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Federspiel JM, Reil JC, Xu A, Scholtz S, Batzner A, Maack C, Sequeira V. Retrofitting the Heart: Explaining the Enigmatic Septal Thickening in Hypertrophic Cardiomyopathy. Circ Heart Fail 2024; 17:e011435. [PMID: 38695186 DOI: 10.1161/circheartfailure.123.011435] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/26/2024] [Indexed: 05/23/2024]
Abstract
Hypertrophic cardiomyopathy is the most common genetic cardiac disease and is characterized by left ventricular hypertrophy. Although this hypertrophy often associates with sarcomeric gene mutations, nongenetic factors also contribute to the disease, leading to diastolic dysfunction. Notably, this dysfunction manifests before hypertrophy and is linked to hypercontractility, as well as nonuniform contraction and relaxation (myofibril asynchrony) of the myocardium. Although the distribution of hypertrophy in hypertrophic cardiomyopathy can vary both between and within individuals, in most cases, it is primarily confined to the interventricular septum. The reasons for septal thickening remain largely unknown. In this article, we propose that alterations in muscle fiber geometry, present from birth, dictate the septal shape. When combined with hypercontractility and exacerbated by left ventricular outflow tract obstruction, these factors predispose the septum to an isometric type of contraction during systole, consequently constraining its mobility. This contraction, or more accurately, this focal increase in biomechanical stress, prompts the septum to adapt and undergo remodeling. Drawing a parallel, this is reminiscent of how earthquake-resistant buildings are retrofitted with vibration dampers to absorb the majority of the shock motion and load. Similarly, the heart adapts by synthesizing viscoelastic elements such as microtubules, titin, desmin, collagen, and intercalated disc components. This pronounced remodeling in the cytoskeletal structure leads to noticeable septal hypertrophy. This structural adaptation acts as a protective measure against damage by attenuating myofibril shortening while reducing cavity tension according to Laplace Law. By examining these events, we provide a coherent explanation for the septum's predisposition toward hypertrophy.
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Affiliation(s)
- Jan M Federspiel
- Comprehensive Heart Failure Center, Department of Translational Science University Clinic Würzburg, Germany (J.M.F., A.X., A.B., C.M., V.S.)
- Saarland University, Faculty of Medicine, Institute for Legal Medicine, Homburg (Saar), Germany (J.M.F.)
| | - Jan-Christian Reil
- Klinik für allgemeine und interventionelle Kardiologie, Herz- und Diabetes-Zentrum Nordrhein-Westphalen, Germany (J.-C.R., S.S.)
| | - Anton Xu
- Comprehensive Heart Failure Center, Department of Translational Science University Clinic Würzburg, Germany (J.M.F., A.X., A.B., C.M., V.S.)
| | - Smita Scholtz
- Klinik für allgemeine und interventionelle Kardiologie, Herz- und Diabetes-Zentrum Nordrhein-Westphalen, Germany (J.-C.R., S.S.)
| | - Angelika Batzner
- Comprehensive Heart Failure Center, Department of Translational Science University Clinic Würzburg, Germany (J.M.F., A.X., A.B., C.M., V.S.)
- Department of Internal Medicine I, University Hospital Würzburg, Germany (A.B.)
| | - Christoph Maack
- Comprehensive Heart Failure Center, Department of Translational Science University Clinic Würzburg, Germany (J.M.F., A.X., A.B., C.M., V.S.)
| | - Vasco Sequeira
- Comprehensive Heart Failure Center, Department of Translational Science University Clinic Würzburg, Germany (J.M.F., A.X., A.B., C.M., V.S.)
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2
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Padget RL, Zeitz MJ, Blair GA, Wu X, North MD, Tanenbaum MT, Stanley KE, Phillips CM, King DR, Lamouille S, Gourdie RG, Hoeker GS, Swanger SA, Poelzing S, Smyth JW. Acute Adenoviral Infection Elicits an Arrhythmogenic Substrate Prior to Myocarditis. Circ Res 2024; 134:892-912. [PMID: 38415360 PMCID: PMC11003857 DOI: 10.1161/circresaha.122.322437] [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: 12/21/2022] [Accepted: 02/12/2024] [Indexed: 02/29/2024]
Abstract
BACKGROUND Viral cardiac infection represents a significant clinical challenge encompassing several etiological agents, disease stages, complex presentation, and a resulting lack of mechanistic understanding. Myocarditis is a major cause of sudden cardiac death in young adults, where current knowledge in the field is dominated by later disease phases and pathological immune responses. However, little is known regarding how infection can acutely induce an arrhythmogenic substrate before significant immune responses. Adenovirus is a leading cause of myocarditis, but due to species specificity, models of infection are lacking, and it is not understood how adenoviral infection may underlie sudden cardiac arrest. Mouse adenovirus type-3 was previously reported as cardiotropic, yet it has not been utilized to understand the mechanisms of cardiac infection and pathology. METHODS We have developed mouse adenovirus type-3 infection as a model to investigate acute cardiac infection and molecular alterations to the infected heart before an appreciable immune response or gross cardiomyopathy. RESULTS Optical mapping of infected hearts exposes decreases in conduction velocity concomitant with increased Cx43Ser368 phosphorylation, a residue known to regulate gap junction function. Hearts from animals harboring a phospho-null mutation at Cx43Ser368 are protected against mouse adenovirus type-3-induced conduction velocity slowing. Additional to gap junction alterations, patch clamping of mouse adenovirus type-3-infected adult mouse ventricular cardiomyocytes reveals prolonged action potential duration as a result of decreased IK1 and IKs current density. Turning to human systems, we find human adenovirus type-5 increases phosphorylation of Cx43Ser368 and disrupts synchrony in human induced pluripotent stem cell-derived cardiomyocytes, indicating common mechanisms with our mouse whole heart and adult cardiomyocyte data. CONCLUSIONS Together, these findings demonstrate that adenoviral infection creates an arrhythmogenic substrate through direct targeting of gap junction and ion channel function in the heart. Such alterations are known to precipitate arrhythmias and likely contribute to sudden cardiac death in acutely infected patients.
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Affiliation(s)
- Rachel L. Padget
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Michael J. Zeitz
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Grace A. Blair
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Xiaobo Wu
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Michael D. North
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
| | | | - Kari E. Stanley
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Chelsea M. Phillips
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - D. Ryan King
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, VA 24061, USA
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Samy Lamouille
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
| | - Robert G. Gourdie
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, College of Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - Gregory S. Hoeker
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
| | - Sharon A. Swanger
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Sciences and Pathobiology, Virginia-Maryland College of Veterinary Medicine, Virginia Tech, Blacksburg, VA 24061, USA
| | - Steven Poelzing
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, College of Engineering, Virginia Tech, Blacksburg, VA 24061, USA
| | - James W. Smyth
- Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, VA 24016, USA
- Center for Vascular and Heart Research, FBRI at VTC, Roanoke, VA 24016, USA
- Virginia Tech Carilion School of Medicine, Roanoke, VA 24016, USA
- Department of Biomedical Engineering and Mechanics, College of Engineering, Virginia Tech, Blacksburg, VA 24061, USA
- Department of Biological Sciences, Virginia Tech, Blacksburg, VA 24061, USA
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Sharma AK, Singh S, Bhat M, Gill K, Zaid M, Kumar S, Shakya A, Tantray J, Jose D, Gupta R, Yangzom T, Sharma RK, Sahu SK, Rathore G, Chandolia P, Singh M, Mishra A, Raj S, Gupta A, Agarwal M, Kifayat S, Gupta A, Gupta P, Vashist A, Vaibhav P, Kathuria N, Yadav V, Singh RP, Garg A. New drug discovery of cardiac anti-arrhythmic drugs: insights in animal models. Sci Rep 2023; 13:16420. [PMID: 37775650 PMCID: PMC10541452 DOI: 10.1038/s41598-023-41942-4] [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: 04/24/2023] [Accepted: 09/04/2023] [Indexed: 10/01/2023] Open
Abstract
Cardiac rhythm regulated by micro-macroscopic structures of heart. Pacemaker abnormalities or disruptions in electrical conduction, lead to arrhythmic disorders may be benign, typical, threatening, ultimately fatal, occurs in clinical practice, patients on digitalis, anaesthesia or acute myocardial infarction. Both traditional and genetic animal models are: In-vitro: Isolated ventricular Myocytes, Guinea pig papillary muscles, Patch-Clamp Experiments, Porcine Atrial Myocytes, Guinea pig ventricular myocytes, Guinea pig papillary muscle: action potential and refractory period, Langendorff technique, Arrhythmia by acetylcholine or potassium. Acquired arrhythmia disorders: Transverse Aortic Constriction, Myocardial Ischemia, Complete Heart Block and AV Node Ablation, Chronic Tachypacing, Inflammation, Metabolic and Drug-Induced Arrhythmia. In-Vivo: Chemically induced arrhythmia: Aconitine antagonism, Digoxin-induced arrhythmia, Strophanthin/ouabain-induced arrhythmia, Adrenaline-induced arrhythmia, and Calcium-induced arrhythmia. Electrically induced arrhythmia: Ventricular fibrillation electrical threshold, Arrhythmia through programmed electrical stimulation, sudden coronary death in dogs, Exercise ventricular fibrillation. Genetic Arrhythmia: Channelopathies, Calcium Release Deficiency Syndrome, Long QT Syndrome, Short QT Syndrome, Brugada Syndrome. Genetic with Structural Heart Disease: Arrhythmogenic Right Ventricular Cardiomyopathy/Dysplasia, Dilated Cardiomyopathy, Hypertrophic Cardiomyopathy, Atrial Fibrillation, Sick Sinus Syndrome, Atrioventricular Block, Preexcitation Syndrome. Arrhythmia in Pluripotent Stem Cell Cardiomyocytes. Conclusion: Both traditional and genetic, experimental models of cardiac arrhythmias' characteristics and significance help in development of new antiarrhythmic drugs.
