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Robinson P, Sparrow AJ, Psaras Y, Steeples V, Simon JN, Broyles CN, Chang YF, Brook FA, Wang YJ, Blease A, Zhang X, Abassi YA, Geeves MA, Toepfer CN, Watkins H, Redwood C, Daniels MJ. Comparing the effects of chemical Ca 2+ dyes and R-GECO on contractility and Ca 2+ transients in adult and human iPSC cardiomyocytes. J Mol Cell Cardiol 2023; 180:44-57. [PMID: 37127261 PMCID: PMC10659987 DOI: 10.1016/j.yjmcc.2023.04.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 04/13/2023] [Accepted: 04/28/2023] [Indexed: 05/03/2023]
Abstract
We compared commonly used BAPTA-derived chemical Ca2+ dyes (fura2, Fluo-4, and Rhod-2) with a newer genetically encoded indicator (R-GECO) in single cell models of the heart. We assessed their performance and effects on cardiomyocyte contractility, determining fluorescent signal-to-noise ratios and sarcomere shortening in primary ventricular myocytes from adult mouse and guinea pig, and in human iPSC-derived cardiomyocytes. Chemical Ca2+ dyes displayed dose-dependent contractile impairment in all cell types, and we observed a negative correlation between contraction and fluorescence signal-to-noise ratio, particularly for fura2 and Fluo-4. R-GECO had no effect on sarcomere shortening. BAPTA-based dyes, but not R-GECO, inhibited in vitro acto-myosin ATPase activity. The presence of fura2 accentuated or diminished changes in contractility and Ca2+ handling caused by small molecule modulators of contractility and intracellular ionic homeostasis (mavacamten, levosimendan, and flecainide), but this was not observed when using R-GECO in adult guinea pig left ventricular cardiomyocytes. Ca2+ handling studies are necessary for cardiotoxicity assessments of small molecules intended for clinical use. Caution should be exercised when interpreting small molecule studies assessing contractile effects and Ca2+ transients derived from BAPTA-like chemical Ca2+ dyes in cellular assays, a common platform for cardiac toxicology testing and mechanistic investigation of cardiac disease physiology and treatment.
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Affiliation(s)
- Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK.
| | - Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Yiangos Psaras
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Jillian N Simon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Connor N Broyles
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Yu-Fen Chang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Frances A Brook
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Ying-Jie Wang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Andrew Blease
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Xiaoyu Zhang
- Agilent Biosciences, Inc., San Diego, CA 92121, USA
| | | | | | - Christopher N Toepfer
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Genetics, Harvard Medical School, Boston, MA, USA
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Cardiology, Oxford University NHS Hospitals Trust, Oxford, UK
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Matthew J Daniels
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK; BHF Centre of Research Excellence, University of Oxford, Oxford, UK; Department of Cardiology, Oxford University NHS Hospitals Trust, Oxford, UK; Department of Cardiovascular Sciences, University of Manchester, Manchester, UK.
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2
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Sequeira V, Wang L, Wijnker PJ, Kim K, Pinto JR, dos Remedios C, Redwood C, Knollmann BC, van der Velden J. Low expression of the K280N TNNT2 mutation is sufficient to increase basal myofilament activation in human hypertrophy cardiomyopathy. J Mol Cell Cardiol Plus 2022; 1:100007. [PMID: 37159677 PMCID: PMC10160007 DOI: 10.1016/j.jmccpl.2022.100007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 04/06/2022] [Indexed: 05/11/2023]
Abstract
Background Hypertrophic cardiomyopathy (HCM) is an autosomal dominant genetic disorder with patients typically showing heterozygous inheritance of a pathogenic variant in a gene encoding a contractile protein. Here, we study the contractile effects of a rare homozygous mutation using explanted tissue and human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) to gain insight into how the balance between mutant and WT protein expression affects cardiomyocyte function. Methods Force measurements were performed in cardiomyocytes isolated from a HCM patient carrying a homozygous troponin T mutation (cTnT-K280N) and healthy donors. To discriminate between mutation-mediated and phosphorylation-related effects on Ca2+-sensitivity, cardiomyocytes were treated with alkaline phosphatase (AP) or protein kinase A (PKA). Troponin exchange experiments characterized the relation between mutant levels and myofilament function. To define mutation-mediated effects on Ca2+-dynamics we used CRISPR/Cas9 to generate hiPSC-CMs harbouring heterozygous and homozygous TnT-K280N mutations. Ca2+-transient and cell shortening experiments compared these lines against isogenic controls. Results Myofilament Ca2+-sensitivity was higher in homozygous cTnT-K280N cardiomyocytes and was not corrected by AP- and PKA-treatment. In cTnT-K280N cells exchanged with cTnT-WT, a low level (14%) of cTnT-K280N mutation elevated Ca2+-sensitivity. Similarly, exchange of donor cells with 45 ± 2% cTnT-K280N increased Ca2+-sensitivity and was not corrected by PKA. cTnT-K280N hiPSC-CMs show elevated diastolic Ca2+ and increases in cell shortening. Impaired cardiomyocyte relaxation was only evident in homozygous cTnT-K280N hiPSC-CMs. Conclusions The cTnT-K280N mutation increases myofilament Ca2+-sensitivity, elevates diastolic Ca2+, enhances contractility and impairs cellular relaxation. A low level (14%) of the cTnT-K280N sensitizes myofilaments to Ca2+, a universal finding of human HCM.
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Affiliation(s)
- Vasco Sequeira
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
- Netherlands Heart Institute, Utrecht, the Netherlands
- Division of Clinical Pharmacology, Vanderbilt School of Medicine, Nashville, United States
- Comprehensive Heart Failure Center (CHFC) University Clinic Würzburg, Würzburg, Germany
| | - Lili Wang
- Division of Clinical Pharmacology, Vanderbilt School of Medicine, Nashville, United States
| | - Paul J.M. Wijnker
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
- Netherlands Heart Institute, Utrecht, the Netherlands
| | - Kyungsoo Kim
- Division of Clinical Pharmacology, Vanderbilt School of Medicine, Nashville, United States
| | - Jose R. Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Cris dos Remedios
- Muscle Research Unit, Discipline of Anatomy & Histology, Bosch Institute, The University of Sydney, Sydney, Australia
| | | | - Bjorn C. Knollmann
- Division of Clinical Pharmacology, Vanderbilt School of Medicine, Nashville, United States
| | - Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
- Amsterdam UMC location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1117, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences, Heart Failure and Arrhythmias, Amsterdam, the Netherlands
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3
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Prondzynski M, Lemoine MD, Zech AT, Horváth A, Di Mauro V, Koivumäki JT, Kresin N, Busch J, Krause T, Krämer E, Schlossarek S, Spohn M, Friedrich FW, Münch J, Laufer SD, Redwood C, Volk AE, Hansen A, Mearini G, Catalucci D, Meyer C, Christ T, Patten M, Eschenhagen T, Carrier L. Disease modeling of a mutation in α-actinin 2 guides clinical therapy in hypertrophic cardiomyopathy. EMBO Mol Med 2022; 14:e16423. [PMID: 35938313 DOI: 10.15252/emmm.202216423] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 06/10/2022] [Indexed: 11/09/2022] Open
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Sontayananon N, Redwood C, Davies B, Gehmlich K. Fluorescent PSC-Derived Cardiomyocyte Reporter Lines: Generation Approaches and Their Applications in Cardiovascular Medicine. Biology (Basel) 2020; 9:biology9110402. [PMID: 33207727 PMCID: PMC7697758 DOI: 10.3390/biology9110402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2020] [Revised: 11/09/2020] [Accepted: 11/10/2020] [Indexed: 12/13/2022]
Abstract
Recent advances have made pluripotent stem cell (PSC)-derived cardiomyocytes an attractive option to model both normal and diseased cardiac function at the single-cell level. However, in vitro differentiation yields heterogeneous populations of cardiomyocytes and other cell types, potentially confounding phenotypic analyses. Fluorescent PSC-derived cardiomyocyte reporter systems allow specific cell lineages to be labelled, facilitating cell isolation for downstream applications including drug testing, disease modelling and cardiac regeneration. In this review, the different genetic strategies used to generate such reporter lines are presented with an emphasis on their relative technical advantages and disadvantages. Next, we explore how the fluorescent reporter lines have provided insights into cardiac development and cardiomyocyte physiology. Finally, we discuss how exciting new approaches using PSC-derived cardiomyocyte reporter lines are contributing to progress in cardiac cell therapy with respect to both graft adaptation and clinical safety.
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Affiliation(s)
- Naeramit Sontayananon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK; (N.S.); (C.R.)
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK; (N.S.); (C.R.)
| | - Benjamin Davies
- Wellcome Centre for Human Genetics, Roosevelt Drive, Oxford OX3 7BN, UK
- Correspondence: (B.D.); (K.G.)
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine and British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford OX3 9DU, UK; (N.S.); (C.R.)
- Institute of Cardiovascular Sciences, University of Birmingham, Birmingham B15 2TT, UK
- Correspondence: (B.D.); (K.G.)
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Moreira LM, Takawale A, Hulsurkar M, Menassa DA, Antanaviciute A, Lahiri SK, Mehta N, Evans N, Psarros C, Robinson P, Sparrow AJ, Gillis MA, Ashley N, Naud P, Barallobre-Barreiro J, Theofilatos K, Lee A, Norris M, Clarke MV, Russell PK, Casadei B, Bhattacharya S, Zajac JD, Davey RA, Sirois M, Mead A, Simmons A, Mayr M, Sayeed R, Krasopoulos G, Redwood C, Channon KM, Tardif JC, Wehrens XHT, Nattel S, Reilly S. Paracrine signalling by cardiac calcitonin controls atrial fibrogenesis and arrhythmia. Nature 2020; 587:460-465. [PMID: 33149301 DOI: 10.1038/s41586-020-2890-8] [Citation(s) in RCA: 48] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Accepted: 08/13/2020] [Indexed: 11/10/2022]
Abstract
Atrial fibrillation, the most common cardiac arrhythmia, is an important contributor to mortality and morbidity, and particularly to the risk of stroke in humans1. Atrial-tissue fibrosis is a central pathophysiological feature of atrial fibrillation that also hampers its treatment; the underlying molecular mechanisms are poorly understood and warrant investigation given the inadequacy of present therapies2. Here we show that calcitonin, a hormone product of the thyroid gland involved in bone metabolism3, is also produced by atrial cardiomyocytes in substantial quantities and acts as a paracrine signal that affects neighbouring collagen-producing fibroblasts to control their proliferation and secretion of extracellular matrix proteins. Global disruption of calcitonin receptor signalling in mice causes atrial fibrosis and increases susceptibility to atrial fibrillation. In mice in which liver kinase B1 is knocked down specifically in the atria, atrial-specific knockdown of calcitonin promotes atrial fibrosis and increases and prolongs spontaneous episodes of atrial fibrillation, whereas atrial-specific overexpression of calcitonin prevents both atrial fibrosis and fibrillation. Human patients with persistent atrial fibrillation show sixfold lower levels of myocardial calcitonin compared to control individuals with normal heart rhythm, with loss of calcitonin receptors in the fibroblast membrane. Although transcriptome analysis of human atrial fibroblasts reveals little change after exposure to calcitonin, proteomic analysis shows extensive alterations in extracellular matrix proteins and pathways related to fibrogenesis, infection and immune responses, and transcriptional regulation. Strategies to restore disrupted myocardial calcitonin signalling thus may offer therapeutic avenues for patients with atrial fibrillation.
