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Guo J, Jiang H, Schuftan D, Moreno JD, Ramahdita G, Aryan L, Bhagavan D, Silva J, Huebsch N. Substrate mechanics unveil early structural and functional pathology in iPSC micro-tissue models of hypertrophic cardiomyopathy. iScience 2024; 27:109954. [PMID: 38827401 PMCID: PMC11141149 DOI: 10.1016/j.isci.2024.109954] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Revised: 03/22/2024] [Accepted: 05/08/2024] [Indexed: 06/04/2024] Open
Abstract
Hypertension is a major cause of morbidity and mortality in patients with hypertrophic cardiomyopathy (HCM), suggesting a potential role for mechanics in HCM pathogenesis. Here, we developed an in vitro physiological model to investigate how mechanics acts together with HCM-linked myosin binding protein C (MYBPC3) mutations to trigger disease. Micro-heart muscles (μHM) were engineered from induced pluripotent stem cell (iPSC)-derived cardiomyocytes bearing MYBPC3+/- mutations and challenged to contract against substrates of different elasticity. μHMs that worked against substrates with stiffness at or exceeding the stiffness of healthy adult heart muscle exhibited several hallmarks of HCM, including cellular hypertrophy, impaired contractile energetics, and maladaptive calcium handling. Remarkably, we discovered changes in troponin C and T localization in MYBPC3+/- μHM that were entirely absent in 2D culture. Pharmacologic studies suggested that excessive Ca2+ intake through membrane-embedded channels underlie the observed electrophysiological abnormalities. These results illustrate the power of physiologically relevant engineered tissue models to study inherited disease with iPSC technology.
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Affiliation(s)
- Jingxuan Guo
- Department of Mechanical Engineering and Material Science, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Huanzhu Jiang
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - David Schuftan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Jonathan D. Moreno
- Division of Cardiology, Department of Medicine, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Ghiska Ramahdita
- Department of Mechanical Engineering and Material Science, Washington University in Saint Louis, Saint Louis, MO 63130, USA
- NSF Science and Technology Center for Engineering Mechanobiology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Lavanya Aryan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Druv Bhagavan
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Jonathan Silva
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
| | - Nathaniel Huebsch
- Department of Biomedical Engineering, Washington University in Saint Louis, Saint Louis, MO 63130, USA
- NSF Science and Technology Center for Engineering Mechanobiology, Washington University in Saint Louis, Saint Louis, MO 63130, USA
- Center for Cardiovascular Research, Center for Regenerative Medicine, Center for Investigation of Membrane Excitability Diseases, Washington University in Saint Louis, Saint Louis, MO 63130, USA
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2
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Burkart V, Kowalski K, Disch A, Hilfiker-Kleiner D, Lal S, Dos Remedios C, Perrot A, Zeug A, Ponimaskin E, Kosanke M, Dittrich-Breiholz O, Kraft T, Montag J. Nonsense mediated decay factor UPF3B is associated with cMyBP-C haploinsufficiency in hypertrophic cardiomyopathy patients. J Mol Cell Cardiol 2023; 185:26-37. [PMID: 37797718 DOI: 10.1016/j.yjmcc.2023.09.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Revised: 09/08/2023] [Accepted: 09/28/2023] [Indexed: 10/07/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is the most prevalent inherited cardiac disease. Up to 40% of cases are associated with heterozygous mutations in myosin binding protein C (cMyBP-C, MYBPC3). Most of these mutations lead to premature termination codons (PTC) and patients show reduction of functional cMyBP-C. This so-called haploinsufficiency most likely contributes to disease development. We analyzed mechanisms underlying haploinsufficiency using cardiac tissue from HCM-patients with truncation mutations in MYBPC3 (MYBPC3trunc). We compared transcriptional activity, mRNA and protein expression to donor controls. To differentiate between HCM-specific and general hypertrophy-induced mechanisms we used patients with left ventricular hypertrophy due to aortic stenosis (AS) as an additional control. We show that cMyBP-C haploinsufficiency starts at the mRNA level, despite hypertrophy-induced increased transcriptional activity. Gene set enrichment analysis (GSEA) of RNA-sequencing data revealed an increased expression of NMD-components. Among them, Up-frameshift protein UPF3B, a regulator of NMD was upregulated in MYBPC3trunc patients and not in AS-patients. Strikingly, we show that in sarcomeres UPF3B but not UPF1 and UPF2 are localized to the Z-discs, the presumed location of sarcomeric protein translation. Our data suggest that cMyBP-C haploinsufficiency in HCM-patients is established by UPF3B-dependent NMD during the initial translation round at the Z-disc.
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Affiliation(s)
- Valentin Burkart
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany.
| | - Kathrin Kowalski
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Alina Disch
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | | | - Sean Lal
- School of Medical Sciences, Faculty of Medicine and Health, University of Sydney, Sydney, Australia
| | - Cristobal Dos Remedios
- Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | - Andreas Perrot
- Charité - Universitätsmedizin Berlin, Experimental & Clinical Research Center, Berlin, Germany
| | - Andre Zeug
- Institute of Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Evgeni Ponimaskin
- Institute of Neurophysiology, Hannover Medical School, Hannover, Germany
| | - Maike Kosanke
- Research Core Unit Genomics, Hannover Medical School, Hannover, Germany
| | | | - Theresia Kraft
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Judith Montag
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
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Hilderink S, Schuldt M, Goebel M, Jansen VJ, Manders E, Moorman S, Dorsch LM, van Steenbeek FG, van der Velden J, Kuster DWD. Characterization of heterozygous and homozygous mouse models with the most common hypertrophic cardiomyopathy mutation MYBPC3 c.2373InsG in the Netherlands. J Mol Cell Cardiol 2023; 185:65-76. [PMID: 37844837 DOI: 10.1016/j.yjmcc.2023.10.008] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/25/2023] [Revised: 09/25/2023] [Accepted: 10/11/2023] [Indexed: 10/18/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is frequently caused by mutations in the cardiac myosin binding protein-C (cMyBP-C) encoding gene MYBPC3. In the Netherlands, approximately 25% of patients carry the MYBPC3c.2373InsG founder mutation. Most patients are heterozygous (MYBPC3+/InsG) and have highly variable phenotypic expression, whereas homozygous (MYBPC3InsG/InsG) patients have severe HCM at a young age. To improve understanding of disease progression and genotype-phenotype relationship based on the hallmarks of human HCM, we characterized mice with CRISPR/Cas9-induced heterozygous and homozygous mutations. At 18-28 weeks of age, we assessed the cardiac phenotype of Mybpc3+/InsG and Mybpc3InsG/InsG mice with echocardiography, and performed histological analyses. Cytoskeletal proteins and cardiomyocyte contractility of 3-4 week old and 18-28 week old Mybpc3c.2373InsG mice were compared to wild-type (WT) mice. Expectedly, knock-in of Mybpc3c.2373InsG resulted in the absence of cMyBP-C and our 18-28 week old homozygous Mybpc3c.2373InsG model developed cardiac hypertrophy and severe left ventricular systolic and diastolic dysfunction, whereas HCM was not evident in Mybpc3+/InsG mice. Mybpc3InsG/InsG cardiomyocytes also presented with slowed contraction-relaxation kinetics, to a greater extent in 18-28 week old mice, partially due to increased levels of detyrosinated tubulin and desmin, and reduced cardiac troponin I (cTnI) phosphorylation. Impaired cardiomyocyte contraction-relaxation kinetics were successfully normalized in 18-28 week old Mybpc3InsG/InsG cardiomyocytes by combining detyrosination inhibitor parthenolide and β-adrenergic receptor agonist isoproterenol. Both the 3-4 week old and 18-28 week old Mybpc3InsG/InsG models recapitulate HCM, with a severe phenotype present in the 18-28 week old model.
