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Wang Q, Yuan J, Shen H, Zhu Q, Chen B, Wang J, Zhu W, Yorek MA, Hall DD, Wang Z, Song LS. Calpain inhibition protects against atrial fibrillation by mitigating diabetes-associated atrial fibrosis and calcium handling dysfunction in type 2 diabetes mice. Heart Rhythm 2024; 21:1143-1151. [PMID: 38395244 DOI: 10.1016/j.hrthm.2024.02.036] [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: 12/06/2023] [Revised: 02/13/2024] [Accepted: 02/15/2024] [Indexed: 02/25/2024]
Abstract
BACKGROUND Diabetes mellitus (DM) is a major risk factor for atrial structural remodeling and atrial fibrillation (AF). Calpain activity is hypothesized to promote atrial remodeling and AF. OBJECTIVE The purpose of this study was to investigate the role of calpain in diabetes-associated AF, fibrosis, and calcium handling dysfunction. METHODS DM-associated AF was induced in wild-type (WT) mice and in mice overexpressing the calpain inhibitor calpastatin (CAST-OE) using high-fat diet feeding followed by low-dose streptozotocin injection (75 mg/kg). DM and AF outcomes were assessed by measuring blood glucose levels, fibrosis, and AF susceptibility during transesophageal atrial pacing. Intracellular Ca2+ transients, spontaneous Ca2+ release events, and intracellular T-tubule membranes were measured by in situ confocal microscopy. RESULTS WT mice with DM had significant hyperglycemia, atrial fibrosis, and AF susceptibility with increased atrial myocyte calpain activity and Ca2+ handling dysfunction relative to control treated animals. CAST-OE mice with DM had a similar level of hyperglycemia as diabetic WT littermates but lacked significant atrial fibrosis and AF susceptibility. DM-induced atrial calpain activity and downregulation of the calpain substrate junctophilin-2 were prevented by CAST-OE. Atrial myocytes of diabetic CAST-OE mice exhibited improved T-tubule membrane organization, Ca2+ handling, and reduced spontaneous Ca2+ release events compared to littermate controls. CONCLUSION This study confirmed that DM promotes calpain activation, atrial fibrosis, and AF in mice. CAST-OE effectively inhibits DM-induced calpain activation and reduces atrial remodeling and AF incidence through improved intracellular Ca2+ homeostasis. Our results support calpain inhibition as a potential therapy for preventing and treating AF in DM patients.
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Affiliation(s)
- Qing Wang
- Department of Thoracic Surgery, Shanghai Chest Hospital, Shanghai Jiaotong University School of Medicine, Shanghai, China; The Collaborative Innovation Center, Jining Medical University, Jining, Shandong, China; Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Jinxiang Yuan
- The Collaborative Innovation Center, Jining Medical University, Jining, Shandong, China; Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Hua Shen
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa; Department of Cardiovascular Surgery, Chinese PLA General Hospital, Beijing, China
| | - Qi Zhu
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa; Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China
| | - Biyi Chen
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Jinxi Wang
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Weizhong Zhu
- Department of Pharmacology, School of Pharmacy, Nantong University, Nantong, Jiangsu, China
| | - Mark A Yorek
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa; Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa
| | - Duane D Hall
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa
| | - Zhinong Wang
- Department of Cardiothoracic Surgery, Changzheng Hospital, Naval Medical University, Shanghai, China.
| | - Long-Sheng Song
- Department of Internal Medicine, University of Iowa Carver College of Medicine, Iowa City, Iowa; Department of Veterans Affairs Iowa City Health Care System, Iowa City, Iowa; Fraternal Order of Eagles Diabetes Research Center, University of Iowa, Iowa City, Iowa.
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2
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Yang Z, Cao Y, Kong L, Xi J, Liu S, Zhang J, Cheng W. Small molecules as modulators of the proteostasis machinery: Implication in cardiovascular diseases. Eur J Med Chem 2024; 264:116030. [PMID: 38071793 DOI: 10.1016/j.ejmech.2023.116030] [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: 10/05/2023] [Revised: 11/25/2023] [Accepted: 12/03/2023] [Indexed: 12/30/2023]
Abstract
With the escalating prevalence of cardiovascular diseases, the substantial socioeconomic burden on healthcare systems is intensifying. Accumulating empirical evidence underscores the pivotal role of the proteostasis network in regulating cardiac homeostasis and function. Disruptions in proteostasis may contribute to the loss of protein function or the acquisition of toxic functions, which are intricately linked to the development of cardiovascular ailments such as atrial fibrillation, heart failure, atherosclerosis, and cardiac aging. It is widely acknowledged that the proteostasis network encompasses molecular chaperones, autophagy, and the ubiquitin proteasome system (UPS). Consequently, the proteostasis network emerges as an appealing target for therapeutic interventions in cardiovascular diseases. Numerous small molecules, acting as modulators of the proteostasis machinery, have exhibited therapeutic efficacy in managing cardiovascular diseases. This review centers on elucidating the role of the proteostasis network in various cardiovascular diseases and explores the potential of small molecules as therapeutic agents.
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Affiliation(s)
- Zhiheng Yang
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China
| | - Yu Cao
- Department of Pharmaceutical Preparation, Hangzhou Xixi Hospital, Hangzhou, 310023, China
| | - Limin Kong
- Department of Clinical Pharmacy, The First Affiliated Hospital, Zhejiang University School of Medicine, China
| | - Jianjun Xi
- Department of Pharmaceutical Preparation, Hangzhou Xixi Hospital, Hangzhou, 310023, China
| | - Shourong Liu
- Department of Pharmaceutical Preparation, Hangzhou Xixi Hospital, Hangzhou, 310023, China.
| | - Jiankang Zhang
- Key Laboratory of Novel Targets and Drug Study for Neural Repair of Zhejiang Province, School of Medicine, Hangzhou City University, Hangzhou, 310015, China.
| | - Weiyan Cheng
- Department of Pharmacy, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, 450052, China.
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3
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Rennison JH, Van Wagoner DR. Dysregulated Ca2+ cycling in atrial fibrillation. Eur Heart J 2023; 44:2495-2497. [PMID: 37012620 PMCID: PMC10344643 DOI: 10.1093/eurheartj/ehad099] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 04/05/2023] Open
Affiliation(s)
- Julie H Rennison
- Department of Cardiovascular & Metabolic Sciences, Cleveland Clinic, M/S ND-50, 9500 Euclid Avenue, Cleveland, OH 44195, USA
| | - David R Van Wagoner
- Department of Cardiovascular & Metabolic Sciences, Cleveland Clinic, M/S ND-50, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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4
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Kishore P, Collinet ACT, Brundel BJJM. Prevention of Atrial Fibrillation: Putting Proteostasis Derailment Back on Track. J Clin Med 2023; 12:4352. [PMID: 37445387 DOI: 10.3390/jcm12134352] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 06/21/2023] [Accepted: 06/23/2023] [Indexed: 07/15/2023] Open
Abstract
Despite the many attempts to treat atrial fibrillation (AF), the most common cardiac tachyarrhythmia in the Western world, the treatment efficacy of AF is still suboptimal. A plausible reason for the suboptimal efficacy is that the current treatments are not directed at the underlying molecular mechanisms that drive AF. Recent discoveries revealed that the derailment of specific molecular proteostasis pathways drive electrical conduction disorders, contractile dysfunction and AF. The degree of this so-called 'electropathology' corresponds to the response to anti-AF treatment. Hence, to develop effective therapies to prevent AF, understanding the molecular mechanisms is of key importance. In this review, we highlight the key modulators of proteostasis derailment and describe the mechanisms that explain how they affect electrical and contractile function in atrial cardiomyocytes and AF. The key modulators of proteostasis derailment include (1) exhaustion of cardioprotective heat shock proteins (HSPs), (2) excessive endoplasmic reticulum (ER) stress and downstream autophagic protein degradation, (3) histone deacetylase 6 (HDAC6)-induced microtubule disruption, (4) activation of DNA damage-PARP1 activation and NAD+ axis and (5) mitochondrial dysfunction. Furthermore, we discuss druggable targets within these pathways that are involved in the prevention of proteostasis derailment, as well as the targets that aid in the recovery from AF. Finally, we will elaborate on the most favorable druggable targets for (future) testing in patients with AF, as well as drugs with potential benefits for AF recovery.
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Affiliation(s)
- Preetam Kishore
- Physiology, Amsterdam UMC, Vrije Universiteit, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, 1081 HZ Amsterdam, The Netherlands
| | - Amelie C T Collinet
- Physiology, Amsterdam UMC, Vrije Universiteit, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, 1081 HZ Amsterdam, The Netherlands
| | - Bianca J J M Brundel
- Physiology, Amsterdam UMC, Vrije Universiteit, Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, 1081 HZ Amsterdam, The Netherlands
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5
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Jabr RI, Salvage SC, Hatch FS, Fry CH. Calcineurin-dependent regulation of gap junction conductance and connexin phosphorylation in guinea pig left atrium. Pflugers Arch 2023; 475:583-593. [PMID: 36917272 PMCID: PMC10105670 DOI: 10.1007/s00424-023-02798-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2022] [Revised: 02/18/2023] [Accepted: 02/20/2023] [Indexed: 03/16/2023]
Abstract
Atrial fibrillation (AF) occurs from disordered atrial action potential conduction and is associated with reduced gap junction electrical conductance (Gj). The Ca2+ and calmodulin-dependent phosphatase, calcineurin, reduces Gj in ventricular myocardium via a protein phosphatase-1 (PP1)-dependent pathway culminating in phosphorylation of serine368 on connexin43 (pSer368-Cx43). However, characterisation of corresponding pathways in left atrial myocardium, which have a more complex connexin subtype profile, is undefined and was the aim of this study. Gj was measured in guinea-pig left atrium from the frequency-dependent variation of intracellular impedance; intracellular [Ca2+], ([Ca2+]i) in low-Na solution was measured by Fura-2 fluorescence. Phosphorylation of guinea-pig Ser368-Cx43 residues was measured by Western blot; Cx40 was immunoprecipitated and probed for serine/threonine residue phosphorylation. Low-Na solution reversibly reduced Gj, in turn attenuated or prevented by calcineurin inhibitors cyclosporin-A or CAIP, respectively. Moreover, Ser368-Cx43 phosphorylation in low-Na solution was also prevented by CAIP. Changes were partially prevented by fostreicin (FST), a protein phosphatase-2A (PP2A) inhibitor; but not by tautomycin, a PP1 inhibitor. Serine/threonine residues on Cx40 were also phosphorylated in low-Na solution; prevented by CAIP and attenuated by FST. Reduced Gj with raised [Ca2+]i is paralleled by a changed Cx43/Cx40 phosphorylation status; changes mediated by calcineurin and PP2A-dependent pathways, but not PP1. The pharmacological profile underlying changes to guinea-pig atrial gap junction electrical conductance with raised intracellular [Ca2+]i is fundamentally different from that in ventricular myocardium. This provides a targeted drug model whereby atrial and ventricular myocardium can be selectively targeted to correct conduction defects.
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Affiliation(s)
- R I Jabr
- Department of Neuroscience, Physiology & Pharmacology, University College London, London, UK
| | - S C Salvage
- Department of Biochemistry, University of Cambridge, Cambridge, UK
| | - F S Hatch
- Department of Biochemistry and Physiology, Surrey University, Guildford, UK
| | - C H Fry
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Biomedical Sciences Building, University Walk, Bristol, BS8 1TD, UK.
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6
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Su W, van Wijk SW, Brundel BJJM. Desmin variants: Trigger for cardiac arrhythmias? Front Cell Dev Biol 2022; 10:986718. [PMID: 36158202 PMCID: PMC9500482 DOI: 10.3389/fcell.2022.986718] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Accepted: 08/22/2022] [Indexed: 11/30/2022] Open
Abstract
Desmin (DES) is a classical type III intermediate filament protein encoded by the DES gene. Desmin is abundantly expressed in cardiac, skeletal, and smooth muscle cells. In these cells, desmin interconnects several protein-protein complexes that cover cell-cell contact, intracellular organelles such as mitochondria and the nucleus, and the cytoskeletal network. The extra- and intracellular localization of the desmin network reveals its crucial role in maintaining the structural and mechanical integrity of cells. In the heart, desmin is present in specific structures of the cardiac conduction system including the sinoatrial node, atrioventricular node, and His-Purkinje system. Genetic variations and loss of desmin drive a variety of conditions, so-called desminopathies, which include desmin-related cardiomyopathy, conduction system-related atrial and ventricular arrhythmias, and sudden cardiac death. The severe cardiac disease outcomes emphasize the clinical need to understand the molecular and cellular role of desmin driving desminopathies. As the role of desmin in cardiomyopathies has been discussed thoroughly, the current review is focused on the role of desmin impairment as a trigger for cardiac arrhythmias. Here, the molecular and cellular mechanisms of desmin to underlie a healthy cardiac conduction system and how impaired desmin triggers cardiac arrhythmias, including atrial fibrillation, are discussed. Furthermore, an overview of available (genetic) desmin model systems for experimental cardiac arrhythmia studies is provided. Finally, potential implications for future clinical treatments of cardiac arrhythmias directed at desmin are highlighted.