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Affiliation(s)
- Lucia M Moreira
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Abhijit Takawale
- Research Centre, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
| | - Mohit Hulsurkar
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - David A Menassa
- Clinical Neurology, Nuffield Department of Clinical Neurosciences, University of Oxford, John Radcliffe Hospital, Oxford, UK
- Biological Sciences, Faculty of Life and Environmental Sciences, University of Southampton, Southampton, UK
| | - Agne Antanaviciute
- Medical Research Council (MRC) Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Satadru K Lahiri
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
| | - Neelam Mehta
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Neil Evans
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Constantinos Psarros
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Marc-Antoine Gillis
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Neil Ashley
- Single-Cell Genomics Facility, Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Patrice Naud
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | | | | | - Angela Lee
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Mary Norris
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Michele V Clarke
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Patricia K Russell
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Barbara Casadei
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Shoumo Bhattacharya
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Jeffrey D Zajac
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Rachel A Davey
- Department of Medicine, Austin Health, The University of Melbourne, Heidelberg, Victoria, Australia
| | - Martin Sirois
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Adam Mead
- Medical Research Council (MRC) Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Alison Simmons
- Medical Research Council (MRC) Human Immunology Unit, MRC Weatherall Institute of Molecular Medicine, University of Oxford, Oxford, UK
| | - Manuel Mayr
- King's British Heart Foundation Centre, King's College London, London, UK
| | - Rana Sayeed
- Cardiothoracic Surgery, Oxford Heart Centre, John Radcliffe Hospital, Oxford, UK
| | - George Krasopoulos
- Cardiothoracic Surgery, Oxford Heart Centre, John Radcliffe Hospital, Oxford, UK
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Keith M Channon
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK
| | - Jean-Claude Tardif
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
| | - Xander H T Wehrens
- Cardiovascular Research Institute, Baylor College of Medicine, Houston, TX, USA
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, TX, USA
- Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Stanley Nattel
- Research Centre, Montreal Heart Institute and University of Montreal, Montreal, Quebec, Canada
- Department of Pharmacology and Therapeutics, McGill University, Montreal, Quebec, Canada
- Department of Pharmacology and Physiology, Faculty of Medicine, University of Montreal, Montreal, Quebec, Canada
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
- IHU LIRYC, Fondation Bordeaux Université, Bordeaux, France
| | - Svetlana Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, John Radcliffe Hospital, Oxford, UK.
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Robinson P, Sparrow AJ, Patel S, Malinowska M, Reilly SN, Zhang YH, Casadei B, Watkins H, Redwood C. Dilated cardiomyopathy mutations in thin-filament regulatory proteins reduce contractility, suppress systolic Ca 2+, and activate NFAT and Akt signaling. Am J Physiol Heart Circ Physiol 2020; 319:H306-H319. [PMID: 32618513 PMCID: PMC7473929 DOI: 10.1152/ajpheart.00272.2020] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Dilated cardiomyopathy (DCM) is clinically characterized by dilated ventricular cavities and reduced ejection fraction, leading to heart failure and increased thromboembolic risk. Mutations in thin-filament regulatory proteins can cause DCM and have been shown in vitro to reduce contractility and myofilament Ca2+-affinity. In this work we have studied the functional consequences of mutations in cardiac troponin T (R131W), cardiac troponin I (K36Q) and α-tropomyosin (E40K) using adenovirally transduced isolated guinea pig left ventricular cardiomyocytes. We find significantly reduced fractional shortening with reduced systolic Ca2+. Contraction and Ca2+ reuptake times were slowed, which contrast with some findings in murine models of myofilament Ca2+ desensitization. We also observe increased sarcoplasmic reticulum (SR) Ca2+ load and smaller fractional SR Ca2+ release. This corresponds to a reduction in SR Ca2+-ATPase activity and increase in sodium-calcium exchanger activity. We also observe dephosphorylation and nuclear translocation of the nuclear factor of activated T cells (NFAT), with concordant RAC-α-serine/threonine protein kinase (Akt) phosphorylation but no change to extracellular signal-regulated kinase activation in chronically paced cardiomyocytes expressing DCM mutations. These changes in Ca2+ handling and signaling are common to all three mutations, indicating an analogous pathway of disease pathogenesis in thin-filament sarcomeric DCM. Previous work has shown that changes to myofilament Ca2+ sensitivity caused by DCM mutations are qualitatively opposite from hypertrophic cardiomyopathy (HCM) mutations in the same genes. However, we find several common pathways such as increased relaxation times and NFAT activation that are also hallmarks of HCM. This suggests more complex intracellular signaling underpinning DCM, driven by the primary mutation.NEW & NOTEWORTHY Dilated cardiomyopathy (DCM) is a frequently occurring cardiac disorder with a degree of genetic inheritance. We have found that DCM mutations in proteins that regulate the contractile machinery cause alterations to contraction, calcium-handling, and some new signaling pathways that provide stimuli for disease development. We have used guinea pig cells that recapitulate human calcium-handling and introduced the mutations using adenovirus gene transduction to look at the initial triggers of disease before remodeling.
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Affiliation(s)
- Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Suketu Patel
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Marta Malinowska
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Svetlana N Reilly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Yin-Hua Zhang
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Barbara Casadei
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom
- British Heart Foundation, Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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7
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Sparrow AJ, Watkins H, Daniels MJ, Redwood C, Robinson P. Mavacamten rescues increased myofilament calcium sensitivity and dysregulation of Ca 2+ flux caused by thin filament hypertrophic cardiomyopathy mutations. Am J Physiol Heart Circ Physiol 2020; 318:H715-H722. [PMID: 32083971 PMCID: PMC7099453 DOI: 10.1152/ajpheart.00023.2020] [Citation(s) in RCA: 35] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Thin filament hypertrophic cardiomyopathy (HCM) mutations increase myofilament Ca2+ sensitivity and alter Ca2+ handling and buffering. The myosin inhibitor mavacamten reverses the increased contractility caused by HCM thick filament mutations, and we here test its effect on HCM thin filament mutations where the mode of action is not known. Mavacamten (250 nM) partially reversed the increased Ca2+ sensitivity caused by HCM mutations Cardiac troponin T (cTnT) R92Q, and cardiac troponin I (cTnI) R145G in in vitro ATPase assays. The effect of mavacamten was also analyzed in cardiomyocyte models of cTnT R92Q and cTnI R145G containing cytoplasmic and myofilament specific Ca2+ sensors. While mavacamten rescued the hypercontracted basal sarcomere length, the reduced fractional shortening did not improve with mavacamten. Both mutations caused an increase in peak systolic Ca2+ detected at the myofilament, and this was completely rescued by 250 nM mavacamten. Systolic Ca2+ detected by the cytoplasmic sensor was also reduced by mavacamten treatment, although only R145G increased cytoplasmic Ca2+. There was also a reversal of Ca2+ decay time prolongation caused by both mutations at the myofilament but not in the cytoplasm. We thus show that mavacamten reverses some of the Ca2+-sensitive molecular and cellular changes caused by the HCM mutations, particularly altered Ca2+ flux at the myofilament. The reduction of peak systolic Ca2+ as a consequence of mavacamten treatment represents a novel mechanism by which the compound is able to reduce contractility, working synergistically with its direct effect on the myosin motor. NEW & NOTEWORTHY Mavacamten, a myosin inhibitor, is currently in phase-3 clinical trials as a pharmacotherapy for hypertrophic cardiomyopathy (HCM). Its efficacy in HCM caused by mutations in thin filament proteins is not known. We show in reductionist and cellular models that mavacamten can rescue the effects of thin filament mutations on calcium sensitivity and calcium handling although it only partially rescues the contractile cellular phenotype and, in some cases, exacerbates the effect of the mutation.
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Affiliation(s)
- Alexander J Sparrow
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Matthew J Daniels
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom.,Division of Cardiovascular Sciences, University of Manchester, Manchester, United Kingdom
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
| | - Paul Robinson
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, United Kingdom.,British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, United Kingdom
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8
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Prondzynski M, Lemoine MD, Zech AT, Horváth A, Di Mauro V, Koivumäki JT, Kresin N, Busch J, Krause T, Krämer E, Schlossarek S, Spohn M, Friedrich FW, Münch J, Laufer SD, Redwood C, Volk AE, Hansen A, Mearini G, Catalucci D, Meyer C, Christ T, Patten M, Eschenhagen T, Carrier L. Disease modeling of a mutation in α-actinin 2 guides clinical therapy in hypertrophic cardiomyopathy. EMBO Mol Med 2019; 11:e11115. [PMID: 31680489 PMCID: PMC6895603 DOI: 10.15252/emmm.201911115] [Citation(s) in RCA: 82] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2019] [Revised: 10/08/2019] [Accepted: 10/09/2019] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a cardiac genetic disease accompanied by structural and contractile alterations. We identified a rare c.740C>T (p.T247M) mutation in ACTN2, encoding α-actinin 2 in a HCM patient, who presented with left ventricular hypertrophy, outflow tract obstruction, and atrial fibrillation. We generated patient-derived human-induced pluripotent stem cells (hiPSCs) and show that hiPSC-derived cardiomyocytes and engineered heart tissues recapitulated several hallmarks of HCM, such as hypertrophy, myofibrillar disarray, hypercontractility, impaired relaxation, and higher myofilament Ca2+ sensitivity, and also prolonged action potential duration and enhanced L-type Ca2+ current. The L-type Ca2+ channel blocker diltiazem reduced force amplitude, relaxation, and action potential duration to a greater extent in HCM than in isogenic control. We translated our findings to patient care and showed that diltiazem application ameliorated the prolonged QTc interval in HCM-affected son and sister of the index patient. These data provide evidence for this ACTN2 mutation to be disease-causing in cardiomyocytes, guiding clinical therapy in this HCM family. This study may serve as a proof-of-principle for the use of hiPSC for personalized treatment of cardiomyopathies.