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Affiliation(s)
- Sarah Hilderink
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Maike Schuldt
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Max Goebel
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Valentijn J Jansen
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Emmy Manders
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands
| | - Stan Moorman
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Larissa M Dorsch
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Frank G van Steenbeek
- Department of Clinical Sciences, Faculty of Veterinary Medicine, Utrecht University, 3584 CL Utrecht, the Netherlands; Department of Cardiology, Division Heart & Lungs, University Medical Center Utrecht, Utrecht University, 3508 GA Utrecht, the Netherlands; Regenerative Medicine Center Utrecht, University Medical Center Utrecht, Utrecht University, 3584 CT Utrecht, the Netherlands
| | - Jolanda van der Velden
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands
| | - Diederik W D Kuster
- Amsterdam UMC Location Vrije Universiteit Amsterdam, Physiology, De Boelelaan 1118, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Heart Failure & Arrhythmias, Amsterdam, the Netherlands.
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Nag S, Gollapudi SK, Del Rio CL, Spudich JA, McDowell R. Mavacamten, a precision medicine for hypertrophic cardiomyopathy: From a motor protein to patients. SCIENCE ADVANCES 2023; 9:eabo7622. [PMID: 37506209 DOI: 10.1126/sciadv.abo7622] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/23/2023] [Indexed: 07/30/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary myocardial disorder characterized by left ventricular hypertrophy, hyperdynamic contraction, and impaired relaxation of the heart. These functional derangements arise directly from altered sarcomeric function due to either mutations in genes encoding sarcomere proteins, or other defects such as abnormal energetics. Current treatment options do not directly address this causal biology but focus on surgical and extra-sarcomeric (sarcolemmal) pharmacological symptomatic relief. Mavacamten (formerly known as MYK-461), is a small molecule designed to regulate cardiac function at the sarcomere level by selectively but reversibly inhibiting the enzymatic activity of myosin, the fundamental motor of the sarcomere. This review summarizes the mechanism and translational progress of mavacamten from proteins to patients, describing how the mechanism of action and pharmacological characteristics, involving both systolic and diastolic effects, can directly target pathophysiological derangements within the cardiac sarcomere to improve cardiac structure and function in HCM. Mavacamten was approved by the Food and Drug Administration in April 2022 for the treatment of obstructive HCM and now goes by the commercial name of Camzyos. Full information about the risks, limitations, and side effects can be found at www.accessdata.fda.gov/drugsatfda_docs/label/2022/214998s000lbl.pdf.
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Affiliation(s)
- Suman Nag
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Sampath K Gollapudi
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
| | - Carlos L Del Rio
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
- Cardiac Consulting, 1630 S Delaware St. #56426, San Mateo, CA 94403, USA
| | | | - Robert McDowell
- MyoKardia Inc., a wholly owned subsidiary of Bristol Myers Squibb, Brisbane, CA 94005, USA
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Tanner BCW, Awinda PO, Agonias KB, Attili S, Blair CA, Thompson MS, Walker LA, Kampourakis T, Campbell KS. Sarcomere length affects Ca2+ sensitivity of contraction in ischemic but not non-ischemic myocardium. J Gen Physiol 2023; 155:213800. [PMID: 36633584 PMCID: PMC9859763 DOI: 10.1085/jgp.202213200] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2022] [Revised: 11/18/2022] [Accepted: 12/22/2022] [Indexed: 01/13/2023] Open
Abstract
In healthy hearts, myofilaments become more sensitive to Ca2+ as the myocardium is stretched. This effect is known as length-dependent activation and is an important cellular-level component of the Frank-Starling mechanism. Few studies have measured length-dependent activation in the myocardium from failing human hearts. We investigated whether ischemic and non-ischemic heart failure results in different length-dependent activation responses at physiological temperature (37°C). Myocardial strips from the left ventricular free wall were chemically permeabilized and Ca2+-activated at sarcomere lengths (SLs) of 1.9 and 2.3 µm. Data were acquired from 12 hearts that were explanted from patients receiving cardiac transplants; 6 had ischemic heart failure and 6 had non-ischemic heart failure. Another 6 hearts were obtained from organ donors. Maximal Ca2+-activated force increased at longer SL for all groups. Ca2+ sensitivity increased with SL in samples from donors (P < 0.001) and patients with ischemic heart failure (P = 0.003) but did not change with SL in samples from patients with non-ischemic heart failure. Compared with donors, troponin I phosphorylation decreased in ischemic samples and even more so in non-ischemic samples; cardiac myosin binding protein-C (cMyBP-C) phosphorylation also decreased with heart failure. These findings support the idea that troponin I and cMyBP-C phosphorylation promote length-dependent activation and show that length-dependent activation of contraction is blunted, yet extant, in the myocardium from patients with ischemic heart failure and further reduced in the myocardium from patients with non-ischemic heart failure. Patients who have a non-ischemic disease may exhibit a diminished contractile response to increased ventricular filling.
