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Risato G, Brañas Casas R, Cason M, Bueno Marinas M, Pinci S, De Gaspari M, Visentin S, Rizzo S, Thiene G, Basso C, Pilichou K, Tiso N, Celeghin R. In Vivo Approaches to Understand Arrhythmogenic Cardiomyopathy: Perspectives on Animal Models. Cells 2024; 13:1264. [PMID: 39120296 PMCID: PMC11311808 DOI: 10.3390/cells13151264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2024] [Revised: 07/23/2024] [Accepted: 07/24/2024] [Indexed: 08/10/2024] Open
Abstract
Arrhythmogenic cardiomyopathy (AC) is a hereditary cardiac disorder characterized by the gradual replacement of cardiomyocytes with fibrous and adipose tissue, leading to ventricular wall thinning, chamber dilation, arrhythmias, and sudden cardiac death. Despite advances in treatment, disease management remains challenging. Animal models, particularly mice and zebrafish, have become invaluable tools for understanding AC's pathophysiology and testing potential therapies. Mice models, although useful for scientific research, cannot fully replicate the complexity of the human AC. However, they have provided valuable insights into gene involvement, signalling pathways, and disease progression. Zebrafish offer a promising alternative to mammalian models, despite the phylogenetic distance, due to their economic and genetic advantages. By combining animal models with in vitro studies, researchers can comprehensively understand AC, paving the way for more effective treatments and interventions for patients and improving their quality of life and prognosis.
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Affiliation(s)
- Giovanni Risato
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
- Department of Biology, University of Padua, I-35131 Padua, Italy;
- Department of Women’s and Children’s Health, University of Padua, I-35128 Padua, Italy;
| | | | - Marco Cason
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Maria Bueno Marinas
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Serena Pinci
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Monica De Gaspari
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Silvia Visentin
- Department of Women’s and Children’s Health, University of Padua, I-35128 Padua, Italy;
| | - Stefania Rizzo
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Gaetano Thiene
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Cristina Basso
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Kalliopi Pilichou
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
| | - Natascia Tiso
- Department of Biology, University of Padua, I-35131 Padua, Italy;
| | - Rudy Celeghin
- Department of Cardio-Thoraco-Vascular Sciences and Public Health, University of Padua, I-35128 Padua, Italy; (G.R.); (M.C.); (M.B.M.); (S.P.); (M.D.G.); (S.R.); (G.T.); (C.B.); (K.P.); (R.C.)
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Zhang H, Ren X, Wu C, He X, Huang Z, Li Y, Liao L, Xiang J, Li M, Wu L. Intracellular calcium dysregulation in heart and brain diseases: Insights from induced pluripotent stem cell studies. J Neuropathol Exp Neurol 2024:nlae078. [PMID: 39001792 DOI: 10.1093/jnen/nlae078] [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: 07/15/2024] Open
Abstract
The central nervous system (CNS) plays a role in regulating heart rate and myocardial contractility through sympathetic and parasympathetic nerves, and the heart can impact the functional equilibrium of the CNS through feedback signals. Although heart and brain diseases often coexist and mutually influence each other, the potential links between heart and brain diseases remain unclear due to a lack of reliable models of these relationships. Induced pluripotent stem cells (iPSCs), which can differentiate into multiple functional cell types, stem cell biology and regenerative medicine may offer tools to clarify the mechanisms of these relationships and facilitate screening of effective therapeutic agents. Because calcium ions play essential roles in regulating both the cardiovascular and nervous systems, this review addresses how recent iPSC disease models reveal how dysregulation of intracellular calcium might be a common pathological factor underlying the relationships between heart and brain diseases.
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Affiliation(s)
- Huayang Zhang
- Department of Cardiology, The Affiliated Hospital, Southwest Medical University, Luzhou, China
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Xueming Ren
- Department of Ophthalmology, The Affiliated Hospital, Southwest Medical University, Luzhou, China
| | - Chunyu Wu
- School of Clinical Medicine, Southwest Medical University, Luzhou, China
| | - Xinsen He
- Department of Gastroenterology, The Affiliated Hospital, Southwest Medical University, Luzhou, China
| | - Zhengxuan Huang
- Department of Neurosurgery, The Affiliated Hospital, Southwest Medical University, Luzhou, China
| | - Yangpeng Li
- Department of Cardiology, The Affiliated Hospital, Southwest Medical University, Luzhou, China
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Lei Liao
- Department of Cardiology, The Affiliated Hospital, Southwest Medical University, Luzhou, China
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Jie Xiang
- Department of Pacing and Electrophysiology, The First Affiliated Hospital of Xinjiang Medical University, Urumqi, China
| | - Miaoling Li
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
| | - Lin Wu
- Key Laboratory of Medical Electrophysiology of Ministry of Education, Institute of Cardiovascular Research, Southwest Medical University, Luzhou, China
- Department of Cardiology, Peking University First Hospital, Beijing, China
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Matsuda Y, Masuda M, Uematsu H, Sugino A, Ooka H, Kudo S, Fujii S, Asai M, Okamoto S, Ishihara T, Nanto K, Tsujimura T, Hata Y, Higashino N, Nakao S, Kusuda M, Mano T. Impact of diabetes mellitus and poor glycemic control on the prevalence of left atrial low-voltage areas and rhythm outcome in patients with atrial fibrillation ablation. J Cardiovasc Electrophysiol 2024; 35:775-784. [PMID: 38375957 DOI: 10.1111/jce.16219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2023] [Revised: 01/07/2024] [Accepted: 02/05/2024] [Indexed: 02/21/2024]
Abstract
INTRODUCTION Left atrial low-voltage areas (LVAs) are known to be correlated with atrial scarring and atrial fibrillation (AF) recurrence after ablation. However, the association between LVAs and glycemic status before ablation has not been fully clarified. The purpose of this study was to investigate associations among the prevalence of diabetes mellitus (DM), glycemic control, and the prevalence of LVAs in patients with AF ablation. METHODS In total, 912 (age, 68 ± 10 years; female, 299 [33%]; persistent AF, 513 [56%]) consecutive patients who underwent initial AF ablation were included. A preprocedure glycated hemoglobin A1c (HbA1c) ≥7% was set as the cutoff for poor glycemic control in patients with DM. LVAs were defined as areas with a bipolar voltage of <0.5 mV covering ≥5 cm2 of left atrium. RESULTS LVAs existed in 208 (23%) patients, and 168 (18%) patients had DM. LVAs were found more frequently in patients with DM and poor glycemic control. On multivariate analysis, DM with HbA1c ≥7% was an independent predictor of LVAs (odds ratio, 3.3; 95% confidence interval: 1.6-6.7; p = .001). In patients with LVAs, freedom from AF recurrence during the 24-month study period was significantly lower in patients who had DM with HbA1c ≥7% than in those without DM (37.9% vs. 54.7%, p = .02). CONCLUSION In patients with AF ablation, LVAs were found more frequently in patients with DM and poor glycemic control. DM with HbA1c ≥7% was an independent predictor of LVAs.
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Affiliation(s)
- Yasuhiro Matsuda
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Masaharu Masuda
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Hiroyuki Uematsu
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Ayako Sugino
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Hirotaka Ooka
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Satoshi Kudo
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Subaru Fujii
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Mitsutoshi Asai
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Shin Okamoto
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Takayuki Ishihara
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Kiyonori Nanto
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Takuya Tsujimura
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Yosuke Hata
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Naoko Higashino
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Sho Nakao
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Masaya Kusuda
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
| | - Toshiaki Mano
- Cardiovascular Center, Kansai Rosai Hospital, Amagasaki, Hyogo, Japan
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Roberts JD, Chalazan B, Andrade JG, Macle L, Nattel S, Tadros R. Clinical Genetic Testing for Atrial Fibrillation: Are We There Yet? Can J Cardiol 2024; 40:540-553. [PMID: 38551553 DOI: 10.1016/j.cjca.2023.11.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2023] [Revised: 10/17/2023] [Accepted: 11/19/2023] [Indexed: 04/13/2024] Open
Abstract
Important progress has been made toward unravelling the complex genetics underlying atrial fibrillation (AF). Initial studies were aimed to identify monogenic causes; however, it has become increasingly clear that the most common predisposing genetic substrate for AF is polygenic. Despite intensive investigations, there is robust evidence for rare variants for only a limited number of genes and cases. Although the current yield for genetic testing in early onset AF might be modest, there is an increasing appreciation that genetic culprits for potentially life-threatening ventricular cardiomyopathies and channelopathies might initially present with AF. The potential clinical significance of this recognition is highlighted by evidence that suggests that identification of a pathogenic or likely pathogenic rare variant in a patient with early onset AF is associated with an increased risk of death. These findings suggest that it might be warranted to screen patients with early onset AF for these potentially more sinister cardiac conditions. Beyond facilitating the early identification of genetic culprits associated with potentially malignant phenotypes, insight into underlying AF genetic substrates might improve the selection of patients for existing therapies and guide the development of novel ones. Herein, we review the evidence that links genetic factors to AF, then discuss an approach to using genetic testing for early onset AF patients in the present context, and finally consider the potential value of genetic testing in the foreseeable future. Although further work might be necessary before recommending uniform integration of genetic testing in cases of early onset AF, ongoing research increasingly highlights its potential contributions to clinical care.
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Affiliation(s)
- Jason D Roberts
- Population Health Research Institute, McMaster University, and Hamilton Health Sciences, Hamilton, Ontario, Canada.
| | - Brandon Chalazan
- Division of Biochemical Genetics, Department of Pediatrics, BC Children's Hospital, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jason G Andrade
- Centre for Cardiovascular Innovation and Division of Cardiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Laurent Macle
- Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute, Université de Montréal, Montreal, Quebec, Canada
| | - Rafik Tadros
- Cardiovascular Genetics Center, Montreal Heart Institute, Faculty of Medicine, Université de Montréal, Montreal, Québec, Canada
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Beqaj H, Sittenfeld L, Chang A, Miotto M, Dridi H, Willson G, Jorge CM, Li JA, Reiken S, Liu Y, Dai Z, Marks AR. Location of ryanodine receptor type 2 mutation predicts age of onset of sudden death in catecholaminergic polymorphic ventricular tachycardia - A systematic review and meta-analysis of case-based literature. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2024.03.15.24304349. [PMID: 38559077 PMCID: PMC10980137 DOI: 10.1101/2024.03.15.24304349] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/04/2024]
Abstract
Background Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a rare inherited arrhythmia caused by mutations in the ryanodine receptor type 2 (RyR2). Diagnosis of CPVT often occurs after a major cardiac event, thus posing a severe threat to the patient's health. Methods Publication databases, including PubMed, Scopus, and Embase, were searched for articles on patients with RyR2-CPVT mutations and their associated clinical presentation. Articles were reviewed by two independent reviewers and mutations were analyzed for demographic information, mutation distribution, and therapeutics. The human RyR2 cryo-EM structure was used to model CPVT mutations and predict the diagnosis and outcomes of CPVT patients. Findings We present a database of 1008 CPVT patients from 227 papers. Data analyses revealed that patients most often experienced exercise-induced syncope in their early teenage years but the diagnosis of CPVT took a decade. Mutations located near key regulatory sites in the channel were associated with earlier onset of CPVT symptoms including sudden cardiac death. Interpretation The present study provides a road map for predicting clinical outcomes based on the location of RyR2 mutations in CPVT patients. The study was partially limited by the inconsistency in the depth of information provided in each article, but nevertheless is an important contribution to the understanding of the clinical and molecular basis of CPVT and suggests the need for early diagnosis and creative approaches to disease management. Funding The work was supported by grant NIH R01HL145473, P01 HL164319 R25HL156002, T32 HL120826.
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Gandon-Renard M, Val-Blasco A, Oughlis C, Gerbaud P, Lefebvre F, Gomez S, Journé C, Courilleau D, Mercier-Nomé F, Pereira L, Benitah JP, Gómez AM, Mercadier JJ. Dual effect of cardiac FKBP12.6 overexpression on excitation-contraction coupling and the incidence of ventricular arrhythmia depending on its expression level. J Mol Cell Cardiol 2024; 188:15-29. [PMID: 38224852 DOI: 10.1016/j.yjmcc.2024.01.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 12/27/2023] [Accepted: 01/11/2024] [Indexed: 01/17/2024]
Abstract
FKBP12.6, a binding protein to the immunosuppressant FK506, which also binds the ryanodine receptor (RyR2) in the heart, has been proposed to regulate RyR2 function and to have antiarrhythmic properties. However, the level of FKBP12.6 expression in normal hearts remains elusive and some controversies still persist regarding its effects, both in basal conditions and during β-adrenergic stimulation. We quantified FKBP12.6 in the left ventricles (LV) of WT (wild-type) mice and in two novel transgenic models expressing distinct levels of FKBP12.6, using a custom-made specific anti-FKBP12.6 antibody and a recombinant protein. FKBP12.6 level in WT LV was very low (0.16 ± 0.02 nmol/g of LV), indicating that <15% RyR2 monomers are bound to the protein. Mice with 14.1 ± 0.2 nmol of FKBP12.6 per g of LV (TG1) had mild cardiac hypertrophy and normal function and were protected against epinephrine/caffeine-evoked arrhythmias. The ventricular myocytes showed higher [Ca2+]i transient amplitudes than WT myocytes and normal SR-Ca2+ load, while fewer myocytes showed Ca2+ sparks. TG1 cardiomyocytes responded to 50 nM Isoproterenol increasing these [Ca2+]i parameters and producing RyR2-Ser2808 phosphorylation. Mice with more than twice the TG1 FKBP12.6 value (TG2) showed marked cardiac hypertrophy with calcineurin activation and more arrhythmias than WT mice during β-adrenergic stimulation, challenging the protective potential of high FKBP12.6. RyR2R420Q CPVT mice overexpressing FKBP12.6 showed fewer proarrhythmic events and decreased incidence and duration of stress-induced bidirectional ventricular tachycardia. Our study, therefore, quantifies for the first time endogenous FKBP12.6 in the mouse heart, questioning its physiological relevance, at least at rest due its low level. By contrast, our work demonstrates that with caution FKBP12.6 remains an interesting target for the development of new antiarrhythmic therapies.