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Affiliation(s)
- Maksymilian Prondzynski
- Institute 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
| | - Marc D Lemoine
- Institute 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.,Department of Cardiology-Electrophysiology, University Heart and Vascular Center, Hamburg, Germany
| | - Antonia Tl Zech
- Institute 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
| | - András Horváth
- Institute 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
| | - Vittoria Di Mauro
- Institute of Genetics and Biomedical Research, Milan Unit, National Research Council, Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Milan, Italy
| | - Jussi T Koivumäki
- Faculty of Medicine and Health Technology, Tampere University, Tampere, Finland
| | - Nico Kresin
- Institute 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
| | - Josefine Busch
- Institute 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
| | - Tobias Krause
- Institute 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
| | - Elisabeth Krämer
- Institute 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
| | - Saskia Schlossarek
- Institute 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
| | - Michael Spohn
- Bioinformatics Core, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Felix W Friedrich
- Institute 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
| | - Julia Münch
- Department of Cardiology-Electrophysiology, University Heart and Vascular Center, Hamburg, Germany.,Department of General and Interventional Cardiology, University Heart and Vascular Center, Hamburg, Germany
| | - Sandra D Laufer
- Institute 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
| | - Charles Redwood
- Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Alexander E Volk
- Institute of Human Genetics, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Arne Hansen
- Institute 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
| | - Giulia Mearini
- Institute 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
| | - Daniele Catalucci
- Institute of Genetics and Biomedical Research, Milan Unit, National Research Council, Milan, Italy.,Humanitas Clinical and Research Center, Rozzano, Milan, Italy
| | - Christian Meyer
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of Cardiology-Electrophysiology, University Heart and Vascular Center, Hamburg, Germany
| | - Torsten Christ
- Institute 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
| | - Monica Patten
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Hamburg, Germany.,Department of General and Interventional Cardiology, University Heart and Vascular Center, Hamburg, Germany
| | - Thomas Eschenhagen
- Institute 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
| | - Lucie Carrier
- Institute 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
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9
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Kresin N, Stücker S, Krämer E, Flenner F, Mearini G, Münch J, Patten M, Redwood C, Carrier L, Friedrich FW. Analysis of Contractile Function of Permeabilized Human Hypertrophic Cardiomyopathy Multicellular Heart Tissue. Front Physiol 2019; 10:239. [PMID: 30984009 PMCID: PMC6447666 DOI: 10.3389/fphys.2019.00239] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2018] [Accepted: 02/22/2019] [Indexed: 01/08/2023] Open
Affiliation(s)
- Nico Kresin
- 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, Hamburg, Germany
| | - Sabrina Stücker
- 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, Hamburg, Germany
| | - Elisabeth Krämer
- 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, Hamburg, Germany
| | - 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, Hamburg, Germany
| | - Giulia Mearini
- 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, Hamburg, Germany
| | - Julia Münch
- University Heart Center Hamburg, Hamburg, Germany
| | | | - Charles Redwood
- Radcliffe Department of Medicine, University of Oxford, John Radcliffe Hospital, Oxford, United Kingdom
| | - 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, Hamburg, Germany
| | - Felix W Friedrich
- 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, Hamburg, Germany
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10
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Ehsan M, Kelly M, Hooper C, Yavari A, Beglov J, Bellahcene M, Ghataorhe K, Poloni G, Goel A, Kyriakou T, Fleischanderl K, Ehler E, Makeyev E, Lange S, Ashrafian H, Redwood C, Davies B, Watkins H, Gehmlich K. Mutant Muscle LIM Protein C58G causes cardiomyopathy through protein depletion. J Mol Cell Cardiol 2018; 121:287-296. [PMID: 30048712 PMCID: PMC6117453 DOI: 10.1016/j.yjmcc.2018.07.248] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Revised: 07/09/2018] [Accepted: 07/21/2018] [Indexed: 12/16/2022]
Abstract
Cysteine and glycine rich protein 3 (CSRP3) encodes Muscle LIM Protein (MLP), a well-established disease gene for Hypertrophic Cardiomyopathy (HCM). MLP, in contrast to the proteins encoded by the other recognised HCM disease genes, is non-sarcomeric, and has important signalling functions in cardiomyocytes. To gain insight into the disease mechanisms involved, we generated a knock-in mouse (KI) model, carrying the well documented HCM-causing CSRP3 mutation C58G. In vivo phenotyping of homozygous KI/KI mice revealed a robust cardiomyopathy phenotype with diastolic and systolic left ventricular dysfunction, which was supported by increased heart weight measurements. Transcriptome analysis by RNA-seq identified activation of pro-fibrotic signalling, induction of the fetal gene programme and activation of markers of hypertrophic signalling in these hearts. Further ex vivo analyses validated the activation of these pathways at transcript and protein level. Intriguingly, the abundance of MLP decreased in KI/KI mice by 80% and in KI/+ mice by 50%. Protein depletion was also observed in cellular studies for two further HCM-causing CSRP3 mutations (L44P and S54R/E55G). We show that MLP depletion is caused by proteasome action. Moreover, MLP C58G interacts with Bag3 and results in a proteotoxic response in the homozygous knock-in mice, as shown by induction of Bag3 and associated heat shock proteins. In conclusion, the newly generated mouse model provides insights into the underlying disease mechanisms of cardiomyopathy caused by mutations in the non-sarcomeric protein MLP. Furthermore, our cellular experiments suggest that protein depletion and proteasomal overload also play a role in other HCM-causing CSPR3 mutations that we investigated, indicating that reduced levels of functional MLP may be a common mechanism for HCM-causing CSPR3 mutations. We present a mouse model for non-sarcomeric hypertrophic cardiomyopathy (HCM). Homozygous Muscle LIM Protein (MLP) C58G mice have systolic and diastolic dysfunction. MLP C58G is depleted via proteasomal pathways. Protein depletion is also a hallmark of further HCM causing MLP mutations. MLP C58G interacts with Bag3 and causes a proteotoxic response.
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Affiliation(s)
- Mehroz Ehsan
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Matthew Kelly
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Charlotte Hooper
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Arash Yavari
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK; Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, UK
| | - Julia Beglov
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Mohamed Bellahcene
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Kirandeep Ghataorhe
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Giulia Poloni
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Anuj Goel
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Theodosios Kyriakou
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Karin Fleischanderl
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King's College London BHF Centre of Research Excellence, London, UK
| | - Elisabeth Ehler
- Randall Centre for Cell and Molecular Biophysics, School of Cardiovascular Medicine and Sciences, King's College London BHF Centre of Research Excellence, London, UK
| | - Eugene Makeyev
- Centre for Developmental Neurobiology, King's College London, London, UK
| | - Stephan Lange
- School of Medicine, University of California, San Diego, La Jolla, CA 92093, USA
| | - Houman Ashrafian
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK; Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, UK
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK
| | - Benjamin Davies
- Transgenic Core, Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, British Heart Foundation Centre of Research Excellence, University of Oxford, Oxford, UK; Wellcome Centre for Human Genetics, University of Oxford, Oxford, UK.
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11
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Robinson P, Liu X, Sparrow A, Patel S, Zhang YH, Casadei B, Watkins H, Redwood C. Hypertrophic cardiomyopathy mutations increase myofilament Ca 2+ buffering, alter intracellular Ca 2+ handling, and stimulate Ca 2+-dependent signaling. J Biol Chem 2018; 293:10487-10499. [PMID: 29760186 PMCID: PMC6036197 DOI: 10.1074/jbc.ra118.002081] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/03/2018] [Indexed: 11/06/2022] Open
Abstract
Mutations in thin filament regulatory proteins that cause hypertrophic cardiomyopathy (HCM) increase myofilament Ca2+ sensitivity. Mouse models exhibit increased Ca2+ buffering and arrhythmias, and we hypothesized that these changes are primary effects of the mutations (independent of compensatory changes) and that increased Ca2+ buffering and altered Ca2+ handling contribute to HCM pathogenesis via activation of Ca2+-dependent signaling. Here, we determined the primary effects of HCM mutations on intracellular Ca2+ handling and Ca2+-dependent signaling in a model system possessing Ca2+-handling mechanisms and contractile protein isoforms closely mirroring the human environment in the absence of potentially confounding remodeling. Using adenovirus, we expressed HCM-causing variants of human troponin-T, troponin-I, and α-tropomyosin (R92Q, R145G, and D175N, respectively) in isolated guinea pig left ventricular cardiomyocytes. After 48 h, each variant had localized to the I-band and comprised ∼50% of the total protein. HCM mutations significantly lowered the Kd of Ca2+ binding, resulting in higher Ca2+ buffering of mutant cardiomyocytes. We observed increased diastolic [Ca2+] and slowed Ca2+ reuptake, coupled with a significant decrease in basal sarcomere length and slowed relaxation. HCM mutant cells had higher sodium/calcium exchanger activity, sarcoplasmic reticulum Ca2+ load, and sarcoplasmic/endoplasmic reticulum calcium ATPase 2 (SERCA2) activity driven by Ca2+/calmodulin-dependent protein kinase II (CaMKII) phosphorylation of phospholamban. The ryanodine receptor (RyR) leak/load relationship was also increased, driven by CaMKII-mediated RyR phosphorylation. Altered Ca2+ homeostasis also increased signaling via both calcineurin/NFAT and extracellular signal-regulated kinase pathways. Altered myofilament Ca2+ buffering is the primary initiator of signaling cascades, indicating that directly targeting myofilament Ca2+ sensitivity provides an attractive therapeutic approach in HCM.
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Affiliation(s)
- Paul Robinson
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Xing Liu
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Alexander Sparrow
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Suketu Patel
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Yin-Hua Zhang
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Barbara Casadei
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Hugh Watkins
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
| | - Charles Redwood
- From the Cardiovascular Medicine Division, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 9DU, United Kingdom
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12
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Ehsan M, Kelly M, Hooper C, Beglov J, Davies B, Fleischanderld K, Ehler E, Redwood C, Watkins H, Gehmlich K. RNAseq reveals mechanisms of cardiomyopathy in Mlp-C58G knock-in mice. J Mol Cell Cardiol 2018. [DOI: 10.1016/j.yjmcc.2018.05.155] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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13
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Prondzynski M, Lemoine M, Horvath A, Krämer E, Zech A, Laufer S, Münch J, Redwood C, Christ T, Patten M, Hansen A, Eschenhagen T, Mearini G, Carrier L. CRISPR/Cas9 genome editing repairs a novel ACTN2 mutation and prevents the disease phenotype in human iPSC-derived cardiomyocytes and engineered heart tissue. J Mol Cell Cardiol 2018. [DOI: 10.1016/j.yjmcc.2018.05.033] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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14
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Singh SR, Zech ATL, Geertz B, Reischmann-Düsener S, Osinska H, Prondzynski M, Krämer E, Meng Q, Redwood C, van der Velden J, Robbins J, Schlossarek S, Carrier L. Activation of Autophagy Ameliorates Cardiomyopathy in Mybpc3-Targeted Knockin Mice. Circ Heart Fail 2017; 10:CIRCHEARTFAILURE.117.004140. [PMID: 29021349 DOI: 10.1161/circheartfailure.117.004140] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/04/2017] [Accepted: 07/26/2017] [Indexed: 12/14/2022]
Abstract
BACKGROUND Alterations in autophagy have been reported in hypertrophic cardiomyopathy (HCM) caused by Danon disease, Vici syndrome, or LEOPARD syndrome, but not in HCM caused by mutations in genes encoding sarcomeric proteins, which account for most of HCM cases. MYBPC3, encoding cMyBP-C (cardiac myosin-binding protein C), is the most frequently mutated HCM gene. METHODS AND RESULTS We evaluated autophagy in patients with HCM carrying MYBPC3 mutations and in a Mybpc3-targeted knockin HCM mouse model, as well as the effect of autophagy modulators on the development of cardiomyopathy in knockin mice. Microtubule-associated protein 1 light chain 3 (LC3)-II protein levels were higher in HCM septal myectomies than in nonfailing control hearts and in 60-week-old knockin than in wild-type mouse hearts. In contrast to wild-type, autophagic flux was blunted and associated with accumulation of residual bodies and glycogen in hearts of 60-week-old knockin mice. We found that Akt-mTORC1 (mammalian target of rapamycin complex 1) signaling was increased, and treatment with 2.24 mg/kg·d rapamycin or 40% caloric restriction for 9 weeks partially rescued cardiomyopathy or heart failure and restored autophagic flux in knockin mice. CONCLUSIONS Altogether, we found that (1) autophagy is altered in patients with HCM carrying MYBPC3 mutations, (2) autophagy is impaired in Mybpc3-targeted knockin mice, and (3) activation of autophagy ameliorated the cardiac disease phenotype in this mouse model. We propose that activation of autophagy might be an attractive option alone or in combination with another therapy to rescue HCM caused by MYBPC3 mutations.