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Affiliation(s)
- Wei Su
- Physiology, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Stan W. van Wijk
- Physiology, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
| | - Bianca J. J. M. Brundel
- Physiology, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam UMC Location Vrije Universiteit Amsterdam, Amsterdam, Netherlands
- *Correspondence: Bianca J. J. M. Brundel,
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7
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Abstract
Atrial fibrillation (AF) is the most common cardiac arrhythmia despite substantial efforts to understand the pathophysiology of the condition and develop improved treatments. Identifying the underlying causative mechanisms of AF in individual patients is difficult and the efficacy of current therapies is suboptimal. Consequently, the incidence of AF is steadily rising and there is a pressing need for novel therapies. Research has revealed that defects in specific molecular pathways underlie AF pathogenesis, resulting in electrical conduction disorders that drive AF. The severity of this so-called electropathology correlates with the stage of AF disease progression and determines the response to AF treatment. Therefore, unravelling the molecular mechanisms underlying electropathology is expected to fuel the development of innovative personalized diagnostic tools and mechanism-based therapies. Moreover, the co-creation of AF studies with patients to implement novel diagnostic tools and therapies is a prerequisite for successful personalized AF management. Currently, various treatment modalities targeting AF-related electropathology, including lifestyle changes, pharmaceutical and nutraceutical therapy, substrate-based ablative therapy, and neuromodulation, are available to maintain sinus rhythm and might offer a novel holistic strategy to treat AF.
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Affiliation(s)
- Bianca J J M Brundel
- Department of Physiology, Amsterdam University Medical Centers, VU Universiteit, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.
| | - Xun Ai
- Department of Physiology and Cell Biology, College of Medicine/Wexner Medical Center, The Ohio State University, Columbus, OH, USA
| | | | - Myrthe F Kuipers
- AFIPonline.org, Atrial Fibrillation Innovation Platform, Amsterdam, Netherlands
| | - Gregory Y H Lip
- Liverpool Centre for Cardiovascular Science, University of Liverpool and Liverpool Heart & Chest Hospital, Liverpool, UK
- Department of Clinical Medicine, Aalborg University, Aalborg, Denmark
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8
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Correlation between genetic polymorphisms in apolipoprotein E and atrial fibrillation. Rev Port Cardiol 2022; 41:417-423. [PMID: 36062643 DOI: 10.1016/j.repc.2021.03.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 11/22/2022] Open
Abstract
This work explores correlations between genetic polymorphisms in apolipoprotein E (ApoE) and atrial fibrillation (AF). We detected polymorphisms in the APOE gene in 64 patients with AF and 49 non-AF volunteers at the Department of Cardiology of Lianyungang Second People's Hospital between July 2017 and July 2019. We found significant differences in age, body mass index, left atrial diameter, and left ventricular ejection fraction between the two groups. Six APOE genotypes were observed: ɛ2/ɛ2; ɛ2/ɛ3; ɛ2/ɛ4; ɛ3/ɛ3; ɛ3/ɛ4; and ɛ4/ɛ4. The ɛ3/ɛ3 genotype was significantly less frequent in the AF group than in the control group, while the ɛ3/ɛ4 and ɛ4/ɛ4 genotypes were significantly more frequent in the AF group than in the control group (p<0.05). ApoE3 penetrance was significantly lower in the AF group than in the control group (p<0.05), while ApoE4 penetrance was significantly higher in the AF group than in the control group (p<0.05). ApoE3 penetrance was significantly lower in the AF group than in the control group (p<0.05). Binary logistic regression analysis showed that age, body mass index, left atrial diameter, left ventricular ejection fraction, and ApoE4 were risk factors for AF. Finally, we found that ApoE polymorphisms impacted the occurrence of AF and that ApoE4 is an AF-sensitive phenotype.
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9
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Cytoskeletal Protein Variants Driving Atrial Fibrillation: Potential Mechanisms of Action. Cells 2022; 11:cells11030416. [PMID: 35159226 PMCID: PMC8834312 DOI: 10.3390/cells11030416] [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: 12/10/2021] [Revised: 01/15/2022] [Accepted: 01/20/2022] [Indexed: 11/16/2022] Open
Abstract
The most common clinical tachyarrhythmia, atrial fibrillation (AF), is present in 1-2% of the population. Although common risk factors, including hypertension, diabetes, and obesity, frequently underlie AF onset, it has been recognized that in 15% of the AF population, AF is familial. In these families, genome and exome sequencing techniques identified variants in the non-coding genome (i.e., variant regulatory elements), genes encoding ion channels, as well as genes encoding cytoskeletal (-associated) proteins. Cytoskeletal protein variants include variants in desmin, lamin A/C, titin, myosin heavy and light chain, junctophilin, nucleoporin, nesprin, and filamin C. These cytoskeletal protein variants have a strong association with the development of cardiomyopathy. Interestingly, AF onset is often represented as the initial manifestation of cardiac disease, sometimes even preceding cardiomyopathy by several years. Although emerging research findings reveal cytoskeletal protein variants to disrupt the cardiomyocyte structure and trigger DNA damage, exploration of the pathophysiological mechanisms of genetic AF is still in its infancy. In this review, we provide an overview of cytoskeletal (-associated) gene variants that relate to genetic AF and highlight potential pathophysiological pathways that drive this arrhythmia.
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10
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Papathanasiou KA, Giotaki SG, Vrachatis DA, Siasos G, Lambadiari V, Iliodromitis KE, Kossyvakis C, Kaoukis A, Raisakis K, Deftereos G, Papaioannou TG, Giannopoulos G, Avramides D, Deftereos SG. Molecular Insights in Atrial Fibrillation Pathogenesis and Therapeutics: A Narrative Review. Diagnostics (Basel) 2021; 11:diagnostics11091584. [PMID: 34573926 PMCID: PMC8470040 DOI: 10.3390/diagnostics11091584] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Revised: 08/29/2021] [Accepted: 08/30/2021] [Indexed: 12/15/2022] Open
Abstract
The prevalence of atrial fibrillation (AF) is bound to increase globally in the following years, affecting the quality of life of millions of people, increasing mortality and morbidity, and beleaguering health care systems. Increasingly effective therapeutic options against AF are the constantly evolving electroanatomic substrate mapping systems of the left atrium (LA) and ablation catheter technologies. Yet, a prerequisite for better long-term success rates is the understanding of AF pathogenesis and maintenance. LA electrical and anatomical remodeling remains in the epicenter of current research for novel diagnostic and treatment modalities. On a molecular level, electrical remodeling lies on impaired calcium handling, enhanced inwardly rectifying potassium currents, and gap junction perturbations. In addition, a wide array of profibrotic stimuli activates fibroblast to an increased extracellular matrix turnover via various intermediaries. Concomitant dysregulation of the autonomic nervous system and the humoral function of increased epicardial adipose tissue (EAT) are established mediators in the pathophysiology of AF. Local atrial lymphomononuclear cells infiltrate and increased inflammasome activity accelerate and perpetuate arrhythmia substrate. Finally, impaired intracellular protein metabolism, excessive oxidative stress, and mitochondrial dysfunction deplete atrial cardiomyocyte ATP and promote arrhythmogenesis. These overlapping cellular and molecular alterations hinder us from distinguishing the cause from the effect in AF pathogenesis. Yet, a plethora of therapeutic modalities target these molecular perturbations and hold promise in combating the AF burden. Namely, atrial selective ion channel inhibitors, AF gene therapy, anti-fibrotic agents, AF drug repurposing, immunomodulators, and indirect cardiac neuromodulation are discussed here.
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Affiliation(s)
- Konstantinos A. Papathanasiou
- Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (K.A.P.); (S.G.G.); (D.A.V.); (G.S.); (V.L.); (T.G.P.)
| | - Sotiria G. Giotaki
- Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (K.A.P.); (S.G.G.); (D.A.V.); (G.S.); (V.L.); (T.G.P.)
| | - Dimitrios A. Vrachatis
- Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (K.A.P.); (S.G.G.); (D.A.V.); (G.S.); (V.L.); (T.G.P.)
| | - Gerasimos Siasos
- Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (K.A.P.); (S.G.G.); (D.A.V.); (G.S.); (V.L.); (T.G.P.)
| | - Vaia Lambadiari
- Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (K.A.P.); (S.G.G.); (D.A.V.); (G.S.); (V.L.); (T.G.P.)
| | | | - Charalampos Kossyvakis
- Department of Cardiology, “G. Gennimatas” General Hospital of Athens, 11527 Athens, Greece; (C.K.); (A.K.); (K.R.); (G.D.); (D.A.)
| | - Andreas Kaoukis
- Department of Cardiology, “G. Gennimatas” General Hospital of Athens, 11527 Athens, Greece; (C.K.); (A.K.); (K.R.); (G.D.); (D.A.)
| | - Konstantinos Raisakis
- Department of Cardiology, “G. Gennimatas” General Hospital of Athens, 11527 Athens, Greece; (C.K.); (A.K.); (K.R.); (G.D.); (D.A.)
| | - Gerasimos Deftereos
- Department of Cardiology, “G. Gennimatas” General Hospital of Athens, 11527 Athens, Greece; (C.K.); (A.K.); (K.R.); (G.D.); (D.A.)
| | - Theodore G. Papaioannou
- Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (K.A.P.); (S.G.G.); (D.A.V.); (G.S.); (V.L.); (T.G.P.)
| | | | - Dimitrios Avramides
- Department of Cardiology, “G. Gennimatas” General Hospital of Athens, 11527 Athens, Greece; (C.K.); (A.K.); (K.R.); (G.D.); (D.A.)
| | - Spyridon G. Deftereos
- Medical School, National and Kapodistrian University of Athens, 11527 Athens, Greece; (K.A.P.); (S.G.G.); (D.A.V.); (G.S.); (V.L.); (T.G.P.)
- Correspondence: ; Tel.: +30-21-0583-2355
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11
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van Wijk SW, Ramos KS, Brundel BJJM. Cardioprotective Role of Heat Shock Proteins in Atrial Fibrillation: From Mechanism of Action to Therapeutic and Diagnostic Target. Int J Mol Sci 2021; 22:ijms22010442. [PMID: 33466228 PMCID: PMC7795054 DOI: 10.3390/ijms22010442] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Revised: 12/30/2020] [Accepted: 12/31/2020] [Indexed: 02/07/2023] Open
Abstract
Atrial fibrillation (AF) is the most common age-related cardiac arrhythmia worldwide and is associated with ischemic stroke, heart failure, and substantial morbidity and mortality. Unfortunately, current AF therapy is only moderately effective and does not prevent AF progression from recurrent intermittent episodes (paroxysmal) to persistent and finally permanent AF. It has been recognized that AF persistence is related to the presence of electropathology. Electropathology is defined as structural damage, including degradation of sarcomere structures, in the atrial tissue which, in turn, impairs electrical conduction and subsequently the contractile function of atrial cardiomyocytes. Recent research findings indicate that derailed proteostasis underlies structural damage and, consequently, electrical conduction impairment. A healthy proteostasis is of vital importance for proper function of cells, including cardiomyocytes. Cells respond to a loss of proteostatic control by inducing a heat shock response (HSR), which results in heat shock protein (HSP) expression. Emerging clinical evidence indicates that AF-induced proteostasis derailment is rooted in exhaustion of HSPs. Cardiomyocytes lose defense against structural damage-inducing pathways, which drives progression of AF and induction of HSP expression. In particular, small HSPB1 conserves sarcomere structures by preventing their degradation by proteases, and overexpression of HSPB1 accelerates recovery from structural damage in experimental AF model systems. In this review, we provide an overview of the mechanisms of action of HSPs in preventing AF and discuss the therapeutic potential of HSP-inducing compounds in clinical AF, as well as the potential of HSPs as biomarkers to discriminate between the various stages of AF and recurrence of AF after treatment.
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Affiliation(s)
- Stan W. van Wijk
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands; (K.S.R.); (B.J.J.M.B.)