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Affiliation(s)
- Marine Gandon-Renard
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Almudena Val-Blasco
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Célia Oughlis
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Pascale Gerbaud
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Florence Lefebvre
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Susana Gomez
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Clément Journé
- Fédération de Recherche en Imagerie Multimodale (FRIM), Université Paris Cité, 75018 Paris, France
| | | | - Françoise Mercier-Nomé
- UMS-IPSIT, Université Paris-Saclay, 91400 Orsay, France; Inflammation, Microbiome and Immunosurveillance, Inserm UMR-996, Université Paris-Saclay, 92140 Clamart, France
| | - Laetitia Pereira
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Jean-Pierre Benitah
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France
| | - Ana Maria Gómez
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France.
| | - Jean-Jacques Mercadier
- Signalling and Cardiovascular Pathophysiology, Inserm UMR-S 1180, Université Paris-Saclay, 91400 Orsay, France; Université Paris Cité, Paris, France.
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Xia Y, Zhang XH, Yamaguchi N, Morad M. Point mutations in RyR2 Ca2+-binding residues of human cardiomyocytes cause cellular remodelling of cardiac excitation contraction-coupling. Cardiovasc Res 2024; 120:44-55. [PMID: 37890099 PMCID: PMC10898933 DOI: 10.1093/cvr/cvad163] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2023] [Revised: 07/17/2023] [Accepted: 09/26/2023] [Indexed: 10/29/2023] Open
Abstract
AIMS CRISPR/Cas9 gene edits of cardiac ryanodine receptor (RyR2) in human-induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) provide a novel platform for introducing mutations in RyR2 Ca2+-binding residues and examining the resulting excitation contraction (EC)-coupling remodelling consequences. METHODS AND RESULTS Ca2+-signalling phenotypes of mutations in RyR2 Ca2+-binding site residues associated with cardiac arrhythmia (RyR2-Q3925E) or not proven to cause cardiac pathology (RyR2-E3848A) were determined using ICa- and caffeine-triggered Ca2+ releases in voltage-clamped and total internal reflection fluorescence-imaged wild type and mutant cardiomyocytes infected with sarcoplasmic reticulum (SR)-targeted ER-GCaMP6 probe. (i) ICa- and caffeine-triggered Fura-2 or ER-GCaMP6 signals were suppressed, even when ICa was significantly enhanced in Q3925E and E3848A mutant cardiomyocytes; (ii) spontaneous beating (Fura-2 Ca2+ transients) persisted in mutant cells without the SR-release signals; (iii) while 5-20 mM caffeine failed to trigger Ca2+-release in voltage-clamped mutant cells, only ∼20% to ∼70% of intact myocytes responded respectively to caffeine; (iv) and 20 mM caffeine transients, however, activated slowly, were delayed, and variably suppressed by 2-APB, FCCP, or ruthenium red. CONCLUSION Mutating RyR2 Ca2+-binding residues, irrespective of their reported pathogenesis, suppressed both ICa- and caffeine-triggered Ca2+ releases, suggesting interaction between Ca2+- and caffeine-binding sites. Enhanced transmembrane calcium influx and remodelling of EC-coupling pathways may underlie the persistence of spontaneous beating in Ca2+-induced Ca2+ release-suppressed mutant myocytes.
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Affiliation(s)
- Yanli Xia
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
| | - Xiao-hua Zhang
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
| | - Naohiro Yamaguchi
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
| | - Martin Morad
- Cardiac Signaling Center of University of South Carolina, Medical University of South Carolina and Clemson University, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, 68 President Street, Bioengineering building Rm 306, Charleston, SC 29425, USA
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Wegener JW, Mitronova GY, ElShareif L, Quentin C, Belov V, Pochechueva T, Hasenfuss G, Ackermann L, Lehnart SE. A dual-targeted drug inhibits cardiac ryanodine receptor Ca 2+ leak but activates SERCA2a Ca 2+ uptake. Life Sci Alliance 2024; 7:e202302278. [PMID: 38012000 PMCID: PMC10681910 DOI: 10.26508/lsa.202302278] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2023] [Revised: 11/16/2023] [Accepted: 11/17/2023] [Indexed: 11/29/2023] Open
Abstract
In the heart, genetic or acquired mishandling of diastolic [Ca2+] by ryanodine receptor type 2 (RyR2) overactivity correlates with risks of arrhythmia and sudden cardiac death. Strategies to avoid these risks include decrease of Ca2+ release by drugs modulating RyR2 activity or increase in Ca2+ uptake by drugs modulating SR Ca2+ ATPase (SERCA2a) activity. Here, we combine these strategies by developing experimental compounds that act simultaneously on both processes. Our screening efforts identified the new 1,4-benzothiazepine derivative GM1869 as a promising compound. Consequently, we comparatively studied the effects of the known RyR2 modulators Dantrolene and S36 together with GM1869 on RyR2 and SERCA2a activity in cardiomyocytes from wild type and arrhythmia-susceptible RyR2R2474S/+ mice by confocal live-cell imaging. All drugs reduced RyR2-mediated Ca2+ spark frequency but only GM1869 accelerated SERCA2a-mediated decay of Ca2+ transients in murine and human cardiomyocytes. Our data indicate that S36 and GM1869 are more suitable than dantrolene to directly modulate RyR2 activity, especially in RyR2R2474S/+ mice. Remarkably, GM1869 may represent a new dual-acting lead compound for maintenance of diastolic [Ca2+].
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Affiliation(s)
- Jörg W Wegener
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Gyuzel Y Mitronova
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Lina ElShareif
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
| | - Christine Quentin
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Vladimir Belov
- Department of NanoBiophotonics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Tatiana Pochechueva
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Lutz Ackermann
- Georg-August University of Göttingen, Institute of Organic and Biomolecular Chemistry, Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Stephan E Lehnart
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center of Göttingen (UMG), Göttingen, Germany
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
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Lin S, Chen S, Lin Q, Xiao T, Hou C, Xie L. Transcriptome analysis of effects of Tecrl deficiency on cardiometabolic and calcium regulation in cardiac tissue. Open Med (Wars) 2024; 19:20230880. [PMID: 38283583 PMCID: PMC10811529 DOI: 10.1515/med-2023-0880] [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: 08/11/2023] [Revised: 12/06/2023] [Accepted: 12/07/2023] [Indexed: 01/30/2024] Open
Abstract
Catecholaminergic polymorphic ventricular tachycardia (CPVT) is a hereditary heart disease characterized by bidirectional or polymorphic ventricular tachycardia and an increased risk of sudden cardiac death. Although trans-2,3-enoyl-CoA reductase like (TECRL) is a newly reported pathogenic gene leading to CPVT that can influence intracellular calcium regulation, the unidentified mechanism underlying the pathogenesis of TECRL deficiency-mediated CPVT remains mainly elusive. In the present study, Tecrl knockout (KO) mice were established and the differentially expressed genes (DEGs) were investigated by RNA-sequencing from the heart tissues. In addition, 857 DEGs were identified in Tecrl KO mice. Subsequently, a weighted gene co-expression network analysis was conducted to discern the pivotal pathways implicated in the Tecrl-mediated regulatory network. Moreover, pathway mapping analyses demonstrated that essential metabolism-related pathways were significantly enriched, notably the fatty acid metabolic process and calcium regulation. Collectively, the data suggested a synergistic relationship between Tecrl deficiency and cardiometabolic and calcium regulation during the development of CPVT. Therefore, further studies on the potential function of TECRL in cardiac tissues would be beneficial to elucidate the pathogenesis of CPVT.
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Affiliation(s)
- Shujia Lin
- Department of Cardiology, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200062, China
| | - Shun Chen
- Department of Cardiology, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200062, China
| | - Qiuping Lin
- Department of Cardiology, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200062, China
| | - Tingting Xiao
- Department of Cardiology, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200062, China
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology, Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, 200040, China
| | - Cuilan Hou
- Department of Cardiology, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200062, China
- NHC Key Laboratory of Medical Embryogenesis and Developmental Molecular Biology, Shanghai Key Laboratory of Embryo and Reproduction Engineering, Shanghai, 200040, China
| | - Lijian Xie
- Department of Cardiology, Shanghai Children’s Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai, 200062, China
- Department of Pediatrics, Jinshan Hospital, Fudan University,
Shanghai, 201508, China
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10
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Curcio A, Scalise R, Indolfi C. Pathophysiology of Atrial Fibrillation and Approach to Therapy in Subjects Less than 60 Years Old. Int J Mol Sci 2024; 25:758. [PMID: 38255832 PMCID: PMC10815447 DOI: 10.3390/ijms25020758] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2023] [Revised: 12/27/2023] [Accepted: 01/03/2024] [Indexed: 01/24/2024] Open
Abstract
Atrial fibrillation (AF) is an arrhythmia that affects the left atrium, cardiac function, and the patients' survival rate. Due to empowered diagnostics, it has become increasingly recognized among young individuals as well, in whom it is influenced by a complex interplay of autoimmune, inflammatory, and electrophysiological mechanisms. Deepening our understanding of these mechanisms could contribute to improving AF management and treatment. Inflammation is a complexly regulated process, with interactions among various immune cell types, signaling molecules, and complement components. Addressing circulating antibodies and designing specific autoantibodies are promising therapeutic options. In cardiomyopathies or channelopathies, the first manifestation could be paroxysmal AF; persistent forms tend not to respond to antiarrhythmic drugs in these conditions. Further research, both in vitro and in vivo, on the use of genomic biotechnology could lead to new therapeutic approaches. Additional triggers that can be encountered in AF patients below 60 years of age are systemic hypertension, overweight, diabetes, and alcohol abuse. The aims of this review are to briefly report evidence from basic science and results of clinical studies that might explain the juvenile burden of the most encountered sustained supraventricular tachyarrhythmias in the general population.
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Affiliation(s)
- Antonio Curcio
- Division of Cardiology, Department of Medical and Surgical Sciences, Magna Graecia University, 88100 Catanzaro, Italy; (R.S.); (C.I.)
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11
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Ramos-Mondragón R, Lozhkin A, Vendrov AE, Runge MS, Isom LL, Madamanchi NR. NADPH Oxidases and Oxidative Stress in the Pathogenesis of Atrial Fibrillation. Antioxidants (Basel) 2023; 12:1833. [PMID: 37891912 PMCID: PMC10604902 DOI: 10.3390/antiox12101833] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2023] [Revised: 09/26/2023] [Accepted: 09/29/2023] [Indexed: 10/29/2023] Open
Abstract
Atrial fibrillation (AF) is the most common type of cardiac arrhythmia and its prevalence increases with age. The irregular and rapid contraction of the atria can lead to ineffective blood pumping, local blood stasis, blood clots, ischemic stroke, and heart failure. NADPH oxidases (NOX) and mitochondria are the main sources of reactive oxygen species in the heart, and dysregulated activation of NOX and mitochondrial dysfunction are associated with AF pathogenesis. NOX- and mitochondria-derived oxidative stress contribute to the onset of paroxysmal AF by inducing electrophysiological changes in atrial myocytes and structural remodeling in the atria. Because high atrial activity causes cardiac myocytes to expend extremely high energy to maintain excitation-contraction coupling during persistent AF, mitochondria, the primary energy source, undergo metabolic stress, affecting their morphology, Ca2+ handling, and ATP generation. In this review, we discuss the role of oxidative stress in activating AF-triggered activities, regulating intracellular Ca2+ handling, and functional and anatomical reentry mechanisms, all of which are associated with AF initiation, perpetuation, and progression. Changes in the extracellular matrix, inflammation, ion channel expression and function, myofibril structure, and mitochondrial function occur during the early transitional stages of AF, opening a window of opportunity to target NOX and mitochondria-derived oxidative stress using isoform-specific NOX inhibitors and mitochondrial ROS scavengers, as well as drugs that improve mitochondrial dynamics and metabolism to treat persistent AF and its transition to permanent AF.
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Affiliation(s)
- Roberto Ramos-Mondragón
- Department of Pharmacology, University of Michigan, 1150 West Medical Center Drive, 2301 Medical Science Research Building III, Ann Arbor, MI 48109, USA; (R.R.-M.); (L.L.I.)
| | - Andrey Lozhkin
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Aleksandr E. Vendrov
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Marschall S. Runge
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
| | - Lori L. Isom
- Department of Pharmacology, University of Michigan, 1150 West Medical Center Drive, 2301 Medical Science Research Building III, Ann Arbor, MI 48109, USA; (R.R.-M.); (L.L.I.)
- Department of Neurology, University of Michigan, Ann Arbor, MI 48109, USA
- Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA
| | - Nageswara R. Madamanchi
- Department of Internal Medicine, Frankel Cardiovascular Center, University of Michigan, Ann Arbor, MI 48019, USA; (A.L.); (A.E.V.); (M.S.R.)