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Affiliation(s)
- Sonia R Singh
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Antonia T L Zech
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Birgit Geertz
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Silke Reischmann-Düsener
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Hanna Osinska
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Maksymilian Prondzynski
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Elisabeth Krämer
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Qinghang Meng
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Charles Redwood
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Jolanda van der Velden
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Jeffrey Robbins
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Saskia Schlossarek
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.)
| | - Lucie Carrier
- From the Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-Eppendorf, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, Germany (S.R.S., A.T.L.Z., B.G., S.R.-D., M.P., E.K., S.S., L.C.); Department of Pediatrics, The Heart Institute, The Cincinnati Children's Hospital Medical Center, OH (S.R.S., H.O., Q.M., J.R.); Radcliffe Department of Medicine, University of Oxford, United Kingdom (C.R.); Department of Physiology, Institute for Cardiovascular Research, VU University Medical Center, Amsterdam, The Netherlands (J.v.d.V.); and ICIN-Netherlands Heart Institute, Utrecht (J.v.d.V.).
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Lemoine M, Prondzynski M, Mearini G, Kraemer E, Redwood C, Patten M, Willems S, Hansen A, Eschenhagen T, Christ T, Carrier L. P5839Patient-specific iPSC-derived cardiomyocytes reveal a disease-causing role of an ACTN2 mutation in HCM and an unexpected LQT phenotype. Eur Heart J 2017. [DOI: 10.1093/eurheartj/ehx493.p5839] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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16
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Prondzynski M, Krämer E, Laufer SD, Shibamiya A, Pless O, Flenner F, Müller OJ, Münch J, Redwood C, Hansen A, Patten M, Eschenhagen T, Mearini G, Carrier L. Evaluation of MYBPC3 trans-Splicing and Gene Replacement as Therapeutic Options in Human iPSC-Derived Cardiomyocytes. Mol Ther Nucleic Acids 2017. [PMID: 28624223 PMCID: PMC5458066 DOI: 10.1016/j.omtn.2017.05.008] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Gene therapy is a promising option for severe forms of genetic diseases. We previously provided evidence for the feasibility of trans-splicing, exon skipping, and gene replacement in a mouse model of hypertrophic cardiomyopathy (HCM) carrying a mutation in MYBPC3, encoding cardiac myosin-binding protein C (cMyBP-C). Here we used human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) from an HCM patient carrying a heterozygous c.1358-1359insC MYBPC3 mutation and from a healthy donor. HCM hiPSC-CMs exhibited ∼50% lower MYBPC3 mRNA and cMyBP-C protein levels than control, no truncated cMyBP-C, larger cell size, and altered gene expression, thus reproducing human HCM features. We evaluated RNA trans-splicing and gene replacement after transducing hiPSC-CMs with adeno-associated virus. trans-splicing with 5' or 3' pre-trans-splicing molecules represented ∼1% of total MYBPC3 transcripts in healthy hiPSC-CMs. In contrast, gene replacement with the full-length MYBPC3 cDNA resulted in ∼2.5-fold higher MYBPC3 mRNA levels in HCM and control hiPSC-CMs. This restored the cMyBP-C level to 81% of the control level, suppressed hypertrophy, and partially restored gene expression to control level in HCM cells. This study provides evidence for (1) the feasibility of trans-splicing, although with low efficiency, and (2) efficient gene replacement in hiPSC-CMs with a MYBPC3 mutation.
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Affiliation(s)
- Maksymilian Prondzynski
- 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, 20246 Hamburg, Germany
| | - Elisabeth Krämer
- 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, 20246 Hamburg, Germany
| | - Sandra D Laufer
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany; Hamburg Zentrum für Experimentelle Therapieforschung (HEXT) Stem Cell Facility, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Aya Shibamiya
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany; Hamburg Zentrum für Experimentelle Therapieforschung (HEXT) Stem Cell Facility, University Medical Center Hamburg-Eppendorf, 20246 Hamburg, Germany
| | - Ole Pless
- Fraunhofer IME Screening-Port, 22525 Hamburg, Germany
| | - Frederik Flenner
- 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, 20246 Hamburg, Germany
| | - Oliver J Müller
- Department of Cardiology, Internal Medicine III, University Hospital Heidelberg, 69120 Heidelberg, Germany; DZHK (German Centre for Cardiovascular Research), partner site Heidelberg/Mannheim, 69120 Heidelberg, Germany
| | - Julia Münch
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany; University Heart Center Hamburg, 20246 Hamburg, Germany
| | - Charles Redwood
- Radcliffe Department of Medicine, University of Oxford, Oxford OX1 3PA, UK
| | - Arne Hansen
- 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, 20246 Hamburg, Germany
| | - Monica Patten
- DZHK (German Centre for Cardiovascular Research), partner site Hamburg/Kiel/Lübeck, 20246 Hamburg, Germany; University Heart Center Hamburg, 20246 Hamburg, Germany
| | - Thomas Eschenhagen
- 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, 20246 Hamburg, Germany
| | - Giulia Mearini
- 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, 20246 Hamburg, Germany.
| | - 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, 20246 Hamburg, Germany.
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17
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Smart N, Riegler J, Turtle CW, Lygate CA, McAndrew DJ, Gehmlich K, Dubé KN, Price AN, Muthurangu V, Taylor AM, Lythgoe MF, Redwood C, Riley PR. Aberrant developmental titin splicing and dysregulated sarcomere length in Thymosin β4 knockout mice. J Mol Cell Cardiol 2017; 102:94-107. [PMID: 27914791 PMCID: PMC5319848 DOI: 10.1016/j.yjmcc.2016.10.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/09/2016] [Revised: 10/20/2016] [Accepted: 10/22/2016] [Indexed: 02/07/2023]
Abstract
Sarcomere assembly is a highly orchestrated and dynamic process which adapts, during perinatal development, to accommodate growth of the heart. Sarcomeric components, including titin, undergo an isoform transition to adjust ventricular filling. Many sarcomeric genes have been implicated in congenital cardiomyopathies, such that understanding developmental sarcomere transitions will inform the aetiology and treatment. We sought to determine whether Thymosin β4 (Tβ4), a peptide that regulates the availability of actin monomers for polymerization in non-muscle cells, plays a role in sarcomere assembly during cardiac morphogenesis and influences adult cardiac function. In Tβ4 null mice, immunofluorescence-based sarcomere analyses revealed shortened thin filament, sarcomere and titin spring length in cardiomyocytes, associated with precocious up-regulation of the short titin isoforms during the postnatal splicing transition. By magnetic resonance imaging, this manifested as diminished stroke volume and limited contractile reserve in adult mice. Extrapolating to an in vitro cardiomyocyte model, the altered postnatal splicing was corrected with addition of synthetic Tβ4, whereby normal sarcomere length was restored. Our data suggest that Tβ4 is required for setting correct sarcomere length and for appropriate splicing of titin, not only in the heart but also in skeletal muscle. Distinguishing between thin filament extension and titin splicing as the primary defect is challenging, as these events are intimately linked. The regulation of titin splicing is a previously unrecognised role of Tβ4 and gives preliminary insight into a mechanism by which titin isoforms may be manipulated to correct cardiac dysfunction.
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Affiliation(s)
- Nicola Smart
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK.
| | - Johannes Riegler
- Centre for Advanced Biomedical Imaging, Department of Medicine, University College London (UCL), London, UK
| | - Cameron W Turtle
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Craig A Lygate
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Debra J McAndrew
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Katja Gehmlich
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | | | - Anthony N Price
- Centre for Advanced Biomedical Imaging, Department of Medicine, University College London (UCL), London, UK
| | - Vivek Muthurangu
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, London, UK
| | - Andrew M Taylor
- Centre for Cardiovascular Imaging, UCL Institute of Cardiovascular Science, London, UK
| | - Mark F Lythgoe
- Centre for Advanced Biomedical Imaging, Department of Medicine, University College London (UCL), London, UK
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - Paul R Riley
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, UK
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18
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Yavari A, Stocker CJ, Ghaffari S, Wargent ET, Steeples V, Czibik G, Pinter K, Bellahcene M, Woods A, Martínez de Morentin PB, Cansell C, Lam BYH, Chuster A, Petkevicius K, Nguyen-Tu MS, Martinez-Sanchez A, Pullen TJ, Oliver PL, Stockenhuber A, Nguyen C, Lazdam M, O'Dowd JF, Harikumar P, Tóth M, Beall C, Kyriakou T, Parnis J, Sarma D, Katritsis G, Wortmann DDJ, Harper AR, Brown LA, Willows R, Gandra S, Poncio V, de Oliveira Figueiredo MJ, Qi NR, Peirson SN, McCrimmon RJ, Gereben B, Tretter L, Fekete C, Redwood C, Yeo GSH, Heisler LK, Rutter GA, Smith MA, Withers DJ, Carling D, Sternick EB, Arch JRS, Cawthorne MA, Watkins H, Ashrafian H. Chronic Activation of γ2 AMPK Induces Obesity and Reduces β Cell Function. Cell Metab 2016; 23:821-36. [PMID: 27133129 PMCID: PMC4873618 DOI: 10.1016/j.cmet.2016.04.003] [Citation(s) in RCA: 74] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2015] [Revised: 03/01/2016] [Accepted: 04/01/2016] [Indexed: 12/02/2022]
Abstract
Despite significant advances in our understanding of the biology determining systemic energy homeostasis, the treatment of obesity remains a medical challenge. Activation of AMP-activated protein kinase (AMPK) has been proposed as an attractive strategy for the treatment of obesity and its complications. AMPK is a conserved, ubiquitously expressed, heterotrimeric serine/threonine kinase whose short-term activation has multiple beneficial metabolic effects. Whether these translate into long-term benefits for obesity and its complications is unknown. Here, we observe that mice with chronic AMPK activation, resulting from mutation of the AMPK γ2 subunit, exhibit ghrelin signaling-dependent hyperphagia, obesity, and impaired pancreatic islet insulin secretion. Humans bearing the homologous mutation manifest a congruent phenotype. Our studies highlight that long-term AMPK activation throughout all tissues can have adverse metabolic consequences, with implications for pharmacological strategies seeking to chronically activate AMPK systemically to treat metabolic disease.