- Correspondence:
| | - Kennedy S. Ramos
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands; (K.S.R.); (B.J.J.M.B.)
- Erasmus Medical Center, Department of Cardiology, 3015 GD Rotterdam, The Netherlands
| | - Bianca J. J. M. Brundel
- Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam UMC, Vrije Universiteit Amsterdam, 1081 HZ Amsterdam, The Netherlands; (K.S.R.); (B.J.J.M.B.)
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12
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Ezeani M, Prabhu S. Pathophysiology and therapeutic relevance of PI3K(p110α) protein in atrial fibrillation: A non-interventional molecular therapy strategy. Pharmacol Res 2021; 165:105415. [PMID: 33412279 DOI: 10.1016/j.phrs.2020.105415] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2020] [Revised: 12/04/2020] [Accepted: 12/23/2020] [Indexed: 10/22/2022]
Abstract
Genetically modified animal studies have revealed specific expression patterns and unequivocal roles of class I PI3K isoenzymes. PI3K(p110α), a catalytic subunit of class I PI3Ks is ubiquitously expressed and is well characterised in the cardiovascular system. Given that genetic inhibition of PI3K(p110α) causes lethal phenotype embryonically, the catalytic subunit is critically important in housekeeping and biological processes. A growing number of studies underpin crucial roles of PI3K(p110α) in cell survival, proliferation, hypertrophy and arrhythmogenesis. While the studies provide great insights, the precise mechanisms involved in PI3K(p110α) hypofunction and atrial fibrillation (AF) are not fully known. AF is a well recognised clinical problem with significant management limitations. In this translational review, we attempted a narration of PI3K(p110α) hypofunction in the molecular basis of AF pathophysiology. We sought to cautiously highlight the relevance of this molecule in the therapeutic approaches for AF management per se (i.e without conditions associate with cell proliferation, like cancer), and in mitigating effects of clinical risk factors in atrial substrate formation leading to AF progression. We also considered PI3K(p110α) in AF gene association, with the aim of identifying mechanistic links between the ever increasingly well-defined genetic loci (regions and genes) and AF. Such mechanisms will aid in identifying new drug targets for arrhythmogenic substrate and AF.
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Affiliation(s)
- Martin Ezeani
- NanoBiotechnology Laboratory, Australian Centre for Blood Diseases, Central Clinical School, Monash University, Melbourne, Victoria, 3004, Australia.
| | - Sandeep Prabhu
- The Alfred, and Baker Heart and Diabetes Institute, Melbourne, Australia; University of Melbourne, Melbourne, Australia
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13
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Kim YM, Lakin R, Zhang H, Liu J, Sachedina A, Singh M, Wilson E, Perez M, Verma S, Quertermous T, Olgin J, Backx PH, Ashley EA. Apelin increases atrial conduction velocity, refractoriness, and prevents inducibility of atrial fibrillation. JCI Insight 2020; 5:126525. [PMID: 32879139 PMCID: PMC7526452 DOI: 10.1172/jci.insight.126525] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Accepted: 07/22/2020] [Indexed: 11/17/2022] Open
Abstract
Previous studies have shown an association between elevated atrial NADPH-dependent oxidative stress and decreased plasma apelin in patients with atrial fibrillation (AF), though the basis for this relationship is unclear. In the current study, RT-PCR and immunofluorescence studies of human right atrial appendages (RAAs) showed expression of the apelin receptor, APJ, and reduced apelin content in the atria, but not in plasma, of patients with AF versus normal sinus rhythm. Disruption of the apelin gene in mice increased (2.4-fold) NADPH-stimulated superoxide levels and slowed atrial conduction velocities in optical mapping of a Langendorff-perfused isolated heart model, suggesting that apelin levels may influence AF vulnerability. Indeed, in mice with increased AF vulnerability (induced by chronic intense exercise), apelin administration reduced the incidence and duration of induced atrial arrhythmias in association with prolonged atrial refractory periods. Moreover, apelin decreased AF induction in isolated atria from exercised mice while accelerating conduction velocity and increasing action potential durations. At the cellular level, these changes were associated with increased atrial cardiomyocyte sodium currents. These findings support the conclusion that reduced atrial apelin is maladaptive in fibrillating human atrial myocardium and that increasing apelin bioavailability may be a worthwhile therapeutic strategy for treating and preventing AF.
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Affiliation(s)
- Young M Kim
- Division of Cardiovascular Medicine, Stanford Medicine, Stanford, California, USA
| | - Robert Lakin
- Department of Biology, York University, Toronto, Ontario, Canada.,Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Hao Zhang
- Division of Cardiovascular Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Jack Liu
- Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Ayaaz Sachedina
- Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Maneesh Singh
- Division of Cardiovascular Medicine, Stanford Medicine, Stanford, California, USA
| | - Emily Wilson
- Division of Cardiovascular Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Marco Perez
- Division of Cardiovascular Medicine, Stanford Medicine, Stanford, California, USA
| | - Subodh Verma
- Department of Biology, York University, Toronto, Ontario, Canada
| | - Thomas Quertermous
- Division of Cardiovascular Medicine, Stanford Medicine, Stanford, California, USA
| | - Jeffrey Olgin
- Division of Cardiovascular Medicine, University of California, San Francisco, San Francisco, California, USA
| | - Peter H Backx
- Department of Biology, York University, Toronto, Ontario, Canada.,Division of Cardiology, University Health Network, Toronto, Ontario, Canada
| | - Euan A Ashley
- Division of Cardiovascular Medicine, Stanford Medicine, Stanford, California, USA
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14
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Miake J. A Novel Treatment for Arrhythmias via the Control of the Degradation of Ion Channel Proteins. Yonago Acta Med 2020; 63:146-153. [PMID: 32884433 DOI: 10.33160/yam.2020.08.002] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Accepted: 06/16/2020] [Indexed: 11/05/2022]
Abstract
Although there are many reports on the regulation of ion channel expression in transcription and translation, few drugs have been studied to influence post-translational modification of ion channel proteins. The Kv1.5 channel is a potassium ion channel expressed in atrial muscle, belongs to the voltage-gated K+ channel superfamily, and forms an ultrarapid delayed rectifier potassium ion current. It is important to understand the fate of these channel proteins, as cardiac Kv1.5 mutations can cause arrhythmias. Disruption of quantitative and qualitative control mechanisms of channels leads to stagnation and degradation of intracellular channel proteins. As a result, ion channel proteins are not transported to the cell membrane and are involved in the development of atrial fibrillation. This review takes the Kv1.5 channel as an example and focuses on the degradation mechanism of ion channel proteins, and discusses its application to the treatment of arrhythmia by drugs that control the mechanism of ion channel protein degradation.
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Affiliation(s)
- Junichiro Miake
- Division of Pharmacology, Department of Pathophysiological and Therapeutic Science, School of Medicine, Faculty of Medicine, Tottori University, Yonago 683-8503, Japan
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15
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Starreveld R, Knops P, Ramos KS, Roos-Serote MC, Bogers AJJC, Brundel BJJM, de Groot NMS. Atrial fibrillation fingerprinting; spotting bio-electrical markers to early recognize atrial fibrillation by the use of a bottom-up approach (AFFIP): Rationale and design. Clin Cardiol 2020; 43:546-552. [PMID: 32304106 PMCID: PMC7298972 DOI: 10.1002/clc.23370] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/25/2020] [Revised: 03/26/2020] [Accepted: 03/30/2020] [Indexed: 12/23/2022] Open
Abstract
Background The exact pathophysiology of atrial fibrillation (AF) remains incompletely understood and treatment of AF is associated with high recurrence rates. Persistence of AF is rooted in the presence of electropathology, defined as complex electrical conduction disorders caused by structural damage of atrial tissue. The atrial fibrillation fingerprinting (AFFIP) study aims to characterize electropathology, enabling development of a novel diagnostic instrument to predict AF onset and early progression. Hypotheses History of AF, development of post‐operative AF, age, gender, underlying heart disease, and other clinical characteristics impact the degree of electropathology. Methods This study is a prospective observational study with a planned duration of 48 months. Three study groups are defined: (1) patients with (longstanding) persistent AF, (2) patients with paroxysmal AF, and (3) patients without a history of AF, all undergoing open‐chest cardiac surgery. Intra‐operative high‐resolution epicardial mapping is performed to identify the patient‐specific electrical profile, whereas the patient‐specific biological profile is assessed by evaluating proteostasis markers in blood samples and atrial appendage tissue samples. Post‐operative continuous rhythm monitoring is performed for detection of early post‐operative AF. Late post‐operative AF (during 5‐year follow‐up) is documented by either electrocardiogram or 24‐hour Holter registration. Results The required sample size for this study is estimated at 447 patients. Up till now, 105 patients were included, of whom 36 have a history of AF. Conclusion The AFFIP study will elucidate whether electrophysiological and structural characteristics represent a novel diagnostic tool, the AF fingerprint, to predict onset and early progression of AF in cardiac surgery patients.
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Affiliation(s)
- Roeliene Starreveld
- Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Paul Knops
- Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Kennedy S Ramos
- Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands.,Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, UK
| | | | - Ad J J C Bogers
- Department of Cardiothoracic Surgery, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, UK
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16
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The Role of Proteostasis in the Regulation of Cardiac Intercellular Communication. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1233:279-302. [DOI: 10.1007/978-3-030-38266-7_12] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
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17
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Lanters EAH, Teuwen CP, Hokken T, Rohde S, Haitsma DB, Zijlstra F, Jordaens LJLM, de Groot NMS. Early markers of atrial fibrillation recurrence after pulmonary vein isolation. J Arrhythm 2020; 36:304-310. [PMID: 32256879 PMCID: PMC7132191 DOI: 10.1002/joa3.12307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2019] [Revised: 01/06/2020] [Accepted: 01/16/2020] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Postprocedural atrial extrasystole (AES) frequency predicts atrial fibrillation (AF) recurrence after pulmonary vein isolation (PVI) in patients with paroxysmal AF. However, the predictive value of preprocedural AES frequency is unknown. We investigate whether preprocedural AES frequency is a feasible marker to predict (timing of) AF recurrence after PVI. METHODS Patients (N = 684) with paroxysmal or persistent AF undergoing first-time PVI were evaluated for (a) the frequency of AES/day on Holter recordings without AF prior to PVI, (b) AF episodes during the 90 days blanking period, and (c) AF recurrences afterward. The correlation between AES/day and both development and timing of AF recurrences was tested. RESULTS Preprocedural AES/day was similar in patients with paroxysmal (66 [20-295] AES/day) and persistent AF (115 [12-248] AES/day, P = .915). During the blanking period, 302 (44.2%) patients showed AF episodes. AF recurred in 379 (55.4%) patients at 203 (105-400) days after PVI. AF recurred more frequently in patients with persistent (N = 104 [69.3%]) than in patients with paroxysmal AF (N = 275 [51.5%], P < .001). Frequency of AES prior to PVI was not correlated with development (P = .203) or timing (P = .478) of AF recurrences. AF recurrences occurred both more frequently (P < .001) and earlier (P < .000) in patients with AF during the blanking period. CONCLUSION AES/day prior to PVI is not correlated with (timing of) AF during the blanking period or AF recurrences, and is therefore not a feasible marker for AF recurrences in patients with PAF. AF during the blanking period is correlated with AF recurrence.
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Affiliation(s)
- Eva A. H. Lanters
- Department of CardiologyErasmus Medical CenterRotterdamThe Netherlands
| | | | - Thijmen Hokken
- Department of CardiologyErasmus Medical CenterRotterdamThe Netherlands
| | - Sofie Rohde
- Department of CardiologyErasmus Medical CenterRotterdamThe Netherlands
| | - David B. Haitsma
- Department of CardiologyErasmus Medical CenterRotterdamThe Netherlands
| | - Felix Zijlstra
- Department of CardiologyErasmus Medical CenterRotterdamThe Netherlands
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18
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Mitochondrial Dysfunction Underlies Cardiomyocyte Remodeling in Experimental and Clinical Atrial Fibrillation. Cells 2019; 8:cells8101202. [PMID: 31590355 PMCID: PMC6829298 DOI: 10.3390/cells8101202] [Citation(s) in RCA: 56] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2019] [Revised: 10/01/2019] [Accepted: 10/03/2019] [Indexed: 12/21/2022] Open
Abstract
Atrial fibrillation (AF), the most common progressive tachyarrhythmia, results in structural remodeling which impairs electrical activation of the atria, rendering them increasingly permissive to the arrhythmia. Previously, we reported on endoplasmic reticulum stress and NAD+ depletion in AF, suggesting a role for mitochondrial dysfunction in AF progression. Here, we examined mitochondrial function in experimental model systems for AF (tachypaced HL-1 atrial cardiomyocytes and Drosophila melanogaster) and validated findings in clinical AF. Tachypacing of HL-1 cardiomyocytes progressively induces mitochondrial dysfunction, evidenced by impairment of mitochondrial Ca2+-handling, upregulation of mitochondrial stress chaperones and a decrease in the mitochondrial membrane potential, respiration and ATP production. Atrial biopsies from AF patients display mitochondrial dysfunction, evidenced by aberrant ATP levels, upregulation of a mitochondrial stress chaperone and fragmentation of the mitochondrial network. The pathophysiological role of mitochondrial dysfunction is substantiated by the attenuation of AF remodeling by preventing an increased mitochondrial Ca2+-influx through partial blocking or downregulation of the mitochondrial calcium uniporter, and by SS31, a compound that improves bioenergetics in mitochondria. Together, these results show that conservation of the mitochondrial function protects against tachypacing-induced cardiomyocyte remodeling and identify this organelle as a potential novel therapeutic target.