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12
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George SA, Brennan-McLean JA, Trampel KA, Rytkin E, Faye NR, Knollmann BC, Efimov IR. Ryanodine receptor inhibition with acute dantrolene treatment reduces arrhythmia susceptibility in human hearts. Am J Physiol Heart Circ Physiol 2023; 325:H720-H728. [PMID: 37566110 DOI: 10.1152/ajpheart.00103.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/21/2023] [Revised: 07/26/2023] [Accepted: 08/03/2023] [Indexed: 08/12/2023]
Abstract
Ryanodine receptor 2 (RyR2) hyperactivity is observed in structural heart diseases that are a result of ischemia or heart failure. It causes abnormal calcium handling and calcium leaks that cause metabolic, electrical, and mechanical dysfunction, which can trigger arrhythmias. Here, we tested the antiarrhythmic potential of dantrolene (RyR inhibitor) in human hearts. Human hearts not used in transplantation were obtained, and right ventricular outflow tract (RVOT) wedges and left ventricular (LV) slices were prepared. Pseudo-ECGs were recorded to determine premature ventricular contraction (PVC) incidences. Optical mapping was performed to determine arrhythmogenic substrates. After baseline optical recordings, tissues were treated with 1) isoproterenol (250 nM), 2) caffeine (200 mM), and 3) dantrolene (2 or 10 mM). Optical recordings were obtained after each treatment. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Isoproterenol shortened action potential duration (APD) in the RV, RVOT, and LV regions and shortened calcium transient duration (CaTD) in the LV. Caffeine further shortened APD in the RV, did not modulate APD in the RVOT, and prolonged APD in the LV. In addition, in the LV, CaTD prolongation was also observed. More importantly, adding dantrolene did not alter APD in the RV or RVOT regions but produced a trend toward APD prolongation and significant CaTD prolongation in the LV, restoring these parameters to baseline values. In conclusions, dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates in the human heart and could be a novel antiarrhythmic therapy in patients with structural heart disease.NEW & NOTEWORTHY Ryanodine receptor 2 hyperactivity is observed in structural heart diseases caused by ischemia or heart failure. It causes abnormal calcium leaks, which can trigger arrhythmias. To prevent arrhythmias, we applied dantrolene in human hearts ex vivo. Isoproterenol and caffeine treatment increased PVC incidence, whereas dantrolene reduced the PVC burden. Dantrolene treatment suppresses triggers and reverses arrhythmogenic substrates and could be a novel antiarrhythmic therapy in patients with structural heart disease.
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Affiliation(s)
- Sharon A George
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia, United States
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States
| | - Jaclyn A Brennan-McLean
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia, United States
| | - Katy A Trampel
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia, United States
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States
| | - Eric Rytkin
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia, United States
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States
| | - N Rokhaya Faye
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia, United States
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Igor R Efimov
- Department of Biomedical Engineering, George Washington University, Washington, District of Columbia, United States
- Department of Biomedical Engineering, Northwestern University, Chicago, Illinois, United States
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13
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Sleiman Y, Reiken S, Charrabi A, Jaffré F, Sittenfeld LR, Pasquié JL, Colombani S, Lerman BB, Chen S, Marks AR, Cheung JW, Evans T, Lacampagne A, Meli AC. Personalized medicine in the dish to prevent calcium leak associated with short-coupled polymorphic ventricular tachycardia in patient-derived cardiomyocytes. Stem Cell Res Ther 2023; 14:266. [PMID: 37740238 PMCID: PMC10517551 DOI: 10.1186/s13287-023-03502-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2023] [Accepted: 09/14/2023] [Indexed: 09/24/2023] Open
Abstract
BACKGROUND Polymorphic ventricular tachycardia (PMVT) is a rare genetic disease associated with structurally normal hearts which in 8% of cases can lead to sudden cardiac death, typically exercise-induced. We previously showed a link between the RyR2-H29D mutation and a clinical phenotype of short-coupled PMVT at rest using patient-specific hiPSC-derived cardiomyocytes (hiPSC-CMs). In the present study, we evaluated the effects of clinical and experimental anti-arrhythmic drugs on the intracellular Ca2+ handling, contractile and molecular properties in PMVT hiPSC-CMs in order to model a personalized medicine approach in vitro. METHODS Previously, a blood sample from a patient carrying the RyR2-H29D mutation was collected and reprogrammed into several clones of RyR2-H29D hiPSCs, and in addition we generated an isogenic control by reverting the RyR2-H29D mutation using CRIPSR/Cas9 technology. Here, we tested 4 drugs with anti-arrhythmic properties: propranolol, verapamil, flecainide, and the Rycal S107. We performed fluorescence confocal microscopy, video-image-based analyses and biochemical analyses to investigate the impact of these drugs on the functional and molecular features of the PMVT RyR2-H29D hiPSC-CMs. RESULTS The voltage-dependent Ca2+ channel inhibitor verapamil did not prevent the aberrant release of sarcoplasmic reticulum (SR) Ca2+ in the RyR2-H29D hiPSC-CMs, whereas it was prevented by S107, flecainide or propranolol. Cardiac tissue comprised of RyR2-H29D hiPSC-CMs exhibited aberrant contractile properties that were largely prevented by S107, flecainide and propranolol. These 3 drugs also recovered synchronous contraction in RyR2-H29D cardiac tissue, while verapamil did not. At the biochemical level, S107 was the only drug able to restore calstabin2 binding to RyR2 as observed in the isogenic control. CONCLUSIONS By testing 4 drugs on patient-specific PMVT hiPSC-CMs, we concluded that S107 and flecainide are the most potent molecules in terms of preventing the abnormal SR Ca2+ release and contractile properties in RyR2-H29D hiPSC-CMs, whereas the effect of propranolol is partial, and verapamil appears ineffective. In contrast with the 3 other drugs, S107 was able to prevent a major post-translational modification of RyR2-H29D mutant channels, the loss of calstabin2 binding to RyR2. Using patient-specific hiPSC and CRISPR/Cas9 technologies, we showed that S107 is the most efficient in vitro candidate for treating the short-coupled PMVT at rest.
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Affiliation(s)
- Yvonne Sleiman
- PhyMedExp, University of Montpellier, CNRS, INSERM, Montpellier , France
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Azzouz Charrabi
- PhyMedExp, University of Montpellier, CNRS, INSERM, Montpellier , France
| | - Fabrice Jaffré
- Department of Surgery, Weill Cornell Medical College, New York, NY, USA
| | - Leah R Sittenfeld
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Jean-Luc Pasquié
- PhyMedExp, University of Montpellier, CNRS, INSERM, Montpellier , France
- Department of Cardiology, CHRU of Montpellier, Montpellier, France
| | - Sarah Colombani
- PhyMedExp, University of Montpellier, CNRS, INSERM, Montpellier , France
| | - Bruce B Lerman
- Division of Cardiology, Weill Cornell Medical College, New York, NY, USA
| | - Shuibing Chen
- Department of Surgery, Weill Cornell Medical College, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Clyde and Helen Wu Center for Molecular Cardiology, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
| | - Jim W Cheung
- Division of Cardiology, Weill Cornell Medical College, New York, NY, USA
| | - Todd Evans
- Department of Surgery, Weill Cornell Medical College, New York, NY, USA
| | - Alain Lacampagne
- PhyMedExp, University of Montpellier, CNRS, INSERM, Montpellier , France
| | - Albano C Meli
- PhyMedExp, University of Montpellier, CNRS, INSERM, Montpellier , France.
- CNRS, INSERM, Montpellier Organoid Platform, Biocampus, University of Montpellier, Montpellier, France.
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14
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Limpitikul WB, Das S. Obesity-Related Atrial Fibrillation: Cardiac Manifestation of a Systemic Disease. J Cardiovasc Dev Dis 2023; 10:323. [PMID: 37623336 PMCID: PMC10455513 DOI: 10.3390/jcdd10080323] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2023] [Revised: 07/27/2023] [Accepted: 07/27/2023] [Indexed: 08/26/2023] Open
Abstract
Atrial fibrillation (AF) is the most common arrhythmia worldwide and is associated with increased morbidity and mortality. The mechanisms underlying AF are complex and multifactorial. Although it is well known that obesity is a strong risk factor for AF, the mechanisms underlying obesity-related AF are not completely understood. Current evidence proposes that in addition to overall hemodynamic changes due to increased body weight, excess adiposity raises systemic inflammation and oxidative stress, which lead to adverse atrial remodeling. This remodeling includes atrial fibrosis, atrial dilation, decreased electrical conduction between atrial myocytes, and altered ionic currents, making atrial tissue more vulnerable to both the initiation and maintenance of AF. However, much remains to be learned about the mechanistic links between obesity and AF. This knowledge will power the development of novel diagnostic tools and treatment options that will help combat the rise of the global AF burden among the obesity epidemic.
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Affiliation(s)
- Worawan B. Limpitikul
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA;
| | - Saumya Das
- Cardiovascular Research Center, Massachusetts General Hospital, Harvard Medical School, Boston, MA 02114, USA;
- Demoulas Family Foundation Center for Cardiac Arrhythmias, Massachusetts General Hospital, Boston, MA 02114, USA
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15
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Shvilkina T, Shapiro N. Sepsis-Induced myocardial dysfunction: heterogeneity of functional effects and clinical significance. Front Cardiovasc Med 2023; 10:1200441. [PMID: 37522079 PMCID: PMC10375025 DOI: 10.3389/fcvm.2023.1200441] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2023] [Accepted: 06/05/2023] [Indexed: 08/01/2023] Open
Abstract
Sepsis is a life-threatening disease state characterized by organ dysfunction and a dysregulated response to infection. The heart is one of the many organs affected by sepsis, in an entity termed sepsis-induced cardiomyopathy. This was initially used to describe a reversible depression in ejection fraction with ventricular dilation but advances in echocardiography and introduction of new techniques such as speckle tracking have led to descriptions of other common abnormalities in cardiac function associated with sepsis. This includes not only depression of systolic function, but also supranormal ejection fraction, diastolic dysfunction, and right ventricular dysfunction. These reports have led to inconsistent definitions of sepsis-induced cardiomyopathy. Just as there is heterogeneity among patients with sepsis, there is heterogeneity in the cardiac response; thus resuscitating these patients with a single approach is likely suboptimal. Many factors affect the heart in sepsis including inflammatory mediators, catecholamine responsiveness, and pathogen related toxins. This review will discuss different functional effects characterized by echocardiographic changes in sepsis and their prognostic and management implications.
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16
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Kim K, Blackwell DJ, Yuen SL, Thorpe MP, Johnston JN, Cornea RL, Knollmann BC. The selective RyR2 inhibitor ent-verticilide suppresses atrial fibrillation susceptibility caused by Pitx2 deficiency. J Mol Cell Cardiol 2023; 180:1-9. [PMID: 37080450 PMCID: PMC10330243 DOI: 10.1016/j.yjmcc.2023.04.005] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Revised: 03/25/2023] [Accepted: 04/17/2023] [Indexed: 04/22/2023]
Abstract
Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major cause of stroke and morbidity. The strongest genetic risk factors for AF in humans are variants on chromosome 4q25, near the paired-like homeobox transcription factor 2 gene PITX2. Although mice deficient in Pitx2 (Pitx2+/-) have increased AF susceptibility, the mechanism remains controversial. Recent evidence has implicated hyperactivation of the cardiac ryanodine receptor (RyR2) in Pitx2 deficiency, which may be associated with AF susceptibility. We investigated pacing-induced AF susceptibility and spontaneous Ca2+ release events in Pitx2 haploinsufficient (+/-) mice and isolated atrial myocytes to test the hypothesis that hyperactivity of RyR2 increases susceptibility to AF, which can be prevented by a potent and selective RyR2 channel inhibitor, ent-verticilide. Compared with littermate wild-type Pitx2+/+, the frequency of Ca2+ sparks and spontaneous Ca2+ release events increased in permeabilized and intact atrial myocytes from Pitx2+/- mice. Atrial burst pacing consistently increased the incidence and duration of AF in Pitx2+/- mice. The RyR2 inhibitor ent-verticilide significantly reduced the frequency of spontaneous Ca2+ release in intact atrial myocytes and attenuated AF susceptibility with reduced AF incidence and duration. Our data demonstrate that RyR2 hyperactivity enhances SR Ca2+ leak and AF inducibility in Pitx2+/- mice via abnormal Ca2+ handling. Therapeutic targeting of hyperactive RyR2 in AF using ent-verticilide may be a viable mechanism-based approach to treat atrial arrhythmias caused by Pitx2 deficiency.
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Affiliation(s)
- Kyungsoo Kim
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Samantha L Yuen
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Madelaine P Thorpe
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
| | - Jeffrey N Johnston
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University, Nashville, TN, USA
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology, and Biophysics, University of Minnesota, Minneapolis, MN 55455, USA
| | - Björn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA.
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17
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Zhang X, Smith CER, Morotti S, Edwards AG, Sato D, Louch WE, Ni H, Grandi E. Mechanisms of spontaneous Ca 2+ release-mediated arrhythmia in a novel 3D human atrial myocyte model: II. Ca 2+ -handling protein variation. J Physiol 2023; 601:2685-2710. [PMID: 36114707 PMCID: PMC10017376 DOI: 10.1113/jp283602] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/02/2022] [Indexed: 11/08/2022] Open
Abstract
Disruption of the transverse-axial tubule system (TATS) in diseases such as heart failure and atrial fibrillation occurs in combination with changes in the expression and distribution of key Ca2+ -handling proteins. Together this ultrastructural and ionic remodelling is associated with aberrant Ca2+ cycling and electrophysiological instabilities that underlie arrhythmic activity. However, due to the concurrent changes in TATs and Ca2+ -handling protein expression and localization that occur in disease it is difficult to distinguish their individual contributions to the arrhythmogenic state. To investigate this, we applied our novel 3D human atrial myocyte model with spatially detailed Ca2+ diffusion and TATS to investigate the isolated and interactive effects of changes in expression and localization of key Ca2+ -handling proteins and variable TATS density on Ca2+ -handling abnormality driven membrane instabilities. We show that modulating the expression and distribution of the sodium-calcium exchanger, ryanodine receptors and the sarcoplasmic reticulum (SR) Ca2+ buffer calsequestrin have varying pro- and anti-arrhythmic effects depending on the balance of opposing influences on SR Ca2+ leak-load and Ca2+ -voltage relationships. Interestingly, the impact of protein remodelling on Ca2+ -driven proarrhythmic behaviour varied dramatically depending on TATS density, with intermediately tubulated cells being more severely affected compared to detubulated and densely tubulated myocytes. This work provides novel mechanistic insight into the distinct and interactive consequences of TATS and Ca2+ -handling protein remodelling that underlies dysfunctional Ca2+ cycling and electrophysiological instability in disease. KEY POINTS: In our companion paper we developed a 3D human atrial myocyte model, coupling electrophysiology and Ca2+ handling with subcellular spatial details governed by the transverse-axial tubule system (TATS). Here we utilize this model to mechanistically examine the impact of TATS loss and changes in the expression and distribution of key Ca2+ -handling proteins known to be remodelled in disease on Ca2+ homeostasis and electrophysiological stability. We demonstrate that varying the expression and localization of these proteins has variable pro- and anti-arrhythmic effects with outcomes displaying dependence on TATS density. Whereas detubulated myocytes typically appear unaffected and densely tubulated cells seem protected, the arrhythmogenic effects of Ca2+ handling protein remodelling are profound in intermediately tubulated cells. Our work shows the interaction between TATS and Ca2+ -handling protein remodelling that underlies the Ca2+ -driven proarrhythmic behaviour observed in atrial fibrillation and may help to predict the effects of antiarrhythmic strategies at varying stages of ultrastructural remodelling.