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Affiliation(s)
- Ashish Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India.
| | - Shivam Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mehvish Bhat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Kartik Gill
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohammad Zaid
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sachin Kumar
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anjali Shakya
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Junaid Tantray
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Divyamol Jose
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rashmi Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Tsering Yangzom
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Rajesh Kumar Sharma
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | | | - Gulshan Rathore
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Priyanka Chandolia
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mithilesh Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anurag Mishra
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Shobhit Raj
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Archita Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Mohit Agarwal
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Sumaiya Kifayat
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Anamika Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Prashant Gupta
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ankit Vashist
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Parth Vaibhav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Nancy Kathuria
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Vipin Yadav
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Ravindra Pal Singh
- NIMS Institute of Pharmacy, NIMS University Rajasthan, Jaipur, Rajasthan, 303121, India
| | - Arun Garg
- MVN University, Palwal, Haryana, India
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Hwang HS, Kahmini AR, Prascak J, Cejas-Carbonell A, Valera IC, Champion S, Corrigan M, Mumbi F, Parvatiyar MS. Sarcospan Deficiency Increases Oxidative Stress and Arrhythmias in Hearts after Acute Ischemia-Reperfusion Injury. Int J Mol Sci 2023; 24:11868. [PMID: 37511627 PMCID: PMC10380899 DOI: 10.3390/ijms241411868] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2023] [Revised: 07/14/2023] [Accepted: 07/20/2023] [Indexed: 07/30/2023] Open
Abstract
The protein sarcospan (SSPN) is an integral member of the dystrophin-glycoprotein complex (DGC) and has been shown to be important in the heart during the development and the response to acute stress. In this study, we investigated the role of SSPN in the cardiac response to acute ischemia-reperfusion (IR) injury in SSPN-deficient (SSPN-/-) mice. First, the hemodynamic response of SSPN-/- mice was tested and was similar to SSPN+/+ (wild-type) mice after isoproterenol injection. Using the in situ Langendorff perfusion method, SSPN-/- hearts were subjected to IR injury and found to have increased infarct size and arrhythmia susceptibility compared to SSPN+/+. Ca2+ handling was assessed in single cardiomyocytes and diastolic Ca2+ levels were increased after acute β-AR stimulation in SSPN+/+ but not SSPN-/-. It was also found that SSPN-/- cardiomyocytes had reduced Ca2+ SR content compared to SSPN+/+ but similar SR Ca2+ release. Next, we used qRT-PCR to examine gene expression of Ca2+ handling proteins after acute IR injury. SSPN-/- hearts showed a significant decrease in L-type Ca2+ channels and a significant increase in Ca2+ release channel (RyR2) expression. Interestingly, under oxidizing conditions reminiscent of IR, SSPN-/- cardiomyocytes, had increased H2O2-induced reactive oxygen species production compared to SSPN+/+. Examination of oxidative stress proteins indicated that NADPH oxidase 4 and oxidized CAMKII were increased in SSPN-/- hearts after acute IR injury. These results suggest that increased arrhythmia susceptibility in SSPN-/- hearts post-IR injury may arise from alterations in Ca2+ handling and a reduced capacity to regulate oxidative stress pathways.
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Affiliation(s)
- Hyun Seok Hwang
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Aida Rahimi Kahmini
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Julia Prascak
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Alexis Cejas-Carbonell
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Isela C Valera
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Samantha Champion
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Mikayla Corrigan
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Florence Mumbi
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
| | - Michelle S Parvatiyar
- Department of Nutrition and Integrative Physiology, Florida State University, 107 Chieftan Way, Biomedical Research Facility, Tallahassee, FL 32306-1490, USA
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5
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Blackwell DJ, Schmeckpeper J, Knollmann BC. Animal Models to Study Cardiac Arrhythmias. Circ Res 2022; 130:1926-1964. [PMID: 35679367 DOI: 10.1161/circresaha.122.320258] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Cardiac arrhythmias are a significant cause of morbidity and mortality worldwide, accounting for 10% to 15% of all deaths. Although most arrhythmias are due to acquired heart disease, inherited channelopathies and cardiomyopathies disproportionately affect children and young adults. Arrhythmogenesis is complex, involving anatomic structure, ion channels and regulatory proteins, and the interplay between cells in the conduction system, cardiomyocytes, fibroblasts, and the immune system. Animal models of arrhythmia are powerful tools for studying not only molecular and cellular mechanism of arrhythmogenesis but also more complex mechanisms at the whole heart level, and for testing therapeutic interventions. This review summarizes basic and clinical arrhythmia mechanisms followed by an in-depth review of published animal models of genetic and acquired arrhythmia disorders.
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Affiliation(s)
- Daniel J Blackwell
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Jeffrey Schmeckpeper
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
| | - Bjorn C Knollmann
- Vanderbilt Center for Arrhythmia Research and Therapeutics, Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN
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6
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Bertero E, Nickel A, Kohlhaas M, Hohl M, Sequeira V, Brune C, Schwemmlein J, Abeßer M, Schuh K, Kutschka I, Carlein C, Münker K, Atighetchi S, Müller A, Kazakov A, Kappl R, von der Malsburg K, van der Laan M, Schiuma AF, Böhm M, Laufs U, Hoth M, Rehling P, Kuhn M, Dudek J, von der Malsburg A, Prates Roma L, Maack C. Loss of Mitochondrial Ca 2+ Uniporter Limits Inotropic Reserve and Provides Trigger and Substrate for Arrhythmias in Barth Syndrome Cardiomyopathy. Circulation 2021; 144:1694-1713. [PMID: 34648376 DOI: 10.1161/circulationaha.121.053755] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Barth syndrome (BTHS) is caused by mutations of the gene encoding tafazzin, which catalyzes maturation of mitochondrial cardiolipin and often manifests with systolic dysfunction during early infancy. Beyond the first months of life, BTHS cardiomyopathy typically transitions to a phenotype of diastolic dysfunction with preserved ejection fraction, blunted contractile reserve during exercise, and arrhythmic vulnerability. Previous studies traced BTHS cardiomyopathy to mitochondrial formation of reactive oxygen species (ROS). Because mitochondrial function and ROS formation are regulated by excitation-contraction coupling, integrated analysis of mechano-energetic coupling is required to delineate the pathomechanisms of BTHS cardiomyopathy. METHODS We analyzed cardiac function and structure in a mouse model with global knockdown of tafazzin (Taz-KD) compared with wild-type littermates. Respiratory chain assembly and function, ROS emission, and Ca2+ uptake were determined in isolated mitochondria. Excitation-contraction coupling was integrated with mitochondrial redox state, ROS, and Ca2+ uptake in isolated, unloaded or preloaded cardiac myocytes, and cardiac hemodynamics analyzed in vivo. RESULTS Taz-KD mice develop heart failure with preserved ejection fraction (>50%) and age-dependent progression of diastolic dysfunction in the absence of fibrosis. Increased myofilament Ca2+ affinity and slowed cross-bridge cycling caused diastolic dysfunction, in part, compensated by accelerated diastolic Ca2+ decay through preactivated sarcoplasmic reticulum Ca2+-ATPase. Taz deficiency provoked heart-specific loss of mitochondrial Ca2+ uniporter protein that prevented Ca2+-induced activation of the Krebs cycle during β-adrenergic stimulation, oxidizing pyridine nucleotides and triggering arrhythmias in cardiac myocytes. In vivo, Taz-KD mice displayed prolonged QRS duration as a substrate for arrhythmias, and a lack of inotropic response to β-adrenergic stimulation. Cellular arrhythmias and QRS prolongation, but not the defective inotropic reserve, were restored by inhibiting Ca2+ export through the mitochondrial Na+/Ca2+ exchanger. All alterations occurred in the absence of excess mitochondrial ROS in vitro or in vivo. CONCLUSIONS Downregulation of mitochondrial Ca2+ uniporter, increased myofilament Ca2+ affinity, and preactivated sarcoplasmic reticulum Ca2+-ATPase provoke mechano-energetic uncoupling that explains diastolic dysfunction and the lack of inotropic reserve in BTHS cardiomyopathy. Furthermore, defective mitochondrial Ca2+ uptake provides a trigger and a substrate for ventricular arrhythmias. These insights can guide the ongoing search for a cure of this orphaned disease.