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Affiliation(s)
- Arash Yavari
- Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK.
| | - Claire J Stocker
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Sahar Ghaffari
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Edward T Wargent
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Violetta Steeples
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Gabor Czibik
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Katalin Pinter
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Mohamed Bellahcene
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Angela Woods
- Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London SW7 2AZ, UK
| | | | - Céline Cansell
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Brian Y H Lam
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - André Chuster
- Pos Graduação Ciências Médicas, Faculdade Ciências Médicas, Universidade Federal de Minas Gerais, Belo Horizonte-MG 31270-901, Brazil
| | - Kasparas Petkevicius
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - Marie-Sophie Nguyen-Tu
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Aida Martinez-Sanchez
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Timothy J Pullen
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Peter L Oliver
- MRC Functional Genomics Unit, Department of Physiology, Anatomy, and Genetics, University of Oxford, Oxford OX1 3PT, UK
| | - Alexander Stockenhuber
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Chinh Nguyen
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Merzaka Lazdam
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK
| | - Jacqueline F O'Dowd
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Parvathy Harikumar
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Mónika Tóth
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary
| | - Craig Beall
- Cardiovascular and Diabetes Medicine, Medical Research Institute, University of Dundee, Dundee DD1 9SY, UK
| | - Theodosios Kyriakou
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Julia Parnis
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Dhruv Sarma
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - George Katritsis
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Diana D J Wortmann
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Andrew R Harper
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Laurence A Brown
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK
| | - Robin Willows
- Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London SW7 2AZ, UK
| | - Silvia Gandra
- Pos Graduação Ciências Médicas, Faculdade Ciências Médicas, Universidade Federal de Minas Gerais, Belo Horizonte-MG 31270-901, Brazil
| | - Victor Poncio
- Universidade Estadual de Campinas, Campinas-SP 13083-970, Brazil
| | | | - Nathan R Qi
- Department of Internal Medicine, Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Medical School, Ann Arbor, MI 48109, USA
| | - Stuart N Peirson
- Nuffield Laboratory of Ophthalmology, Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, OX3 9DU, UK
| | - Rory J McCrimmon
- Cardiovascular and Diabetes Medicine, Medical Research Institute, University of Dundee, Dundee DD1 9SY, UK
| | - Balázs Gereben
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary
| | - László Tretter
- Department of Medical Biochemistry, Semmelweis University, Budapest 1085, Hungary; MTA-SE Laboratory for Neurobiochemistry, Semmelweis University, Budapest 1085, Hungary
| | - Csaba Fekete
- Department of Endocrine Neurobiology, Institute of Experimental Medicine, Hungarian Academy of Sciences, Budapest 1083, Hungary; Department of Medicine, Division of Endocrinology, Diabetes, and Metabolism, Tupper Research Institute, Tufts Medical Center, Boston, MA 02111, USA
| | - Charles Redwood
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Giles S H Yeo
- University of Cambridge Metabolic Research Laboratories, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - Lora K Heisler
- Rowett Institute of Nutrition and Health, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Guy A Rutter
- Cell Biology and Functional Genomics, Division of Diabetes, Endocrinology, and Metabolism, Imperial College London, London SW7 2AZ, UK
| | - Mark A Smith
- Metabolic Signalling Group, MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, UK
| | - Dominic J Withers
- Metabolic Signalling Group, MRC Clinical Sciences Centre, Imperial College London, London W12 0NN, UK
| | - David Carling
- Cellular Stress Group, MRC Clinical Sciences Centre, Imperial College London, London SW7 2AZ, UK
| | - Eduardo B Sternick
- Pos Graduação Ciências Médicas, Faculdade Ciências Médicas, Universidade Federal de Minas Gerais, Belo Horizonte-MG 31270-901, Brazil
| | - Jonathan R S Arch
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Michael A Cawthorne
- The Buckingham Institute for Translational Medicine, University of Buckingham, Buckingham MK18 1EG, UK
| | - Hugh Watkins
- Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK
| | - Houman Ashrafian
- Experimental Therapeutics, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Division of Cardiovascular Medicine, Radcliffe Department of Medicine, University of Oxford, Oxford, OX3 9DU, UK; Wellcome Trust Centre for Human Genetics, University of Oxford, Oxford OX3 7BN, UK; Experimental Therapeutics, Clinical Science Group, New Medicines, UCB Pharma S.A., Slough, Berkshire SL1 3WE, UK.
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Turtle CW, Hochberg G, Müller H, Gehmlich K, Baldwin A, Redwood C, Benesch J. AB-Crystallin Binds to Titin Ig Domains and Increases Stiffness of Skinned Cardiac Trabeculae. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.2428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Redwood C, Townsend GC, Ghabriel M, Brook AH. Under your nose: a rare finding during dissection provides insights into maxillary supernumerary teeth. Aust Dent J 2014; 59:379-85. [PMID: 24861905 DOI: 10.1111/adj.12194] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/24/2013] [Indexed: 11/29/2022]
Abstract
BACKGROUND A supernumerary tooth was found during anatomical dissection. The position of this tooth, still impacted in the maxilla, and the associated pathology make this a rare case. METHODS During dissection by dental students of the sagittally-sectioned head of a cadaver, a supernumerary tooth was identified in the mid-palatal area. Further dissection revealed a swelling with a thin bony covering related to the crown of the tooth. The maxilla was removed en bloc and radiographic examination, CT scanning, electron microscopy and histology were undertaken. RESULTS The tooth had a crenulated occlusal surface and a single root. It was 25 mm posterior to the root apex of the permanent upper central incisor. The swelling, confirmed by radiographs and CT imaging to be associated with the crown, occupied approximately one-third of the maxillary sinus. The 3D shape of the cystic lesion was visualized by a composite digital movie. CONCLUSIONS The crown form, position of the tooth and the associated dentigerous cyst suggested it was a palatally developing supernumerary premolar which had been displaced to the palatal midline by the expanding cyst. This rare case highlights the learning and teaching opportunities available during dissection, showing important variations in both development and clinical anatomy.
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Affiliation(s)
- C Redwood
- Centre for Orofacial Research and Learning, School of Dentistry, The University of Adelaide, South Australia
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Turtle C, Robinson P, Yavari A, Ghaffari S, Pinter K, Watkins H, Redwood C. P387Knock-in mouse model of PRKAG2 cardiomyopathy (R299Q) exhibits altered Ca2+-dependent cardiac contractility and reduced protein kinase A activity. Cardiovasc Res 2014. [DOI: 10.1093/cvr/cvu091.69] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Robinson P, Liu X, Zhang YH, Khandelwal A, Blagg B, Casadei B, Watkins H, Redwood C. P123The rescue of Ca2+ cycling abnormalities conferred by HCM-causing mutations with analogues of the green tea polyphenol epigallocatechin-3-gallate. Cardiovasc Res 2014. [DOI: 10.1093/cvr/cvu082.63] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Redwood C, Robinson P. Alpha-tropomyosin mutations in inherited cardiomyopathies. J Muscle Res Cell Motil 2013; 34:285-94. [DOI: 10.1007/s10974-013-9358-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2013] [Accepted: 08/23/2013] [Indexed: 10/26/2022]
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Robinson P, Luo X, Hua Zhang Y, Casadei B, Watkins H, Redwood C. Cardiomyopathy-Causing Mutations in Thin Filament Regulatory Proteins Acutely Affeect Ca2+-Buffering and Ca2+-Dependent Signalling In Situ. Biophys J 2013. [DOI: 10.1016/j.bpj.2012.11.2009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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Kuster DWD, Sequeira V, Najafi A, Boontje NM, Wijnker PJM, Witjas-Paalberends ER, Marston SB, Dos Remedios CG, Carrier L, Demmers JAA, Redwood C, Sadayappan S, van der Velden J. GSK3β phosphorylates newly identified site in the proline-alanine-rich region of cardiac myosin-binding protein C and alters cross-bridge cycling kinetics in human: short communication. Circ Res 2012; 112:633-9. [PMID: 23277198 DOI: 10.1161/circresaha.112.275602] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Cardiac myosin-binding protein C (cMyBP-C) regulates cross-bridge cycling kinetics and, thereby, fine-tunes the rate of cardiac muscle contraction and relaxation. Its effects on cardiac kinetics are modified by phosphorylation. Three phosphorylation sites (Ser275, Ser284, and Ser304) have been identified in vivo, all located in the cardiac-specific M-domain of cMyBP-C. However, recent work has shown that up to 4 phosphate groups are present in human cMyBP-C. OBJECTIVE To identify and characterize additional phosphorylation sites in human cMyBP-C. METHODS AND RESULTS Cardiac MyBP-C was semipurified from human heart tissue. Tandem mass spectrometry analysis identified a novel phosphorylation site on serine 133 in the proline-alanine-rich linker sequence between the C0 and C1 domains of cMyBP-C. Unlike the known sites, Ser133 was not a target of protein kinase A. In silico kinase prediction revealed glycogen synthase kinase 3β (GSK3β) as the most likely kinase to phosphorylate Ser133. In vitro incubation of the C0C2 fragment of cMyBP-C with GSK3β showed phosphorylation on Ser133. In addition, GSK3β phosphorylated Ser304, although the degree of phosphorylation was less compared with protein kinase A-induced phosphorylation at Ser304. GSK3β treatment of single membrane-permeabilized human cardiomyocytes significantly enhanced the maximal rate of tension redevelopment. CONCLUSIONS GSK3β phosphorylates cMyBP-C on a novel site, which is positioned in the proline-alanine-rich region and increases kinetics of force development, suggesting a noncanonical role for GSK3β at the sarcomere level. Phosphorylation of Ser133 in the linker domain of cMyBP-C may be a novel mechanism to regulate sarcomere kinetics.
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Affiliation(s)
- Diederik W D Kuster
- Cell and Molecular Physiology, Health Science Division, Loyola University of Chicago, 2160 First Ave, Bldg 102, Room 4637, Maywood, IL 60153, USA.
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Pinter K, Grignani RT, Czibik G, Farza H, Watkins H, Redwood C. Embryonic expression of AMPK γ subunits and the identification of a novel γ2 transcript variant in adult heart. J Mol Cell Cardiol 2012; 53:342-9. [PMID: 22683324 PMCID: PMC3477313 DOI: 10.1016/j.yjmcc.2012.05.017] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 05/28/2012] [Accepted: 05/29/2012] [Indexed: 11/16/2022]
Abstract
AMP-activated protein kinase (AMPK), the key sensor and regulator of cellular energy status, is a heterotrimeric enzyme with multiple isoforms for each subunit (α1/α 2; β1/β2; γ1/γ2/γ3). Mutations in PRKAG2, which encodes the γ2 regulatory subunit, cause a cardiomyopathy characterized by hypertrophy and conduction abnormalities. The two reported PRKAG2 transcript variants, γ2-short and γ2-long (encoding 328 and 569 amino acids respectively), are both widely expressed in adult tissues. We show that both γ2 variants are also expressed during cardiogenesis in mouse embryos; expression of the γ3 isoform was also detected unexpectedly at this stage. As neither γ2 transcript is cardiac specific nor differentially expressed during embryogenesis, it is paradoxical that the disease is largely restricted to the heart. However, a recently annotated γ2 transcript, termed γ2-3B as transcription starts at an alternative exon 3b, has been identified; it is spliced in-frame to exon 4 thus generating a protein of 443 residues in mouse with the first 32 residues being unique. It is increasingly expressed in the developing mouse heart and quantitative PCR analysis established that γ2-3B is the major PRKAG2 transcript (~ 60%) in human heart. Antibody against the novel N-terminal sequence showed that γ2-3B is predominantly expressed in the heart where it is the most abundant γ2 protein. The abundance of γ2-3B and its tissue specificity indicate that γ2-3B may have non-redundant role in the heart and hence mediate the predominantly cardiac phenotype caused by PRKAG2 mutations.