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Affiliation(s)
- Bertrand C W Tanner
- Department of Integrative Physiology and Neuroscience, Washington State University , Pullman, WA, USA
| | - Peter O Awinda
- Department of Integrative Physiology and Neuroscience, Washington State University , Pullman, WA, USA
| | - Keinan B Agonias
- Department of Integrative Physiology and Neuroscience, Washington State University , Pullman, WA, USA
| | - Seetharamaiah Attili
- Randall Centre for Cell and Molecular Biophysics, King's College London , London, UK
| | - Cheavar A Blair
- Department of Physiology, University of Kentucky , Lexington, KY, USA
| | - Mindy S Thompson
- Department of Physiology, University of Kentucky , Lexington, KY, USA
| | - Lori A Walker
- Division of Cardiology, Department of Medicine, University of Colorado Anschutz Medical Campus , Aurora, CO, USA
| | - Thomas Kampourakis
- Randall Centre for Cell and Molecular Biophysics, King's College London , London, UK
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky , Lexington, KY, USA.,Division of Cardiovascular Medicine, University of Kentucky , Lexington, KY, USA
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6
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Joshua J, Caswell J, O’Sullivan ML, Wood G, Fonfara S. Feline myocardial transcriptome in health and in hypertrophic cardiomyopathy-A translational animal model for human disease. PLoS One 2023; 18:e0283244. [PMID: 36928240 PMCID: PMC10019628 DOI: 10.1371/journal.pone.0283244] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2022] [Accepted: 03/03/2023] [Indexed: 03/18/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common heart disease in cats, characterized by primary left ventricular hypertrophy. Feline HCM closely resembles human HCM and is suggested as translational animal model for the human disease. A genetic cause is established in humans and suspected for cats, but little is known about the gene expression and pathways involved in the pathogenesis of HCM. To investigate the myocardial transcriptome changes in HCM, RNA sequencing was conducted on left ventricle (LV) and left atrium (LA) samples of healthy cats and cats with HCM (each n = 5; 20 samples). Ingenuity Pathway Analysis was used to determine functional pathways, regulators, and networks. Distinct gene expression profiles were identified in the LV and LA of the feline healthy and HCM myocardium. Analysis of differentially expressed mRNAs (>2 fold; FDR < 0.01) found chamber-specific (LV vs. LA) expression in both healthy and HCM groups, with higher transcriptional activity in the LA. Genes that contribute to the distinct structure and function of each chamber in health and HCM were identified in the regional comparison. The gene expression profiles of HCM compared to healthy hearts revealed disease related genes, including THBS4 and KLHL33 (LV), FAM177B and THRSP (LA), the latter 3 have not been reported for the myocardium so far, as the top differently expressed genes in the HCM heart. Differently expressed genes and functional pathways found in the HCM heart are associated with cardiac remodeling and fibrosis, inflammation, microvascular changes, calcium signaling and cardiac metabolism, with some regional differences. RhoGDI-RhoGTPase signaling, integrin and ILK signaling pathways, the LXR/RXR pathway in the LA, and the PPARα/RXRα, HIF1α and CXCR4 pathways in the LV might be of particular importance in the HCM disease process. This study identified region-specific myocardial gene transcription patterns as well as novel genes and pathways associated with HCM.
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Affiliation(s)
- Jessica Joshua
- University of Guelph, Ontario Veterinary College, Department of Pathobiology, Guelph, Ontario, Canada
- University of Guelph, Ontario Veterinary College, Department of Clinical Studies, Guelph, Ontario, Canada
| | - Jeff Caswell
- University of Guelph, Ontario Veterinary College, Department of Pathobiology, Guelph, Ontario, Canada
| | - M. Lynne O’Sullivan
- University of Prince Edward Island, Department of Companion Animals, Charlottetown, Prince Edward Island, Canada
| | - Geoffrey Wood
- University of Guelph, Ontario Veterinary College, Department of Pathobiology, Guelph, Ontario, Canada
| | - Sonja Fonfara
- University of Guelph, Ontario Veterinary College, Department of Clinical Studies, Guelph, Ontario, Canada
- * E-mail:
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7
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Sewanan LR, Shimada YJ. Prospects for remodeling the hypertrophic heart with myosin modulators. Front Cardiovasc Med 2022; 9:1051564. [DOI: 10.3389/fcvm.2022.1051564] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2022] [Accepted: 10/06/2022] [Indexed: 11/13/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a complex but relatively common genetic disease that usually arises from pathogenic variants that disrupt sarcomere function and lead to variable structural, hypertrophic, and fibrotic remodeling of the heart which result in substantial adverse clinical outcomes including arrhythmias, heart failure, and sudden cardiac death. HCM has had few effective treatments with the potential to ameliorate disease progression until the recent advent of inhibitory myosin modulators like mavacamten. Preclinical investigations and clinical trials utilizing this treatment targeted to this specific pathophysiological mechanism of sarcomere hypercontractility in HCM have confirmed that myosin modulators can alter disease expression and attenuate hypertrophic remodeling. Here, we summarize the state of hypertrophic remodeling and consider the arguments for and against salutary HCM disease modification using targeted myosin modulators. Further, we consider critical unanswered questions for future investigative and therapeutic avenues in HCM disease modification. We are at the precipice of a new era in understanding and treating HCM, with the potential to target agents toward modifying disease expression and natural history of this most common inherited disease of the heart.
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8
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Singh RR, Slater RE, Wang J, Wang C, Guo Q, Motani AS, Hartman JJ, Sadayappan S, Ason BL. Distinct Mechanisms for Increased Cardiac Contraction Through Selective Alteration of Either Myosin or Troponin Activity. JACC Basic Transl Sci 2022; 7:1021-1037. [DOI: 10.1016/j.jacbts.2022.04.013] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 04/15/2022] [Accepted: 04/18/2022] [Indexed: 10/14/2022]
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Burkart V, Kowalski K, Aldag-Niebling D, Beck J, Frick DA, Holler T, Radocaj A, Piep B, Zeug A, Hilfiker-Kleiner D, dos Remedios CG, van der Velden J, Montag J, Kraft T. Transcriptional bursts and heterogeneity among cardiomyocytes in hypertrophic cardiomyopathy. Front Cardiovasc Med 2022; 9:987889. [PMID: 36082122 PMCID: PMC9445301 DOI: 10.3389/fcvm.2022.987889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2022] [Accepted: 08/02/2022] [Indexed: 12/01/2022] Open
Abstract
Transcriptional bursting is a common expression mode for most genes where independent transcription of alleles leads to different ratios of allelic mRNA from cell to cell. Here we investigated burst-like transcription and its consequences in cardiac tissue from Hypertrophic Cardiomyopathy (HCM) patients with heterozygous mutations in the sarcomeric proteins cardiac myosin binding protein C (cMyBP-C, MYBPC3) and cardiac troponin I (cTnI, TNNI3). Using fluorescence in situ hybridization (RNA-FISH) we found that both, MYBPC3 and TNNI3 are transcribed burst-like. Along with that, we show unequal allelic ratios of TNNI3-mRNA among single cardiomyocytes and unequally distributed wildtype cMyBP-C protein across tissue sections from heterozygous HCM-patients. The mutations led to opposing functional alterations, namely increasing (cMyBP-Cc.927−2A>G) or decreasing (cTnIR145W) calcium sensitivity. Regardless, all patients revealed highly variable calcium-dependent force generation between individual cardiomyocytes, indicating contractile imbalance, which appears widespread in HCM-patients. Altogether, we provide strong evidence that burst-like transcription of sarcomeric genes can lead to an allelic mosaic among neighboring cardiomyocytes at mRNA and protein level. In HCM-patients, this presumably induces the observed contractile imbalance among individual cardiomyocytes and promotes HCM-development.