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Affiliation(s)
- Edoardo Bertero
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Now with Department of Internal Medicine and Specialties (Di.M.I.), University of Genoa, Italy (E.B.)
| | - Alexander Nickel
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Michael Kohlhaas
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Mathias Hohl
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Vasco Sequeira
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Carolin Brune
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Julia Schwemmlein
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Marco Abeßer
- Institute of Physiology, University of Würzburg, Germany (M.A., K.S., M. Kuhn)
| | - Kai Schuh
- Institute of Physiology, University of Würzburg, Germany (M.A., K.S., M. Kuhn)
| | - Ilona Kutschka
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Christopher Carlein
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Kai Münker
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Sarah Atighetchi
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Andreas Müller
- Clinic for Radiology (A.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Andrey Kazakov
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Reinhard Kappl
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Karina von der Malsburg
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine (K.v.d.M., M.v.d.L., A.v.d.M.), Saarland University, Homburg/Saar, Germany
| | - Martin van der Laan
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine (K.v.d.M., M.v.d.L., A.v.d.M.), Saarland University, Homburg/Saar, Germany
| | - Anna-Florentine Schiuma
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.)
| | - Michael Böhm
- Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany
| | - Ulrich Laufs
- Now with Klinik und Poliklinik für Kardiologie, Universitätsklinikum Leipzig, Germany (U.L.)
| | - Markus Hoth
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Peter Rehling
- Department of Cellular Biochemistry, Georg-August University, Göttingen, Germany (P.R., J.D.).,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Germany (P.R.).,Max-Planck Institute for Biophysical Chemistry, Göttingen, Germany (P.R.)
| | - Michaela Kuhn
- Institute of Physiology, University of Würzburg, Germany (M.A., K.S., M. Kuhn)
| | - Jan Dudek
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Department of Cellular Biochemistry, Georg-August University, Göttingen, Germany (P.R., J.D.)
| | - Alexander von der Malsburg
- Medical Biochemistry and Molecular Biology, Center for Molecular Signaling, PZMS, Faculty of Medicine (K.v.d.M., M.v.d.L., A.v.d.M.), Saarland University, Homburg/Saar, Germany
| | - Leticia Prates Roma
- Department for Biophysics, ZHMB, CIPMM (C.C., R.K., M. Hoth, L.P.R.), Saarland University, Homburg/Saar, Germany
| | - Christoph Maack
- Department of Translational Research, Comprehensive Heart Failure Center, University Clinic, Würzburg, Germany (E.B., A.N., M. Kohlhaas, V.S., J.S., I.K., K.M., S.A., A.-F.S., J.D., C.M.).,Clinic for Internal Medicine III (M. Hohl, C.B., K.M., S.A., A.K., M.B., C.M.), Saarland University Clinic, Homburg/Saar, Germany.,Department for Internal Medicine 1, University Clinic Würzburg, Germany (C.M.)
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7
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Cheng Z, Fang T, Huang J, Guo Y, Alam M, Qian H. Hypertrophic Cardiomyopathy: From Phenotype and Pathogenesis to Treatment. Front Cardiovasc Med 2021; 8:722340. [PMID: 34760939 PMCID: PMC8572854 DOI: 10.3389/fcvm.2021.722340] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Accepted: 09/17/2021] [Indexed: 02/05/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a very common inherited cardiovascular disease (CAD) and the incidence is about 1/500 of the common population. It is caused by more than 1,400 mutations in 11 or more genes encoding the proteins of the cardiac sarcomere. HCM presents a heterogeneous clinical profile and complex pathophysiology and HCM is the most important cause of sudden cardiac death (SCD) in young people. HCM also contributes to functional disability from heart failure and stroke (caused by atrial fibrillation). Current treatments for HCM (medication, myectomy, and alcohol septal ablation) are geared toward slowing down the disease progression and symptom relief and implanted cardiac defibrillator (ICD) to prevent SCD. HCM is, however, entering a period of tight translational research that holds promise for the major advances in disease-specific therapy. Main insights into the genetic landscape of HCM have improved our understanding of molecular pathogenesis and pointed the potential targets for the development of therapeutic agents. We reviewed the critical discoveries about the treatments, mechanism of HCM, and their implications for future research.
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Affiliation(s)
- Zeyi Cheng
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Tingting Fang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
| | - Jinglei Huang
- School of Medicine, Lanzhou University, Lanzhou, China
| | - Yingqiang Guo
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, China
| | - Mahboob Alam
- Division of Cardiovascular Medicine, Department of Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Hong Qian
- Department of Cardiovascular Surgery, West China Hospital, Sichuan University, Chengdu, China
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8
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Flenner F, Jungen C, Küpker N, Ibel A, Kruse M, Koivumäki JT, Rinas A, Zech ATL, Rhoden A, Wijnker PJM, Lemoine MD, Steenpass A, Girdauskas E, Eschenhagen T, Meyer C, van der Velden J, Patten-Hamel M, Christ T, Carrier L. Translational investigation of electrophysiology in hypertrophic cardiomyopathy. J Mol Cell Cardiol 2021; 157:77-89. [PMID: 33957110 PMCID: PMC8320769 DOI: 10.1016/j.yjmcc.2021.04.009] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2021] [Revised: 04/14/2021] [Accepted: 04/29/2021] [Indexed: 12/25/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) patients are at increased risk of ventricular arrhythmias and sudden cardiac death, which can occur even in the absence of structural changes of the heart. HCM mouse models suggest mutations in myofilament components to affect Ca2+ homeostasis and thereby favor arrhythmia development. Additionally, some of them show indications of pro-arrhythmic changes in cardiac electrophysiology. In this study, we explored arrhythmia mechanisms in mice carrying a HCM mutation in Mybpc3 (Mybpc3-KI) and tested the translatability of our findings in human engineered heart tissues (EHTs) derived from CRISPR/Cas9-generated homozygous MYBPC3 mutant (MYBPC3hom) in induced pluripotent stem cells (iPSC) and to left ventricular septum samples obtained from HCM patients. We observed higher arrhythmia susceptibility in contractility measurements of field-stimulated intact cardiomyocytes and ventricular muscle strips as well as in electromyogram recordings of Langendorff-perfused hearts from adult Mybpc3-KI mice than in wild-type (WT) controls. The latter only occurred in homozygous (Hom-KI) but not in heterozygous (Het-KI) mouse hearts. Both Het- and Hom-KI are known to display pro-arrhythmic increased Ca2+ myofilament sensitivity as a direct consequence of the mutation. In the electrophysiological characterization of the model, we observed smaller repolarizing K+ currents in single cell patch clamp, longer ventricular action potentials in sharp microelectrode recordings and longer ventricular refractory periods in Langendorff-perfused hearts in Hom-KI, but not Het-KI. Interestingly, reduced K+ channel subunit transcript levels and prolonged action potentials were already detectable in newborn, pre-hypertrophic Hom-KI mice. Human iPSC-derived MYBPC3hom EHTs, which genetically mimicked the Hom-KI mice, did exhibit lower mutant mRNA and protein levels, lower force, beating frequency and relaxation time, but no significant alteration of the force-Ca2+ relation in skinned EHTs. Furthermore, MYBPC3hom EHTs did show higher spontaneous arrhythmic behavior, whereas action potentials measured by sharp microelectrode did not differ to isogenic controls. Action potentials measured in septal myectomy samples did not differ between patients with HCM and patients with aortic stenosis, except for the only sample with a MYBPC3 mutation. The data demonstrate that increased myofilament Ca2+ sensitivity is not sufficient to induce arrhythmias in the Mybpc3-KI mouse model and suggest that reduced K+ currents can be a pro-arrhythmic trigger in Hom-KI mice, probably already in early disease stages. However, neither data from EHTs nor from left ventricular samples indicate relevant reduction of K+ currents in human HCM. Therefore, our study highlights the species difference between mouse and human and emphasizes the importance of research in human samples and human-like models. Sudden cardiac death is threatening hypertrophic cardiomyopathy (HCM) patients. Arrhythmia mechanisms are not well understood. Mouse HCM models showed relevant reduction in K+ currents. Human iPSC-EHT model and HCM patient septal myectomies did not display this mechanism.
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Affiliation(s)
- Frederik Flenner
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Christiane Jungen
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany; Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart and Vascular Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany; Department of Cardiology, Willem Einthoven Center for Cardiac Arrhythmia Research and Management, Leiden University Medical Center, Leiden, the Netherlands
| | - Nadine Küpker
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Antonia Ibel
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Martin Kruse
- Department of Biology and Program in Neuroscience, Bates College, Lewiston, ME, USA
| | - Jussi T Koivumäki
- BioMediTech, Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Anna Rinas
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Antonia T L Zech
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Alexandra Rhoden
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Paul J M Wijnker
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Marc D Lemoine
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany; Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart and Vascular Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Anna Steenpass
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Evaldas Girdauskas
- Department of Cardiovascular Surgery, University Heart and Vascular Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Thomas Eschenhagen
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Christian Meyer
- Department of Cardiology-Electrophysiology, cardiac Neuro- and Electrophysiology Research Group (cNEP), University Heart and Vascular Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany; Division of Cardiology/Angiology/Intensiv Care, cardiac Neuro- and Electrophysiology Research Consortium (cNEP), EVK Düsseldorf, Teaching Hospital University of Düsseldorf, Düsseldorf, Germany; Institute of Neural and Sensory Physiology, cardiac Neuro- and Electrophysiology Research Consortium (cNEP), University of Düsseldorf, Düsseldorf, Germany
| | - Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Department of Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Monica Patten-Hamel
- Department of General and Interventional Cardiology, University Heart Center, University Hospital Hamburg-Eppendorf, Hamburg, Germany
| | - Torsten Christ
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Hamburg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany.