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Affiliation(s)
- Xianwei Zhang
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Stefano Morotti
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | | | - Daisuke Sato
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - William E Louch
- Institute for Experimental Medical Research, Oslo University Hospital and University of Oslo, Oslo, Norway
- K.G. Jebsen Centre for Cardiac Research, University of Oslo, Oslo, Norway
| | - Haibo Ni
- Department of Pharmacology, University of California Davis, Davis, CA, USA
| | - Eleonora Grandi
- Department of Pharmacology, University of California Davis, Davis, CA, USA
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18
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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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19
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Falco L, Tessitore V, Ciccarelli G, Malvezzi M, D'Andrea A, Imbalzano E, Golino P, Russo V. Antioxidant Properties of Oral Antithrombotic Therapies in Atherosclerotic Disease and Atrial Fibrillation. Antioxidants (Basel) 2023; 12:1185. [PMID: 37371915 DOI: 10.3390/antiox12061185] [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] [Received: 05/04/2023] [Revised: 05/22/2023] [Accepted: 05/29/2023] [Indexed: 06/29/2023] Open
Abstract
The thrombosis-related diseases are one of the leading causes of illness and death in the general population, and despite significant improvements in long-term survival due to remarkable advances in pharmacologic therapy, they continue to pose a tremendous burden on healthcare systems. The oxidative stress plays a role of pivotal importance in thrombosis pathophysiology. The anticoagulant and antiplatelet drugs commonly used in the management of thrombosis-related diseases show several pleiotropic effects, beyond the antithrombotic effects. The present review aims to describe the current evidence about the antioxidant effects of the oral antithrombotic therapies in patients with atherosclerotic disease and atrial fibrillation.
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Affiliation(s)
- Luigi Falco
- Cardiology Unit, Department of Medical Translational Science, University of Campania "Luigi Vanvitelli"-Monaldi Hospital, 80126 Naples, Italy
| | - Viviana Tessitore
- Cardiology Unit, Department of Medical Translational Science, University of Campania "Luigi Vanvitelli"-Monaldi Hospital, 80126 Naples, Italy
| | - Giovanni Ciccarelli
- Cardiology Unit, Department of Medical Translational Science, University of Campania "Luigi Vanvitelli"-Monaldi Hospital, 80126 Naples, Italy
| | - Marco Malvezzi
- Cardiology Unit, Department of Medical Translational Science, University of Campania "Luigi Vanvitelli"-Monaldi Hospital, 80126 Naples, Italy
| | | | - Egidio Imbalzano
- Department of Clinical and Experimental Medicine, University of Messina, 98122 Messina, Italy
| | - Paolo Golino
- Cardiology Unit, Department of Medical Translational Science, University of Campania "Luigi Vanvitelli"-Monaldi Hospital, 80126 Naples, Italy
| | - Vincenzo Russo
- Cardiology Unit, Department of Medical Translational Science, University of Campania "Luigi Vanvitelli"-Monaldi Hospital, 80126 Naples, Italy
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20
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Kryzhanovskii SA, Zinchenko VP, Tsorin IB, Teplov IY, Vititnova MB, Mokrov GV, Stolyaruk VN. To the Mechanism of the Antiarrhythmic Action of Compound ALM-802: the Role of Ryanodine Receptors. Bull Exp Biol Med 2023; 174:734-737. [PMID: 37170020 DOI: 10.1007/s10517-023-05781-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Indexed: 05/13/2023]
Abstract
The effect of the compound N1-(2,3,4-trimethoxy)-N2-{2-[(2,3,4-trimethoxybenzyl)amino]ethyl}-1,2-ethane-diamine (code ALM-802) on the amplitude of the Ca2+ response in the cell was studied in in vitro experiments. The concentration of intracellular calcium was assessed using a Fura-2 two-wave probe. The experiments were performed on a culture of isolated rat hippocampal neurons. The effect of compound ALM-802 on the activity of ryanodine receptors (RyR2) was studied on an isolated strip of rat myocardium. The compound ALM-802 (69.8 μM) in hippocampal neurons causes a significant decrease in the amplitude of the Ca2+ response induced by addition of KCl to the medium. Experiments performed on an isolated myocardial strip showed that compound ALM-802 (10-5 M) almost completely blocked the positive inotropic reaction of the strip to the RyR2 agonist caffeine (5×10-5 M). The data obtained indicate that the decrease in the concentration of Ca2+ ions in the cell caused by ALM-802 is due to its ability to block RyR2 located on the membrane of the sarcoplasmic reticulum, which can be associated with the antiarrhythmic activity of the compound.
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Affiliation(s)
| | - V P Zinchenko
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow region, Russia
| | - I B Tsorin
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia.
| | - I Yu Teplov
- Institute of Cell Biophysics, Russian Academy of Sciences, Pushchino, Moscow region, Russia
| | - M B Vititnova
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - G V Mokrov
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
| | - V N Stolyaruk
- V. V. Zakusov Research Institute of Pharmacology, Moscow, Russia
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21
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Divya S, Ravanan P. Cellular battle against endoplasmic reticulum stress and its adverse effect on health. Life Sci 2023; 323:121705. [PMID: 37075943 DOI: 10.1016/j.lfs.2023.121705] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Revised: 04/10/2023] [Accepted: 04/12/2023] [Indexed: 04/21/2023]
Abstract
The endoplasmic reticulum (ER) is a dynamic organelle and a reliable performer for precisely folded proteins. To maintain its function and integrity, arrays of sensory and quality control systems enhance protein folding fidelity and resolve the highest error-prone areas. Yet numerous internal and external factors disrupt its homeostasis and trigger ER stress responses. Cells try to reduce the number of misfolded proteins via the UPR mechanism, and ER-related garbage disposals systems like ER-associated degradation (ERAD), ER-lysosome-associated degradation (ERLAD), ER-Associated RNA Silencing (ERAS), extracellular chaperoning, and autophagy systems, which activates and increase the cell survival rate by degrading misfolded proteins, prevent the aggregated proteins and remove the dysfunctional organelles. Throughout life, organisms must confront environmental stress to survive and develop. Communication between the ER & other organelles, signaling events mediated by calcium, reactive oxygen species, and inflammation are linked to diverse stress signaling pathways and regulate cell survival or cell death mechanisms. Unresolved cellular damages can cross the threshold limit of their survival, resulting in cell death or driving for various diseases. The multifaceted ability of unfolded protein response facilitates the therapeutic target and a biomarker for various diseases, helping with early diagnosis and detecting the severity of diseases.
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Affiliation(s)
- Subramaniyan Divya
- Functional Genomics Laboratory, Department of Microbiology, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, 610005, Tamil Nadu, India
| | - Palaniyandi Ravanan
- Functional Genomics Laboratory, Department of Microbiology, School of Life Sciences, Central University of Tamil Nadu, Thiruvarur, 610005, Tamil Nadu, India.
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22
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The Role of RYR2 in Atrial Fibrillation. Case Rep Cardiol 2023; 2023:6555998. [PMID: 36969731 PMCID: PMC10033205 DOI: 10.1155/2023/6555998] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2023] [Revised: 02/20/2023] [Accepted: 03/04/2023] [Indexed: 03/17/2023] Open
Abstract
Background. Atrial fibrillation (AF) is a common arrhythmia in elderly patients and is associated with increased risk of mortality. The pathogenesis of AF is complex and based on multiple genetic and environmental factors. Genome-wide association studies identified several loci in AF patients, indicating the complex genetic architecture of this disease. In rare cases, familial forms of AF have been described. Today, pathogenic variants in at least 11 different genes are associated with monogenic AF. Case presentation. The 37-year-old male patient presented to our emergency department with AF. At the age of 35, he had already been diagnosed with paroxysmal AF. Additionally, his 34-year-old brother had also been diagnosed with AF as well as nonobstructive hypertrophic cardiomyopathy. Moreover, the patient’s father was diagnosed with AF in his twenties. Transthoracic echocardiography and cardiac MRI revealed a reduced systolic left ventricular ejection without any signs of hypertrophic cardiomyopathy. Genetic testing identified the heterozygous missense variants c.3371C > T, p.(Pro1124Leu) in RYR2 (NM_001035.3) and c.2524C > A, p.(Pro842Thr) in HCN4 (NM_005477.3) in the patient’s and his brother’s DNA. Discussion. This case of familial AF helps to strengthen the role of RYR2 as a disease gene in the context of AF. Although the variant in RYR2 needs to be classified formally as variant of unknown significance, we regard it as probably disease-causing due to the previously published data. As RYR2 has already been identified as a possible target for prevention and therapy of AF, the knowledge of variants in RYR2 might become even more crucial for individual molecular therapies in the future.
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23
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Yamada Y, Iemura J, Kambara A, Tateishi N, Kozaki Y, Yamada M, Maruyama J, Azuma E. Association of postoperative atrial fibrillation with higher dosing ratios of protamine-to-heparin. THE JOURNAL OF EXTRACORPOREAL TECHNOLOGY 2023; 55:23-29. [PMID: 37034101 PMCID: PMC10071503 DOI: 10.1051/ject/2023003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Accepted: 12/29/2022] [Indexed: 03/29/2023]
Abstract
Background: Postoperative atrial fibrillation (POAF) is defined as new-onset AF in the immediate postoperative period. The relatively high incidence of POAF after cardiac surgery is well described, but pathophysiological mechanisms underlying the initiation, maintenance, and progression of POAF may be multifactorial and have not yet been comprehensively characterized. One of the mechanisms includes altered Ca2+ kinetics. Accumulating evidence has suggested that altered atrial cytosolic calcium handling contributes to the development of POAF, protamine reversibly modulates the calcium release channel/ryanodine receptor 2 (RyR2) and voltage-dependent cardiac RyR2. However, it is currently unknown whether such abnormalities contribute to the arrhythmogenic substrate predisposing patients to the development of POAF. Methods: We have retrospectively analyzed 147 patients who underwent cardiac surgery with cardiopulmonary bypass support. Of these, 40 patients were excluded from the analysis because of pre-existing AF. All patients received heparin followed by protamine at different dosing ratios of protamine-to-heparin, depending on the periods studied. Results: The dosing ratio of protamine-to-heparin = 1.0 was compared with higher dosing ratios of protamine-to-heparin >1.0 up to 1.7. POAF developed in 15 patients (15/107 = 14%), of these, 5 out of 57 patients (33.3%) in the dosing ratio of protamine-to-heparin = 1.0 and 10 out of 35 patients (66.7%) in the higher dosing ratios of protamine-to-heparin. Statistical significance was observed in patients with higher dosing ratios of protamine-to-heparin, compared with the dosing ratio of protamine-to-heparin = 1.0 (odds ratio = 3.890, 95% CI = 1.130–13.300, p-value = 0.031). When types of diseases were analyzed in terms of higher dosing ratios of protamine-to-heparin, only valvular disorders were significantly associated with POAF (p = 0.04). Conclusions: Protamine is clinically utilized to reverse heparin overdose and has been shown to display immunological and inflammatory alterations. However, its association with POAF has not been reported. Our results provide evidence that higher dosing ratios of protamine-to-heparin may increase the incidence of POAF.