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Affiliation(s)
- Valentin Burkart
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
- Valentin Burkart
| | - Kathrin Kowalski
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - David Aldag-Niebling
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Julia Beck
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Dirk Alexander Frick
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Tim Holler
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Ante Radocaj
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Birgit Piep
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Andre Zeug
- Institute for Cellular Neurophysiology, Hannover Medical School, Hannover, Germany
| | | | - Cristobal G. dos Remedios
- Mechanosensory Biophysics Laboratory, Victor Chang Cardiac Research Institute, Darlinghurst, NSW, Australia
| | | | - Judith Montag
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
- *Correspondence: Judith Montag
| | - Theresia Kraft
- Institute for Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
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10
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Da’as SI, Hasan W, Salem R, Younes N, Abdelrahman D, Mohamed IA, Aldaalis A, Temanni R, Mathew LS, Lorenz S, Yacoub M, Nomikos M, Nasrallah GK, Fakhro KA. Transcriptome Profile Identifies Actin as an Essential Regulator of Cardiac Myosin Binding Protein C3 Hypertrophic Cardiomyopathy in a Zebrafish Model. Int J Mol Sci 2022; 23:ijms23168840. [PMID: 36012114 PMCID: PMC9408294 DOI: 10.3390/ijms23168840] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 07/24/2022] [Accepted: 07/26/2022] [Indexed: 01/15/2023] Open
Abstract
Variants in cardiac myosin-binding protein C (cMyBP-C) are the leading cause of inherited hypertrophic cardiomyopathy (HCM), demonstrating the key role that cMyBP-C plays in the heart’s contractile machinery. To investigate the c-MYBPC3 HCM-related cardiac impairment, we generated a zebrafish mypbc3-knockout model. These knockout zebrafish displayed significant morphological heart alterations related to a significant decrease in ventricular and atrial diameters at systolic and diastolic states at the larval stages. Immunofluorescence staining revealed significant hyperplasia in the mutant’s total cardiac and ventricular cardiomyocytes. Although cardiac contractility was similar to the wild-type control, the ejection fraction was significantly increased in the mypbc3 mutants. At later stages of larval development, the mutants demonstrated an early cardiac phenotype of myocardium remodeling, concurrent cardiomyocyte hyperplasia, and increased ejection fraction as critical processes in HCM initiation to counteract the increased ventricular myocardial wall stress. The examination of zebrafish adults showed a thickened ventricular cardiac wall with reduced heart rate, swimming speed, and endurance ability in both the mypbc3 heterozygous and homozygous groups. Furthermore, heart transcriptome profiling showed a significant downregulation of the actin-filament-based process, indicating an impaired actin cytoskeleton organization as the main dysregulating factor associated with the early ventricular cardiac hypertrophy in the zebrafish mypbc3 HCM model.
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Affiliation(s)
- Sahar Isa Da’as
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
- Australian Regenerative Medicine Institute, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
- Correspondence:
| | - Waseem Hasan
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Rola Salem
- Health Center, Qatar University, Doha P.O. Box 2713, Qatar
| | - Nadine Younes
- Department of Biomedical Sciences, College of Health Science, Member of QU Health, Qatar University, Doha P.O. Box 2713, Qatar
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar
| | - Doua Abdelrahman
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Iman A. Mohamed
- Australian Regenerative Medicine Institute, Monash University, Melbourne 3168, Australia
| | - Arwa Aldaalis
- Australian Regenerative Medicine Institute, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
| | - Ramzi Temanni
- Integrated Genomics Services, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Lisa Sara Mathew
- Integrated Genomics Services, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | - Stephan Lorenz
- Integrated Genomics Services, Sidra Medicine, Doha P.O. Box 26999, Qatar
| | | | - Michail Nomikos
- College of Medicine, Member of QU Health, Qatar University, Doha P.O. Box 2713, Qatar
| | - Gheyath K. Nasrallah
- Department of Biomedical Sciences, College of Health Science, Member of QU Health, Qatar University, Doha P.O. Box 2713, Qatar
- Biomedical Research Center, Qatar University, Doha P.O. Box 2713, Qatar
| | - Khalid A. Fakhro
- Department of Human Genetics, Sidra Medicine, Doha P.O. Box 26999, Qatar
- Australian Regenerative Medicine Institute, College of Health and Life Sciences, Hamad Bin Khalifa University, Doha P.O. Box 34110, Qatar
- Weill Cornell Medical College, Doha P.O. Box 24811, Qatar
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11
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Previs MJ, O’Leary TS, Morley MP, Palmer B, LeWinter M, Yob J, Pagani FD, Petucci C, Kim MS, Margulies KB, Arany Z, Kelly DP, Day SM. Defects in the Proteome and Metabolome in Human Hypertrophic Cardiomyopathy. Circ Heart Fail 2022; 15:e009521. [PMID: 35543134 PMCID: PMC9708114 DOI: 10.1161/circheartfailure.121.009521] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
BACKGROUND Defects in energetics are thought to be central to the pathophysiology of hypertrophic cardiomyopathy (HCM); yet, the determinants of ATP availability are not known. The purpose of this study is to ascertain the nature and extent of metabolic reprogramming in human HCM, and its potential impact on contractile function. METHODS We conducted proteomic and targeted, quantitative metabolomic analyses on heart tissue from patients with HCM and from nonfailing control human hearts. RESULTS In the proteomic analysis, the greatest differences observed in HCM samples compared with controls were increased abundances of extracellular matrix and intermediate filament proteins and decreased abundances of muscle creatine kinase and mitochondrial proteins involved in fatty acid oxidation. These differences in protein abundance were coupled with marked reductions in acyl carnitines, byproducts of fatty acid oxidation, in HCM samples. Conversely, the ketone body 3-hydroxybutyrate, branched chain amino acids, and their breakdown products, were all significantly increased in HCM hearts. ATP content, phosphocreatine, nicotinamide adenine dinucleotide and its phosphate derivatives, NADP and NADPH, and acetyl CoA were also severely reduced in HCM compared with control hearts. Functional assays performed on human skinned myocardial fibers demonstrated that the magnitude of observed reduction in ATP content in the HCM samples would be expected to decrease the rate of cross-bridge detachment. Moreover, left atrial size, an indicator of diastolic compliance, was inversely correlated with ATP content in hearts from patients with HCM. CONCLUSIONS HCM hearts display profound deficits in nucleotide availability with markedly reduced capacity for fatty acid oxidation and increases in ketone bodies and branched chain amino acids. These results have important therapeutic implications for the future design of metabolic modulators to treat HCM.
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Affiliation(s)
- Michael J. Previs
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Thomas S. O’Leary
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Michael P. Morley
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Brad Palmer
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Martin LeWinter
- Department of Molecular Physiology and Biophysics, University of Vermont, Larner College of Medicine
| | - Jaime Yob
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Francis D. Pagani
- Department of Cardiothoracic Surgery, University of Michigan School of Medicine
| | - Christopher Petucci
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Min-Soo Kim
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Kenneth B. Margulies
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Zoltan Arany
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Daniel P. Kelly
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
| | - Sharlene M. Day
- Division of Cardiovascular Medicine and the Penn Cardiovascular Institute, Perelman School of Medicine, University of Pennsylvania
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12
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Edelberg JM, Sehnert AJ, Mealiffe ME, Del Rio CL, McDowell R. The Impact of Mavacamten on the Pathophysiology of Hypertrophic Cardiomyopathy: A Narrative Review. Am J Cardiovasc Drugs 2022; 22:497-510. [PMID: 35435607 PMCID: PMC9467968 DOI: 10.1007/s40256-022-00532-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/24/2022] [Indexed: 11/25/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a chronic, progressive disease of the cardiomyocyte with a diverse and heterogeneous clinical presentation and course. This diversity and heterogeneity have added to the complexity of modeling the pathophysiological pathways that contribute to the disease burden. The development of novel therapeutic approaches targeting precise mechanisms within the underlying biology of HCM provides a tool to model and test these pathways. Here, we integrate the results of clinical observations with mavacamten, an allosteric, selective, and reversible inhibitor of cardiac myosin, the motor unit of the sarcomere, to develop an integrated pathophysiological pathway model of HCM, confirming the key role of excess sarcomeric activity. This model may serve as a foundation to understand the role of HCM pathophysiological pathways in the clinical presentation of the disease, and how a targeted therapeutic intervention capable of normalizing sarcomeric activity and repopulating low-energy utilization states may reduce the impact of these pathways in HCM and potentially related disease states.
