while on beta-blockers) has remained free of arrhythmias (for 7 months) since the addition of verapamil therapy. CONCLUSIONS This preliminary evidence suggests that beta-blockers and calcium blockers could be better than beta-blockers alone for preventing exercise-induced arrhythmias in CPVT.
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Affiliation(s)
- Rafael Rosso
- Department of Cardiology, Tel Aviv Sourasky Medical Center, Sackler School of Medicine, Tel Aviv University, Israel
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