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Affiliation(s)
- Yasuharu Yamada
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Department of Clinical Engineering, Faculty of Medical Engineering, Suzuka University of Medical Science Mie 513-8670 Japan
- Corresponding author:
| | - Junzo Iemura
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Department of Cardiovascular Surgery, Okanami General Hospital Mie 518-0121 Japan
| | - Atushi Kambara
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Department of Cardiovascular Surgery, Okanami General Hospital Mie 518-0121 Japan
| | - Noboru Tateishi
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Division of Clinical Engineering, Okanami General Hospital Mie 518-0121 Japan
| | - Yuji Kozaki
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Division of Clinical Engineering, Okanami General Hospital Mie 518-0121 Japan
| | - Masako Yamada
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Department of Clinical Engineering, Mie University Hospital Mie 514-0001 Japan
| | - Junko Maruyama
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Department of Clinical Engineering, Faculty of Medical Engineering, Suzuka University of Medical Science Mie 513-8670 Japan
| | - Eiichi Azuma
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Department of Clinical Engineering, Faculty of Medical Engineering, Suzuka University of Medical Science Mie 513-8670 Japan
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24
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Mitochondrial Dysfunction in Cardiac Arrhythmias. Cells 2023; 12:cells12050679. [PMID: 36899814 PMCID: PMC10001005 DOI: 10.3390/cells12050679] [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] [Received: 12/26/2022] [Revised: 02/14/2023] [Accepted: 02/17/2023] [Indexed: 02/24/2023] Open
Abstract
Electrophysiological and structural disruptions in cardiac arrhythmias are closely related to mitochondrial dysfunction. Mitochondria are an organelle generating ATP, thereby satisfying the energy demand of the incessant electrical activity in the heart. In arrhythmias, the homeostatic supply-demand relationship is impaired, which is often accompanied by progressive mitochondrial dysfunction leading to reduced ATP production and elevated reactive oxidative species generation. Furthermore, ion homeostasis, membrane excitability, and cardiac structure can be disrupted through pathological changes in gap junctions and inflammatory signaling, which results in impaired cardiac electrical homeostasis. Herein, we review the electrical and molecular mechanisms of cardiac arrhythmias, with a particular focus on mitochondrial dysfunction in ionic regulation and gap junction action. We provide an update on inherited and acquired mitochondrial dysfunction to explore the pathophysiology of different types of arrhythmias. In addition, we highlight the role of mitochondria in bradyarrhythmia, including sinus node dysfunction and atrioventricular node dysfunction. Finally, we discuss how confounding factors, such as aging, gut microbiome, cardiac reperfusion injury, and electrical stimulation, modulate mitochondrial function and cause tachyarrhythmia.
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25
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Donniacuo M, De Angelis A, Telesca M, Bellocchio G, Riemma MA, Paolisso P, Scisciola L, Cianflone E, Torella D, Castaldo G, Capuano A, Urbanek K, Berrino L, Rossi F, Cappetta D. Atrial fibrillation: Epigenetic aspects and role of sodium-glucose cotransporter 2 inhibitors. Pharmacol Res 2023; 188:106591. [PMID: 36502999 DOI: 10.1016/j.phrs.2022.106591] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/26/2022] [Revised: 11/30/2022] [Accepted: 11/30/2022] [Indexed: 12/13/2022]
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmia and is associated with substantial morbidity and mortality. Pathophysiological aspects consist in the activation of pro-fibrotic signaling and Ca2+ handling abnormalities at atrial level. Structural and electrical remodeling creates a substrate for AF by triggering conduction abnormalities and cardiac arrhythmias. The care of AF patients focuses predominantly on anticoagulation, symptoms control and the management of risk factors and comorbidities. The goal of AF therapy points to restore sinus rhythm, re-establish atrioventricular synchrony and improve atrial contribution to the stroke volume. New layer of information to better comprehend AF pathophysiology, and identify targets for novel pharmacological interventions consists of the epigenetic phenomena including, among others, DNA methylation, histone modifications and noncoding RNAs. Moreover, the benefits of sodium-glucose cotransporter 2 inhibitors (SGLT2i) in diabetic and non-diabetic patients at cardiovascular risk as well as emerging evidence on the ability of SGLT2i to modify epigenetic signature in cardiovascular diseases provide a solid background to investigate a possible role of this drug class in the onset and progression of AF. In this review, following a summary of pathophysiology and management, epigenetic mechanisms in AF and the potential of sodium-glucose SGLT2i in AF patients are discussed.
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Affiliation(s)
- M Donniacuo
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - A De Angelis
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - M Telesca
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - G Bellocchio
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - M A Riemma
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - P Paolisso
- Cardiovascular Center Aalst, OLV Hospital, Aalst, Belgium; Department of Advanced Biomedical Sciences, University of Naples "Federico II", Via A. Pansini 5, 80131 Naples, Italy
| | - L Scisciola
- Department of Advanced Medical and Surgical Sciences, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - E Cianflone
- Department of Medical and Surgical Sciences, Magna Graecia University, Viale Europa, 88100 Catanzaro, Italy
| | - D Torella
- Department of Experimental and Clinical Medicine, Magna Graecia University, Viale Europa, 88100 Catanzaro, Italy
| | - G Castaldo
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples "Federico II", Via A. Pansini 5, 80131 Naples, Italy; CEINGE-Advanced, Via G. Salvatore 486, 80131 Naples, Italy
| | - A Capuano
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - K Urbanek
- Department of Molecular Medicine and Medical Biotechnologies, University of Naples "Federico II", Via A. Pansini 5, 80131 Naples, Italy; CEINGE-Advanced, Via G. Salvatore 486, 80131 Naples, Italy.
| | - L Berrino
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - F Rossi
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
| | - D Cappetta
- Department of Experimental Medicine, University of Campania "Luigi Vanvitelli", Via Costantinopoli 16, 80138 Naples, Italy
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26
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Abstract
This Review provides an update on ryanodine receptors (RyRs) and their role in human diseases of heart, muscle, and brain. Calcium (Ca2+) is a requisite second messenger in all living organisms. From C. elegans to mammals, Ca2+ is necessary for locomotion, bodily functions, and neural activity. However, too much of a good thing can be bad. Intracellular Ca2+ overload can result in loss of function and death. Intracellular Ca2+ release channels evolved to safely provide large, rapid Ca2+ signals without exposure to toxic extracellular Ca2+. RyRs are intracellular Ca2+ release channels present throughout the zoosphere. Over the past 35 years, our knowledge of RyRs has advanced to the level of atomic-resolution structures revealing their role in the mechanisms underlying the pathogenesis of human disorders of heart, muscle, and brain. Stress-induced RyR-mediated intracellular Ca2+ leak in the heart can promote heart failure and cardiac arrhythmias. In skeletal muscle, RyR1 leak contributes to muscle weakness in inherited myopathies, to age-related loss of muscle function and cancer-associated muscle weakness, and to impaired muscle function in muscular dystrophies, including Duchenne. In the brain, leaky RyR channels contribute to cognitive dysfunction in Alzheimer's disease, posttraumatic stress disorder, and Huntington's disease. Novel therapeutics targeting dysfunctional RyRs are showing promise.
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27
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Proietti R, Giordani AS, Lorenzo CA. ROCK (RhoA/Rho Kinase) Activation in Atrial Fibrillation: Molecular Pathways and Clinical Implications. Curr Cardiol Rev 2023; 19:e171122210986. [PMID: 36625201 PMCID: PMC10280999 DOI: 10.2174/1573403x19666221117092951] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2022] [Revised: 11/07/2022] [Accepted: 11/07/2022] [Indexed: 12/15/2022] Open
Abstract
Among the complex mechanisms of AF pathogenesis, intracellular calcium overload and oxidative stress play a major role, both triggered by inflammatory processes. The additional basic event taking place in AF is atrial fibrotic remodeling, again triggered by oxidative stress, which is determined by connexins rearrangement and differentiation of fibroblasts into active collagensecreting myofibroblasts. RhoA/ROCK system is the final pathway of a wide spectrum of molecular effectors such as Angiotensin II, platelet-derived growth factor, connective tissue growth factor and transforming growth factor β, that overall determine calcium dysregulation and pro-fibrotic remodeling. Both in experimental and clinical studies, RhoA/ROCK activation has been linked to superoxide ion production, fibrotic remodeling and connexins rearrangement, with important consequences for AF pathogenesis. ROCK pathway inhibition may therefore be a therapeutic or preventive target for special AF subgroups of patients.
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Affiliation(s)
- Riccardo Proietti
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, United Kingdom
| | - Andrea S. Giordani
- Department of Cardiac, Thoracic, Vascular Sciences and Public Health, University of Padua, Padua, Italy
| | - Calò A. Lorenzo
- Department of Medicine (DIMED), Nephrology, Dialysis and Transplantation Unit, University of Padua and Azienda Ospedale Università di Padova, Padua, Italy
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28
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Su Y, Huang J, Sun S, He T, Wang T, Fan M, Yu H, Yan J, Yao L, Xia Y, Zhang M, Zheng Y, Luo X, Zhang Y, Lu M, Zou M, Liu C, Chen Y. Restoring the Autonomic Balance in an Atrial Fibrillation Rat Model by Electroacupuncture at the Neiguan Point. Neuromodulation 2022:S1094-7159(22)01366-6. [PMID: 36522251 DOI: 10.1016/j.neurom.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2022] [Revised: 10/26/2022] [Accepted: 11/01/2022] [Indexed: 12/15/2022]
Abstract
OBJECTIVES Autonomic nervous activity imbalance plays an important role in atrial fibrillation (AF). AF can be treated by acupuncture at the Neiguan point (PC6), but the mechanism remains elusive. Here, we investigated autonomic nervous system activity in electroacupuncture (EA) at PC6 in a rat AF model. MATERIAL AND METHODS In this study, we established a rat AF model via tail vein injection with ACh-CaCl2 for ten consecutive days with or without EA at PC6. AF inducibility and heart rate variability (HRV) were assessed by electrocardiogram. Next, we completed in vivo recording of the activity of cervical sympathetic and vagal nerves, respectively. Finally, the activities of brain regions related to autonomic nerve regulation were assessed by c-Fos immunofluorescence and multichannel recording. RESULTS EA at PC6 decreased AF inducibility and prevented changes in HRV caused by ACh-CaCl2 injection. Meanwhile, EA at PC6 reversed the increased sympathetic and decreased vagal nerve activity in AF rats. Furthermore, EA treatment downregulated increased c-Fos expression in brain regions, including paraventricular nucleus, rostral ventrolateral medulla, and dorsal motor nucleus of the vagus in AF, while c-Fos expression in nucleus ambiguus was upregulated with EA. CONCLUSION The protective effect of EA at PC6 on AF is associated with balance between sympathetic and vagal nerve activities.
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Affiliation(s)
- Yang Su
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Jing Huang
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Shengxuan Sun
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Teng He
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Taiyi Wang
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Mengyue Fan
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Huanhuan Yu
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Jinglan Yan
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Lin Yao
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yucen Xia
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Meng Zhang
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Yuanjia Zheng
- Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Xiaoyan Luo
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Yuewen Zhang
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Manqi Lu
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Meixia Zou
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China
| | - Cunzhi Liu
- International Acupuncture and Moxibustion Innovation Institute, School of Acupuncture-Moxibustion and Tuina, Beijing University of Chinese Medicine, Chaoyang District, Beijing, China
| | - Yongjun Chen
- South China Research Center for Acupuncture and Moxibustion, Medical College of Acu-Moxi and Rehabilitation, Guangzhou University of Chinese Medicine, Guangzhou, China; Research Institute of Acupuncture and Moxibustion, Shandong University of Traditional Chinese Medicine, Jinan, China; Guangdong-Hong Kong-Macao Greater Bay Area Center for Brain Science and Brain-Inspired Intelligence, Guangzhou, China.
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29
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Gillis AM, Dobrev D. Targeting the RyR2 to Prevent Atrial Fibrillation. Circ Arrhythm Electrophysiol 2022; 15:e011514. [PMID: 36178743 PMCID: PMC9592734 DOI: 10.1161/circep.122.011514] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Anne M. Gillis
- Department of Cardiac Sciences, University of Calgary and Libin Cardiovascular Institute, Calgary, Alberta, Canada
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
- Department of Molecular Physiology & Biophysics, Baylor College of Medicine, Houston, TX
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30
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Shoemaker MB, Yoneda ZT, Crawford DM, Akers WS, Richardson T, Montgomery JA, Phillips S, Shyr Y, Saavedra P, Estrada J, Kanagasundram A, Shen ST, Michaud G, Crossley G, Ellis CR, Knollmann BC. A Mechanistic Clinical Trial Using ( R)- Versus (S)-Propafenone to Test RyR2 (Ryanodine Receptor) Inhibition for the Prevention of Atrial Fibrillation Induction. Circ Arrhythm Electrophysiol 2022; 15:e010713. [PMID: 36166682 PMCID: PMC9588733 DOI: 10.1161/circep.121.010713] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Accepted: 08/16/2022] [Indexed: 11/16/2022]
Abstract
BACKGROUND Experimental data suggest ryanodine receptor-mediated intracellular calcium leak is a mechanism for atrial fibrillation (AF), but evidence in humans is still needed. Propafenone is composed of two enantiomers that are equally potent sodium-channel blockers; however, (R)-propafenone is an ryanodine receptor inhibitor whereas (S)-propafenone is not. This study tested the hypothesis that ryanodine receptor inhibition with (R)-propafenone prevents induction of AF compared to (S)-propafenone or placebo in patients referred for AF ablation. METHODS Participants were randomized 4:4:1 to a one-time intravenous dose of (R)-propafenone, (S)-propafenone, or placebo. The study drug was given at the start of the procedure and an AF induction protocol using rapid atrial pacing was performed before ablation. The primary endpoint was 30 s of AF or atrial flutter. RESULTS A total of 193 participants were enrolled and 165 (85%) completed the study protocol (median age: 63 years, 58% male, 95% paroxysmal AF). Sustained AF and/or atrial flutter was induced in 60 participants (84.5%) receiving (R)-propafenone, 60 (80.0%) receiving (S)-propafenone group, and 12 (63.2%) receiving placebo. Atrial flutter occurred significantly more often in the (R)-propafenone (N=23, 32.4%) and (S)-propafenone (N=26, 34.7%) groups compared to placebo (N=1, 5.3%, P=0.029). There was no significant difference between (R)-propafenone and (S)-propafenone for the primary outcome of AF and/or atrial flutter induction in univariable (P=0.522) or multivariable analysis (P=0.199, adjusted for age and serum drug level). CONCLUSIONS There is no difference in AF inducibility between (R)-propafenone and (S)-propafenone at clinically relevant concentrations. These results are confounded by a high rate of inducible atrial flutter due to sodium-channel blockade. REGISTRATION https://clinicaltrials.gov; Unique Identifier: NCT02710669.