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Affiliation(s)
- Jay M Edelberg
- Clinical Development, Cardiovascular Global Drug Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Amy J Sehnert
- Clinical Development, Cardiovascular Global Drug Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Matthew E Mealiffe
- Early Clinical Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Carlos L Del Rio
- Clinical Development, Cardiovascular Global Drug Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, Brisbane, CA, USA
| | - Robert McDowell
- Research & Early Development, MyoKardia, Inc., A Wholly Owned Subsidiary of Bristol Myers Squibb, 1000 Sierra Point Parkway, Brisbane, CA, 94005, USA.
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13
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Suay-Corredera C, Alegre-Cebollada J. The mechanics of the heart: zooming in on hypertrophic cardiomyopathy and cMyBP-C. FEBS Lett 2022; 596:703-746. [PMID: 35224729 DOI: 10.1002/1873-3468.14301] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Revised: 01/10/2022] [Accepted: 01/14/2022] [Indexed: 11/10/2022]
Abstract
Hypertrophic cardiomyopathy (HCM), a disease characterized by cardiac muscle hypertrophy and hypercontractility, is the most frequently inherited disorder of the heart. HCM is mainly caused by variants in genes encoding proteins of the sarcomere, the basic contractile unit of cardiomyocytes. The most frequently mutated among them is MYBPC3, which encodes cardiac myosin-binding protein C (cMyBP-C), a key regulator of sarcomere contraction. In this review, we summarize clinical and genetic aspects of HCM and provide updated information on the function of the healthy and HCM sarcomere, as well as on emerging therapeutic options targeting sarcomere mechanical activity. Building on what is known about cMyBP-C activity, we examine different pathogenicity drivers by which MYBPC3 variants can cause disease, focussing on protein haploinsufficiency as a common pathomechanism also in nontruncating variants. Finally, we discuss recent evidence correlating altered cMyBP-C mechanical properties with HCM development.
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14
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Ion Channel Impairment and Myofilament Ca 2+ Sensitization: Two Parallel Mechanisms Underlying Arrhythmogenesis in Hypertrophic Cardiomyopathy. Cells 2021; 10:cells10102789. [PMID: 34685769 PMCID: PMC8534456 DOI: 10.3390/cells10102789] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2021] [Revised: 10/07/2021] [Accepted: 10/13/2021] [Indexed: 11/17/2022] Open
Abstract
Life-threatening ventricular arrhythmias are the main clinical burden in patients with hypertrophic cardiomyopathy (HCM), and frequently occur in young patients with mild structural disease. While massive hypertrophy, fibrosis and microvascular ischemia are the main mechanisms underlying sustained reentry-based ventricular arrhythmias in advanced HCM, cardiomyocyte-based functional arrhythmogenic mechanisms are likely prevalent at earlier stages of the disease. In this review, we will describe studies conducted in human surgical samples from HCM patients, transgenic animal models and human cultured cell lines derived from induced pluripotent stem cells. Current pieces of evidence concur to attribute the increased risk of ventricular arrhythmias in early HCM to different cellular mechanisms. The increase of late sodium current and L-type calcium current is an early observation in HCM, which follows post-translation channel modifications and increases the occurrence of early and delayed afterdepolarizations. Increased myofilament Ca2+ sensitivity, commonly observed in HCM, may promote afterdepolarizations and reentry arrhythmias with direct mechanisms. Decrease of K+-currents due to transcriptional regulation occurs in the advanced disease and contributes to reducing the repolarization-reserve and increasing the early afterdepolarizations (EADs). The presented evidence supports the idea that patients with early-stage HCM should be considered and managed as subjects with an acquired channelopathy rather than with a structural cardiac disease.
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15
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Iorga B, Kraft T. Why make a strong muscle weaker? J Gen Physiol 2021; 153:212267. [PMID: 34106212 PMCID: PMC8193566 DOI: 10.1085/jgp.202112928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
Affiliation(s)
- Bogdan Iorga
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany.,Department of Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Theresia Kraft
- Department of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
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16
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Nollet EE, Westenbrink BD, de Boer RA, Kuster DWD, van der Velden J. Unraveling the Genotype-Phenotype Relationship in Hypertrophic Cardiomyopathy: Obesity-Related Cardiac Defects as a Major Disease Modifier. J Am Heart Assoc 2020; 9:e018641. [PMID: 33174505 PMCID: PMC7763714 DOI: 10.1161/jaha.120.018641] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and is characterized by asymmetric septal thickening and diastolic dysfunction. More than 1500 mutations in genes encoding sarcomere proteins are associated with HCM. However, the genotype‐phenotype relationship in HCM is incompletely understood and involves modification by additional disease hits. Recent cohort studies identify obesity as a major adverse modifier of disease penetrance, severity, and clinical course. In this review, we provide an overview of these clinical findings. Moreover, we explore putative mechanisms underlying obesity‐induced sensitization and aggravation of the HCM phenotype. We hypothesize obesity‐related stressors to impact on cardiomyocyte structure, metabolism, and homeostasis. These may impair cardiac function by directly acting on the primary mutation‐induced myofilament defects and by independently adding to the total cardiac disease burden. Last, we address important clinical and pharmacological implications of the involvement of obesity in HCM disease modification.