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19
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Dilaveris P, Antoniou CK, Manolakou P, Tsiamis E, Gatzoulis K, Tousoulis D. Biomarkers Associated with Atrial Fibrosis and Remodeling. Curr Med Chem 2019; 26:780-802. [PMID: 28925871 DOI: 10.2174/0929867324666170918122502] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2016] [Revised: 12/16/2016] [Accepted: 12/23/2016] [Indexed: 12/22/2022]
Abstract
Atrial fibrillation is the most common rhythm disturbance encountered in clinical practice. Although often considered as solely arrhythmic in nature, current evidence has established that atrial myopathy constitutes both the substrate and the outcome of atrial fibrillation, thus initiating a vicious, self-perpetuating cycle. This myopathy is triggered by stress-induced (including pressure/volume overload, inflammation, oxidative stress) responses of atrial tissue, which in the long term become maladaptive, and combine elements of both structural, especially fibrosis, and electrical remodeling, with contemporary approaches yielding potentially useful biomarkers of these processes. Biomarker value becomes greater given the fact that they can both predict atrial fibrillation occurrence and treatment outcome. This mini-review will focus on the biomarkers of atrial remodeling (both electrical and structural) and fibrosis that have been validated in human studies, including biochemical, histological and imaging approaches.
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Affiliation(s)
- Polychronis Dilaveris
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | | | - Panagiota Manolakou
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Eleftherios Tsiamis
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Konstantinos Gatzoulis
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
| | - Dimitris Tousoulis
- First Department of Cardiology, School of Medicine, National and Kapodistrian University of Athens, Athens, Greece
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20
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Reduced hybrid/complex N-glycosylation disrupts cardiac electrical signaling and calcium handling in a model of dilated cardiomyopathy. J Mol Cell Cardiol 2019; 132:13-23. [PMID: 31071333 DOI: 10.1016/j.yjmcc.2019.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2019] [Revised: 04/12/2019] [Accepted: 05/01/2019] [Indexed: 12/19/2022]
Abstract
Dilated cardiomyopathy (DCM) is the third most common cause of heart failure, with ~70% of DCM cases considered idiopathic. We showed recently, through genetic ablation of the MGAT1 gene, which encodes an essential glycosyltransferase (GlcNAcT1), that prevention of cardiomyocyte hybrid/complex N-glycosylation was sufficient to cause DCM that led to heart failure and early death. Our findings are consistent with increasing evidence suggesting a link between aberrant glycosylation and heart diseases of acquired and congenital etiologies. However, the mechanisms by which changes in glycosylation contribute to disease onset and progression remain largely unknown. Activity and gating of voltage-gated Na+ and K+ channels (Nav and Kv respectively) play pivotal roles in the initiation, shaping and conduction of cardiomyocyte action potentials (APs) and aberrant channel activity was shown to contribute to cardiac disease. We and others showed that glycosylation can impact Nav and Kv function; therefore, here, we investigated the effects of reduced cardiomyocyte hybrid/complex N-glycosylation on channel activity to investigate whether chronic aberrant channel function can contribute to DCM. Ventricular cardiomyocytes from MGAT1 deficient (MGAT1KO) mice display prolonged APs and pacing-induced aberrant early re-activation that can be attributed to, at least in part, a significant reduction in Kv expression and activity that worsens over time suggesting heart disease-related remodeling. MGAT1KO Nav demonstrate no change in expression or maximal conductance but show depolarizing shifts in voltage-dependent gating. Together, the changes in MGAT1KO Nav and Kv function likely contribute to observed anomalous electrocardiograms and Ca2+ handling. These findings provide insight into mechanisms by which altered glycosylation contributes to DCM through changes in Nav and Kv activity that impact conduction, Ca2+ handling and contraction. The MGAT1KO can also serve as a useful model to study the effects of aberrant electrical signaling on cardiac function and the remodeling events that can occur with heart disease progression.
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21
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Zhang D, Hu X, Li J, Liu J, Baks-Te Bulte L, Wiersma M, Malik NUA, van Marion DMS, Tolouee M, Hoogstra-Berends F, Lanters EAH, van Roon AM, de Vries AAF, Pijnappels DA, de Groot NMS, Henning RH, Brundel BJJM. DNA damage-induced PARP1 activation confers cardiomyocyte dysfunction through NAD + depletion in experimental atrial fibrillation. Nat Commun 2019; 10:1307. [PMID: 30898999 PMCID: PMC6428932 DOI: 10.1038/s41467-019-09014-2] [Citation(s) in RCA: 62] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 01/28/2019] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common clinical tachyarrhythmia with a strong tendency to progress in time. AF progression is driven by derailment of protein homeostasis, which ultimately causes contractile dysfunction of the atria. Here we report that tachypacing-induced functional loss of atrial cardiomyocytes is precipitated by excessive poly(ADP)-ribose polymerase 1 (PARP1) activation in response to oxidative DNA damage. PARP1-mediated synthesis of ADP-ribose chains in turn depletes nicotinamide adenine dinucleotide (NAD+), induces further DNA damage and contractile dysfunction. Accordingly, NAD+ replenishment or PARP1 depletion precludes functional loss. Moreover, inhibition of PARP1 protects against tachypacing-induced NAD+ depletion, oxidative stress, DNA damage and contractile dysfunction in atrial cardiomyocytes and Drosophila. Consistently, cardiomyocytes of persistent AF patients show significant DNA damage, which correlates with PARP1 activity. The findings uncover a mechanism by which tachypacing impairs cardiomyocyte function and implicates PARP1 as a possible therapeutic target that may preserve cardiomyocyte function in clinical AF.
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Affiliation(s)
- Deli Zhang
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands.
| | - Xu Hu
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands
| | - Jin Li
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands
| | - Jia Liu
- Department of Cardiology, Laboratory of Experimental Cardiology, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Luciënne Baks-Te Bulte
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands
| | - Marit Wiersma
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands
| | - Noor-Ul-Ann Malik
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands
| | - Denise M S van Marion
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands
| | - Marziyeh Tolouee
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, 9700 RB, Groningen, The Netherlands
| | - Femke Hoogstra-Berends
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, 9700 RB, Groningen, The Netherlands
| | - Eva A H Lanters
- Department of Cardiology, Erasmus Medical Center, 3015 GD, Rotterdam, The Netherlands
| | - Arie M van Roon
- Department of Internal Medicine, Division of Vascular Medicine, University of Groningen, University Medical Center Groningen, 9700 RB, Groningen, The Netherlands
| | - Antoine A F de Vries
- Department of Cardiology, Laboratory of Experimental Cardiology, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Daniël A Pijnappels
- Department of Cardiology, Laboratory of Experimental Cardiology, Leiden University Medical Center, 2300 RC, Leiden, The Netherlands
| | - Natasja M S de Groot
- Department of Cardiology, Erasmus Medical Center, 3015 GD, Rotterdam, The Netherlands
| | - Robert H Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, 9700 RB, Groningen, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HZ, Amsterdam, The Netherlands.
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22
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Meyer T, Voigt N. In search for novel functions of adenosine 5'-triphosphate (ATP) in the heart. Cardiovasc Res 2019; 113:e59-e60. [PMID: 29186438 DOI: 10.1093/cvr/cvx207] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Affiliation(s)
- Thomas Meyer
- Department of Psychosomatic Medicine and Psychotherapy, University Medical Center Göttingen, Georg-August University Göttingen, Von-Siebold-Str. 5, 37075 Göttingen, Germany.,German Center for Cardiovascular Research (DZHK), partner site Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
| | - Niels Voigt
- German Center for Cardiovascular Research (DZHK), partner site Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany.,Institute of Pharmacology and Toxicology, University Medical Center Göttingen, Georg-August University Göttingen, Robert-Koch-Straße 40, 37075 Göttingen, Germany
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23
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Liu X, Qu C, Yang H, Shi S, Zhang C, Zhang Y, Liang J, Yang B. Chronic stimulation of the sigma-1 receptor ameliorates autonomic nerve dysfunction and atrial fibrillation susceptibility in a rat model of depression. Am J Physiol Heart Circ Physiol 2018; 315:H1521-H1531. [PMID: 30216117 DOI: 10.1152/ajpheart.00607.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The present study aimed to assess the effect of sigma-1 receptor (S1R) stimulation on autonomic nerve dysfunction and susceptibility to atrial fibrillation (AF) in a rat depression model. Male rats were randomly divided into one of the following four treatment groups: saline [control (CTL)]; saline + intragastric administration of SA4503, an agonist of S1R (CTS); chronic unpredictable mild stress (CUMS) to produce depression (MDD); and CUMS + intragastric administration of SA4503 (MDS). Depression-like behaviors, such as reduced sucrose preference, decreased body weight gain, and increased immobility time during forced swimming, improved in the MDS group after 4 wk of SA4503 treatment. Compared with rats in the CTL group, rats in the MDD group showed significantly augmented sympathetic activity, reduced parasympathetic activity, decreased heart rate variability, and lowered S1R expression in the atrium and hippocampus (all P < 0.01). However, rats in the MDS group showed mitigated aforementioned alterations and improved electrical remodeling compared with rats in the MDD group (all P < 0.01). Furthermore, rats in the MDS group showed shortened activation latencies, increased effective refractory periods, and lowered frequency of AF incidence duration and fibrosis compared with rats in the MDD group (all P < 0.01). The results indicate that S1R stimulation reduces sympathetic activity and susceptibility to AF by improving depressive behaviors, modulating cardiac autonomic nerve balance, lightening nerve remodeling, and upregulating S1R and ion channel protein expression. NEW & NOTEWORTHY Chronic stimulation of the sigma-1 receptor (S1R) ameliorates depression-induced autonomic nerve dysfunction by modulating the imbalance between overactivated sympathetic activity and decreased vagal activity. Chronic S1R stimulation alleviates atrial electrical remodeling, fibrosis, and susceptibility to atrial fibrillation (AF). The S1R agonist may target the underlying mechanisms related to AF occurrence. The results indicate that the S1R could be a potential clinical target for atrial arrhythmia, especially when it is combined with major depressive disorders.