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9
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Nollet EE, Westenbrink BD, de Boer RA, Kuster DWD, van der Velden J. Unraveling the Genotype-Phenotype Relationship in Hypertrophic Cardiomyopathy: Obesity-Related Cardiac Defects as a Major Disease Modifier. J Am Heart Assoc 2020; 9:e018641. [PMID: 33174505 PMCID: PMC7763714 DOI: 10.1161/jaha.120.018641] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and is characterized by asymmetric septal thickening and diastolic dysfunction. More than 1500 mutations in genes encoding sarcomere proteins are associated with HCM. However, the genotype‐phenotype relationship in HCM is incompletely understood and involves modification by additional disease hits. Recent cohort studies identify obesity as a major adverse modifier of disease penetrance, severity, and clinical course. In this review, we provide an overview of these clinical findings. Moreover, we explore putative mechanisms underlying obesity‐induced sensitization and aggravation of the HCM phenotype. We hypothesize obesity‐related stressors to impact on cardiomyocyte structure, metabolism, and homeostasis. These may impair cardiac function by directly acting on the primary mutation‐induced myofilament defects and by independently adding to the total cardiac disease burden. Last, we address important clinical and pharmacological implications of the involvement of obesity in HCM disease modification.
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Affiliation(s)
- Edgar E Nollet
- Department of Physiology Amsterdam UMC Vrije Universiteit Amsterdam Amsterdam Cardiovascular Sciences Amsterdam The Netherlands
| | - B Daan Westenbrink
- Department of Cardiology University of Groningen University Medical Center Groningen Groningen The Netherlands
| | - Rudolf A de Boer
- Department of Cardiology University of Groningen University Medical Center Groningen Groningen The Netherlands
| | - Diederik W D Kuster
- Department of Physiology Amsterdam UMC Vrije Universiteit Amsterdam Amsterdam Cardiovascular Sciences Amsterdam The Netherlands
| | - Jolanda van der Velden
- Department of Physiology Amsterdam UMC Vrije Universiteit Amsterdam Amsterdam Cardiovascular Sciences Amsterdam The Netherlands.,Netherlands Heart Institute Utrecht The Netherlands
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10
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Wijnker PJM, Sequeira V, Kuster DWD, Velden JVD. Hypertrophic Cardiomyopathy: A Vicious Cycle Triggered by Sarcomere Mutations and Secondary Disease Hits. Antioxid Redox Signal 2019; 31:318-358. [PMID: 29490477 PMCID: PMC6602117 DOI: 10.1089/ars.2017.7236] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Significance: Hypertrophic cardiomyopathy (HCM) is a cardiac genetic disease characterized by left ventricular hypertrophy, diastolic dysfunction, and myocardial disarray. Disease onset occurs between 20 and 50 years of age, thus affecting patients in the prime of their life. HCM is caused by mutations in sarcomere proteins, the contractile building blocks of the heart. Despite increased knowledge of causal mutations, the exact path from genetic defect leading to cardiomyopathy is complex and involves additional disease hits. Recent Advances: Laboratory-based studies indicate that HCM development not only depends on the primary sarcomere impairment caused by the mutation but also on secondary disease-related alterations in the heart. Here we propose a vicious mutation-induced disease cycle, in which a mutation-induced energy depletion alters cellular metabolism with increased mitochondrial work, which triggers secondary disease modifiers that will worsen disease and ultimately lead to end-stage HCM. Critical Issues: Evidence shows excessive cellular reactive oxygen species (ROS) in HCM patients and HCM animal models. Oxidative stress markers are increased in the heart (oxidized proteins, DNA, and lipids) and serum of HCM patients. In addition, increased mitochondrial ROS production and changes in endogenous antioxidants are reported in HCM. Mutant sarcomeric protein may drive excessive levels of cardiac ROS via changes in cardiac efficiency and metabolism, mitochondrial activation and/or dysfunction, impaired protein quality control, and microvascular dysfunction. Future Directions: Interventions restoring metabolism, mitochondrial function, and improved ROS balance may be promising therapeutic approaches. We discuss the effects of current HCM pharmacological therapies and potential future therapies to prevent and reverse HCM. Antioxid. Redox Signal. 31, 318-358.
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Affiliation(s)
- Paul J M Wijnker
- 1 Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Vasco Sequeira
- 1 Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Diederik W D Kuster
- 1 Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Jolanda van der Velden
- 1 Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands.,2 Netherlands Heart Institute, Utrecht, The Netherlands
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11
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Sequeira V, Bertero E, Maack C. Energetic drain driving hypertrophic cardiomyopathy. FEBS Lett 2019; 593:1616-1626. [PMID: 31209876 DOI: 10.1002/1873-3468.13496] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 06/07/2019] [Accepted: 06/13/2019] [Indexed: 01/09/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common form of hereditary cardiomyopathy and is mainly caused by mutations of genes encoding cardiac sarcomeric proteins. HCM is characterized by hypertrophy of the left ventricle, frequently involving the septum, that is not explained solely by loading conditions. HCM has a heterogeneous clinical profile, but diastolic dysfunction and ventricular arrhythmias represent two dominant features of the disease. Preclinical evidence indicates that the enhanced Calcium (Ca2+ ) sensitivity of the myofilaments plays a key role in the pathophysiology of HCM. Notably, this is not always a direct consequence of sarcomeric mutations, but can also result from secondary mutation-driven alterations. Here, we review experimental and clinical evidence indicating that increased myofilament Ca2+ sensitivity lies upstream of numerous cellular derangements which potentially contribute to the progression of HCM toward heart failure and sudden cardiac death.
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Affiliation(s)
- Vasco Sequeira
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Germany
| | - Edoardo Bertero
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Germany
| | - Christoph Maack
- Comprehensive Heart Failure Center (CHFC), University Clinic Würzburg, Germany
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12
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van der Velden J, Stienen GJM. Cardiac Disorders and Pathophysiology of Sarcomeric Proteins. Physiol Rev 2019; 99:381-426. [PMID: 30379622 DOI: 10.1152/physrev.00040.2017] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The sarcomeric proteins represent the structural building blocks of heart muscle, which are essential for contraction and relaxation. During recent years, it has become evident that posttranslational modifications of sarcomeric proteins, in particular phosphorylation, tune cardiac pump function at rest and during exercise. This delicate, orchestrated interaction is also influenced by mutations, predominantly in sarcomeric proteins, which cause hypertrophic or dilated cardiomyopathy. In this review, we follow a bottom-up approach starting from a description of the basic components of cardiac muscle at the molecular level up to the various forms of cardiac disorders at the organ level. An overview is given of sarcomere changes in acquired and inherited forms of cardiac disease and the underlying disease mechanisms with particular reference to human tissue. A distinction will be made between the primary defect and maladaptive/adaptive secondary changes. Techniques used to unravel functional consequences of disease-induced protein changes are described, and an overview of current and future treatments targeted at sarcomeric proteins is given. The current evidence presented suggests that sarcomeres not only form the basis of cardiac muscle function but also represent a therapeutic target to combat cardiac disease.
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Affiliation(s)
- Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Ger J M Stienen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
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13
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Dieseldorff Jones KM, Koh Y, Weller RS, Turna RS, Ahmad F, Huke S, Knollmann BC, Pinto JR, Hwang HS. Pathogenic troponin T mutants with opposing effects on myofilament Ca 2+ sensitivity attenuate cardiomyopathy phenotypes in mice. Arch Biochem Biophys 2018; 661:125-131. [PMID: 30445044 DOI: 10.1016/j.abb.2018.11.006] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2018] [Revised: 08/28/2018] [Accepted: 11/08/2018] [Indexed: 01/14/2023]
Abstract
Mutations in cardiac troponin T (TnT) associated with hypertrophic cardiomyopathy generally lead to an increase in the Ca2+ sensitivity of contraction and susceptibility to arrhythmias. In contrast, TnT mutations linked to dilated cardiomyopathy decrease the Ca2+ sensitivity of contraction. Here we tested the hypothesis that two TnT disease mutations with opposite effects on myofilament Ca2+ sensitivity can attenuate each other's phenotype. We crossed transgenic mice expressing the HCM TnT-I79N mutation (I79N) with a DCM knock-in mouse model carrying the heterozygous TnT-R141W mutation (HET). The results of the Ca2+ sensitivity in skinned cardiac muscle preparations ranked from highest to lowest were as follow: I79N > I79N/HET > NTg > HET. Echocardiographic measurements revealed an improvement in hemodynamic parameters in I79N/HET compared to I79N and normalization of left ventricular dimensions and volumes compared to both I79N and HET. Ex vivo testing showed that the I79N/HET mouse hearts had reduced arrhythmia susceptibility compared to I79N mice. These results suggest that two disease mutations in TnT that have opposite effects on the myofilament Ca2+ sensitivity can paradoxically ameliorate each other's disease phenotype. Normalizing myofilament Ca2+ sensitivity may be a promising new treatment approach for a variety of diseases.