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Affiliation(s)
- Edgar E Nollet
- Department of Physiology Amsterdam UMC Vrije Universiteit Amsterdam Amsterdam Cardiovascular Sciences Amsterdam The Netherlands
| | - B Daan Westenbrink
- Department of Cardiology University of Groningen University Medical Center Groningen Groningen The Netherlands
| | - Rudolf A de Boer
- Department of Cardiology University of Groningen University Medical Center Groningen Groningen The Netherlands
| | - Diederik W D Kuster
- Department of Physiology Amsterdam UMC Vrije Universiteit Amsterdam Amsterdam Cardiovascular Sciences Amsterdam The Netherlands
| | - Jolanda van der Velden
- Department of Physiology Amsterdam UMC Vrije Universiteit Amsterdam Amsterdam Cardiovascular Sciences Amsterdam The Netherlands.,Netherlands Heart Institute Utrecht The Netherlands
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17
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Stochastic allelic expression as trigger for contractile imbalance in hypertrophic cardiomyopathy. Biophys Rev 2020; 12:1055-1064. [PMID: 32661905 PMCID: PMC7429642 DOI: 10.1007/s12551-020-00719-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2020] [Accepted: 07/02/2020] [Indexed: 12/17/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM), the most common inherited cardiac disease, is caused by several mostly heterozygous mutations in sarcomeric genes. Hallmarks of HCM are cardiomyocyte and myofibrillar disarray and hypertrophy and fibrosis of the septum and the left ventricle. To date, a pathomechanism common to all mutations remains elusive. We have proposed that contractile imbalance, an unequal force generation of neighboring cardiomyocytes, may contribute to development of HCM hallmarks. At the same calcium concentration, we found substantial differences in force generation between individual cardiomyocytes from HCM patients with mutations in β-MyHC (β-myosin heavy chain). Variability among cardiomyocytes was significantly larger in HCM patients as compared with donor controls. We assume that this heterogeneity in force generation among cardiomyocytes may lead to myocardial disarray and trigger hypertrophy and fibrosis. We provided evidence that burst-like transcription of the MYH7-gene, encoding for β-MyHC, is associated with unequal fractions of mutant per wild-type mRNA from cell to cell (cell-to-cell allelic imbalance). This will presumably lead to unequal fractions of mutant per wild-type protein from cell to cell which may underlie contractile imbalance. In this review, we discuss molecular mechanisms of burst-like transcription with regard to contractile imbalance and disease development in HCM.
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18
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Bos JM, Hebl VB, Oberg AL, Sun Z, Herman DS, Teekakirikul P, Seidman JG, Seidman CE, Dos Remedios CG, Maleszewski JJ, Schaff HV, Dearani JA, Noseworthy PA, Friedman PA, Ommen SR, Brozovich FV, Ackerman MJ. Marked Up-Regulation of ACE2 in Hearts of Patients With Obstructive Hypertrophic Cardiomyopathy: Implications for SARS-CoV-2-Mediated COVID-19. Mayo Clin Proc 2020; 95:1354-1368. [PMID: 32448590 PMCID: PMC7186205 DOI: 10.1016/j.mayocp.2020.04.028] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 04/21/2020] [Accepted: 04/23/2020] [Indexed: 01/19/2023]
Abstract
OBJECTIVE To explore the transcriptomic differences between patients with hypertrophic cardiomyopathy (HCM) and controls. PATIENTS AND METHODS RNA was extracted from cardiac tissue flash frozen at therapeutic surgical septal myectomy for 106 patients with HCM and 39 healthy donor hearts. Expression profiling of 37,846 genes was performed using the Illumina Human HT-12v3 Expression BeadChip. All patients with HCM were genotyped for pathogenic variants causing HCM. Technical validation was performed using quantitative real-time polymerase chain reaction (qRT-PCR) and Western blot. This study was started on January 1, 1999, and final analysis was completed on April 20, 2020. RESULTS Overall, 22% of the transcriptome (8443 of 37,846 genes) was expressed differentially between HCM and control tissues. Analysis by genotype revealed that gene expression changes were similar among genotypic subgroups of HCM, with only 4% (1502 of 37,846) to 6% (2336 of 37,846) of the transcriptome exhibiting differential expression between genotypic subgroups. The qRT-PCR confirmed differential expression in 92% (11 of 12 genes) of tested transcripts. Notably, in the context of coronavirus disease 2019 (COVID-19), the transcript for angiotensin I converting enzyme 2 (ACE2), a negative regulator of the angiotensin system, was the single most up-regulated gene in HCM (fold-change, 3.53; q-value =1.30×10-23), which was confirmed by qRT-PCR in triplicate (fold change, 3.78; P=5.22×10-4), and Western blot confirmed greater than 5-fold overexpression of ACE2 protein (fold change, 5.34; P=1.66×10-6). CONCLUSION More than 20% of the transcriptome is expressed differentially between HCM and control tissues. Importantly, ACE2 was the most up-regulated gene in HCM, indicating perhaps the heart's compensatory effort to mount an antihypertrophic, antifibrotic response. However, given that the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) uses ACE2 for viral entry, this 5-fold increase in ACE2 protein may confer increased risk for COVID-19 manifestations and outcomes in patients with increased ACE2 transcript expression and protein levels in the heart.
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Key Words
- δct, transcript of interest minus gapdh control
- ace2, angiotensin i converting enzyme 2
- acei, angiotensin-converting enzyme inhibitor
- arb, angiotensin receptor blocker
- at1r, angiotensin type 1 receptor
- bp, blood pressure
- cdna, complementary dna
- chf, congestive heart failure
- covid-19, coronavirus disease 2019
- ecg, electrocardiogram
- gtp, guanosine triphosphate
- hcm, hypertrophic cardiomyopathy
- hrsace2, human recombinant soluble angiotensin i converting enzyme 2
- htn, hypertension
- icu, intensive care unit
- iqr, interquartile range
- lv, left ventricular
- mig, maximum instantaneous gradient
- mrna, messenger rna
- mybpc3, myosin binding protein c
- myh7, beta myosin heavy chain
- na, not available
- ns, not significant
- nyha, new york heart association
- qrt-pcr, quantitative real-time polymerase chain reaction
- raas, renin-angiotensin-aldosterone system
- sars-cov-2, severe acute respiratory syndrome coronavirus 2
- scd, sudden cardiac death
- utr, untranslated region
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Affiliation(s)
- J Martijn Bos
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN
| | - Virginia B Hebl
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Ann L Oberg
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN
| | - Zhifu Sun
- Division of Biomedical Statistics and Informatics, Department of Health Sciences Research, Mayo Clinic, Rochester, MN
| | | | | | | | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, MA; Cardiovascular Division, Brigham and Women's Hospital, Boston, MA; Howard Hughes Medical Institute, Chevy Chase, MD
| | | | | | | | - Joseph A Dearani
- Department of Cardiovascular Surgery, Mayo Clinic, Rochester, MN
| | | | - Paul A Friedman
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | - Steve R Ommen
- Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN
| | | | - Michael J Ackerman
- Department of Molecular Pharmacology & Experimental Therapeutics, Windland Smith Rice Sudden Death Genomics Laboratory, Mayo Clinic, Rochester, MN; Department of Cardiovascular Medicine, Mayo Clinic, Rochester, MN; Division of Pediatric Cardiology, Department of Pediatric and Adolescent Medicine, Windland Smith Rice Genetic Heart Rhythm Clinic, Mayo Clinic, Rochester, MN.
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19
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Wijnker PJM, van der Velden J. Mutation-specific pathology and treatment of hypertrophic cardiomyopathy in patients, mouse models and human engineered heart tissue. Biochim Biophys Acta Mol Basis Dis 2020; 1866:165774. [PMID: 32217077 DOI: 10.1016/j.bbadis.2020.165774] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2019] [Revised: 03/16/2020] [Accepted: 03/17/2020] [Indexed: 01/04/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiomyopathy and is characterized by asymmetric left ventricular hypertrophy and diastolic dysfunction, and a frequent cause of sudden cardiac death at young age. Pharmacological treatment to prevent or reverse HCM is lacking. This may be partly explained by the variety of underlying disease causes. Over 1500 mutations have been associated with HCM, of which the majority reside in genes encoding sarcomere proteins, the cardiac contractile building blocks. Several mutation-mediated disease mechanisms have been identified, with proof for gene- and mutation-specific cellular perturbations. In line with mutation-specific changes in cellular pathology, the response to treatment may depend on the underlying sarcomere gene mutation. In this review, we will discuss evidence for mutation-specific pathology and treatment responses in HCM patients, mouse models and engineered heart tissue. The pros and cons of these experimental models for studying mutation-specific HCM pathology and therapies will be outlined.