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Affiliation(s)
- M. Benjamin Shoemaker
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Zachary T. Yoneda
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Diane M. Crawford
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Wendell S. Akers
- Department of Pharmacology, Vanderbilt University School of Medicine
- Department of Pharmaceutical Sciences, Lipscomb University College of Pharmacy, Nashville, TN
| | - Travis Richardson
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Jay A. Montgomery
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Sharon Phillips
- Department of Biostatistics, Vanderbilt University School of Medicine
| | - Yu Shyr
- Department of Biostatistics, Vanderbilt University School of Medicine
| | - Pablo Saavedra
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - J.C. Estrada
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Arvindh Kanagasundram
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Sharon T. Shen
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Greg Michaud
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - George Crossley
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
| | - Christopher R. Ellis
- Division of Cardiology, Department of Medicine, Vanderbilt University Medical Center
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Miotto MC, Weninger G, Dridi H, Yuan Q, Liu Y, Wronska A, Melville Z, Sittenfeld L, Reiken S, Marks AR. Structural analyses of human ryanodine receptor type 2 channels reveal the mechanisms for sudden cardiac death and treatment. SCIENCE ADVANCES 2022; 8:eabo1272. [PMID: 35857850 PMCID: PMC9299551 DOI: 10.1126/sciadv.abo1272] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/14/2022] [Accepted: 06/03/2022] [Indexed: 05/29/2023]
Abstract
Ryanodine receptor type 2 (RyR2) mutations have been linked to an inherited form of exercise-induced sudden cardiac death called catecholaminergic polymorphic ventricular tachycardia (CPVT). CPVT results from stress-induced sarcoplasmic reticular Ca2+ leak via the mutant RyR2 channels during diastole. We present atomic models of human wild-type (WT) RyR2 and the CPVT mutant RyR2-R2474S determined by cryo-electron microscopy with overall resolutions in the range of 2.6 to 3.6 Å, and reaching local resolutions of 2.25 Å, unprecedented for RyR2 channels. Under nonactivating conditions, the RyR2-R2474S channel is in a "primed" state between the closed and open states of WT RyR2, rendering it more sensitive to activation that results in stress-induced Ca2+ leak. The Rycal drug ARM210 binds to RyR2-R2474S, reverting the primed state toward the closed state. Together, these studies provide a mechanism for CPVT and for the therapeutic actions of ARM210.
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Affiliation(s)
- Marco C. Miotto
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Gunnar Weninger
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Haikel Dridi
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Qi Yuan
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Yang Liu
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Anetta Wronska
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Zephan Melville
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Leah Sittenfeld
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
| | - Andrew R. Marks
- Department of Physiology and Cellular Biophysics, Columbia University Vagelos College of Physicians and Surgeons, New York, NY, USA
- Clyde and Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA
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Melville Z, Dridi H, Yuan Q, Reiken S, Wronska A, Liu Y, Clarke OB, Marks AR. A drug and ATP binding site in type 1 ryanodine receptor. Structure 2022; 30:1025-1034.e4. [PMID: 35580609 DOI: 10.1016/j.str.2022.04.010] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2022] [Revised: 03/02/2022] [Accepted: 04/21/2022] [Indexed: 12/12/2022]
Abstract
The ryanodine receptor (RyR)/calcium release channel on the sarcoplasmic reticulum (SR) is required for excitation-contraction coupling in skeletal and cardiac muscle. Inherited mutations and stress-induced post-translational modifications result in an SR Ca2+ leak that causes skeletal myopathies, heart failure, and exercise-induced sudden death. A class of therapeutics known as Rycals prevent the RyR-mediated leak, are effective in preventing disease progression and restoring function in animal models, and are in clinical trials for patients with muscle and heart disorders. Using cryogenic-electron microscopy, we present a model of RyR1 with a 2.45-Å resolution before local refinement, revealing a binding site in the RY1&2 domain (3.10 Å local resolution), where the Rycal ARM210 binds cooperatively with ATP and stabilizes the closed state of RyR1.
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Affiliation(s)
- Zephan Melville
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Haikel Dridi
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Qi Yuan
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Steven Reiken
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Anetta Wronska
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Yang Liu
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA
| | - Oliver B Clarke
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA; Department of Anesthesiology, Columbia University, New York, NY, USA
| | - Andrew R Marks
- Department of Physiology and Cellular Biophysics, Columbia University, New York, NY, USA; Clyde & Helen Wu Center for Molecular Cardiology, Columbia University, New York, NY, USA.
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Rebbeck R, Ginsburg KS, Ko CY, Fasoli A, Rusch K, Cai GF, Dong X, Thomas DD, Bers DM, Cornea RL. Synergistic FRET assays for drug discovery targeting RyR2 channels. J Mol Cell Cardiol 2022; 168:13-23. [PMID: 35405106 PMCID: PMC10088286 DOI: 10.1016/j.yjmcc.2022.04.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/23/2021] [Revised: 03/09/2022] [Accepted: 04/05/2022] [Indexed: 10/18/2022]
Abstract
A key therapeutic target for heart failure and arrhythmia is the deleterious leak through sarcoplasmic reticulum (SR) ryanodine receptor 2 (RyR2) calcium release channels. We have previously developed methods to detect the pathologically leaky state of RyR2 in adult cardiomyocytes by monitoring RyR2 binding to either calmodulin (CaM) or a biosensor peptide (DPc10). Here, we test whether these complementary binding measurements are effective as high-throughput screening (HTS) assays to discover small molecules that target leaky RyR2. Using FRET, we developed and validated HTS procedures under conditions that mimic a pathological state, to screen the library of 1280 pharmaceutically active compounds (LOPAC) for modulators of RyR2 in cardiac SR membrane preparations. Complementary FRET assays with acceptor-labeled CaM and DPc10 were used for Hit prioritization based on the opposing binding properties of CaM vs. DPc10. This approach narrowed the Hit list to one compound, Ro 90-7501, which altered FRET to suggest increased RyR2-CaM binding and decreased DPc10 binding. Follow-up studies revealed that Ro 90-7501 does not detrimentally affect myocyte Ca2+ transients. Moreover, Ro 90-7501 partially inhibits overall Ca2+ leak, as assessed by Ca2+ sparks in permeabilized rat cardiomyocytes. Together, these results demonstrate (1) the effectiveness of our HTS approach where two complementary assays synergize for Hit ranking and (2) a drug discovery process that combines high-throughput, high-precision in vitro structural assays with in situ myocyte assays of the pathologic RyR2 leak. These provide a drug discovery platform compatible with large-scale HTS campaigns, to identify agents that inhibit RyR2 for therapeutic development.
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Affiliation(s)
- RobynT Rebbeck
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA
| | | | - Christopher Y Ko
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Anna Fasoli
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Katherine Rusch
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA
| | - George F Cai
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA
| | - Xiaoqiong Dong
- Department of Pharmacology, University of California, Davis, CA, USA
| | - David D Thomas
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA; Photonic Pharma LLC, Minneapolis, MN, USA
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Razvan L Cornea
- Department of Biochemistry, Molecular Biology and Biophysics, University of Minnesota, MN, USA; Photonic Pharma LLC, Minneapolis, MN, USA.
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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35
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Emerging Antiarrhythmic Drugs for Atrial Fibrillation. Int J Mol Sci 2022; 23:ijms23084096. [PMID: 35456912 PMCID: PMC9029767 DOI: 10.3390/ijms23084096] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Revised: 03/28/2022] [Accepted: 04/01/2022] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF), the most common cardiac arrhythmia worldwide, is driven by complex mechanisms that differ between subgroups of patients. This complexity is apparent from the different forms in which AF presents itself (post-operative, paroxysmal and persistent), each with heterogeneous patterns and variable progression. Our current understanding of the mechanisms responsible for initiation, maintenance and progression of the different forms of AF has increased significantly in recent years. Nevertheless, antiarrhythmic drugs for the management of AF have not been developed based on the underlying arrhythmia mechanisms and none of the currently used drugs were specifically developed to target AF. With the increased knowledge on the mechanisms underlying different forms of AF, new opportunities for developing more effective and safer AF therapies are emerging. In this review, we provide an overview of potential novel antiarrhythmic approaches based on the underlying mechanisms of AF, focusing both on the development of novel antiarrhythmic agents and on the possibility of repurposing already marketed drugs. In addition, we discuss the opportunity of targeting some of the key players involved in the underlying AF mechanisms, such as ryanodine receptor type-2 (RyR2) channels and atrial-selective K+-currents (IK2P and ISK) for antiarrhythmic therapy. In addition, we highlight the opportunities for targeting components of inflammatory signaling (e.g., the NLRP3-inflammasome) and upstream mechanisms targeting fibroblast function to prevent structural remodeling and progression of AF. Finally, we critically appraise emerging antiarrhythmic drug principles and future directions for antiarrhythmic drug development, as well as their potential for improving AF management.
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36
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Caveolin-3 and Arrhythmias: Insights into the Molecular Mechanisms. J Clin Med 2022; 11:jcm11061595. [PMID: 35329921 PMCID: PMC8952412 DOI: 10.3390/jcm11061595] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 03/02/2022] [Accepted: 03/09/2022] [Indexed: 02/07/2023] Open
Abstract
Caveolin-3 is a muscle-specific protein on the membrane of myocytes correlated with a variety of cardiovascular diseases. It is now clear that the caveolin-3 plays a critical role in the cardiovascular system and a significant role in cardiac protective signaling. Mutations in the gene encoding caveolin-3 cause a broad spectrum of clinical phenotypes, ranging from persistent elevations in the serum levels of creatine kinase in asymptomatic humans to cardiomyopathy. The influence of Caveolin-3(CAV-3) mutations on current density parallels the effect on channel trafficking. For example, mutations in the CAV-3 gene promote ventricular arrhythmogenesis in long QT syndrome 9 by a combined decrease in the loss of the inward rectifier current (IK1) and gain of the late sodium current (INa-L). The functional significance of the caveolin-3 has proved that caveolin-3 overexpression or knockdown contributes to the occurrence and development of arrhythmias. Caveolin-3 overexpression could lead to reduced diastolic spontaneous Ca2+ waves, thus leading to the abnormal L-Type calcium channel current-induced ventricular arrhythmias. Moreover, CAV-3 knockdown resulted in a shift to more negative values in the hyperpolarization-activated cyclic nucleotide channel 4 current (IHCN4) activation curve and a significant decrease in IHCN4 whole-cell current density. Recent evidence indicates that caveolin-3 plays a significant role in adipose tissue and is related to obesity development. The role of caveolin-3 in glucose homeostasis has attracted increasing attention. This review highlights the underlining mechanisms of caveolin-3 in arrhythmia. Progress in this field may contribute to novel therapeutic approaches for patients prone to developing arrhythmia.
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Wegener JW, Wagdi A, Wagner E, Katschinski DM, Hasenfuss G, Bruegmann T, Lehnart SE. The RyR2-R2474S Mutation Sensitizes Cardiomyocytes and Hearts to Catecholaminergic Stress-Induced Oxidation of the Mitochondrial Glutathione Pool. Front Physiol 2021; 12:777770. [PMID: 34955889 PMCID: PMC8696262 DOI: 10.3389/fphys.2021.777770] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 11/19/2021] [Indexed: 11/24/2022] Open
Abstract
Missense mutations in the cardiac ryanodine receptor type 2 (RyR2) characteristically cause catecholaminergic arrhythmias. Reminiscent of the phenotype in patients, RyR2-R2474S knockin mice develop exercise-induced ventricular tachyarrhythmias. In cardiomyocytes, increased mitochondrial matrix Ca2+ uptake was recently linked to non-linearly enhanced ATP synthesis with important implications for cardiac redox metabolism. We hypothesize that catecholaminergic stimulation and contractile activity amplify mitochondrial oxidation pathologically in RyR2-R2474S cardiomyocytes. To investigate this question, we generated double transgenic RyR2-R2474S mice expressing a mitochondria-restricted fluorescent biosensor to monitor the glutathione redox potential (EGSH). Electrical field pacing-evoked RyR2-WT and RyR2-R2474S cardiomyocyte contractions resulted in a small but significant baseline EGSH increase. Importantly, β-adrenergic stimulation resulted in excessive EGSH oxidization of the mitochondrial matrix in RyR2-R2474S cardiomyocytes compared to baseline and RyR2-WT control. Physiologically β-adrenergic stimulation significantly increased mitochondrial EGSH further in intact beating RyR2-R2474S but not in RyR2-WT control Langendorff perfused hearts. Finally, this catecholaminergic EGSH increase was significantly attenuated following treatment with the RyR2 channel blocker dantrolene. Together, catecholaminergic stimulation and increased diastolic Ca2+ leak induce a strong, but dantrolene-inhibited mitochondrial EGSH oxidization in RyR2-R2474S cardiomyocytes.