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Affiliation(s)
- Xin Liu
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
| | - Chuan Qu
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
| | - Hongjie Yang
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
| | - Shaobo Shi
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
| | - Cui Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
| | - Yan Zhang
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
| | - Jinjun Liang
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
| | - Bo Yang
- Department of Cardiology, Renmin Hospital of Wuhan University , Wuhan , China
- Cardiovascular Research Institute, Wuhan University , Wuhan , China
- Hubei Key Laboratory of Cardiology , Wuhan , China
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24
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Wiersma M, Meijering RAM, Qi XY, Zhang D, Liu T, Hoogstra-Berends F, Sibon OCM, Henning RH, Nattel S, Brundel BJJM. Endoplasmic Reticulum Stress Is Associated With Autophagy and Cardiomyocyte Remodeling in Experimental and Human Atrial Fibrillation. J Am Heart Assoc 2017; 6:e006458. [PMID: 29066441 PMCID: PMC5721854 DOI: 10.1161/jaha.117.006458] [Citation(s) in RCA: 74] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 08/28/2017] [Indexed: 01/09/2023]
Abstract
BACKGROUND Derailment of proteostasis, the homeostasis of production, function, and breakdown of proteins, contributes importantly to the self-perpetuating nature of atrial fibrillation (AF), the most common heart rhythm disorder in humans. Autophagy plays an important role in proteostasis by degrading aberrant proteins and organelles. Herein, we investigated the role of autophagy and its activation pathway in experimental and clinical AF. METHODS AND RESULTS Tachypacing of HL-1 atrial cardiomyocytes causes a gradual and significant activation of autophagy, as evidenced by enhanced LC3B-II expression, autophagic flux and autophagosome formation, and degradation of p62, resulting in reduction of Ca2+ amplitude. Autophagy is activated downstream of endoplasmic reticulum (ER) stress: blocking ER stress by the chemical chaperone 4-phenyl butyrate, overexpression of the ER chaperone-protein heat shock protein A5, or overexpression of a phosphorylation-blocked mutant of eukaryotic initiation factor 2α (eIF2α) prevents autophagy activation and Ca2+-transient loss in tachypaced HL-1 cardiomyocytes. Moreover, pharmacological inhibition of ER stress in tachypaced Drosophila confirms its role in derailing cardiomyocyte function. In vivo treatment with sodium salt of phenyl butyrate protected atrial-tachypaced dog cardiomyocytes from electrical remodeling (action potential duration shortening, L-type Ca2+-current reduction), cellular Ca2+-handling/contractile dysfunction, and ER stress and autophagy; it also attenuated AF progression. Finally, atrial tissue from patients with persistent AF reveals activation of autophagy and induction of ER stress, which correlates with markers of cardiomyocyte damage. CONCLUSIONS These results identify ER stress-associated autophagy as an important pathway in AF progression and demonstrate the potential therapeutic action of the ER-stress inhibitor 4-phenyl butyrate.
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Affiliation(s)
- Marit Wiersma
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Roelien A M Meijering
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Xiao-Yan Qi
- Department of Medicine, Montreal Heart Institute and Université de Montréal, the Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec, Canada
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University of Duisburg-Essen, Duisburg, Germany
| | - Deli Zhang
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Tao Liu
- Department of Cardiology, Renmin Hospital of Wuhan University, Wuhan, China
| | - Femke Hoogstra-Berends
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Ody C M Sibon
- Department of Cell Biology, University Medical Center Groningen, University of Groningen, The Netherlands
| | - Robert H Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Stanley Nattel
- Department of Medicine, Montreal Heart Institute and Université de Montréal, the Department of Pharmacology and Therapeutics, McGill University, Montreal, Québec, Canada
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University of Duisburg-Essen, Duisburg, Germany
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
- Department of Clinical Pharmacy and Pharmacology, University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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Hu X, Van Marion DMS, Wiersma M, Zhang D, Brundel BJJM. The protective role of small heat shock proteins in cardiac diseases: key role in atrial fibrillation. Cell Stress Chaperones 2017; 22:665-674. [PMID: 28484965 PMCID: PMC5465041 DOI: 10.1007/s12192-017-0799-4] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2016] [Revised: 04/06/2017] [Accepted: 04/08/2017] [Indexed: 02/06/2023] Open
Abstract
Atrial fibrillation (AF) is the most common tachyarrhythmia which is associated with increased morbidity and mortality. AF usually progresses from a self-terminating paroxysmal to persistent disease. It has been recognized that AF progression is driven by structural remodeling of cardiomyocytes, which results in electrical and contractile dysfunction of the atria. We recently showed that structural remodeling is rooted in derailment of proteostasis, i.e., homeostasis of protein production, function, and degradation. Since heat shock proteins (HSPs) play an important role in maintaining a healthy proteostasis, the role of HSPs was investigated in AF. It was found that especially small heat shock protein (HSPB) levels get exhausted in atrial tissue of patients with persistent AF and that genetic or pharmacological induction of HSPB protects against cardiomyocyte remodeling in experimental models for AF. In this review, we provide an overview of HSPBs as a potential therapeutic target for normalizing proteostasis and suppressing the substrates for AF progression in experimental and clinical AF and discuss HSP activators as a promising therapy to prevent AF onset and progression.
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Affiliation(s)
- Xu Hu
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Denise M S Van Marion
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Marit Wiersma
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Deli Zhang
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, De Boelelaan 1117, 1081 HV, Amsterdam, The Netherlands.
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Abstract
The incidence and prevalence of cardiac diseases, which are the main cause of death worldwide, are likely to increase because of population ageing. Prevailing theories about the mechanisms of ageing feature the gradual derailment of cellular protein homeostasis (proteostasis) and loss of protein quality control as central factors. In the heart, loss of protein patency, owing to flaws in genetically-determined design or because of environmentally-induced 'wear and tear', can overwhelm protein quality control, thereby triggering derailment of proteostasis and contributing to cardiac ageing. Failure of protein quality control involves impairment of chaperones, ubiquitin-proteosomal systems, autophagy, and loss of sarcomeric and cytoskeletal proteins, all of which relate to induction of cardiomyocyte senescence. Targeting protein quality control to maintain cardiac proteostasis offers a novel therapeutic strategy to promote cardiac health and combat cardiac disease. Currently marketed drugs are available to explore this concept in the clinical setting.
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Affiliation(s)
- Robert H Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, 9713 GZ Groningen, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, De Boelelaan 1117, 1081 HZ Amsterdam, The Netherlands
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27
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Stirbys P. Neuro-atriomyodegenerative origin of atrial fibrillation and superimposed conventional risk factors: continued search to configure the genuine etiology of "eternal arrhythmia". J Atr Fibrillation 2016; 9:1503. [PMID: 29250260 PMCID: PMC5673319 DOI: 10.4022/jafib.1503] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2016] [Revised: 12/19/2016] [Accepted: 12/22/2016] [Indexed: 01/26/2023]
Abstract
Atrial fibrillation (AF) is the most challenging rhythm disturbance worldwide. Arrhythmia and its behavior represent complex pathogenesis highly opposing to contemporary curative modalities. Increasing age of patients carries a certain level of risk for AF. Some underlying diseases in concordance with aging actually accelerate the occurrence of AF. Underestimated superimposed risk factors - aging plus any known risk factor or condition (hypertension, diabetes etc.) - elicit great interest and concern. In light of these concerns we offer an elaborated universal hypothesis in attempt to elucidate the genuine origin of AF substrate. Putative chronic toxicity - toxins and/or involution related pseudo-toxins potentially generate micro- and macro-structural changes in atrial myocardium thus inciting both intracellular damage (degeneration of myocites, apoptosis) and extracellular fibrotic proliferation (interstitial fibrosis, formation of matrices, degeneration of cells with fibrotic replacement). The co-products of related underlying diseases in cooperation with cellular senescence, endogenous overproduction of specific lipids/lipoproteins and other pro-atherosclerotic and/or inflammatory components generate a total atrial response - vascular/microvascular damage, intracellular and extracellular injuries. These organizational arrangements covering the entire atrial myocardium and perhaps ganglionated plexi/autonomic branches of the nervous system eventually cause clinical havoc - atrial overstretch, atrial adaptation/maladaptation, electromechanical dysfunction, arrhythmias, heart failure, etc. In essence, valvular heart disease potentially evokes similar changes "violating" thin atrial walls to obey the same scenario. Depicted atriomyodegenerative processes most likely represent the true nature of AF substrate development. Available clinical and morphological evidence potentially designates the atriomyodegenerative or plausible neuro-atriomyodegenerative origin of AF. Deductively fusion of reasons rather than purely heterogeneity is responsible for AF induction. Thus, the uniform approach and synoptic vision of clinical and pathohistological entity may offer an alternative or refreshed viewpoint in AF substrate formation.
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Arvanitidis A, Henriksen K, Karsdal M, Nedergaard A. Neo-epitope Peptides as Biomarkers of Disease Progression for Muscular Dystrophies and Other Myopathies. J Neuromuscul Dis 2016; 3:333-346. [PMID: 27854226 PMCID: PMC5123625 DOI: 10.3233/jnd-160150] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
For several decades, serological biomarkers of neuromuscular diseases as dystrophies, myopathies and myositis have been limited to routine clinical biochemistry panels. Gauging the pathological progression is a prerequisite for proper treatment and therefore identifying accessible, easy to monitor biomarkers that can predict the disease progression would be an important advancement. Most muscle diseases involve accelerated muscle fiber degradation, inflammation, fatty tissue substitution and/or fibrosis. All these pathological traits have been shown to give rise to serological peptide biomarkers in other tissues, underlining the potential application of existing biomarkers of such traits in muscle disorders. A significant quantity of tissue is involved in these pathological mechanisms alongside with qualitative changes in protein turnover in myofibrillar, extra-cellular matrix and immunological cell protein fractions accompanied by alterations in body fluids. We propose that protein and peptides can leak out of the afflicted muscles and can be of use in diagnosis, prediction of pathology trajectory and treatment efficacy. Proteolytic cleavage systems are especially modulated during a range of muscle pathologies, thereby giving rise to peptides that are differentially released during disease manifestation. Therefore, we believe that pathology-specific post-translational modifications like cleavages can give rise to neoepitope peptides that may represent a promising class of peptides for discovery of biomarkers pertaining to neuromuscular diseases.
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Affiliation(s)
- A. Arvanitidis
- Nordic Bioscience, Musculoskeletal Diseases, Herlev, Denmark
| | - K. Henriksen
- Nordic Bioscience, Musculoskeletal Diseases, Herlev, Denmark
| | - M.A. Karsdal
- Nordic Bioscience, Musculoskeletal Diseases, Herlev, Denmark
| | - A. Nedergaard
- Nordic Bioscience, Musculoskeletal Diseases, Herlev, Denmark
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Abstract
Atrial fibrillation (AF) is an extremely prevalent arrhythmia that presents a wide range of therapeutic challenges. AF usually begins in a self-terminating paroxysmal form (pAF). With time, the AF pattern often evolves to become persistent (nonterminating within 7 days). Important differences exist between pAF and persistent AF in terms of clinical features, in particular the responsiveness to antiarrhythmic drugs and ablation therapy. AF mechanisms have been extensively reviewed, but few or no Reviews focus specifically on the pathophysiology of pAF. Accordingly, in this Review, we examine the available data on the electrophysiological basis for pAF occurrence and maintenance, as well as the molecular mechanisms forming the underlying substrate. We first consider the mechanistic insights that have been obtained from clinical studies in the electrophysiology laboratory, noninvasive observations, and genetic studies. We then discuss the information about underlying molecular mechanisms that has been obtained from experimental studies on animal models and patient samples. Finally, we discuss the data available from animal models with spontaneous AF presentation, their relationship to clinical findings, and their relevance to understanding the mechanisms underlying pAF. Our analysis then turns to potential factors governing cases of progression from pAF to persistent AF and the clinical implications of the basic mechanisms we review. We conclude by identifying and discussing questions that we consider particularly important to address through future research in this area.
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30
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Wasson S, Reddy HK, Dohrmann ML. Current Perspectives of Electrical Remodeling and Its Therapeutic Implications. J Cardiovasc Pharmacol Ther 2016; 9:129-44. [PMID: 15309249 DOI: 10.1177/107424840400900208] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Electrical remodeling involves alterations in the electrophysiologic milieu of myocardium in various disease states, such as ventricular hypertrophy, heart failure, atrial tachyarrhythmias, myocardial ischemia, and infarction that are associated with cardiac arrhythmias. Although research in this area dates back to early part of the 19th century, we still lack the exact knowledge of ionic remodeling, the role of various genes and channel proteins, and their relevance for the newer antiarrhythmic therapies. Structural remodeling may also have an impact on the electrical remodeling process, although differences in both structural and electrical remodeling are associated with different disease states. Various electrophysiologic, cellular, and structural alterations, including anisotropic conduction, increased intracellular calcium levels, and gap junction remodeling predispose to increased dispersion of action potential duration and refractoriness. This constitutes a favorable substrate for early and late afterdepolarizations and reentrant arrhythmias. Studying the role of ionic remodeling in the initiation and propagation of cardiac arrhythmias has significant relevance for developing newer antiarrhythmic therapies, for identifying patients at risk of developing fatal arrhythmias, and for implementing effective preventive measures. Further research is required to understand the specific effects of individual ion channel remodeling, to understand the signal transduction mechanisms, and to address whether detrimental effects of electrical remodeling can be altered.