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Affiliation(s)
- Katalin Pinter
- Department of Cardiovascular Medicine, University of Oxford, West Wing Level 6, John Radcliffe Hospital, Oxford OX3 9DU, UK
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Oliveira SM, Zhang YH, Solis RS, Isackson H, Bellahcene M, Yavari A, Pinter K, Davies JK, Ge Y, Ashrafian H, Walker JW, Carling D, Watkins H, Casadei B, Redwood C. AMP-activated protein kinase phosphorylates cardiac troponin I and alters contractility of murine ventricular myocytes. Circ Res 2012; 110:1192-201. [PMID: 22456184 DOI: 10.1161/circresaha.111.259952] [Citation(s) in RCA: 60] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
RATIONALE AMP-activated protein kinase (AMPK) is an important regulator of energy balance and signaling in the heart. Mutations affecting the regulatory γ2 subunit have been shown to cause an essentially cardiac-restricted phenotype of hypertrophy and conduction disease, suggesting a specific role for this subunit in the heart. OBJECTIVE The γ isoforms are highly conserved at their C-termini but have unique N-terminal sequences, and we hypothesized that the N-terminus of γ2 may be involved in conferring substrate specificity or in determining intracellular localization. METHODS AND RESULTS A yeast 2-hybrid screen of a human heart cDNA library using the N-terminal 273 residues of γ2 as bait identified cardiac troponin I (cTnI) as a putative interactor. In vitro studies showed that cTnI is a good AMPK substrate and that Ser150 is the principal residue phosphorylated. Furthermore, on AMPK activation during ischemia, Ser150 is phosphorylated in whole hearts. Using phosphomimics, measurements of actomyosin ATPase in vitro and force generation in demembraneated trabeculae showed that modification at Ser150 resulted in increased Ca(2+) sensitivity of contractile regulation. Treatment of cardiomyocytes with the AMPK activator 5-aminoimidazole-4-carboxamide ribonucleotide (AICAR) resulted in increased myocyte contractility without changing the amplitude of Ca(2+) transient and prolonged relaxation despite shortening the time constant of Ca(2+) transient decay (tau). Compound C prevented the effect of AICAR on myocyte function. These results suggest that AMPK activation increases myocyte contraction and prolongs relaxation by increasing myofilament Ca(2+) sensitivity. CONCLUSIONS We conclude that cTnI phosphorylation by AMPK may represent a novel mechanism of regulation of cardiac function.
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Leone A, Aquila I, Vicinanza C, Iaconetti C, Bochicchio A, Ottolenghi S, Indolfi C, Nadal-Ginard B, Ellison GM, Torella D, Mias C, Genet G, Guilbeau-Frugier C, Pathak A, Senard JM, Gales C, Egorova AD, Khedoe PSJ, Goumans MTH, Nauli SM, Ten Dijke P, Poelmann RE, Hierck BP, Miragoli M, Lab MJ, Singh A, Sikkel M, Lyon A, Gorelik J, Cheung C, Bernardo AS, Trotter MW, Pedersen RA, Sinha S, Mioulane M, Foldes G, Harding SE, Reglin B, Secomb TW, Pries AR, Buckingham M, Lescroart F, Meilhac S, Le Garrec JF, Rozmaritsa N, Christ T, Wettwer E, Knaut M, Ravens U, Tokar S, Schobesberger S, Singh A, Wright PT, Miragoli M, Lyon AR, Sikkel M, Harding SE, Gorelik J, Van Mil A, Grundmann S, Goumans MJ, Jaksani S, Doevendans PA, Sluijter JP, Tijsen AJ, Amin AS, Giudicessi JR, Tanck MW, Bezzina CR, Creemers EE, Wilde AM, Ackerman MJ, Pinto YM, Gedicke-Hornung C, Behrens-Gawlik V, Khajetoorians D, Mearini G, Reischmann S, Geertz B, Voit T, Dreyfus P, Eschenhagen T, Carrier L, Duerr GD, Heinemann JC, Wenzel D, Ghanem A, Alferink JC, Zimmer A, Lutz B, Welz A, Fleischmann BK, Dewald O, Sbroggio' M, Bertero A, Giuliano L, Brancaccio M, Tarone G, Meiser M, Kohlhaas M, Chen Y, Csordas G, Dorn G, Maack C, Stapel B, Hoch M, Haghikia A, Fischer P, Maack C, Hilfiker-Kleiner D, Schroen B, Corsten M, Verhesen W, De Windt L, Pinto YM, Zacchigna S, Thum T, Carmeliet P, Papageorgiou A, Heymans S, Lunde IG, Finsen AV, Florholmen G, Skrbic B, Kvaloy H, Jarstadmarken HO, Sjaastad I, Tonnessen T, Carlson CR, Christensen G, Paavola J, Schliffke S, Rossetti S, Kuo I, Yuan S, Sun Z, Harris P, Torres V, Ehrlich B, Robinson P, Adams K, Zhang YH, Casadei B, Watkins H, Redwood C, Seneviratne AN, Cole JE, Goddard ME, Mohri Z, Cross AJ, Krams R, Monaco C, Everaert BR, Van Laere SJ, Hoymans VY, Timmermans JP, Vrints CJ. Oral abstract presentations & Young Investigators Competition. Cardiovasc Res 2012. [DOI: 10.1093/cvr/cvr333] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
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Pinter K, Jefferson A, Czibik G, Watkins H, Redwood C. Subunit composition of AMPK trimers present in the cytokinetic apparatus: Implications for drug target identification. Cell Cycle 2012; 11:917-21. [PMID: 22333580 DOI: 10.4161/cc.11.5.19412] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
AMP-activated protein kinase has been shown to be a key regulator of energy homeostasis; it has also been identified as a tumor suppressor and is required for correct cell division and chromosome segregation during mitosis. The enzyme is a heterotrimer, with each subunit having more than one isoform, each encoded by a separate gene (two α, two β and three γ isoforms). In human endothelial cells, the activated kinase subunit of AMPK in the cytokinetic apparatus is α2, the minority α subunit, which co-localizes with β2 and γ2. This is the first demonstration of a trimeric complex of AMPK containing the γ2 regulatory subunit becoming selectively activated and being linked to mitotic processes. We also show that α1 and γ1, the predominant AMPK subunits, are almost exclusively localized in the cytoskeleton, while α2 and γ2 are present in all subcellular fractions, including the nuclei. These data suggest that pharmacological interventions targeted to specific AMPK subunit isoforms have the potential to modify selective functions of AMPK.
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Affiliation(s)
- Katalin Pinter
- Department of Cardiovascular Medicine, University of Oxford, West Wing Level 6, John Radcliffe Hospital, Oxford, United Kingdom
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Affiliation(s)
- Hugh Watkins
- Department of Cardiovascular Medicine, University of Oxford, Oxford, United Kingdom.
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Song W, Dyer E, Stuckey D, Leung MC, Memo M, Mansfield C, Ferenczi M, Liu K, Redwood C, Nowak K, Harding S, Clarke K, Wells D, Marston S. Investigation of a transgenic mouse model of familial dilated cardiomyopathy. J Mol Cell Cardiol 2010; 49:380-9. [DOI: 10.1016/j.yjmcc.2010.05.009] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/02/2009] [Revised: 05/17/2010] [Accepted: 05/18/2010] [Indexed: 11/25/2022]
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Redwood C, Winning T, Lekkas D, Townsend G. Improving clinical assessment: evaluating students' ability to identify and apply clinical criteria. Eur J Dent Educ 2010; 14:136-144. [PMID: 20646039 DOI: 10.1111/j.1600-0579.2009.00606.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
AIM There is ongoing concern by health educators over the inability of professionals to accurately self-assess their clinical behaviour and standards, resulting in doubts over a key expectation of effective self-regulation in the health professions. Participation by students in the assessment process has been shown to increase the understanding of assessment criteria in written assessment tasks. How this might transfer to the clinical setting is the focus of this study. This paper is part of an ongoing investigation of the impact on learning of a series of activities that provides students with opportunities to discuss and apply criteria and standards associated with self-assessment in clinical dentistry. Our aim was to evaluate whether participation in these assessment activities improved the ability of first-year dental students to recognise behaviours demonstrated by 'peers' in videos of clinical scenarios and to relate these to the assessment criteria. MATERIALS AND METHODS A series of three workshops in conjunction with weekly clinical assessment activities in Semesters 1 and 2 were use to support first-year students' learning of clinical assessment criteria. The design of the workshops was based on the principles of social constructivist theories of learning and the concept of tacit knowledge. Accordingly workshop activities were planned around videos that were specifically constructed to illustrate procedures and behaviours typical of those observed by staff and tutors in the first year of the dental course at The University of Adelaide, Australia. First-year students viewed the videos prior to and after the workshops and recorded observed behaviours that related to the assessment criteria that were used in their clinical practice course. Student learning outcomes were assessed 10-14 weeks after the initial workshop and again up to 42 weeks later. To check whether learning resulted from repeated viewing of the videos without formal discussion, a reference group of third-year students who did not attend the workshops also viewed the videos two times, separated by 12 weeks, and recorded observations in the same way. RESULTS There was no consistent evidence that repeat viewing of the videos in isolation resulted in improved recognition of 'peer' behaviours by third-year dental students. Results for the first-year students indicated that the workshops and clinical assessment activities had a significantly positive effect on the ability of students to identify 'peer' behaviours related to the criteria used for clinical assessment. In particular, students' recognition in others of knowledge and professional behaviours improved significantly. This improvement was retained over the year and students were able to recognise these behaviours in other scenarios relevant to their year level. CONCLUSIONS This early exposure to the process of clinical assessment, coupled with ongoing self-assessment and tutor feedback throughout first year, improved the ability of first-year students to identify and apply some key assessment criteria to observed 'peer' behaviour, and this ability was retained over time.