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Affiliation(s)
- Jörg W Wegener
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Georg August University of Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), Georg-August University of Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Ahmed Wagdi
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg August University of Göttingen, Göttingen, Germany
| | - Eva Wagner
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Georg August University of Göttingen, Göttingen, Germany
| | - Dörthe M Katschinski
- DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg August University of Göttingen, Göttingen, Germany
| | - Gerd Hasenfuss
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Georg August University of Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
| | - Tobias Bruegmann
- Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), Georg-August University of Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany.,Institute of Cardiovascular Physiology, University Medical Center Göttingen, Georg August University of Göttingen, Göttingen, Germany
| | - Stephan E Lehnart
- Department of Cardiology and Pulmonology, Heart Research Center Göttingen, University Medical Center Göttingen, Georg August University of Göttingen, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: From Molecular Machines to Networks of Excitable Cells" (MBExC), Georg-August University of Göttingen, Göttingen, Germany.,DZHK (German Centre for Cardiovascular Research), Partner Site Göttingen, Göttingen, Germany
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Sagris M, Vardas EP, Theofilis P, Antonopoulos AS, Oikonomou E, Tousoulis D. Atrial Fibrillation: Pathogenesis, Predisposing Factors, and Genetics. Int J Mol Sci 2021; 23:ijms23010006. [PMID: 35008432 PMCID: PMC8744894 DOI: 10.3390/ijms23010006] [Citation(s) in RCA: 99] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 12/07/2021] [Accepted: 12/15/2021] [Indexed: 02/07/2023] Open
Abstract
Atrial fibrillation (AF) is the most frequent arrhythmia managed in clinical practice, and it is linked to an increased risk of death, stroke, and peripheral embolism. The Global Burden of Disease shows that the estimated prevalence of AF is up to 33.5 million patients. So far, successful therapeutic techniques have been implemented, with a high health-care cost burden. As a result, identifying modifiable risk factors for AF and suitable preventive measures may play a significant role in enhancing community health and lowering health-care system expenditures. Several mechanisms, including electrical and structural remodeling of atrial tissue, have been proposed to contribute to the development of AF. This review article discusses the predisposing factors in AF including the different pathogenic mechanisms, sedentary lifestyle, and dietary habits, as well as the potential genetic burden.
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Affiliation(s)
- Marios Sagris
- 1st Cardiology Clinic, ‘Hippokration’ General Hospital, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.P.V.); (P.T.); (A.S.A.); (E.O.); (D.T.)
- Correspondence: ; Tel.: +30-213-2088099; Fax: +30-213-2088676
| | - Emmanouil P. Vardas
- 1st Cardiology Clinic, ‘Hippokration’ General Hospital, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.P.V.); (P.T.); (A.S.A.); (E.O.); (D.T.)
- Department of Cardiology, General Hospital of Athens “G. Gennimatas”, 11527 Athens, Greece
| | - Panagiotis Theofilis
- 1st Cardiology Clinic, ‘Hippokration’ General Hospital, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.P.V.); (P.T.); (A.S.A.); (E.O.); (D.T.)
| | - Alexios S. Antonopoulos
- 1st Cardiology Clinic, ‘Hippokration’ General Hospital, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.P.V.); (P.T.); (A.S.A.); (E.O.); (D.T.)
| | - Evangelos Oikonomou
- 1st Cardiology Clinic, ‘Hippokration’ General Hospital, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.P.V.); (P.T.); (A.S.A.); (E.O.); (D.T.)
- 3rd Department of Cardiology, “Sotiria” Thoracic Diseases Hospital of Athens, University of Athens Medical School, 11527 Athens, Greece
| | - Dimitris Tousoulis
- 1st Cardiology Clinic, ‘Hippokration’ General Hospital, School of Medicine, National and Kapodistrian University of Athens, 11528 Athens, Greece; (E.P.V.); (P.T.); (A.S.A.); (E.O.); (D.T.)
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Liu C, Ma N, Guo Z, Zhang Y, Zhang J, Yang F, Su X, Zhang G, Xiong X, Xing Y. Relevance of mitochondrial oxidative stress to arrhythmias: Innovative concepts to target treatments. Pharmacol Res 2021; 175:106027. [PMID: 34890774 DOI: 10.1016/j.phrs.2021.106027] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2021] [Revised: 11/26/2021] [Accepted: 12/05/2021] [Indexed: 12/13/2022]
Abstract
Cardiac arrhythmia occurs frequently worldwide, and in severe cases can be fatal. Mitochondria are the power plants of cardiomyocytes. In recent studies, mitochondria under certain stimuli produced excessive reactive oxygen species (ROS), which affect the normal function of cardiomyocytes through ion channels and related proteins. Mitochondrial oxidative stress (MOS) plays a key role in diseases with multifactorial etiopathogenesis, such as arrhythmia; MOS can lead to arrhythmias such as atrial fibrillation and ventricular tachycardia. This review discusses the mechanisms of arrhythmias caused by MOS, particularly of ROS produced by mitochondria. MOS can cause arrhythmias by affecting the activities of Ca2+-related proteins, the mitochondrial permeability transition pore protein, connexin 43, hyperpolarization-activated cyclic nucleotide-gated potassium channel 4, and ion channels. Based on these mechanisms, we discuss possible new treatments for arrhythmia. Targeted treatments focusing on mitochondria may reduce the progression of arrhythmias, as well as the occurrence of severe arrhythmias, and may be effective for personalized disease prevention.
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Affiliation(s)
- Can Liu
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Ning Ma
- Dezhou Second People's Hospital, Dezhou 253000, China
| | - Ziru Guo
- Xingtai People's Hospital, Xingtai 054001, China
| | - Yijun Zhang
- The First Affiliated Hospital, Hebei North University, Zhangjiakou 075000, China
| | - Jianzhen Zhang
- Dongzhimen Hospital, Beijing University of Chinese Medicine, Beijing 100700, China
| | - Fan Yang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xin Su
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Guoxia Zhang
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Xingjiang Xiong
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
| | - Yanwei Xing
- Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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Yang S, Li R, Chen J, Li Z, Huang Z, Xie W. Calcium Spark Detection and Event-Based Classification of Single Cardiomyocyte Using Deep Learning. Front Physiol 2021; 12:770051. [PMID: 34819876 PMCID: PMC8607692 DOI: 10.3389/fphys.2021.770051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 10/15/2021] [Indexed: 11/13/2022] Open
Abstract
Ca2+ sparks are the elementary Ca2+ release events in cardiomyocytes, altered properties of which lead to impaired Ca2+ handling and finally contribute to cardiac pathology under various diseases. Despite increasing use of machine-learning algorithms in deciphering the content of biological and medical data, Ca2+ spark images and data are yet to be deeply learnt and analyzed. In the present study, we developed a deep residual convolutional neural network method to detect Ca2+ sparks. Compared to traditional detection methods with arbitrarily defined thresholds to distinguish signals from noises, our new method detected more Ca2+ sparks with lower amplitudes but similar spatiotemporal distributions, thereby indicating that our new algorithm detected many very weak events that are usually omitted when using traditional detection methods. Furthermore, we proposed an event-based logistic regression and binary classification model to classify single cardiomyocytes using Ca2+ spark characteristics, which to date have generally been used only for simple statistical analyses and comparison between normal and diseased groups. Using this new detection algorithm and classification model, we succeeded in distinguishing wild type (WT) vs RyR2-R2474S± cardiomyocytes with 100% accuracy, and vehicle vs isoprenaline-insulted WT cardiomyocytes with 95.6% accuracy. The model can be extended to judge whether a small number of cardiomyocytes (and so the whole heart) are under a specific cardiac disease. Thus, this study provides a novel and powerful approach for the research and application of calcium signaling in cardiac diseases.
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Affiliation(s)
- Shengqi Yang
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Ran Li
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Jiliang Chen
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Zhen Li
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Zhangqin Huang
- Beijing Engineering Research Center for IoT Software and Systems, Beijing University of Technology, Beijing, China
| | - Wenjun Xie
- The Key Laboratory of Biomedical Information Engineering of Ministry of Education, Institute of Health and Rehabilitation Science, School of Life Science and Technology, Xi'an Jiaotong University, Xi'an, China
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Cardiac ryanodine receptor N-terminal region biosensors identify novel inhibitors via FRET-based high-throughput screening. J Biol Chem 2021; 298:101412. [PMID: 34793835 PMCID: PMC8689225 DOI: 10.1016/j.jbc.2021.101412] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2021] [Revised: 11/08/2021] [Accepted: 11/11/2021] [Indexed: 12/15/2022] Open
Abstract
The N-terminal region (NTR) of ryanodine receptor (RyR) channels is critical for the regulation of Ca2+ release during excitation–contraction (EC) coupling in muscle. The NTR hosts numerous mutations linked to skeletal (RyR1) and cardiac (RyR2) myopathies, highlighting its potential as a therapeutic target. Here, we constructed two biosensors by labeling the mouse RyR2 NTR at domains A, B, and C with FRET pairs. Using fluorescence lifetime (FLT) detection of intramolecular FRET signal, we developed high-throughput screening (HTS) assays with these biosensors to identify small-molecule RyR modulators. We then screened a small validation library and identified several hits. Hits with saturable FRET dose–response profiles and previously unreported effects on RyR were further tested using [3H]ryanodine binding to isolated sarcoplasmic reticulum vesicles to determine effects on intact RyR opening in its natural membrane. We identified three novel inhibitors of both RyR1 and RyR2 and two RyR1-selective inhibitors effective at nanomolar Ca2+. Two of these hits activated RyR1 only at micromolar Ca2+, highlighting them as potential enhancers of excitation–contraction coupling. To determine whether such hits can inhibit RyR leak in muscle, we further focused on one, an FDA-approved natural antibiotic, fusidic acid (FA). In skinned skeletal myofibers and permeabilized cardiomyocytes, FA inhibited RyR leak with no detrimental effect on skeletal myofiber excitation–contraction coupling. However, in intact cardiomyocytes, FA induced arrhythmogenic Ca2+ transients, a cautionary observation for a compound with an otherwise solid safety record. These results indicate that HTS campaigns using the NTR biosensor can identify compounds with therapeutic potential.
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Gluvic Z, Obradovic M, Stewart AJ, Essack M, Pitt SJ, Samardzic V, Soskic S, Gojobori T, Isenovic ER. Levothyroxine Treatment and the Risk of Cardiac Arrhythmias - Focus on the Patient Submitted to Thyroid Surgery. Front Endocrinol (Lausanne) 2021; 12:758043. [PMID: 34803920 PMCID: PMC8600254 DOI: 10.3389/fendo.2021.758043] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Accepted: 10/11/2021] [Indexed: 02/05/2023] Open
Abstract
Levothyroxine (LT4) is used to treat frequently encountered endocrinopathies such as thyroid diseases. It is regularly used in clinical (overt) hypothyroidism cases and subclinical (latent) hypothyroidism cases in the last decade. Suppressive LT4 therapy is also part of the medical regimen used to manage thyroid malignancies after a thyroidectomy. LT4 treatment possesses dual effects: substituting new-onset thyroid hormone deficiency and suppressing the local and distant malignancy spreading in cancer. It is the practice to administer LT4 in less-than-high suppressive doses for growth control of thyroid nodules and goiter, even in patients with preserved thyroid function. Despite its approved safety for clinical use, LT4 can sometimes induce side-effects, more often recorded with patients under treatment with LT4 suppressive doses than in unintentionally LT4-overdosed patients. Cardiac arrhythmias and the deterioration of osteoporosis are the most frequently documented side-effects of LT4 therapy. It also lowers the threshold for the onset or aggravation of cardiac arrhythmias for patients with pre-existing heart diseases. To improve the quality of life in LT4-substituted patients, clinicians often prescribe higher doses of LT4 to reach low normal TSH levels to achieve cellular euthyroidism. In such circumstances, the risk of cardiac arrhythmias, particularly atrial fibrillation, increases, and the combined use of LT4 and triiodothyronine further complicates such risk. This review summarizes the relevant available data related to LT4 suppressive treatment and the associated risk of cardiac arrhythmia.
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Affiliation(s)
- Zoran Gluvic
- Clinic for Internal Medicine, Department of Endocrinology and Diabetes, Zemun Clinical Hospital, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Milan Obradovic
- Department of Radiobiology and Molecular Genetics, VINČA Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Alan J. Stewart
- School of Medicine, University of St Andrews, St Andrews, United Kingdom
| | - Magbubah Essack
- King Abdullah University of Science and Technology (KAUST), Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, Computational Bioscience Research Center (CBRC), Thuwal, Saudi Arabia
| | - Samantha J. Pitt
- School of Medicine, University of St Andrews, St Andrews, United Kingdom
| | - Vladimir Samardzic
- Clinic for Internal Medicine, Department of Endocrinology and Diabetes, Zemun Clinical Hospital, School of Medicine, University of Belgrade, Belgrade, Serbia
| | - Sanja Soskic
- Department of Radiobiology and Molecular Genetics, VINČA Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
| | - Takashi Gojobori
- King Abdullah University of Science and Technology (KAUST), Computer, Electrical, and Mathematical Sciences and Engineering (CEMSE) Division, Computational Bioscience Research Center (CBRC), Thuwal, Saudi Arabia
| | - Esma R. Isenovic
- Department of Radiobiology and Molecular Genetics, VINČA Institute of Nuclear Sciences - National Institute of the Republic of Serbia, University of Belgrade, Belgrade, Serbia
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Avula UMR, Dridi H, Chen BX, Yuan Q, Katchman AN, Reiken SR, Desai AD, Parsons S, Baksh H, Ma E, Dasrat P, Ji R, Lin Y, Sison C, Lederer WJ, Joca HC, Ward CW, Greiser M, Marks AR, Marx SO, Wan EY. Attenuating persistent sodium current-induced atrial myopathy and fibrillation by preventing mitochondrial oxidative stress. JCI Insight 2021; 6:e147371. [PMID: 34710060 PMCID: PMC8675199 DOI: 10.1172/jci.insight.147371] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Accepted: 10/27/2021] [Indexed: 12/19/2022] Open
Abstract
Mechanistically driven therapies for atrial fibrillation (AF), the most common cardiac arrhythmia, are urgently needed, the development of which requires improved understanding of the cellular signaling pathways that facilitate the structural and electrophysiological remodeling that occurs in the atria. Similar to humans, increased persistent Na+ current leads to the development of an atrial myopathy and spontaneous and long-lasting episodes of AF in mice. How increased persistent Na+ current causes both structural and electrophysiological remodeling in the atria is unknown. We crossbred mice expressing human F1759A-NaV1.5 channels with mice expressing human mitochondrial catalase (mCAT). Increased expression of mCAT attenuated mitochondrial and cellular reactive oxygen species (ROS) and the structural remodeling that was induced by persistent F1759A-Na+ current. Despite the heterogeneously prolonged atrial action potential, which was unaffected by the reduction in ROS, the incidences of spontaneous AF, pacing-induced after-depolarizations, and AF were substantially reduced. Expression of mCAT markedly reduced persistent Na+ current-induced ryanodine receptor oxidation and dysfunction. In summary, increased persistent Na+ current in atrial cardiomyocytes, which is observed in patients with AF, induced atrial enlargement, fibrosis, mitochondrial dysmorphology, early after-depolarizations, and AF, all of which can be attenuated by resolving mitochondrial oxidative stress.