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Affiliation(s)
- Sanjeev Wasson
- Division of Cardiology, University of Missouri Hospital, Columbia, Missouri 65212, USA
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Zhao Y, Cui GM, Zhou NN, Li C, Zhang Q, Sun H, Han B, Zou CW, Wang LJ, Li XD, Wang JC. Calpain-Calcineurin-Nuclear Factor Signaling and the Development of Atrial Fibrillation in Patients with Valvular Heart Disease and Diabetes. J Diabetes Res 2016; 2016:4639654. [PMID: 27123462 PMCID: PMC4830711 DOI: 10.1155/2016/4639654] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2015] [Accepted: 03/17/2016] [Indexed: 12/28/2022] Open
Abstract
Calpain, calcineurin (CaN), and nuclear factor of activated T cell (NFAT) play a key role in the development of atrial fibrillation. Patients with valvular heart disease (VHD) are prone to develop atrial fibrillation (AF). Thus, our current study was aimed at investigating whether activation of calpain-CaN-NFAT pathway is associated with the incidence of AF in the patients with VHD and diabetes. The expressions of calpain 2 and alpha- and beta-isoforms of CaN catalytic subunit (CnA) as well as NFAT-c3 and NFAT-c4 were quantified by quantitative reverse transcription-polymerase chain reaction in atrial tissues from 77 hospitalized patients with VHD and diabetes. The relevant protein content was measured by Western blot and calpain 2 in human atrium was localized by immunohistochemistry. We found that the expressions of calpain 2, CnA alpha and CnA beta, and NFAT-c3 but not NFAT-c4 were significantly elevated in the samples from patients with AF compared to those with sinus rhythm (SR). Elevated protein levels of calpain 2 and CnA were observed in patients with AF, and so was the enhanced localization of calpain 2. We thereby concluded that CaN together with its upstream molecule, calpain 2, and its downstream effector, NFAT-c3, might contribute to the development of AF in patients with VHD and diabetes.
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Affiliation(s)
- Yong Zhao
- Department of Geriatric Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Guo-ming Cui
- Shandong Medicinal Imaging Research Institute, Jinan 250021, China
| | - Nan-nan Zhou
- Department of Geriatric Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Cong Li
- Intensive Care Unit, Shouguang People's Hospital, Weifang 262700, China
| | - Qing Zhang
- Department of Geriatric Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Hui Sun
- Department of Cardiology, Jinan Central Hospital Affiliated to Shandong University, Jinan, Shandong 250013, China
| | - Bo Han
- Department of Cardiac Surgery, The 4th Hospital of Jinan, Jinan 250031, China
| | - Cheng-wei Zou
- Department of Cardiac Surgery, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Li-juan Wang
- Department of Geriatric Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Xiao-dong Li
- Department of Geriatric Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
| | - Jian-chun Wang
- Department of Geriatric Cardiology, Shandong Provincial Hospital Affiliated to Shandong University, Jinan 250021, China
- *Jian-chun Wang:
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Heijman J, Algalarrondo V, Voigt N, Melka J, Wehrens XHT, Dobrev D, Nattel S. The value of basic research insights into atrial fibrillation mechanisms as a guide to therapeutic innovation: a critical analysis. Cardiovasc Res 2015; 109:467-79. [PMID: 26705366 DOI: 10.1093/cvr/cvv275] [Citation(s) in RCA: 142] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2015] [Accepted: 12/11/2015] [Indexed: 02/07/2023] Open
Abstract
Atrial fibrillation (AF) is an extremely common clinical problem associated with increased morbidity and mortality. Current antiarrhythmic options include pharmacological, ablation, and surgical therapies, and have significantly improved clinical outcomes. However, their efficacy remains suboptimal, and their use is limited by a variety of potentially serious adverse effects. There is a clear need for improved therapeutic options. Several decades of research have substantially expanded our understanding of the basic mechanisms of AF. Ectopic firing and re-entrant activity have been identified as the predominant mechanisms for arrhythmia initiation and maintenance. However, it has become clear that the clinical factors predisposing to AF and the cellular and molecular mechanisms involved are extremely complex. Moreover, all AF-promoting and maintaining mechanisms are dynamically regulated and subject to remodelling caused by both AF and cardiovascular disease. Accordingly, the initial presentation and clinical progression of AF patients are enormously heterogeneous. An understanding of arrhythmia mechanisms is widely assumed to be the basis of therapeutic innovation, but while this assumption seems self-evident, we are not aware of any papers that have critically examined the practical contributions of basic research into AF mechanisms to arrhythmia management. Here, we review recent insights into the basic mechanisms of AF, critically analyse the role of basic research insights in the development of presently used anti-AF therapeutic options and assess the potential value of contemporary experimental discoveries for future therapeutic innovation. Finally, we highlight some of the important challenges to the translation of basic science findings to clinical application.
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Affiliation(s)
- Jordi Heijman
- Department of Cardiology, Cardiovascular Research Institute Maastricht, Faculty of Health, Medicine, and Life Sciences, Maastricht University, Maastricht, The Netherlands
| | - Vincent Algalarrondo
- Department of Medicine, Montreal Heart Institute and Université de Montréal, 5000 Belanger St. E., Montreal, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Niels Voigt
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Hufelandstr. 55, D-45122 Essen, Germany
| | - Jonathan Melka
- Department of Medicine, Montreal Heart Institute and Université de Montréal, 5000 Belanger St. E., Montreal, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA Department of Medicine (Cardiology), Baylor College of Medicine, Houston, TX, USA Pediatrics, Baylor College of Medicine, Houston, TX, USA
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Hufelandstr. 55, D-45122 Essen, Germany
| | - Stanley Nattel
- Department of Medicine, Montreal Heart Institute and Université de Montréal, 5000 Belanger St. E., Montreal, Canada H1T 1C8 Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Hufelandstr. 55, D-45122 Essen, Germany
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Zhang D, Hu X, Henning RH, Brundel BJJM. Keeping up the balance: role of HDACs in cardiac proteostasis and therapeutic implications for atrial fibrillation. Cardiovasc Res 2015; 109:519-26. [PMID: 26645980 DOI: 10.1093/cvr/cvv265] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/16/2015] [Accepted: 10/29/2015] [Indexed: 12/16/2022] Open
Abstract
Cardiomyocytes are long-lived post-mitotic cells with limited regenerative capacity. Proper cardiomyocyte function depends critically on the maintenance of a healthy homeostasis of protein expression, folding, assembly, trafficking, function, and degradation, together commonly referred to as proteostasis. Impairment of proteostasis has a prominent role in the pathophysiology of ageing-related neurodegenerative diseases including Huntington's, Parkinson's, and Alzheimer's disease. Emerging evidence reveals also a role for impaired proteostasis in the pathophysiology of common human cardiac diseases such as cardiac hypertrophy, dilated and ischaemic cardiomyopathies, and atrial fibrillation (AF). Histone deacetylases (HDACs) have recently been recognized as key modulators which control cardiac proteostasis by deacetylating various proteins. By deacetylating chromatin proteins, including histones, HDACs modulate epigenetic regulation of pathological gene expression. Also, HDACs exert a broad range of functions outside the nucleus by deacetylating structural and contractile proteins. The cytosolic actions of HDACs result in changed protein function through post-translational modifications and/or modulation of their degradation. This review describes the mechanisms underlying the derailment of proteostasis in AF and subsequently focuses on the role of HDACs herein. In addition, the therapeutic potential of HDAC inhibition to maintain a healthy proteostasis resulting in a delay in AF onset and progression is discussed.
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Affiliation(s)
- Deli Zhang
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands
| | - Xu Hu
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands
| | - Robert H Henning
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands
| | - Bianca J J M Brundel
- Department of Clinical Pharmacy and Pharmacology, University Medical Centre Groningen, University of Groningen, Hanzeplein 1, PO Box 30 001, 9700RB Groningen, The Netherlands Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands
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van Marion DMS, Lanters EAH, Wiersma M, Allessie MA, Brundel BBJJM, de Groot NMS. Diagnosis and Therapy of Atrial Fibrillation: The Past, The Present and The Future. J Atr Fibrillation 2015; 8:1216. [PMID: 27957185 DOI: 10.4022/jafib.1216] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2015] [Revised: 07/05/2015] [Accepted: 01/10/2015] [Indexed: 02/03/2023]
Abstract
Atrial fibrillation (AF) is the most common age-related cardiac arrhythmia. It is a progressive disease, which makes treatment difficult. The progression of AF is caused by the accumulation of damage in cardiomyocytes which makes the atria more vulnerable for AF. Especially structural remodeling and electrical remodeling, together called electropathology are sustainable in the atria and impair functional recovery to sinus rhythm after cardioversion. The exact electropathological mechanisms underlying persistence of AF are at present unknown. High resolution wavemapping studies in patients with different types of AF showed that longitudinal dissociation in conduction and epicardial breakthrough were the key elements of the substrate of longstanding persistent AF. A double layer of electrically dissociated waves propagating transmurally can explain persistence of AF (Double Layer Hypothesis) but the molecular mechanism is unknown. Derailment of proteasis -defined as the homeostasis in protein synthesis, folding, assembly, trafficking, guided by chaperones, and clearance by protein degradation systems - may play an important role in remodeling of the cardiomyocyte. As current therapies are not effective in attenuating AF progression, step-by-step analysis of this process, in order to identify potential targets for drug therapy, is essential. In addition, novel mapping approaches enabling assessment of the degree of electropathology in the individual patient are mandatory to develop patient-tailored therapies. The aims of this review are to 1) summarize current knowledge of the electrical and molecular mechanisms underlying AF 2) discuss the shortcomings of present diagnostic instruments and therapeutic options and 3) to present potential novel diagnostic tools and therapeutic targets.
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Affiliation(s)
- Denise M S van Marion
- Department of Clinical Pharmacy and Pharmacology, University Institute for Drug Exploration (GUIDE), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Eva A H Lanters
- Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Marit Wiersma
- Department of Cardiology, Erasmus Medical Center, Rotterdam, The Netherlands
| | - Maurits A Allessie
- Department of Clinical Pharmacy and Pharmacology, University Institute for Drug Exploration (GUIDE), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Bianca B J J M Brundel
- Department of Clinical Pharmacy and Pharmacology, University Institute for Drug Exploration (GUIDE), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Department of Clinical Pharmacy and Pharmacology, University Institute for Drug Exploration (GUIDE), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
| | - Natasja M S de Groot
- Department of Clinical Pharmacy and Pharmacology, University Institute for Drug Exploration (GUIDE), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands
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The future of atrial fibrillation therapy: intervention on heat shock proteins influencing electropathology is the next in line. Neth Heart J 2015; 23:327-33. [PMID: 25947079 PMCID: PMC4446279 DOI: 10.1007/s12471-015-0699-0] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Atrial fibrillation (AF) is the most common age-related cardiac arrhythmia accounting for one-third of hospitalisations. Treatment of AF is difficult, which is rooted in the progressive nature of electrical and structural remodelling, called electropathology, which makes the atria more vulnerable for AF. Importantly, structural damage of the myocardium is already present when AF is diagnosed for the first time. Currently, no effective therapy is known that can resolve this damage. Previously, we observed that exhaustion of cardioprotective heat shock proteins (HSPs) contributes to structural damage in AF patients. Also, boosting of HSPs, by the heat shock factor-1 activator geranylgeranylacetone, halted AF initiation and progression in experimental cardiomyocyte and dog models for AF. However, it is still unclear whether induction of HSPs also prolongs the arrhythmia-free interval after, for example, cardioversion of AF. In this review, we discuss the role of HSPs in the pathophysiology of AF and give an outline of the HALT&REVERSE project, initiated by the HALT&REVERSE Consortium and the AF Innovation Platform. This project will elucidate whether HSPs (1) reverse cardiomyocyte electropathology and thereby halt AF initiation and progression and (2) represent novel biomarkers that predict the outcome of AF conversion and/or occurrence of post-surgery AF.
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Sharma S, Sharma G, Hote M, Devagourou V, Kesari V, Arava S, Airan B, Ray R. Light and electron microscopic features of surgically excised left atrial appendage in rheumatic heart disease patients with atrial fibrillation and sinus rhythm. Cardiovasc Pathol 2014; 23:319-26. [DOI: 10.1016/j.carpath.2014.07.008] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/08/2013] [Revised: 07/29/2014] [Accepted: 07/30/2014] [Indexed: 11/30/2022] Open
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37
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Gu J, Hu W, Liu X. Pioglitazone improves potassium channel remodeling induced by angiotensin II in atrial myocytes. Med Sci Monit Basic Res 2014; 20:153-60. [PMID: 25296378 PMCID: PMC4206483 DOI: 10.12659/msmbr.892450] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND It has been demonstrated that atrial electrical remodeling contributes toward atrial fibrillation (AF) maintenance, and that angiotensin II (AngII) is involved in the pathogenesis of atrial electrical remodeling. Peroxisome proliferator activated receptor-γ (PPAR-γ) agonists have been shown to inhibit atrial electrical remodeling, but the underlying mechanisms are poorly understood. In the present study we investigated the regulating effects of PPAR-g agonist on AngII-induced potassium channel remodeling in atrial myocytes. MATERIAL/METHODS Whole-cell patch-clamp technique was used to record transient outward potassium current (Ito), ultra-rapid delayed rectifier potassium (Ikur), and inward rectifier potassium current (Ik1). Real-time PCR was used to assess potassium channel subunit mRNA expression. RESULTS Compared with the control group, AngII reduced Ito and Ikur current density as well as amplified Ik1 current density, which were partially prevented by pioglitazone. Furthermore, pioglitazone alleviated the downregulation of Ito subunit (Kv 4.2) and Ikur subunit (Kv 1.5), as well as the upregulation of Ik1 subunit (Kir 2.1 and Kir 2.2) mRNA expression stimulated by AngII. CONCLUSIONS These results suggest that pioglitazone exhibits a beneficial effect on AngII-induced potassium channel remodeling. PPAR-γ agonists may be potentially effective up-stream therapies for AF.