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Affiliation(s)
- C Redwood
- Centre for Orofacial Research and Learning, School of Dentistry, The University of Adelaide, Adelaide, Australia
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Hoskins AC, Jacques A, Bardswell SC, McKenna WJ, Tsang V, dos Remedios CG, Ehler E, Adams K, Jalilzadeh S, Avkiran M, Watkins H, Redwood C, Marston SB, Kentish JC. Normal passive viscoelasticity but abnormal myofibrillar force generation in human hypertrophic cardiomyopathy. J Mol Cell Cardiol 2010; 49:737-45. [PMID: 20615414 PMCID: PMC2954357 DOI: 10.1016/j.yjmcc.2010.06.006] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/22/2010] [Revised: 06/02/2010] [Accepted: 06/20/2010] [Indexed: 01/13/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is characterized by left ventricular hypertrophy, increased ventricular stiffness and impaired diastolic filling. We investigated to what extent myocardial functional defects can be explained by alterations in the passive and active properties of human cardiac myofibrils. Skinned ventricular myocytes were prepared from patients with obstructive HCM (two patients with MYBPC3 mutations, one with a MYH7 mutation, and three with no mutation in either gene) and from four donors. Passive stiffness, viscous properties, and titin isoform expression were similar in HCM myocytes and donor myocytes. Maximal Ca2+-activated force was much lower in HCM myocytes (14 ± 1 kN/m2) than in donor myocytes (23 ± 3 kN/m2; P < 0.01), though cross-bridge kinetics (ktr) during maximal Ca2+ activation were 10% faster in HCM myocytes. Myofibrillar Ca2+ sensitivity in HCM myocytes (pCa50 = 6.40 ± 0.05) was higher than for donor myocytes (pCa50 = 6.09 ± 0.02; P < 0.001) and was associated with reduced phosphorylation of troponin-I (ser-23/24) and MyBP-C (ser-282) in HCM myocytes. These characteristics were common to all six HCM patients and may therefore represent a secondary consequence of the known and unknown underlying genetic variants. Some HCM patients did however exhibit an altered relationship between force and cross-bridge kinetics at submaximal Ca2+ concentrations, which may reflect the primary mutation. We conclude that the passive viscoelastic properties of the myocytes are unlikely to account for the increased stiffness of the HCM ventricle. However, the low maximum Ca2+-activated force and high Ca2+ sensitivity of the myofilaments are likely to contribute substantially to any systolic and diastolic dysfunction, respectively, in hearts of HCM patients.
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Affiliation(s)
- Anita C Hoskins
- Cardiovascular Division, King's College London British Heart Foundation Centre, London, UK
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Robinson PJ, Zhang YH, Casadei B, Watkins H, Redwood C. Investigating the Effect of Cardiomyopathy-Causing Mutations in Cardiac Troponin-T on Calcium Buffering In Situ. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.1909] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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Carballo S, Robinson P, Otway R, Fatkin D, Jongbloed JDH, de Jonge N, Blair E, van Tintelen JP, Redwood C, Watkins H. Identification and functional characterization of cardiac troponin I as a novel disease gene in autosomal dominant dilated cardiomyopathy. Circ Res 2009; 105:375-82. [PMID: 19590045 DOI: 10.1161/circresaha.109.196055] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Idiopathic dilated cardiomyopathy (DCM) is inherited in approximately one third of cases, usually as an autosomal dominant trait. More than 30 loci have been identified, several of which encode sarcomeric proteins which can also be mutated to cause hypertrophic cardiomyopathy. One contractile protein gene well known as a hypertrophic cardiomyopathy disease gene, but with no reported mutation in autosomal dominant DCM, is TNNI3 which encodes cardiac troponin I. OBJECTIVE To test TNNI3 as a candidate gene, a panel of 96 probands with DCM was analyzed. METHODS AND RESULTS Genomic DNA was isolated and TNNI3 exons screened by heteroduplex analysis. Exons with aberrant profiles were sequenced and variants evaluated by segregation analysis and study of normal controls. We report 2 novel TNNI3 missense mutations, Lys36Gln and Asn185Lys, each associated with severe and early onset familial DCM. Of the 5 mutation carriers, cardiac transplantation was required in 3, at ages 6, 15, and 24 years. Analysis of Ca(2+) regulation of actin-tropomyosin-activated myosin ATPase by troponin revealed that troponin reconstituted with either mutant troponin I gave lower maximum ATPase rates and lower Ca(2+) sensitivity than wild type. Furthermore, mutant thin filaments had reduced Ca(2+) affinity compared with normal. CONCLUSIONS The functional alterations mirror closely a consistent phenotype found in proven DCM mutations in other thin filament proteins, thus supporting the interpretation that these mutations are disease-causing. These are the first reported autosomal dominant DCM-causing mutations in TNNI3, and so the findings expand the spectrum of disease-causing genes that lead to either hypertrophic cardiomyopathy or DCM depending on the specific mutation.
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Affiliation(s)
- Sebastian Carballo
- Department of Cardiovascular Medicine, University of Oxford, Wellcome Trust Centre for Human Genetics, Oxford United Kingdom
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Marston S, Copeland O, Jacques A, Livesey K, Tsang V, McKenna WJ, Jalilzadeh S, Carballo S, Redwood C, Watkins H. Evidence from human myectomy samples that MYBPC3 mutations cause hypertrophic cardiomyopathy through haploinsufficiency. Circ Res 2009; 105:219-22. [PMID: 19574547 DOI: 10.1161/circresaha.109.202440] [Citation(s) in RCA: 183] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
RATIONALE Most sarcomere gene mutations that cause hypertrophic cardiomyopathy are missense alleles that encode dominant negative proteins. The potential exceptions are mutations in the MYBPC3 gene (encoding cardiac myosin-binding protein-C [MyBP-C]), which frequently encode truncated proteins. OBJECTIVE We sought to determine whether there was evidence of haploinsufficiency in hypertrophic cardiomyopathy caused by MYBPC3 mutations by comparing left ventricular muscle from patients undergoing surgical myectomy with samples from donor hearts. METHODS AND RESULTS MyBP-C protein and mRNA levels were quantitated using immunoblotting and RT-PCR. Nine of 37 myectomy samples had mutations in MYBPC3: 2 missense alleles (Glu258Lys, Arg502Trp) and 7 premature terminations. No specific truncated MyBP-C peptides were detected in whole muscle homogenates of hypertrophic cardiomyopathy tissue. However, the overall level of MyBP-C in myofibrils was significantly reduced (P<0.0005) in tissue containing either a truncation or missense MYBPC3 mutation: 0.76+/-0.03 compared with 1.00+/-0.05 in donor and 1.01+/-0.06 in non-MYBPC3 mutant myectomies. CONCLUSIONS The absence of any detectable truncated MyBP-C argues against its incorporation in the myofiber and any dominant negative effect. In contrast, the lowered relative level of full length protein in both truncation and missense MYBPC3 mutations argues strongly that haploinsufficiency is sufficient to cause the disease.
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Affiliation(s)
- Steven Marston
- Department of Cardiovascular Medicine, University of Oxford, Level 6 West Wing, John Radcliffe Hospital, Oxford OX39DU, United Kingdom
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Renz B, Davies JK, Carling D, Watkins H, Redwood C. Determination of AMP-activated protein kinase phosphorylation sites in recombinant protein expressed using the pET28a vector: a cautionary tale. Protein Expr Purif 2009; 66:181-4. [PMID: 19269329 PMCID: PMC2691924 DOI: 10.1016/j.pep.2009.02.016] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 02/20/2009] [Accepted: 02/20/2009] [Indexed: 11/28/2022]
Abstract
AMP-activated protein kinase (AMPK) is responsible for sensing of the cell’s energetic status and it phosphorylates numerous substrates involved in anabolic and catabolic processes as well as interacting with signaling cascades. Mutations in the gene encoding the γ2 regulatory subunit have been shown to cause hypertrophic cardiomyopathy (HCM) with conduction abnormalities. As part of a study to examine the role of AMPK in the heart, we tested whether specific domains of the thick filament component cardiac myosin binding protein-C (cMyBP-C) were good in vitro AMPK substrates. The commercially available pET28a expression vector was used to generate a recombinant form of the cMyBP-C C8 domain as a fusion protein with a hexahistidine tag. In vitro phosphorylation with activated kinase showed that the purified fusion protein was a good AMPK substrate, phosphorylated at a similar rate to the control SAMS peptide and with phosphate incorporation specifically in serine residues. However, subsequent analysis of alanine replacement mutants and thrombin digestion revealed that the strong AMPK phosphorylation site was contained within the thrombin cleavage sequence encoded by the vector. As this sequence is common to many commercial pET vectors, caution is advised in the mapping of AMPK phosphorylation sites when this sequence is present.
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Affiliation(s)
- Bernhard Renz
- Department of Cardiovascular Medicine, University of Oxford, West Wing Level 6, John Radcliffe Hospital, Oxford OX3 9DU, UK
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Fisher SJ, Helliwell JR, Khurshid S, Govada L, Redwood C, Squire JM, Chayen NE. An investigation into the protonation states of the C1 domain of cardiac myosin-binding protein C. Acta Crystallogr D Biol Crystallogr 2008; 64:658-64. [DOI: 10.1107/s0907444908008792] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/19/2008] [Accepted: 04/01/2008] [Indexed: 11/10/2022]
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41
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Govada L, Carpenter L, da Fonseca PCA, Helliwell JR, Rizkallah P, Flashman E, Chayen NE, Redwood C, Squire JM. Crystal structure of the C1 domain of cardiac myosin binding protein-C: implications for hypertrophic cardiomyopathy. J Mol Biol 2008; 378:387-97. [PMID: 18374358 DOI: 10.1016/j.jmb.2008.02.044] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2008] [Revised: 02/17/2008] [Accepted: 02/19/2008] [Indexed: 11/24/2022]
Abstract
C-protein is a major component of skeletal and cardiac muscle thick filaments. Mutations in the gene encoding cardiac C-protein [cardiac myosin binding protein-C (cMyBP-C)] are one of the principal causes of hypertrophic cardiomyopathy. cMyBP-C is a string of globular domains including eight immunoglobulin-like and three fibronectin-like domains termed C0-C10. It binds to myosin and titin, and probably to actin, and may have both a structural and a regulatory role in muscle function. To help to understand the pathology of the known mutations, we have solved the structure of the immunoglobulin-like C1 domain of MyBP-C by X-ray crystallography to a resolution of 1.55 A. Mutations associated with hypertrophic cardiomyopathy are clustered at one end towards the C-terminus, close to the important C1C2 linker, where they alter the structural integrity of this region and its interactions.
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Affiliation(s)
- Lata Govada
- Biomolecular Medicine Department, SORA Division, Imperial College London, London SW7 2AZ, UK
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Zhang YH, Zhang MH, Sears CE, Emanuel K, Redwood C, El-Armouche A, Kranias EG, Casadei B. Reduced phospholamban phosphorylation is associated with impaired relaxation in left ventricular myocytes from neuronal NO synthase-deficient mice. Circ Res 2007; 102:242-9. [PMID: 18007024 DOI: 10.1161/circresaha.107.164798] [Citation(s) in RCA: 96] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Stimulation of nitric oxide (NO) release from the coronary endothelium facilitates myocardial relaxation via a cGMP-dependent reduction in myofilament Ca2+ sensitivity. Recent evidence suggests that NO released by a neuronal NO synthase (nNOS) in the myocardium can also hasten left ventricular relaxation; however, the mechanism underlying these findings is uncertain. Here we show that both relaxation (TR50) and the rate of [Ca2+]i transient decay (tau) are significantly prolonged in field-stimulated or voltage-clamped left ventricular myocytes from nNOS-/- mice and in wild-type myocytes (nNOS+/+) after acute nNOS inhibition. Disabling the sarcoplasmic reticulum abolished the differences in TR50 and tau, suggesting that impaired sarcoplasmic reticulum Ca2+ reuptake may account for the slower relaxation in nNOS-/- mice. In line with these findings, disruption of nNOS (but not of endothelial NOS) decreased phospholamban phosphorylation (P-Ser16 PLN), whereas nNOS inhibition had no effect on TR50 or tau in PLN-/- myocytes. Inhibition of cGMP signaling had no effect on relaxation in either group whereas protein kinase A inhibition abolished the difference in relaxation and PLN phosphorylation by decreasing P-Ser16 PLN and prolonging TR50 in nNOS+/+ myocytes. Conversely, inhibition of type 1 or 2A protein phosphatases shortened TR50 and increased P-Ser16 PLN in nNOS-/- but not in nNOS+/+ myocytes, in agreement with data showing increased protein phosphatase activity in nNOS-/- hearts. Taken together, our findings identify a novel mechanism by which myocardial nNOS promotes left ventricular relaxation by regulating the protein kinase A-mediated phosphorylation of PLN and the rate of sarcoplasmic reticulum Ca2+ reuptake via a cGMP-independent effect on protein phosphatase activity.