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Affiliation(s)
| | - Yeojung Koh
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA
| | - Rebecca S Weller
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | - Rajdeep S Turna
- Biomedical Sciences, Florida State University, Tallahassee, FL, USA
| | - Ferhaan Ahmad
- Department of Internal Medicine University of Iowa, Iowa City, IA, USA
| | - Sabine Huke
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA; Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Björn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University, Nashville, TN, USA
| | | | - Hyun Seok Hwang
- Department of Nutrition, Food and Exercise Sciences, Florida State University, Tallahassee, FL, USA.
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14
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Abstract
Although the mechanism of sudden cardiac death (SCD) in heart failure is not completely known, genetic variations are known to play key roles in this process. Increasing numbers of mutations and variants are being discovered through genome-wide association studies. The genetic variations involved in the mechanisms of SCD have aroused widespread concern. Comprehensive understanding of the genetic variations involved in SCD may help prevent it. To this end, we briefly reviewed the genetic variations involved in SCD and their associations and interactions, and observed that cardiac ion channels are the core molecules involved in this process. Genetic variations involved in cardiac structure, cardiogenesis and development, cell division and differentiation, and DNA replication and transcription are all speculated to be loci involved in SCD. Additionally, the systems involved in neurohumoral regulation as well as substance and energy metabolism are also potentially responsible for susceptibility to SCD. They form an elaborate network and mutually interact with each other to govern the fate of SCD-susceptible individuals.
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15
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An S, Fan C, Yang Y, Hang F, Wang Z, Zhang Y, Zhang J. Long-Term Prognosis after Myectomy in Hypertrophic Obstructive Cardiomyopathy with Severe Left Ventricular Hypertrophy. Cardiology 2018; 139:83-89. [DOI: 10.1159/000484628] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/23/2017] [Accepted: 10/27/2017] [Indexed: 12/27/2022]
Abstract
Objectives: Patients with hypertrophic obstructive cardiomyopathy (HOCM) and severe left ventricular hypertrophy (maximal left ventricular wall thickness ≥30 mm) are at high risk of sudden cardiac death (SCD). In this study, we aimed to determine whether HOCM patients with severe hypertrophy had a lower incidence of SCD after myectomy. Methods: HOCM patients with severe hypertrophy were consecutively enrolled from Fuwai Hospital in China between 2000 and 2013. Long-term outcomes were retrospectively compared between the 2 groups, namely the myectomy group and medical group. Results: A total of 244 patients (118 in the myectomy group and 126 in the medical group) were involved. The mean follow-up durations for the myectomy and medical groups were 5.07 ± 3.73 and 6.23 ± 4.15 years, respectively. During the follow-up period, the annual cardiovascular mortality rate was 0.84% in the myectomy group and 2.04% in the medical group (p = 0.041). The annual SCD rate was 0.33% in the myectomy group and 1.40% in the medical group (p = 0.040). Multivariate Cox regression analysis showed that myectomy was independently associated with lower rates of cardiovascular death and SCD. Conclusions: In HOCM patients with severe hypertrophy, those that underwent myectomy had a lower risk of cardiovascular death and SCD than those treated with medicines only.
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16
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Toischer K, Zhu W, Hünlich M, Mohamed BA, Khadjeh S, Reuter SP, Schäfer K, Ramanujam D, Engelhardt S, Field LJ, Hasenfuss G. Cardiomyocyte proliferation prevents failure in pressure overload but not volume overload. J Clin Invest 2017; 127:4285-4296. [PMID: 29083322 DOI: 10.1172/jci81870] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Accepted: 09/26/2017] [Indexed: 12/17/2022] Open
Abstract
Induction of the cell cycle is emerging as an intervention to treat heart failure. Here, we tested the hypothesis that enhanced cardiomyocyte renewal in transgenic mice expressing cyclin D2 would be beneficial during hemodynamic overload. We induced pressure overload by transthoracic aortic constriction (TAC) or volume overload by aortocaval shunt in cyclin D2-expressing and WT mice. Although cyclin D2 expression dramatically improved survival following TAC, it did not confer a survival advantage to mice following aortocaval shunt. Cardiac function decreased following TAC in WT mice, but was preserved in cyclin D2-expressing mice. On the other hand, cardiac structure and function were compromised in response to aortocaval shunt in both WT and cyclin D2-expressing mice. The preserved function and improved survival in cyclin D2-expressing mice after TAC was associated with an approximately 50% increase in cardiomyocyte number and exaggerated cardiac hypertrophy, as indicated by increased septum thickness. Aortocaval shunt did not further impact cardiomyocyte number in mice expressing cyclin D2. Following TAC, cyclin D2 expression attenuated cardiomyocyte hypertrophy, reduced cardiomyocyte apoptosis, fibrosis, calcium/calmodulin-dependent protein kinase IIδ phosphorylation, brain natriuretic peptide expression, and sustained capillarization. Thus, we show that cyclin D2-induced cardiomyocyte renewal reduced myocardial remodeling and dysfunction after pressure overload but not after volume overload.
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Affiliation(s)
- Karl Toischer
- Department of Cardiology and Pneumology, Heart Center, Georg-August-University, Goettingen, Germany.,DZHK (German Center for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
| | - Wuqiang Zhu
- Krannert Institute of Cardiology and Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Mark Hünlich
- Department of Cardiology and Pneumology, Heart Center, Georg-August-University, Goettingen, Germany
| | - Belal A Mohamed
- Department of Cardiology and Pneumology, Heart Center, Georg-August-University, Goettingen, Germany.,Department of Medical Biochemistry and Molecular Biology, Faculty of Medicine, Mansoura University, Mansoura, Egypt
| | - Sara Khadjeh
- Department of Cardiology and Pneumology, Heart Center, Georg-August-University, Goettingen, Germany
| | - Sean P Reuter
- Krannert Institute of Cardiology and Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Katrin Schäfer
- Department of Cardiology and Pneumology, Heart Center, Georg-August-University, Goettingen, Germany.,Center for Cardiology, Cardiology I, University Medical Center Mainz, Mainz, Germany
| | - Deepak Ramanujam
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany.,DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Stefan Engelhardt
- Institute of Pharmacology and Toxicology, Technical University of Munich, Munich, Germany.,DZHK (German Center for Cardiovascular Research), partner site Munich Heart Alliance, Munich, Germany
| | - Loren J Field
- Krannert Institute of Cardiology and Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - Gerd Hasenfuss
- Department of Cardiology and Pneumology, Heart Center, Georg-August-University, Goettingen, Germany.,DZHK (German Center for Cardiovascular Research), partner site Goettingen, Goettingen, Germany
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17
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Clinical outcomes associated with sarcomere mutations in hypertrophic cardiomyopathy: a meta-analysis on 7675 individuals. Clin Res Cardiol 2017; 107:30-41. [PMID: 28840316 DOI: 10.1007/s00392-017-1155-5] [Citation(s) in RCA: 89] [Impact Index Per Article: 12.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2017] [Accepted: 08/17/2017] [Indexed: 12/13/2022]
Abstract
BACKGROUND Hypertrophic cardiomyopathy (HCM) is the most common genetic cardiovascular disease, which goes along with increased risk for sudden cardiac death (SCD). Despite the knowledge about the different causal genes, the relationship between individual genotypes and phenotypes is incomplete. METHODS AND RESULTS We retrieved PubMed/Medline literatures on genotype-phenotype associations in patients with HCM and mutations in MYBPC3, MYH7, TNNT2, and TNNI3. Altogether, 51 studies with 7675 HCM patients were included in our meta-analysis. The average frequency of mutations in MYBPC3 (20%) and MYH7 (14%) was higher than TNNT2 and TNNI3 (2% each). The mean age of HCM onset for MYH7 mutation positive patients was the beginning of the fourth decade, significantly earlier than patients without sarcomeric mutations. A high male proportion was observed in TNNT2 (69%), MYBPC3 (62%) and mutation negative group (64%). Cardiac conduction disease, ventricular arrhythmia and heart transplantation (HTx) rate were higher in HCM patients with MYH7 mutations in comparison to MYBPC3 (p < 0.05). Furthermore, SCD was significantly higher in patients with sarcomeric mutations (p < 0.01). CONCLUSION A pooled dataset and a comprehensive genotype-phenotype analysis show that the age at disease onset of HCM patients with MYH7 is earlier and leads to a more severe phenotype than in patient without such mutations. Furthermore, patients with sarcomeric mutations are more susceptible to SCD. The present study further supports the clinical interpretation of sarcomeric mutations in HCM patients.