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Affiliation(s)
- Jun Gu
- Department of Cardiology, Shanghai Minhang District Central Hospital, Fudan University, Shanghai, China (mainland)
| | - Wei Hu
- Department of Cardiology, Shanghai Minhang District Central Hospital, Fudan University, Shanghai, China (mainland)
| | - Xu Liu
- Department of Cardiology, Shanghai Chest Hospital, Shanghai Jiaotong University, Shanghai, China (mainland)
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38
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Gemel J, Simon AR, Patel D, Xu Q, Matiukas A, Veenstra RD, Beyer EC. Degradation of a connexin40 mutant linked to atrial fibrillation is accelerated. J Mol Cell Cardiol 2014; 74:330-9. [PMID: 24973497 PMCID: PMC4135452 DOI: 10.1016/j.yjmcc.2014.06.010] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/27/2014] [Revised: 06/12/2014] [Accepted: 06/18/2014] [Indexed: 12/31/2022]
Abstract
Several Cx40 mutants have been identified in patients with atrial fibrillation (AF). We have been working to identify physiological or cell biological abnormalities of several of these human mutants that might explain how they contribute to disease pathogenesis. Wild type (wt) Cx40 or four different mutants (P88S, G38D, V85I, and L229M) were expressed by the transfection of communication-deficient HeLa cells or HL-1 cardiomyocytes. Biophysical channel properties and the sub-cellular localization and protein levels of Cx40 were characterized. Wild type Cx40 and all mutants except P88S formed gap junction plaques and induced significant gap junctional conductances. The functional mutants showed only modest alterations of single channel conductances or gating by trans-junctional voltage as compared to wtCx40. However, immunoblotting indicated that the steady state levels of G38D, V85I, and L229M were reduced relative to wtCx40; most strikingly, G38D was only 20-31% of wild type levels. After the inhibition of protein synthesis with cycloheximide, G38D (and to a lesser extent the other mutants) disappeared much faster than wtCx40. Treatment with the proteasomal inhibitor, epoxomicin, greatly increased levels of G38D and restored the abundance of gap junctions and the extent of intercellular dye transfer. Thus, G38D, V85I, and L229M are functional mutants of Cx40 with small alterations of physiological properties, but accelerated degradation by the proteasome. These findings suggest a novel mechanism (protein instability) for the pathogenesis of AF due to a connexin mutation and a novel approach to therapy (protease inhibition).
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Affiliation(s)
- Joanna Gemel
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
| | - Adria R Simon
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA
| | - Dakshesh Patel
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Qin Xu
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Arvydas Matiukas
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Richard D Veenstra
- Department of Pharmacology, SUNY Upstate Medical University, Syracuse, NY 13210, USA; Cell and Developmental Biology, SUNY Upstate Medical University, Syracuse, NY 13210, USA
| | - Eric C Beyer
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA.
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39
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Heijman J, Voigt N, Nattel S, Dobrev D. Cellular and molecular electrophysiology of atrial fibrillation initiation, maintenance, and progression. Circ Res 2014; 114:1483-99. [PMID: 24763466 DOI: 10.1161/circresaha.114.302226] [Citation(s) in RCA: 478] [Impact Index Per Article: 47.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Atrial fibrillation (AF) is the most common clinically relevant arrhythmia and is associated with increased morbidity and mortality. The incidence of AF is expected to continue to rise with the aging of the population. AF is generally considered to be a progressive condition, occurring first in a paroxysmal form, then in persistent, and then long-standing persistent (chronic or permanent) forms. However, not all patients go through every phase, and the time spent in each can vary widely. Research over the past decades has identified a multitude of pathophysiological processes contributing to the initiation, maintenance, and progression of AF. However, many aspects of AF pathophysiology remain incompletely understood. In this review, we discuss the cellular and molecular electrophysiology of AF initiation, maintenance, and progression, predominantly based on recent data obtained in human tissue and animal models. The central role of Ca(2+)-handling abnormalities in both focal ectopic activity and AF substrate progression is discussed, along with the underlying molecular basis. We also deal with the ionic determinants that govern AF initiation and maintenance, as well as the structural remodeling that stabilizes AF-maintaining re-entrant mechanisms and finally makes the arrhythmia refractory to therapy. In addition, we highlight important gaps in our current understanding, particularly with respect to the translation of these concepts to the clinical setting. Ultimately, a comprehensive understanding of AF pathophysiology is expected to foster the development of improved pharmacological and nonpharmacological therapeutic approaches and to greatly improve clinical management.
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Affiliation(s)
- Jordi Heijman
- From the Institute of Pharmacology, Faculty of Medicine, University Duisburg-Essen, Essen, Germany (J.H., N.V., D.D.); Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada (S.N.); and Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada (S.N.)
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40
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Schumacher-Bass SM, Vesely ED, Zhang L, Ryland KE, McEwen DP, Chan PJ, Frasier CR, McIntyre JC, Shaw RM, Martens JR. Role for myosin-V motor proteins in the selective delivery of Kv channel isoforms to the membrane surface of cardiac myocytes. Circ Res 2014; 114:982-92. [PMID: 24508725 DOI: 10.1161/circresaha.114.302711] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Kv1.5 (KCNA5) mediates the ultra-rapid delayed rectifier current that controls atrial action potential duration. Given its atrial-specific expression and alterations in human atrial fibrillation, Kv1.5 has emerged as a promising target for the treatment of atrial fibrillation. A necessary step in the development of novel agents that selectively modulate trafficking pathways is the identification of the cellular machinery controlling Kv1.5 surface density, of which little is yet known. OBJECTIVE To investigate the role of the unconventional myosin-V (MYO5A and MYO5B) motors in determining the cell surface density of Kv1.5. METHODS AND RESULTS Western blot analysis showed MYO5A and MYO5B expression in the heart, whereas disruption of endogenous motors selectively reduced IKur current in adult rat cardiomyocytes. Dominant negative constructs and short hairpin RNA silencing demonstrated a role for MYO5A and MYO5B in the surface trafficking of Kv1.5 and connexin-43 but not potassium voltage-gated channel, subfamily H (eag-related), member 2 (KCNH2). Live-cell imaging of Kv1.5-GFP and retrospective labeling of phalloidin demonstrated motility of Kv1.5 vesicles on actin tracts. MYO5A participated in anterograde trafficking, whereas MYO5B regulated postendocytic recycling. Overexpression of mutant motors revealed a selective role for Rab11 in coupling MYO5B to Kv1.5 recycling. CONCLUSIONS MYO5A and MYO5B control functionally distinct steps in the surface trafficking of Kv1.5. These isoform-specific trafficking pathways determine Kv1.5-encoded IKur in myocytes to regulate repolarizing current and, consequently, cardiac excitability. Therapeutic strategies that manipulate Kv1.5 selective trafficking pathways may prove useful in the treatment of arrhythmias.
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Affiliation(s)
- Sarah M Schumacher-Bass
- From the Department of Pharmacology, University of Michigan, Ann Arbor (S.M.S.-B., E.D.V., L.Z., K.E.R., D.P.M., C.R.F., J.C.M., J.R.M.); Cardiovascular Research Institute Robin Shaw, Department of Medicine, University of California, San Francisco (P.J.C.); and Cedars-Sinai Medical Center, Los Angeles, CA (R.M.S.)
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41
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Zhang D, Wu CT, Qi X, Meijering RAM, Hoogstra-Berends F, Tadevosyan A, Cubukcuoglu Deniz G, Durdu S, Akar AR, Sibon OCM, Nattel S, Henning RH, Brundel BJJM. Activation of histone deacetylase-6 induces contractile dysfunction through derailment of α-tubulin proteostasis in experimental and human atrial fibrillation. Circulation 2013; 129:346-58. [PMID: 24146251 DOI: 10.1161/circulationaha.113.005300] [Citation(s) in RCA: 111] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Atrial fibrillation (AF) is characterized by structural remodeling, contractile dysfunction, and AF progression. Histone deacetylases (HDACs) influence acetylation of both histones and cytosolic proteins, thereby mediating epigenetic regulation and influencing cell proteostasis. Because the exact function of HDACs in AF is unknown, we investigated their role in experimental and clinical AF models. METHODS AND RESULTS Tachypacing of HL-1 atrial cardiomyocytes and Drosophila pupae hearts significantly impaired contractile function (amplitude of Ca(2+) transients and heart wall contractions). This dysfunction was prevented by inhibition of HDAC6 (tubacin) and sirtuins (nicotinamide). Tachypacing induced specific activation of HDAC6, resulting in α-tubulin deacetylation, depolymerization, and degradation by calpain. Tachypacing-induced contractile dysfunction was completely rescued by dominant-negative HDAC6 mutants with loss of deacetylase activity in the second catalytic domain, which bears α-tubulin deacetylase activity. Furthermore, in vivo treatment with the HDAC6 inhibitor tubastatin A protected atrial tachypaced dogs from electric remodeling (action potential duration shortening, L-type Ca(2+) current reduction, AF promotion) and cellular Ca(2+)-handling/contractile dysfunction (loss of Ca(2+) transient amplitude, sarcomere contractility). Finally, atrial tissue from patients with AF also showed a significant increase in HDAC6 activity and reduction in the expression of both acetylated and total α-tubulin. CONCLUSIONS AF induces remodeling and loss of contractile function, at least in part through HDAC6 activation and subsequent derailment of α-tubulin proteostasis and disruption of the cardiomyocyte microtubule structure. In vivo inhibition of HDAC6 protects against AF-related atrial remodeling, disclosing the potential of HDAC6 as a therapeutic target in clinical AF.
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Affiliation(s)
- Deli Zhang
- Departments of Clinical Pharmacology (D.Z., R.A.M.M., F.H.-B., R.H.H., B.J.J.M.B.) and Cell Biology (O.C.M.S.), University Medical Center Groningen, University of Groningen, Groningen, The Netherlands; Research Center and Department of Medicine, Montreal Heart Institute and Université de Montréal, Montreal, QB, Canada (C.T.W., X.Y.Q., A.T., S.N.); Chang-Gung Memorial Hospital and Chang-Gung University, Taoyuan, Taiwan, Republic of China (C.T.W.); Nyken BV, Groningen, The Netherlands (F.-H.B.); Ankara University Biotechnology Institute, Ankara, Turkey (G.C.D., S.D.); Ankara University Stem Cell Institute, Ankara, Turkey (G.C.D., S.D., A.R.A.); Department of Cardiovascular Surgery, Ankara University School of Medicine, Ankara, Turkey (S.D., A.R.A.); and Department of Pharmacology, McGill University, Montreal, QB, Canada (S.N.)