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Affiliation(s)
- Yin Hua Zhang
- Department of Cardiovascular Medicine, University of Oxford, John Radcliffe Hospital, United Kingdom
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Marston S, Mirza M, Robinson P, Kremneva E, Levitsky D, Redwood C, EL-Mezgueldi M. Mutations in tropomyosin that cause DCM, affect cooperativity of cardiac muscle thin filaments. J Mol Cell Cardiol 2007. [DOI: 10.1016/j.yjmcc.2007.03.433] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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44
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Dyer E, Wells D, Redwood C, Marston S. In vitro motility studies of a DCM mutation in cardiac muscle actin. J Mol Cell Cardiol 2007. [DOI: 10.1016/j.yjmcc.2007.03.423] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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45
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Moolman-Smook J, Flashman E, Korkie L, Redwood C. Support for a trimeric collar of myosin binding protein C in cardiac and fast, but not slow, skeletal muscle. J Mol Cell Cardiol 2007. [DOI: 10.1016/j.yjmcc.2007.03.260] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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46
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Mirza M, Robinson P, Kremneva E, Copeland O, Nikolaeva O, Watkins H, Levitsky D, Redwood C, El-Mezgueldi M, Marston S. The Effect of Mutations in α-Tropomyosin (E40K and E54K) That Cause Familial Dilated Cardiomyopathy on the Regulatory Mechanism of Cardiac Muscle Thin Filaments. J Biol Chem 2007; 282:13487-97. [PMID: 17360712 DOI: 10.1074/jbc.m701071200] [Citation(s) in RCA: 64] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
E40K and E54K mutations in alpha-tropomyosin cause inherited dilated cardiomyopathy. Previously we showed, using Ala-Ser alpha-tropomyosin (AS-alpha-Tm) expressed in Escherichia coli, that both mutations decrease Ca(2+) sensitivity. E40K also reduces V(max) of actin-Tm-activated S-1 ATPase by 18%. We investigated cooperative allosteric regulation by native Tm, AS-alpha-Tm, and the two dilated cardiomyopathy-causing mutants. AS-alpha-Tm has a lower cooperative unit size (6.5) than native alpha-tropomyosin (10.0). The E40K mutation reduced the size of the cooperative unit to 3.7, whereas E54K increased it to 8.0. For the equilibrium between On and Off states, the K(T) value was the same for all actin-Tm species; however, the K(T) value of actin-Tm-troponin at pCa 5 was 50% less for AS-alpha-Tm E40K than for AS-alpha-Tm and AS-alpha-Tm E54K. K(b), the "closed" to "blocked" equilibrium constant, was the same for all tropomyosin species. The E40K mutation reduced the affinity of tropomyosin for actin by 1.74-fold, but only when in the On state (in the presence of S-1). In contrast the E54K mutation reduced affinity by 3.5-fold only in the Off state. Differential scanning calorimetry measurements of AS-alpha-Tm showed that domain 3, assigned to the N terminus of tropomyosin, was strongly destabilized by both mutations. Additionally with AS-alpha-Tm E54K, we observed a unique new domain at 55 degrees C accounting for 25% of enthalpy indicating stabilization of part of the tropomyosin. The disease-causing mechanism of the E40K mutation may be accounted for by destabilization of the On state of the thin filaments; however, the E54K mutation has a more complex effect on tropomyosin structure and function.
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Affiliation(s)
- Mahmooda Mirza
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, United Kingdom
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47
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Moolman-Smook J, Flashman E, Korkie L, Redwood C. WITHDRAWN: Support for a trimeric collar of myosin binding protein C in cardiac and fast, but not slow, skeletal muscle. J Mol Cell Cardiol 2007. [DOI: 10.1016/j.yjmcc.2007.03.864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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48
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Flashman E, Watkins H, Redwood C. Localization of the binding site of the C-terminal domain of cardiac myosin-binding protein-C on the myosin rod. Biochem J 2007; 401:97-102. [PMID: 16918501 PMCID: PMC1698665 DOI: 10.1042/bj20060500] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
cMyBP-C [cardiac (MyBP-C) myosin-binding protein-C)] is a sarcomeric protein involved both in thick filament structure and in the regulation of contractility. It is composed of eight IgI-like and three fibronectin-3-like domains (termed C0-C10). Mutations in the gene encoding cMyBP-C are a principal cause of HCM (hypertrophic cardiomyopathy). cMyBP-C binds to the LMM (light meromyosin) portion of the myosin rod via its C-terminal domain, C10. We investigated this interaction in detail to determine whether HCM mutations in beta myosin heavy chain located within the LMM portion alter the binding of cMyBP-C, and to define the precise region of LMM that binds C10 to aid in developing models of the arrangement of MyBP-C on the thick filament. In co-sedimentation experiments recombinant C10 bound full-length LMM with a K(d) of 3.52 microM and at a stoichiometry of 1.14 C10 per LMM. C10 was also shown to bind with similar affinity to LMM containing either the HCM mutations A1379T or S1776G, suggesting that these HCM mutations do not perturb C10 binding. Using a range of N-terminally truncated LMM fragments, the cMyBP-C-binding site on LMM was shown to lie between residues 1554 and 1581. Since it had been reported previously that acidic residues on myosin mediate the C10 interaction, three clusters of acidic amino acids (Glu1554/Glu1555, Glu1571/Glu1573 and Glu1578/Asp1580/Glu1581/Glu1582) were mutated in full-length LMM and the proteins tested for C10 binding. No effect of these mutations on C10 binding was however detected. We interpret our results with respect to the localization of the proposed trimeric collar on the thick filament.
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Affiliation(s)
- Emily Flashman
- Department of Cardiovascular Medicine, University of Oxford, Wellcome Trust Centre of Human Genetics, Oxford OX3 7BN, U.K
| | - Hugh Watkins
- Department of Cardiovascular Medicine, University of Oxford, Wellcome Trust Centre of Human Genetics, Oxford OX3 7BN, U.K
| | - Charles Redwood
- Department of Cardiovascular Medicine, University of Oxford, Wellcome Trust Centre of Human Genetics, Oxford OX3 7BN, U.K
- To whom correspondence should be addressed (email )
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Mirza M, Marston S, Willott R, Ashley C, Mogensen J, McKenna W, Robinson P, Redwood C, Watkins H. Dilated cardiomyopathy mutations in three thin filament regulatory proteins result in a common functional phenotype. J Biol Chem 2005; 280:28498-506. [PMID: 15923195 DOI: 10.1074/jbc.m412281200] [Citation(s) in RCA: 126] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Dilated cardiomyopathy (DCM), characterized by cardiac dilatation and contractile dysfunction, is a major cause of heart failure. Inherited DCM can result from mutations in the genes encoding cardiac troponin T, troponin C, and alpha-tropomyosin; different mutations in the same genes cause hypertrophic cardiomyopathy. To understand how certain mutations lead specifically to DCM, we have investigated their effect on contractile function by comparing wild-type and mutant recombinant proteins. Because initial studies on two troponin T mutations have generated conflicting findings, we analyzed all eight published DCM mutations in troponin T, troponin C, and alpha-tropomyosin in a range of in vitro assays. Thin filaments, reconstituted with a 1:1 ratio of mutant/wild-type proteins (the likely in vivo ratio), all showed reduced Ca(2+) sensitivity of activation in ATPase and motility assays, and except for one alpha-tropomyosin mutant showed lower maximum Ca(2+) activation. Incorporation of either of two troponin T mutants in skinned cardiac trabeculae also decreased Ca(2+) sensitivity of force generation. Structure/function considerations imply that the diverse thin filament DCM mutations affect different aspects of regulatory function yet change contractility in a consistent manner. The DCM mutations depress myofibrillar function, an effect fundamentally opposite to that of hypertrophic cardiomyopathy-causing thin filament mutations, suggesting that decreased contractility may trigger pathways that ultimately lead to the clinical phenotype.
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Affiliation(s)
- Mahmooda Mirza
- National Heart and Lung Institute, Imperial College London, London SW3 6LY, United Kingdom
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50
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Kruger M, Zittrich S, Redwood C, Blaudeck N, James J, Robbins J, Pfitzer G, Stehle R. Effects of the mutation R145G in human cardiac troponin I on the kinetics of the contraction-relaxation cycle in isolated cardiac myofibrils. J Physiol 2005; 564:347-57. [PMID: 15718266 PMCID: PMC1464436 DOI: 10.1113/jphysiol.2004.079095] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Familial hypertrophic cardiomyopathy (FHC) has been linked to mutations in sarcomeric proteins such as human cardiac troponin I (hcTnI). To elucidate the functional consequences of the mutation hcTnI(R145G) on crossbridge kinetics, force kinetics were analysed in murine cardiac myofibrils carrying either the mutant or the wild-type protein. The mutation was introduced into the myofibrils in two different ways: in the first approach, the endogenous Tn was replaced by incubation of the myofibrils with an excess of reconstituted recombinant hcTn containing either hcTnI(WT) or hcTnI(R145G). Alternatively, myofibrils were isolated either from non-transgenic or transgenic mice expressing the corresponding mcTnI(R146G) mutation. In myofibrils from both models, the mutation leads to a significant upward shift of the passive force-sarcomere length relation determined at pCa 7.5. Addition of 5 mm BDM (2,3-butandione-2-monoxime), an inhibitor of actomyosin ATPase partially reverses this shift, suggesting that the mutation impairs the normal function of cTnI to fully inhibit formation of force-generating crossbridges in the absence of Ca(2)(+). Maximum force development (F(max)) is significantly decreased by the mutation only in myofibrils exchanged with hcTnI(R145G) in vitro. Ca(2)(+) sensitivity of force development was reduced by the mutation in myofibrils from transgenic mice but not in exchanged myofibrils. In both models the rate constant of force development k(ACT) is reduced at maximal [Ca(2)(+)] but not at low [Ca(2)(+)] where it is rather increased. Force relaxation is significantly prolonged due to a reduction of the relaxation rate constant k(REL). We therefore assume that the impairment in the regulatory function of TnI by the mutation leads to modulations in crossbridge kinetics that significantly alter the dynamics of myofibrillar contraction and relaxation.
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Affiliation(s)
- M Kruger
- Department of Vegetative Physiology, University of Cologne, Koeln, Germany.
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