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Affiliation(s)
- Paul J M Wijnker
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, De Boelelaan 1117, Amsterdam, the Netherlands.
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, De Boelelaan 1117, Amsterdam, the Netherlands; Netherlands Heart Institute, Utrecht, the Netherlands.
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20
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Helms AS, Tang VT, O'Leary TS, Friedline S, Wauchope M, Arora A, Wasserman AH, Smith ED, Lee LM, Wen XW, Shavit JA, Liu AP, Previs MJ, Day SM. Effects of MYBPC3 loss-of-function mutations preceding hypertrophic cardiomyopathy. JCI Insight 2020; 5:133782. [PMID: 31877118 DOI: 10.1172/jci.insight.133782] [Citation(s) in RCA: 54] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2019] [Accepted: 12/10/2019] [Indexed: 12/21/2022] Open
Abstract
Mutations in cardiac myosin binding protein C (MyBP-C, encoded by MYBPC3) are the most common cause of hypertrophic cardiomyopathy (HCM). Most MYBPC3 mutations result in premature termination codons (PTCs) that cause RNA degradation and a reduction of MyBP-C in HCM patient hearts. However, a reduction in MyBP-C has not been consistently observed in MYBPC3-mutant induced pluripotent stem cell cardiomyocytes (iPSCMs). To determine early MYBPC3 mutation effects, we used patient and genome-engineered iPSCMs. iPSCMs with frameshift mutations were compared with iPSCMs with MYBPC3 promoter and translational start site deletions, revealing that allelic loss of function is the primary inciting consequence of mutations causing PTCs. Despite a reduction in wild-type mRNA in all heterozygous iPSCMs, no reduction in MyBP-C protein was observed, indicating protein-level compensation through what we believe is a previously uncharacterized mechanism. Although homozygous mutant iPSCMs exhibited contractile dysregulation, heterozygous mutant iPSCMs had normal contractile function in the context of compensated MyBP-C levels. Agnostic RNA-Seq analysis revealed differential expression in genes involved in protein folding as the only dysregulated gene set. To determine how MYBPC3-mutant iPSCMs achieve compensated MyBP-C levels, sarcomeric protein synthesis and degradation were measured with stable isotope labeling. Heterozygous mutant iPSCMs showed reduced MyBP-C synthesis rates but a slower rate of MyBP-C degradation. These findings indicate that cardiomyocytes have an innate capacity to attain normal MyBP-C stoichiometry despite MYBPC3 allelic loss of function due to truncating mutations. Modulating MyBP-C degradation to maintain MyBP-C protein levels may be a novel treatment approach upstream of contractile dysfunction for HCM.
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Affiliation(s)
- Adam S Helms
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Vi T Tang
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Thomas S O'Leary
- Department of Molecular Physiology & Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Sabrina Friedline
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Mick Wauchope
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Akul Arora
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | - Eric D Smith
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | | | | | | | - Allen P Liu
- Mechanical Engineering.,Biophysics, University of Michigan, Ann Arbor, Michigan, USA
| | - Michael J Previs
- Department of Molecular Physiology & Biophysics, University of Vermont, Burlington, Vermont, USA
| | - Sharlene M Day
- Department of Internal Medicine, Division of Cardiovascular Medicine, University of Michigan, Ann Arbor, Michigan, USA.,Departments of Molecular and Integrative Physiology
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21
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Phosphomimetic cardiac myosin-binding protein C partially rescues a cardiomyopathy phenotype in murine engineered heart tissue. Sci Rep 2019; 9:18152. [PMID: 31796859 PMCID: PMC6890639 DOI: 10.1038/s41598-019-54665-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2019] [Accepted: 11/15/2019] [Indexed: 12/20/2022] Open
Abstract
Phosphorylation of cardiac myosin-binding protein C (cMyBP-C), encoded by MYBPC3, increases the availability of myosin heads for interaction with actin thus enhancing contraction. cMyBP-C phosphorylation level is lower in septal myectomies of patients with hypertrophic cardiomyopathy (HCM) than in non-failing hearts. Here we compared the effect of phosphomimetic (D282) and wild-type (S282) cMyBP-C gene transfer on the HCM phenotype of engineered heart tissues (EHTs) generated from a mouse model carrying a Mybpc3 mutation (KI). KI EHTs showed lower levels of mutant Mybpc3 mRNA and protein, and altered gene expression compared with wild-type (WT) EHTs. Furthermore, KI EHTs exhibited faster spontaneous contractions and higher maximal force and sensitivity to external [Ca2+] under pacing. Adeno-associated virus-mediated gene transfer of D282 and S282 similarly restored Mybpc3 mRNA and protein levels and suppressed mutant Mybpc3 transcripts. Moreover, both exogenous cMyBP-C proteins were properly incorporated in the sarcomere. KI EHTs hypercontractility was similarly prevented by both treatments, but S282 had a stronger effect than D282 to normalize the force-Ca2+-relationship and the expression of dysregulated genes. These findings in an in vitro model indicate that S282 is a better choice than D282 to restore the HCM EHT phenotype. To which extent the results apply to human HCM remains to be seen.
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22
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Rosas PC, Warren CM, Creed HA, Trzeciakowski JP, Solaro RJ, Tong CW. Cardiac Myosin Binding Protein-C Phosphorylation Mitigates Age-Related Cardiac Dysfunction: Hope for Better Aging? JACC Basic Transl Sci 2019; 4:817-830. [PMID: 31998850 PMCID: PMC6978553 DOI: 10.1016/j.jacbts.2019.06.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 06/14/2019] [Accepted: 06/19/2019] [Indexed: 12/29/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) phosphorylation prevents aging-related cardiac dysfunction. We tested this hypothesis by aging genetic mouse models of hypophosphorylated cMyBP-C, wild-type equivalent, and phosphorylated-mimetic cMyBP-C for 18 to 20 months. Phosphorylated-mimetic cMyBP-C mice exhibited better survival, better preservation of systolic and diastolic functions, and unchanging wall thickness. Wild-type equivalent mice showed decreasing cMyBP-C phosphorylation along with worsening cardiac function and hypertrophy approaching those found in hypophosphorylated cMyBP-C mice. Intact papillary muscle experiments suggested that cMyBP-C phosphorylation increased cross-bridge detachment rates as the underlying mechanism. Thus, phosphorylating cMyBP-C is a novel mechanism with potential to treat aging-related cardiac dysfunction.