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18
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Toib A, Zhang C, Borghetti G, Zhang X, Wallner M, Yang Y, Troupes CD, Kubo H, Sharp TE, Feldsott E, Berretta RM, Zalavadia N, Trappanese DM, Harper S, Gross P, Chen X, Mohsin S, Houser SR. Remodeling of repolarization and arrhythmia susceptibility in a myosin-binding protein C knockout mouse model. Am J Physiol Heart Circ Physiol 2017. [PMID: 28646025 DOI: 10.1152/ajpheart.00167.2017] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is one of the most common genetic cardiac diseases and among the leading causes of sudden cardiac death (SCD) in the young. The cellular mechanisms leading to SCD in HCM are not well known. Prolongation of the action potential (AP) duration (APD) is a common feature predisposing hypertrophied hearts to SCD. Previous studies have explored the roles of inward Na+ and Ca2+ in the development of HCM, but the role of repolarizing K+ currents has not been defined. The objective of this study was to characterize the arrhythmogenic phenotype and cellular electrophysiological properties of mice with HCM, induced by myosin-binding protein C (MyBPC) knockout (KO), and to test the hypothesis that remodeling of repolarizing K+ currents causes APD prolongation in MyBPC KO myocytes. We demonstrated that MyBPC KO mice developed severe hypertrophy and cardiac dysfunction compared with wild-type (WT) control mice. Telemetric electrocardiographic recordings of awake mice revealed prolongation of the corrected QT interval in the KO compared with WT control mice, with overt ventricular arrhythmias. Whole cell current- and voltage-clamp experiments comparing KO with WT mice demonstrated ventricular myocyte hypertrophy, AP prolongation, and decreased repolarizing K+ currents. Quantitative RT-PCR analysis revealed decreased mRNA levels of several key K+ channel subunits. In conclusion, decrease in repolarizing K+ currents in MyBPC KO ventricular myocytes contributes to AP and corrected QT interval prolongation and could account for the arrhythmia susceptibility.NEW & NOTEWORTHY Ventricular myocytes isolated from the myosin-binding protein C knockout hypertrophic cardiomyopathy mouse model demonstrate decreased repolarizing K+ currents and action potential and QT interval prolongation, linking cellular repolarization abnormalities with arrhythmia susceptibility and the risk for sudden cardiac death in hypertrophic cardiomyopathy.
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Affiliation(s)
- Amir Toib
- Section of Pediatric Cardiology, St. Christopher's Hospital for Children and Department of Pediatrics, Drexel University College of Medicine, Philadelphia, Pennsylvania; and.,Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Chen Zhang
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Giulia Borghetti
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Xiaoxiao Zhang
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Markus Wallner
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Yijun Yang
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Constantine D Troupes
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Hajime Kubo
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Thomas E Sharp
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Eric Feldsott
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Remus M Berretta
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Neil Zalavadia
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Danielle M Trappanese
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Shavonn Harper
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Polina Gross
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Xiongwen Chen
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Sadia Mohsin
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
| | - Steven R Houser
- Cardiovascular Research Center and Department of Physiology, Lewis Katz School of Medicine, Temple University, Philadelphia, Pennsylvania
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19
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FRET biosensor uncovers cAMP nano-domains at β-adrenergic targets that dictate precise tuning of cardiac contractility. Nat Commun 2017; 8:15031. [PMID: 28425435 PMCID: PMC5411486 DOI: 10.1038/ncomms15031] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 02/21/2017] [Indexed: 12/18/2022] Open
Abstract
Compartmentalized cAMP/PKA signalling is now recognized as important for physiology and pathophysiology, yet a detailed understanding of the properties, regulation and function of local cAMP/PKA signals is lacking. Here we present a fluorescence resonance energy transfer (FRET)-based sensor, CUTie, which detects compartmentalized cAMP with unprecedented accuracy. CUTie, targeted to specific multiprotein complexes at discrete plasmalemmal, sarcoplasmic reticular and myofilament sites, reveals differential kinetics and amplitudes of localized cAMP signals. This nanoscopic heterogeneity of cAMP signals is necessary to optimize cardiac contractility upon adrenergic activation. At low adrenergic levels, and those mimicking heart failure, differential local cAMP responses are exacerbated, with near abolition of cAMP signalling at certain locations. This work provides tools and fundamental mechanistic insights into subcellular adrenergic signalling in normal and pathological cardiac function.
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20
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Huke S. Linking myofilaments to sudden cardiac death: recent advances. J Physiol 2017; 595:3939-3947. [PMID: 28205229 DOI: 10.1113/jp273047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2016] [Accepted: 01/06/2017] [Indexed: 12/11/2022] Open
Abstract
The major goal of this focused review is to highlight some of the recent advances and remaining open questions about how a mutation in a myofilament protein leads to an increased risk for sudden cardiac death (SCD). The link between myofilaments and SCD has been known for over 25 years, but identifying mutation carriers at risk for SCD is still a challenge and currently the only effective prevention is implantation of a defibrillator (ICD). In addition to recognized risk factors, other contributing factors need to be considered and assessed, e.g. 'microvascular dysfunction', to calibrate individual risk more accurately. Similarly, improving our understanding about the underlying mechanisms of SCD in patients with sarcomeric mutations will also allow us to design new and less invasive treatment options that will minimize risk and hopefully make implantation of an ICD unnecessary.
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Affiliation(s)
- Sabine Huke
- Department of Medicine, Division of Cardiovascular Disease, University of Alabama at Birmingham, Birmingham, AL, USA
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21
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Flenner F, Geertz B, Reischmann-Düsener S, Weinberger F, Eschenhagen T, Carrier L, Friedrich FW. Diltiazem prevents stress-induced contractile deficits in cardiomyocytes, but does not reverse the cardiomyopathy phenotype in Mybpc3-knock-in mice. J Physiol 2017; 595:3987-3999. [PMID: 28090637 DOI: 10.1113/jp273769] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2016] [Accepted: 01/06/2017] [Indexed: 12/16/2022] Open
Abstract
KEY POINTS Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac illness and can lead to diastolic dysfunction, sudden cardiac death and heart failure. Treatment of HCM patients is empirical and current pharmacological treatments are unable to stop disease progression or reverse hypertrophy. In this study, we tested if the non-dihydropyridine Ca2+ channel blocker diltiazem, which previously showed potential to stop disease progression, can improve the phenotype of a HCM mouse model (Mybpc3-targeted knock-in), which is based on a mutation commonly found in patients. Diltiazem improved contractile function of isolated ventricular cardiomyocytes acutely, but chronic application did not improve the phenotype of adult mice with a fully developed HCM. Our study shows that diltiazem has beneficial effects in HCM, but long-term treatment success is likely to depend on characteristics and cause of HCM and onset of treatment. ABSTRACT Left ventricular hypertrophy, diastolic dysfunction and fibrosis are the main features of hypertrophic cardiomyopathy (HCM). Guidelines recommend β-adrenoceptor or Ca2+ channel antagonists as pharmacological treatment. The Ca2+ channel blocker diltiazem recently showed promising beneficial effects in pre-clinical HCM, particularly in patients carrying MYBPC3 mutations. In the present study we evaluated whether diltiazem could ameliorate or reverse the disease phenotype in cells and in vivo in an Mybpc3-targeted knock-in (KI) mouse model of HCM. Sarcomere shortening and Ca2+ transients were measured in KI and wild-type (WT) cardiomyocytes in basal conditions (1-Hz pacing) and under stress conditions (30 nm isoprenaline, 5-Hz pacing) with or without pre-treatment with 1 μm diltiazem. KI cardiomyocytes exhibited lower diastolic sarcomere length (dSL) at baseline, a tendency to a stronger positive inotropic response to isoprenaline than WT, a marked reduction of dSL and a tendency towards arrhythmias under stress conditions. Pre-treatment of cardiomyocytes with 1 μm diltiazem reduced the drop in dSL and arrhythmia frequency in KI, and attenuated the positive inotropic effect of isoprenaline. Furthermore, diltiazem reduced the contraction amplitude at 5 Hz but did not affect diastolic Ca2+ load and Ca2+ transient amplitude. Six months of diltiazem treatment of KI mice did not reverse cardiac hypertrophy and dysfunction, activation of the fetal gene program or fibrosis. In conclusion, diltiazem blunted the response to isoprenaline in WT and KI cardiomyocytes and improved diastolic relaxation under stress conditions in KI cardiomyocytes. This beneficial effect of diltiazem in cells did not translate in therapeutic efficacy when applied chronically in KI mice.