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42
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XU GUOJUN, GAN TIANYI, TANG BAOPENG, CHEN ZUHENG, MAHEMUTI AILIMAN, JIANG TAO, SONG JIANGUO, GUO XIA, LI YAODONG, ZHOU XIANHUI, ZHANG YU, LI JINXIN. Alterations in the expression of atrial calpains in electrical and structural remodeling during aging and atrial fibrillation. Mol Med Rep 2013; 8:1343-52. [DOI: 10.3892/mmr.2013.1684] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2013] [Accepted: 08/16/2013] [Indexed: 11/06/2022] Open
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43
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Atrial remodeling: New pathophysiological mechanism of atrial fibrillation. Med Hypotheses 2013; 80:53-6. [DOI: 10.1016/j.mehy.2012.10.009] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Accepted: 10/18/2012] [Indexed: 11/17/2022]
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44
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Suzuki S, Kurata Y, Li P, Notsu T, Hasegawa A, Ikeda N, Kato M, Miake J, Sakata S, Shiota G, Yoshida A, Ninomiya H, Higaki K, Yamamoto K, Shirayoshi Y, Hisatome I. Stabilization of Kv1.5 channel protein by bepridil through its action as a chemical chaperone. Eur J Pharmacol 2012; 696:28-34. [PMID: 23026372 DOI: 10.1016/j.ejphar.2012.09.025] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2012] [Revised: 09/07/2012] [Accepted: 09/22/2012] [Indexed: 11/15/2022]
Abstract
While bepridil has been reported to alter the stability of ion channel proteins, the precise mechanism of action remains unclear. We examined the effect of bepridil on the stability of Kv1.5 channel proteins expressed in COS7 cells. Bepridil at 0.3-30 μM increased the protein level of Kv1.5 channels in a concentration-dependent manner. Chase experiments showed that bepridil delayed the degradation process of Kv1.5 channel proteins in the same manner as a proteasomal inhibitor, MG132, did. Bepridil increased the immunofluorescent signal of Kv1.5 channel proteins in the endoplasmic reticulum (ER) and Golgi apparatus and on the cell surface. The cell fraction experiment also showed bepridil-induced increases in Kv1.5 in the ER, Golgi apparatus, and the cell membrane. Bepridil at a lower concentration of 1 μM had no effect on the proteasome activity in vitro. A blocker of the ultrarapid delayed-rectifier K(+) channel current, 4-aminopyridine (4AP), abolished bepridil-induced increases in Kv1.5. Kv1.5-medicated membrane currents measured as 4AP-sensitive currents were increased by bepridil. Taken together, we conclude that bepridil stabilizes Kv1.5 proteins at the ER through an action as a chemical chaperone, thereby increasing the density of Kv1.5 channels in the cell membrane.
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Affiliation(s)
- Sayuri Suzuki
- Division of Regenerative Medicine and Therapeutics, Department of Genetic Medicine and Regenerative Therapeutics, Institute of Regenerative Medicine and Biofunction, Tottori University Graduate School of Medical Science, Yonago 683-8503, Japan
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45
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Kashef F, Li J, Wright P, Snyder J, Suliman F, Kilic A, Higgins RSD, Anderson ME, Binkley PF, Hund TJ, Mohler PJ. Ankyrin-B protein in heart failure: identification of a new component of metazoan cardioprotection. J Biol Chem 2012; 287:30268-81. [PMID: 22778271 DOI: 10.1074/jbc.m112.368415] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ankyrins (ankyrin-R, -B, and -G) are adapter proteins linked with defects in metazoan physiology. Ankyrin-B (encoded by ANK2) loss-of-function mutations are directly associated with human cardiovascular phenotypes including sinus node disease, atrial fibrillation, ventricular tachycardia, and sudden cardiac death. Despite the link between ankyrin-B dysfunction and monogenic disease, there are no data linking ankyrin-B regulation with common forms of human heart failure. Here, we report that ankyrin-B levels are altered in both ischemic and non-ischemic human heart failure. Mechanistically, we demonstrate that cardiac ankyrin-B levels are tightly regulated downstream of reactive oxygen species, intracellular calcium, and the calcium-dependent protease calpain, all hallmarks of human myocardial injury and heart failure. Surprisingly, β(II)-spectrin, previously thought to mediate ankyrin-dependent modulation in the nervous system and heart, is not coordinately regulated with ankyrin-B or its downstream partners. Finally, our data implicate ankyrin-B expression as required for vertebrate myocardial protection as hearts deficient in ankyrin-B show increased cardiac damage and impaired function relative to wild-type mouse hearts following ischemia reperfusion. In summary, our findings provide the data of ankyrin-B regulation in human heart failure, provide insight into candidate pathways for ankyrin-B regulation in acquired human cardiovascular disease, and surprisingly, implicate ankyrin-B as a molecular component for cardioprotection following ischemia.
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Affiliation(s)
- Farshid Kashef
- Dorothy M. Davis Heart and Lung Research Institute, Columbus, OH 43210, USA
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46
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Meijering RAM, Zhang D, Hoogstra-Berends F, Henning RH, Brundel BJJM. Loss of proteostatic control as a substrate for atrial fibrillation: a novel target for upstream therapy by heat shock proteins. Front Physiol 2012; 3:36. [PMID: 22375124 PMCID: PMC3284689 DOI: 10.3389/fphys.2012.00036] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2011] [Accepted: 02/09/2012] [Indexed: 12/19/2022] Open
Abstract
Atrial fibrillation (AF) is the most common, sustained clinical tachyarrhythmia associated with significant morbidity and mortality. AF is a persistent condition with progressive structural remodeling of the atrial cardiomyocytes due to the AF itself, resulting in cellular changes commonly observed in aging and in other heart diseases. While rhythm control by electrocardioversion or drug treatment is the treatment of choice in symptomatic AF patients, its efficacy is still limited. Current research is directed at preventing first-onset AF by limiting the development of substrates underlying AF progression and resembles mechanism-based therapy. Upstream therapy refers to the use of non-ion channel anti-arrhythmic drugs that modify the atrial substrate- or target-specific mechanisms of AF, with the ultimate aim to prevent the occurrence (primary prevention) or recurrence of the arrhythmia following (spontaneous) conversion (secondary prevention). Heat shock proteins (HSPs) are molecular chaperones and comprise a large family of proteins involved in the protection against various forms of cellular stress. Their classical function is the conservation of proteostasis via prevention of toxic protein aggregation by binding to (partially) unfolded proteins. Our recent data reveal that HSPs prevent electrical, contractile, and structural remodeling of cardiomyocytes, thus attenuating the AF substrate in cellular, Drosophila melanogaster, and animal experimental models. Furthermore, studies in humans suggest a protective role for HSPs against the progression from paroxysmal AF to persistent AF and in recurrence of AF. In this review, we discuss upregulation of the heat shock response system as a novel target for upstream therapy to prevent derailment of proteostasis and consequently progression and recurrence of AF.
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Affiliation(s)
- Roelien A M Meijering
- Department of Clinical Pharmacology, Groningen University Institute for Drug Exploration, University Medical Center Groningen, University of Groningen Groningen, Netherlands
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47
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Voigt N, Nattel S, Dobrev D. Proarrhythmic atrial calcium cycling in the diseased heart. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2012; 740:1175-91. [PMID: 22453988 DOI: 10.1007/978-94-007-2888-2_53] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
During the last decades Ca(2+) has been found to play a crucial role in cardiac arrhythmias associated with heart failure and a number of congenital arrhythmia syndromes. Recent studies demonstrated that altered atrial Ca(2+) cycling may promote the initiation and maintenance of atrial fibrillation, the most common clinical arrhythmia that contributes significantly to population morbidity and mortality. This article describes physiological Ca(2+) cycling mechanisms in atrial cardiomyocytes and relates them to fundamental cellular proarrhythmic mechanisms involving Ca(2+) signaling abnormalities in the atrium during atrial fibrillation.
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Affiliation(s)
- Niels Voigt
- Division of Experimental Cardiology, Medical Faculty Mannheim, University of Heidelberg, Theodor-Kutzer-Ufer 1-3, 68167 Mannheim, Germany.
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48
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Sharma D, Li G, Xu G, Liu Y, Xu Y. Atrial remodeling in atrial fibrillation and some related microRNAs. Cardiology 2011; 120:111-21. [PMID: 22179059 DOI: 10.1159/000334434] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/22/2011] [Accepted: 10/12/2011] [Indexed: 01/17/2023]
Abstract
Atrial fibrillation is the most common sustained arrhythmia associated with substantial cardiovascular morbidity and mortality, with stroke being the most critical complication. The role of atrial remodeling has emerged as the new pathophysiological mechanism of atrial fibrillation. Electrical remodeling and structural remodeling will increase the probability of generating multiple atrial wavelets by enabling rapid atrial activation and dispersion of refractoriness. MicroRNAs (miRNAs) are small non-coding RNAs of 20-25 nucleotides in length that regulate expression of target genes through sequence-specific hybridization to the 3' untranslated region of messenger RNAs and either block translation or direct degradation of their target messenger RNA. They have also been implicated in a variety of pathological conditions, such as arrhythmogenesis and atrial fibrillation. Target genes of miRNAs have the potential to affect atrial fibrillation vulnerability.
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Affiliation(s)
- Deepak Sharma
- International College of Tianjin Medical University, Tianjin, China
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49
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Bahrudin U, Morikawa K, Takeuchi A, Kurata Y, Miake J, Mizuta E, Adachi K, Higaki K, Yamamoto Y, Shirayoshi Y, Yoshida A, Kato M, Yamamoto K, Nanba E, Morisaki H, Morisaki T, Matsuoka S, Ninomiya H, Hisatome I. Impairment of Ubiquitin–Proteasome System by E334K cMyBPC Modifies Channel Proteins, Leading to Electrophysiological Dysfunction. J Mol Biol 2011; 413:857-78. [DOI: 10.1016/j.jmb.2011.09.006] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 08/25/2011] [Accepted: 09/05/2011] [Indexed: 11/28/2022]
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50
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Makary S, Voigt N, Maguy A, Wakili R, Nishida K, Harada M, Dobrev D, Nattel S. Differential Protein Kinase C Isoform Regulation and Increased Constitutive Activity of Acetylcholine-Regulated Potassium Channels in Atrial Remodeling. Circ Res 2011; 109:1031-43. [DOI: 10.1161/circresaha.111.253120] [Citation(s) in RCA: 81] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Rationale:
Atrial fibrillation (AF) causes atrial-tachycardia remodeling (ATR), with enhanced constitutive acetylcholine-regulated K
+
current (I
KAChC
) contributing to action potential duration shortening and AF promotion. The underlying mechanisms are unknown.
Objective:
To evaluate the role of protein-kinase C (PKC) isoforms in ATR-induced I
KAChC
activation.
Methods and Results:
Cells from ATR-dogs (400-bpm atrial pacing for 1 week) were compared to control dog cells. In vitro tachypaced (TP; 3 Hz) canine atrial cardiomyocytes were compared to parallel 1-Hz paced cells. I
KAChC
single-channel activity was assessed in cell-attached and cell-free (inside-out) patches. Protein expression was assessed by immunoblot. In vitro TP activated I
KAChC
, mimicking effects of in vivo ATR. Discrepant effects of PKC activation and inhibition between control and ATR cells suggested isoform-selective effects and altered PKC isoform distribution. Conventional PKC isoforms (cPKC; including PKCα) inhibited, whereas novel isoforms (including PKCε) enhanced, acetylcholine-regulated K
+
current (I
KACh
) in inside-out patches. TP and ATR downregulated PKCα (by 33% and 37%, respectively) and caused membrane translocation of PKCε, switching PKC predominance to the stimulatory novel isoform. TP increased [Ca
2+
]
i
at 2 hours by 30%, with return to baseline at 24 hours. Buffering [Ca
2+
]
i
during TP with the cell-permeable Ca
2+
chelator BAPTA-AM (1 μmol/L) or inhibiting the Ca
2+
-dependent protease calpain with PD150606 (20 μmol/L) prevented PKCα downregulation and TP enhancement of I
KAChC
. PKCε inhibition with a cell-permeable peptide inhibitor suppressed TP/ATR-induced I
KAChC
activation, whereas cPKC inhibition enhanced I
KAChC
activity in 1-Hz cells.
Conclusions:
PKC isoforms differentially modulate I
KACh
, with conventional Ca
2+
-dependent isoforms inhibiting and novel isoforms enhancing activity. ATR causes a rate-dependent PKC isoform switch, with Ca
2+
/calpain-dependent downregulation of inhibitory PKCα and membrane translocation of stimulatory PKCε, enhancing I
KAChC
. These findings provide novel insights into mechanisms underlying I
KAChC
dysregulation in AF.
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Affiliation(s)
- Samy Makary
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Niels Voigt
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Ange Maguy
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Reza Wakili
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Kunihiro Nishida
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Masahide Harada
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Dobromir Dobrev
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
| | - Stanley Nattel
- From the Department of Medicine and Research Center (S.M., A.M., R.W., K.N., M.H., S.N.), Montreal Heart Institute and Université de Montréal, Montreal, Quebec, Canada; Physiology Department, Faculty of Medicine, Suez Canal University, Egypt (S.M.); Department of Pharmacology and Therapeutics (S.N.), McGill University, Montreal, Quebec, Canada; Division of Experimental Cardiology (S.M., N.V., D.D.), Medical Faculty Mannheim, University of Heidelberg, Mannheim, Germany; Department of Medicine I (R.W
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