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Affiliation(s)
| | - Haikel Dridi
- Department of Physiology and Cellular Biophysics and Clyde & Helen Wu Center for Molecular Cardiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Bi-xing Chen
- Division of Cardiology, Department of Medicine, and
| | - Qi Yuan
- Department of Physiology and Cellular Biophysics and Clyde & Helen Wu Center for Molecular Cardiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | | | - Steven R. Reiken
- Department of Physiology and Cellular Biophysics and Clyde & Helen Wu Center for Molecular Cardiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | | | | | - Haajra Baksh
- Division of Cardiology, Department of Medicine, and
| | - Elaine Ma
- Division of Cardiology, Department of Medicine, and
| | | | - Ruiping Ji
- Division of Cardiology, Department of Medicine, and
| | - Yejun Lin
- Division of Cardiology, Department of Medicine, and
| | | | - W. Jonathan Lederer
- Center for Biomedical Engineering and Technology and Department of Physiology and
| | - Humberto C. Joca
- Center for Biomedical Engineering and Technology and Department of Physiology and
| | - Christopher W. Ward
- Center for Biomedical Engineering and Technology and Department of Physiology and
- Department of Orthopaedics, University of Maryland School of Medicine, Baltimore, Maryland, USA
| | - Maura Greiser
- Center for Biomedical Engineering and Technology and Department of Physiology and
| | - Andrew R. Marks
- Department of Physiology and Cellular Biophysics and Clyde & Helen Wu Center for Molecular Cardiology, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
| | - Steven O. Marx
- Division of Cardiology, Department of Medicine, and
- Department of Molecular Pharmacology and Therapeutics, Vagelos College of Physicians and Surgeons, Columbia University, New York, New York, USA
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Goette A, Lendeckel U. Atrial Cardiomyopathy: Pathophysiology and Clinical Consequences. Cells 2021; 10:cells10102605. [PMID: 34685585 PMCID: PMC8533786 DOI: 10.3390/cells10102605] [Citation(s) in RCA: 30] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2021] [Accepted: 09/26/2021] [Indexed: 12/18/2022] Open
Abstract
Around the world there are 33.5 million patients suffering from atrial fibrillation (AF) with an annual increase of 5 million cases. Most AF patients have an established form of an atrial cardiomyopathy. The concept of atrial cardiomyopathy was introduced in 2016. Thus, therapy of underlying diseases and atrial tissue changes appear as a cornerstone of AF therapy. Furthermore, therapy or prevention of atrial endocardial changes has the potential to reduce atrial thrombogenesis and thereby cerebral stroke. The present manuscript will summarize the underlying pathophysiology and remodeling processes observed in the development of an atrial cardiomyopathy, thrombogenesis, and atrial fibrillation. In particular, the impact of oxidative stress, inflammation, diabetes, and obesity will be addressed.
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Affiliation(s)
- Andreas Goette
- Department of Cardiology and Intensive Care Medicine, St. Vincenz Hospital, 33098 Paderborn, Germany
- MAESTRIA Consortium/AFNET, 48149 Münster, Germany
- Correspondence:
| | - Uwe Lendeckel
- Institute of Medical Biochemistry and Molecular Biology, University Medicine Greifswald, 17475 Greifswald, Germany;
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Loncke J, Vervliet T, Parys JB, Kaasik A, Bultynck G. Uniting the divergent Wolfram syndrome-linked proteins WFS1 and CISD2 as modulators of Ca 2+ signaling. Sci Signal 2021; 14:eabc6165. [PMID: 34582248 DOI: 10.1126/scisignal.abc6165] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
[Figure: see text].
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Affiliation(s)
- Jens Loncke
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Tim Vervliet
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Jan B Parys
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, BE-3000 Leuven, Belgium
| | - Allen Kaasik
- University of Tartu, Institute of Biomedicine and Translational Medicine, Department of Pharmacology, Tartu, Estonia
| | - Geert Bultynck
- KU Leuven, Laboratory for Molecular and Cellular Signaling, Department of Cellular and Molecular Medicine, Leuven Kanker Instituut, Campus Gasthuisberg O/N-1 B-802, Herestraat 49, BE-3000 Leuven, Belgium
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46
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Miguel-Dos-Santos R, Moreira JBN, Loennechen JP, Wisløff U, Mesquita T. Exercising immune cells: The immunomodulatory role of exercise on atrial fibrillation. Prog Cardiovasc Dis 2021; 68:52-59. [PMID: 34274371 DOI: 10.1016/j.pcad.2021.07.008] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2021] [Accepted: 07/12/2021] [Indexed: 12/17/2022]
Abstract
Exercise training is generally beneficial for cardiovascular health, improving stroke volume, cardiac output, and aerobic capacity. Despite these benefits, some evidence indicates that endurance training may increase the risk of atrial fibrillation (AF), particularly in highly trained individuals. Among multiple mechanisms, autonomic tone changes and atrial remodeling have been proposed as main contributors for exercise-induced AF. However, the contribution of local and systemic immunity is poorly understood in the development of atrial arrhythmogenic substrates. Here we aim to update the field of immunomodulation in the context of exercise and AF by compiling and reconciling the most recent evidence from preclinical and human studies and rationalize the applicability of "lone" AF terminology in athletes.
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Affiliation(s)
- Rodrigo Miguel-Dos-Santos
- Department of Physiology, Federal University of Sergipe, Sergipe, Brazil; Cardiac Exercise Research Group (CERG), Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - José Bianco Nascimento Moreira
- Cardiac Exercise Research Group (CERG), Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway
| | - Jan Pål Loennechen
- Cardiac Exercise Research Group (CERG), Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; Department of Cardiology, St. Olav's University Hospital, Trondheim, Norway
| | - Ulrik Wisløff
- Cardiac Exercise Research Group (CERG), Department of Circulation and Medical Imaging, Norwegian University of Science and Technology (NTNU), Trondheim, Norway; School of Human Movement and Nutrition Science, University of Queensland, Queensland, Australia.
| | - Thássio Mesquita
- Smidt Heart Institute, Cedars-Sinai Medical Center, California, United States..
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Pabel S, Mustroph J, Stehle T, Lebek S, Dybkova N, Keyser A, Rupprecht L, Wagner S, Neef S, Maier LS, Sossalla S. Dantrolene reduces CaMKIIδC-mediated atrial arrhythmias. Europace 2021; 22:1111-1118. [PMID: 32413138 DOI: 10.1093/europace/euaa079] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/10/2020] [Accepted: 03/17/2020] [Indexed: 01/29/2023] Open
Abstract
AIMS In atrial fibrillation (AF), an increased diastolic Ca2+ leak from the sarcoplasmic reticulum (SR) mediated by calcium/calmodulin-dependent-protein-kinaseIIδC (CaMKII) can serve as a substrate for arrhythmia induction and persistence. Dantrolene has been shown to stabilize the cardiac ryanodine-receptor. This study investigated the effects of dantrolene on arrhythmogenesis in human and mouse atria with enhanced CaMKII activity. METHODS AND RESULTS Human atrial cardiomyocytes (CMs) were isolated from patients with AF. To investigate CaMKII-mediated arrhythmogenesis, atrial CMs from mice overexpressing CaMKIIδC (TG) and the respective wildtype (WT) were studied using confocal microscopy (Fluo-4), patch-clamp technique, and in vivo atrial catheter-based burst stimulations. Dantrolene potently reduced Ca2+ spark frequency (CaSpF) and diastolic SR Ca2+ leak in AF CMs. Additional CaMKII inhibition did not further reduce CaSpF or leak compared to dantrolene alone. While the increased SR CaSpF and leak in TG mice were reduced by dantrolene, no effects could be detected in WT. Dantrolene also potently reduced the pathologically enhanced frequency of diastolic SR Ca2+ waves in TG without having effects in WT. As an increased diastolic SR Ca2+ release can induce a depolarizing transient inward current, we could demonstrate that the incidence of afterdepolarizations in TG, but not in WT, mice was significantly diminished in the presence of dantrolene. To translate these findings into an in vivo situation we could show that dantrolene strongly suppressed the inducibility of AF in vivo in TG mice. CONCLUSION Dantrolene reduces CaMKII-mediated atrial arrhythmogenesis and may therefore constitute an interesting antiarrhythmic drug for treating patients with atrial arrhythmias driven by an enhanced CaMKII activity, such as AF.
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Affiliation(s)
- Steffen Pabel
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Julian Mustroph
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Thea Stehle
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Simon Lebek
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Nataliya Dybkova
- Clinic for Cardiology & Pneumology, Georg-August University Göttingen, DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075 Göttingen, Germany
| | - Andreas Keyser
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Leopold Rupprecht
- Department of Cardiothoracic Surgery, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Stefan Wagner
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Stefan Neef
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Lars S Maier
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany
| | - Samuel Sossalla
- Department of Internal Medicine II, University Medical Center Regensburg, Franz-Josef-Strauß-Allee 11, 93053 Regensburg, Germany.,Clinic for Cardiology & Pneumology, Georg-August University Göttingen, DZHK (German Center for Cardiovascular Research), Partner Site Göttingen, Robert Koch Str. 40, 37075 Göttingen, Germany
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Mitochondrial Dysfunction in Atrial Fibrillation-Mechanisms and Pharmacological Interventions. J Clin Med 2021; 10:jcm10112385. [PMID: 34071563 PMCID: PMC8199309 DOI: 10.3390/jcm10112385] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 05/20/2021] [Accepted: 05/25/2021] [Indexed: 12/22/2022] Open
Abstract
Despite the enormous progress in the treatment of atrial fibrillation, mainly with the use of invasive techniques, many questions remain unanswered regarding the pathomechanism of the arrhythmia and its prevention methods. The development of atrial fibrillation requires functional changes in the myocardium that result from disturbed ionic fluxes and altered electrophysiology of the cardiomyocyte. Electrical instability and electrical remodeling underlying the arrhythmia may result from a cellular energy deficit and oxidative stress, which are caused by mitochondrial dysfunction. The significance of mitochondrial dysfunction in the pathogenesis of atrial fibrillation remains not fully elucidated; however, it is emphasized by the reduction of atrial fibrillation burden after therapeutic interventions improving the mitochondrial welfare. This review summarizes the mechanisms of mitochondrial dysfunction related to atrial fibrillation and current pharmacological treatment options targeting mitochondria to prevent or improve the outcome of atrial fibrillation.
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Identification of loss-of-function RyR2 mutations associated with idiopathic ventricular fibrillation and sudden death. Biosci Rep 2021; 41:228220. [PMID: 33825858 PMCID: PMC8062958 DOI: 10.1042/bsr20210209] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2021] [Revised: 03/24/2021] [Accepted: 04/06/2021] [Indexed: 11/23/2022] Open
Abstract
Mutations in cardiac ryanodine receptor (RyR2) are linked to catecholaminergic polymorphic ventricular tachycardia (CPVT). Most CPVT RyR2 mutations characterized are gain-of-function (GOF), indicating enhanced RyR2 function as a major cause of CPVT. Loss-of-function (LOF) RyR2 mutations have also been identified and are linked to a distinct entity of cardiac arrhythmia termed RyR2 Ca2+ release deficiency syndrome (CRDS). Exercise stress testing (EST) is routinely used to diagnose CPVT, but it is ineffective for CRDS. There is currently no effective diagnostic tool for CRDS in humans. An alternative strategy to assess the risk for CRDS is to directly determine the functional impact of the associated RyR2 mutations. To this end, we have functionally screened 18 RyR2 mutations that are associated with idiopathic ventricular fibrillation (IVF) or sudden death. We found two additional RyR2 LOF mutations E4146K and G4935R. The E4146K mutation markedly suppressed caffeine activation of RyR2 and abolished store overload induced Ca2+ release (SOICR) in human embryonic kidney 293 (HEK293) cells. E4146K also severely reduced cytosolic Ca2+ activation and abolished luminal Ca2+ activation of single RyR2 channels. The G4935R mutation completely abolished caffeine activation of and [3H]ryanodine binding to RyR2. Co-expression studies showed that the G4935R mutation exerted dominant negative impact on the RyR2 wildtype (WT) channel. Interestingly, the RyR2-G4935R mutant carrier had a negative EST, and the E4146K carrier had a family history of sudden death during sleep, which are different from phenotypes of typical CPVT. Thus, our data further support the link between RyR2 LOF and a new entity of cardiac arrhythmias distinct from CPVT.
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Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia, largely associated to morbidity and mortality. Over the past decades, research in appearance and progression of this arrhythmia have turned into significant advances in its management. However, the incidence of AF continues to increase with the aging of the population and many important fundamental and translational underlaying mechanisms remain elusive. Here, we review recent advances in molecular and cellular basis for AF initiation, maintenance and progression. We first provide an overview of the basic molecular and electrophysiological mechanisms that lead and characterize AF. Next, we discuss the upstream regulatory factors conducting the underlying mechanisms which drive electrical and structural AF-associated remodeling, including genetic factors (risk variants associated to AF as transcriptional regulators and genetic changes associated to AF), neurohormonal regulation (i.e., cAMP) and oxidative stress imbalance (cGMP and mitochondrial dysfunction). Finally, we discuss the potential therapeutic implications of those findings, the knowledge gaps and consider future approaches to improve clinical management.
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