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Affiliation(s)
- Frederik Flenner
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Birgit Geertz
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Silke Reischmann-Düsener
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Florian Weinberger
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Thomas Eschenhagen
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
| | - Felix W Friedrich
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Centre, University Medical Centre Hamburg-Eppendorf, Hamburg, Germany.,DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
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22
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23
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Thompson BR, Martindale J, Metzger JM. Sarcomere neutralization in inherited cardiomyopathy: small-molecule proof-of-concept to correct hyper-Ca2+-sensitive myofilaments. Am J Physiol Heart Circ Physiol 2016; 311:H36-43. [PMID: 27199134 DOI: 10.1152/ajpheart.00981.2015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2015] [Accepted: 05/05/2016] [Indexed: 11/22/2022]
Abstract
The sarcomere is the functional unit of the heart. Alterations in sarcomere activation lead to disease states such as hypertrophic and restrictive cardiomyopathy (HCM/RCM). Mutations in many of the sarcomeric genes are causal for HCM/RCM. In most cases, these mutations result in increased Ca(2+) sensitivity of the sarcomere, giving rise to altered systolic and diastolic function. There is emerging evidence that small-molecule sarcomere neutralization is a potential therapeutic strategy for HCM/RCM. To pursue proof-of-concept, W7 was used here because of its well-known Ca(2+) desensitizer biochemical effects at the level of cardiac troponin C. Acute treatment of adult cardiac myocytes with W7 caused a dose-dependent (1-10 μM) decrease in contractility in a Ca(2+)-independent manner. Alkalosis was used as an in vitro experimental model of acquired heightened Ca(2+) sensitivity, resulting in increased live cell contractility and decreased baseline sarcomere length, which were rapidly corrected with W7. As an inherited cardiomyopathy model, R193H cardiac troponin I (cTnI) transgenic myocytes showed significant decreased baseline sarcomere length and slowed relaxation that were rapidly and dose-dependently corrected by W7. Langendorff whole heart pacing stress showed that R193H cTnI transgenic hearts had elevated end-diastolic pressures at all pacing frequencies compared with hearts from nontransgenic mice. Acute treatment with W7 rapidly restored end-diastolic pressures to normal values in R193H cTnI hearts, supporting a sarcomere intrinsic mechanism of dysfunction. The known off-target effects of W7 notwithstanding, these results provide further proof-of-concept that small-molecule-based sarcomere neutralization is a potential approach to remediate hyper-Ca(2+)-sensitive sarcomere function.
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Affiliation(s)
- Brian R Thompson
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Joshua Martindale
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
| | - Joseph M Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota
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24
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Gilda JE, Lai X, Witzmann FA, Gomes AV. Delineation of Molecular Pathways Involved in Cardiomyopathies Caused by Troponin T Mutations. Mol Cell Proteomics 2016; 15:1962-81. [PMID: 27022107 DOI: 10.1074/mcp.m115.057380] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Indexed: 11/06/2022] Open
Abstract
Familial hypertrophic cardiomyopathy (FHC) is associated with mild to severe cardiac problems and is the leading cause of sudden death in young people and athletes. Although the genetic basis for FHC is well-established, the molecular mechanisms that ultimately lead to cardiac dysfunction are not well understood. To obtain important insights into the molecular mechanism(s) involved in FHC, hearts from two FHC troponin T models (Ile79Asn [I79N] and Arg278Cys [R278C]) were investigated using label-free proteomics and metabolomics. Mutations in troponin T are the third most common cause of FHC, and the I79N mutation is associated with a high risk of sudden cardiac death. Most FHC-causing mutations, including I79N, increase the Ca(2+) sensitivity of the myofilament; however, the R278C mutation does not alter Ca(2+) sensitivity and is associated with a better prognosis than most FHC mutations. Out of more than 1200 identified proteins, 53 and 76 proteins were differentially expressed in I79N and R278C hearts, respectively, when compared with wild-type hearts. Interestingly, more than 400 proteins were differentially expressed when the I79N and R278C hearts were directly compared. The three major pathways affected in I79N hearts relative to R278C and wild-type hearts were the ubiquitin-proteasome system, antioxidant systems, and energy production pathways. Further investigation of the proteasome system using Western blotting and activity assays showed that proteasome dysfunction occurs in I79N hearts. Metabolomic results corroborate the proteomic data and suggest the glycolytic, citric acid, and electron transport chain pathways are important pathways that are altered in I79N hearts relative to R278C or wild-type hearts. Our findings suggest that impaired energy production and protein degradation dysfunction are important mechanisms in FHCs associated with poor prognosis and that cardiac hypertrophy is not likely needed for a switch from fatty acid to glucose metabolism.
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Affiliation(s)
| | - Xianyin Lai
- ¶Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Frank A Witzmann
- ¶Department of Cellular and Integrative Physiology, Indiana University School of Medicine, Indianapolis, Indiana 46202
| | - Aldrin V Gomes
- From the ‡Department of Neurobiology, Physiology, and Behavior, §Department of Physiology and Membrane Biology, University of California, Davis, California 95616;
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25
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van der Velden J, Ho CY, Tardiff JC, Olivotto I, Knollmann BC, Carrier L. Research priorities in sarcomeric cardiomyopathies. Cardiovasc Res 2015; 105:449-56. [PMID: 25631582 PMCID: PMC4375392 DOI: 10.1093/cvr/cvv019] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/04/2015] [Accepted: 01/09/2015] [Indexed: 12/12/2022] Open
Abstract
The clinical variability in patients with sarcomeric cardiomyopathies is striking: a mutation causes cardiomyopathy in one individual, while the identical mutation is harmless in a family member. Moreover, the clinical phenotype varies ranging from asymmetric hypertrophy to severe dilatation of the heart. Identification of a single phenotype-associated disease mechanism would facilitate the design of targeted treatments for patient groups with different clinical phenotypes. However, evidence from both the clinic and basic knowledge of functional and structural properties of the sarcomere argues against a 'one size fits all' therapy for treatment of one clinical phenotype. Meticulous clinical and basic studies are needed to unravel the initial and progressive changes initiated by sarcomere mutations to better understand why mutations in the same gene can lead to such opposing phenotypes. Ultimately, we need to design an 'integrative physiology' approach to fully realize patient/gene-tailored therapy. Expertise within different research fields (cardiology, genetics, cellular biology, physiology, and pharmacology) must be joined to link longitudinal clinical studies with mechanistic insights obtained from molecular and functional studies in novel cardiac muscle systems. New animal models, which reflect both initial and more advanced stages of sarcomeric cardiomyopathy, will also aid in achieving these goals. Here, we discuss current priorities in clinical and preclinical investigation aimed at increasing our understanding of pathophysiological mechanisms leading from mutation to disease. Such information will provide the basis to improve risk stratification and to develop therapies to prevent/rescue cardiac dysfunction and remodelling caused by sarcomere mutations.
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Affiliation(s)
- Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, van der Boechorststraat 7, 1081BT Amsterdam, The Netherlands ICIN-Netherlands Heart Institute, Utrecht, The Netherlands
| | - Carolyn Y Ho
- Brigham and Women's Hospital, Cardiology, Boston, MA, USA
| | - Jil C Tardiff
- Department of Medicine and Cellular and Molecular Medicine, University of Arizona, Tucson, AZ, USA
| | - Iacopo Olivotto
- Referral Center for Cardiomyopathies, Careggi University Hospital, Florence, Italy
| | - Bjorn C Knollmann
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany
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26
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Affiliation(s)
- Gerd Hasenfuss
- Department of Cardiology and Pneumology, Heart Center, University of Göttingen, DZHK (German Center for Cardiovascular Research), Site Göttingen, Robert-Koch-Strasse 40, Göttingen 37075, Germany
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27
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Tardiff JC, Carrier L, Bers DM, Poggesi C, Ferrantini C, Coppini R, Maier LS, Ashrafian H, Huke S, van der Velden J. Targets for therapy in sarcomeric cardiomyopathies. Cardiovasc Res 2015; 105:457-70. [PMID: 25634554 DOI: 10.1093/cvr/cvv023] [Citation(s) in RCA: 106] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
To date, no compounds or interventions exist that treat or prevent sarcomeric cardiomyopathies. Established therapies currently improve the outcome, but novel therapies may be able to more fundamentally affect the disease process and course. Investigations of the pathomechanisms are generating molecular insights that can be useful for the design of novel specific drugs suitable for clinical use. As perturbations in the heart are stage-specific, proper timing of drug treatment is essential to prevent initiation and progression of cardiac disease in mutation carrier individuals. In this review, we emphasize potential novel therapies which may prevent, delay, or even reverse hypertrophic cardiomyopathy caused by sarcomeric gene mutations. These include corrections of genetic defects, altered sarcomere function, perturbations in intracellular ion homeostasis, and impaired myocardial energetics.
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Affiliation(s)
- Jil C Tardiff
- Department of Medicine and Cellular and Molecular Medicine, University of Arizona, 1656 East Mabel Street, MRB 312, Tucson, AZ 85724-5217, USA
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany
| | - Donald M Bers
- Department of Pharmacology, University of California, Davis, CA, USA
| | - Corrado Poggesi
- Center of Molecular Medicine and Applied Biophysics (CIMMBA), University of Florence, Florence, Italy
| | - Cecilia Ferrantini
- Center of Molecular Medicine and Applied Biophysics (CIMMBA), University of Florence, Florence, Italy
| | - Raffaele Coppini
- Center of Molecular Medicine and Applied Biophysics (CIMMBA), University of Florence, Florence, Italy
| | - Lars S Maier
- Klinik und Poliklinik für Innere Medizin II, Universitätsklinikum, Regensburg, Germany
| | - Houman Ashrafian
- Experimental Therapeutics and Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Sabine Huke
- Division of Clinical Pharmacology, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research (ICaR-VU), VU University Medical Center, van der Boechorststraat 7, 1081 BT Amsterdam, The Netherlands ICIN-Netherlands Heart Institute, Utrecht, the Netherlands
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28
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Williams R. Circulation Research
“In This Issue” Anthology. Circ Res 2014. [DOI: 10.1161/res.0000000000000042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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29
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Pavón N, Hernández-Esquivel L, Buelna-Chontal M, Chávez E. Antiarrhythmic effect of tamoxifen on the vulnerability induced by hyperthyroidism to heart ischemia/reperfusion damage. J Steroid Biochem Mol Biol 2014; 143:416-23. [PMID: 24923730 DOI: 10.1016/j.jsbmb.2014.06.006] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Revised: 05/06/2014] [Accepted: 06/05/2014] [Indexed: 01/08/2023]
Abstract
Hyperthyroidism, known to have deleterious effects on heart function, and is associated with an enhanced metabolic state, implying an increased production of reactive oxygen species. Tamoxifen is a selective antagonist of estrogen receptors. These receptors make the hyperthyroid heart more susceptible to ischemia/reperfusion. Tamoxifen is also well-known as an antioxidant. The aim of the present study was to explore the possible protective effect of tamoxifen on heart function in hyperthyroid rats. Rats were injected daily with 3,5,3'-triiodothyronine at 2mg/kg body weight during 5 days to induce hyperthyroidism. One group was treated with 10mg/kg tamoxifen and another was not. The protective effect of the drug on heart rhythm was analyzed after 5 min of coronary occlusion followed by 5 min reperfusion. In hyperthyroid rats not treated with tamoxifen, ECG tracings showed post-reperfusion arrhythmias, and heart mitochondria isolated from the ventricular free wall lost the ability to accumulate and retain matrix Ca(2+) and to form a high electric gradient. Both of these adverse effects were avoided with tamoxifen treatment. Hyperthyroidism-induced oxidative stress caused inhibition of cis-aconitase and disruption of mitochondrial DNA, effects which were also avoided by tamoxifen treatment. The current results support the idea that tamoxifen inhibits the hypersensitivity of hyperthyroid rat myocardium to reperfusion damage, probably because its antioxidant activity inhibits the mitochondrial permeability transition.
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Affiliation(s)
- Natalia Pavón
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, México D.F., Mexico
| | - Luz Hernández-Esquivel
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, México D.F., Mexico
| | - Mabel Buelna-Chontal
- Departamento de Biomedicina Cardiovascular, Instituto Nacional de Cardiología Ignacio Chávez, México D.F., Mexico
| | - Edmundo Chávez
- Departamento de Bioquímica, Instituto Nacional de Cardiología Ignacio Chávez, México D.F., Mexico.
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30
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Puglisi JL, Goldspink PH, Gomes AV, Utter MS, Bers DM, Solaro RJ. Influence of a constitutive increase in myofilament Ca(2+)-sensitivity on Ca(2+)-fluxes and contraction of mouse heart ventricular myocytes. Arch Biochem Biophys 2014; 552-553:50-9. [PMID: 24480308 PMCID: PMC4043955 DOI: 10.1016/j.abb.2014.01.019] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2013] [Revised: 01/02/2014] [Accepted: 01/18/2014] [Indexed: 11/25/2022]
Abstract
Chronic increases in myofilament Ca(2+)-sensitivity in the heart are known to alter gene expression potentially modifying Ca(2+)-homeostasis and inducing arrhythmias. We tested age-dependent effects of a chronic increase in myofilament Ca(2+)-sensitivity on induction of altered alter gene expression and activity of Ca(2+) transport systems in cardiac myocytes. Our approach was to determine the relative contributions of the major mechanisms responsible for restoring Ca(2+) to basal levels in field stimulated ventricular myocytes. Comparisons were made from ventricular myocytes isolated from non-transgenic (NTG) controls and transgenic mice expressing the fetal, slow skeletal troponin I (TG-ssTnI) in place of cardiac TnI (cTnI). Replacement of cTnI by ssTnI induces an increase in myofilament Ca(2+)-sensitivity. Comparisons included myocytes from relatively young (5-7months) and older mice (11-13months). Employing application of caffeine in normal Tyrode and in 0Na(+) 0Ca(2+) solution, we were able to dissect the contribution of the sarcoplasmic reticulum Ca(2+) pump (SR Ca(2+)-ATPase), the Na(+)/Ca(2+) exchanger (NCX), and "slow mechanisms" representing the activity of the sarcolemmal Ca(2+) pump and the mitochondrial Ca(2+) uniporter. The relative contribution of the SR Ca(2+)-ATPase to restoration of basal Ca(2+) levels in younger TG-ssTnI myocytes was lower than in NTG (81.12±2.8% vs 92.70±1.02%), but the same in the older myocytes. Younger and older NTG myocytes demonstrated similar contributions from the SR Ca(2+)-ATPase and NCX to restoration of basal Ca(2+). However, the slow mechanisms for Ca(2+) removal were increased in the older NTG (3.4±0.3%) vs the younger NTG myocytes (1.4±0.1%). Compared to NTG, younger TG-ssTnI myocytes demonstrated a significantly bigger contribution of the NCX (16±2.7% in TG vs 6.9±0.9% in NTG) and slow mechanisms (3.3±0.4% in TG vs 1.4±0.1% in NTG). In older TG-ssTnI myocytes the contributions were not significantly different from NTG (NCX: 4.9±0.6% in TG vs 5.5±0.7% in NTG; slow mechanisms: 2.5±0.3% in TG vs 3.4±0.3% in NTG). Our data indicate that constitutive increases in myofilament Ca(2+)-sensitivity alter the relative significance of the NCX transport system involved in Ca(2+)-homeostasis only in a younger group of mice. This modification may be of significance in early changes in altered gene expression and electrical stability hearts with increased myofilament Ca-sensitivity.
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Affiliation(s)
- Jose L Puglisi
- Department of Pharmacology, University of California Davis, Davis, CA 95616, United States
| | - Paul H Goldspink
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behavior, University of California Davis, Davis, CA 95616, United States
| | - Megan S Utter
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, United States
| | - Donald M Bers
- Department of Pharmacology, University of California Davis, Davis, CA 95616, United States
| | - R John Solaro
- Department of Physiology and Biophysics, College of Medicine, University of Illinois at Chicago, Chicago, IL 60612, United States.
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Li AY, Stevens CM, Liang B, Rayani K, Little S, Davis J, Tibbits GF. Familial hypertrophic cardiomyopathy related cardiac troponin C L29Q mutation alters length-dependent activation and functional effects of phosphomimetic troponin I*. PLoS One 2013; 8:e79363. [PMID: 24260207 PMCID: PMC3832503 DOI: 10.1371/journal.pone.0079363] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2013] [Accepted: 09/27/2013] [Indexed: 11/18/2022] Open
Abstract
The Ca(2+) binding properties of the FHC-associated cardiac troponin C (cTnC) mutation L29Q were examined in isolated cTnC, troponin complexes, reconstituted thin filament preparations, and skinned cardiomyocytes. While higher Ca(2+) binding affinity was apparent for the L29Q mutant in isolated cTnC, this phenomenon was not observed in the cTn complex. At the level of the thin filament in the presence of phosphomimetic TnI, L29Q cTnC further reduced the Ca(2+) affinity by 27% in the steady-state measurement and increased the Ca(2+) dissociation rate by 20% in the kinetic studies. Molecular dynamics simulations suggest that L29Q destabilizes the conformation of cNTnC in the presence of phosphomimetic cTnI and potentially modulates the Ca(2+) sensitivity due to the changes of the opening/closing equilibrium of cNTnC. In the skinned cardiomyocyte preparation, L29Q cTnC increased Ca(2+) sensitivity in a highly sarcomere length (SL)-dependent manner. The well-established reduction of Ca(2+) sensitivity by phosphomimetic cTnI was diminished by 68% in the presence of the mutation and it also depressed the SL-dependent increase in myofilament Ca(2+) sensitivity. This might result from its modified interaction with cTnI which altered the feedback effects of cross-bridges on the L29Q cTnC-cTnI-Tm complex. This study demonstrates that the L29Q mutation alters the contractility and the functional effects of the phosphomimetic cTnI in both thin filament and single skinned cardiomyocytes and importantly that this effect is highly sarcomere length dependent.
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Affiliation(s)
- Alison Y. Li
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Charles M. Stevens
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Bo Liang
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Kaveh Rayani
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
| | - Sean Little
- Physiology and Cell Biology, The Ohio State University, Columbia, Ohio, United States of America
| | - Jonathan Davis
- Physiology and Cell Biology, The Ohio State University, Columbia, Ohio, United States of America
| | - Glen F. Tibbits
- Biomedical Physiology and Kinesiology, Simon Fraser University, Burnaby, British Columbia, Canada
- Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia, Canada
- Cardiovascular Sciences, Child and Family Research Institute, Vancouver, British Columbia, Canada
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