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Key Words
- 3SA, mutated 3 serines to 3 alanines to mimic hypophosphorylated cardiac myosin binding protein-C (S273A, S282A, and S302A)
- 3SD, mutated 3 serines to 3 aspartic acids to mimic phosphorylated cMyBP-C (S273D, S282D, and S302D)
- ANOVA, analysis of variance
- EF, ejection fraction
- HF, heart failure
- HFpEF, heart failure with preserved ejection fraction
- HOP, hydroxyproline
- LV, left ventricular
- aging
- cMyBP-C, cardiac myosin binding protein-C
- cTnI, cardiac troponin I
- cardiac myosin binding protein-C
- dyastolic dysfunction
- heart failure
- phosphorylation
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Affiliation(s)
- Paola C. Rosas
- Department of Physiology and Biophysics, Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Chad M. Warren
- Department of Physiology and Biophysics, Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Heidi A. Creed
- Department of Medical Physiology, Texas A and M University Health Science Center, College of Medicine, College Station, Texas
| | - Jerome P. Trzeciakowski
- Department of Medical Physiology, Texas A and M University Health Science Center, College of Medicine, College Station, Texas
| | - R. John Solaro
- Department of Physiology and Biophysics, Center for Cardiovascular Research, College of Medicine, University of Illinois at Chicago, Chicago, Illinois
| | - Carl W. Tong
- Department of Medical Physiology, Texas A and M University Health Science Center, College of Medicine, College Station, Texas
- Catholic Health Initiatives-St. Joseph Health, Bryan, Texas
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23
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Reda SM, Chandra M. Dilated cardiomyopathy mutation (R174W) in troponin T attenuates the length-mediated increase in cross-bridge recruitment and myofilament Ca 2+ sensitivity. Am J Physiol Heart Circ Physiol 2019; 317:H648-H657. [PMID: 31373515 DOI: 10.1152/ajpheart.00171.2019] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
Alterations in length-dependent activation (LDA) may constitute a mechanism by which cardiomyopathy mutations lead to deleterious phenotypes and compromised heart function, because LDA underlies the molecular basis by which the heart tunes myocardial force production on a beat-to-beat basis (Frank-Starling mechanism). In this study, we investigated the effect of DCM-linked mutation (R173W) in human cardiac troponin T (TnT) on myofilament LDA. R173W mutation is associated with left ventricular dilatation and systolic dysfunction and is found in multiple families. R173W mutation is in the central region (residues 80-180) of TnT, which is known to be important for myofilament cooperativity and cross-bridge (XB) recruitment. Steady-state and dynamic contractile parameters were measured in detergent-skinned guinea pig left ventricular muscle fibers reconstituted with recombinant guinea pig wild-type TnT (TnTWT) or mutant TnT (TnTR174W; guinea pig analog of human R173W mutation) at two different sarcomere lengths (SL): short (1.9 µm) and long (2.3 µm). TnTR174W decreased pCa50 (-log [Ca2+]free required for half-maximal activation) to a greater extent at long than at short SL; for example, pCa50 decreased by 0.12 pCa units at long SL and by 0.06 pCa units at short SL. Differential changes in pCa50 at short and long SL attenuated the SL-dependent increase in myofilament Ca2+ sensitivity (ΔpCa50) in TnTR174W fibers; ΔpCa50 was 0.10 units in TnTWT fibers but only 0.04 units in TnTR174W fibers. Furthermore, TnTR174W blunted the SL-dependent increase in the magnitude of XB recruitment. Our observations suggest that the R173W mutation in human cardiac TnT may impair Frank-Starling mechanism.NEW & NOTEWORTHY This work characterizes the effect of dilated cardiomyopathy mutation in cardiac troponin T (TnTR174W) on myofilament length-dependent activation. TnTR174W attenuates the length-dependent increase in cross-bridge recruitment and myofilament Ca2+ sensitivity.
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Affiliation(s)
- Sherif M Reda
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
| | - Murali Chandra
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, Washington
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24
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Weismann CG, Blice-Baum A, Tong T, Li J, Huang BK, Jonas SM, Cammarato A, Choma MA. Multi-modal and multiscale imaging approaches reveal novel cardiovascular pathophysiology in Drosophila melanogaster. Biol Open 2019; 8:bio.044339. [PMID: 31455664 PMCID: PMC6737974 DOI: 10.1242/bio.044339] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Establishing connections between changes in linear DNA sequences and complex downstream mesoscopic pathology remains a major challenge in biology. Herein, we report a novel, multi-modal and multiscale imaging approach for comprehensive assessment of cardiovascular physiology in Drosophila melanogaster We employed high-speed angiography, optical coherence tomography (OCT) and confocal microscopy to reveal functional and structural abnormalities in the hdp2 mutant, pre-pupal heart tube and aorta relative to controls. hdp2 harbor a mutation in wupA, which encodes an ortholog of human troponin I (TNNI3). TNNI3 variants frequently engender cardiomyopathy. We demonstrate that the hdp2 aortic and cardiac muscle walls are disrupted and that shorter sarcomeres are associated with smaller, stiffer aortas, which consequently result in increased flow and pulse wave velocities. The mutant hearts also displayed diastolic and latent systolic dysfunction. We conclude that hdp2 pre-pupal hearts are exposed to increased afterload due to aortic hypoplasia. This may in turn contribute to diastolic and subtle systolic dysfunction via vascular-heart tube interaction, which describes the effect of the arterial loading system on cardiac function. Ultimately, the cardiovascular pathophysiology caused by a point mutation in a sarcomeric protein demonstrates that complex and dynamic micro- and mesoscopic phenotypes can be mechanistically explained in a gene sequence- and molecular-specific manner.
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Affiliation(s)
- Constance G Weismann
- Yale School of Medicine, Department of Pediatrics, Division of Pediatric Cardiology, New Haven, CT 06510, USA .,Lund University, Skane University Hospital, Department of Clinical Sciences Lund, Pediatric Cardiology, 22184 Lund, Sweden
| | - Anna Blice-Baum
- Johns Hopkins University School of Medicine, Division of Cardiology, Department of Medicine, Department of Physiology, Baltimore, MD 21205, USA
| | - Tangji Tong
- Yale Departments of Diagnostic Radiology, Pediatrics, Biomedical Engineering, and Applied Physics, New Haven, CT 06510, USA
| | - Joyce Li
- Yale Departments of Diagnostic Radiology, Pediatrics, Biomedical Engineering, and Applied Physics, New Haven, CT 06510, USA
| | - Brendan K Huang
- Yale Departments of Diagnostic Radiology, Pediatrics, Biomedical Engineering, and Applied Physics, New Haven, CT 06510, USA
| | - Stephan M Jonas
- Yale Departments of Diagnostic Radiology, Pediatrics, Biomedical Engineering, and Applied Physics, New Haven, CT 06510, USA.,Department of Informatics, Technical University of Munich, 85748 Garching, Germany
| | - Anthony Cammarato
- Johns Hopkins University School of Medicine, Division of Cardiology, Department of Medicine, Department of Physiology, Baltimore, MD 21205, USA
| | - Michael A Choma
- Yale Departments of Diagnostic Radiology, Pediatrics, Biomedical Engineering, and Applied Physics, New Haven, CT 06510, USA
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25
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van der Velden J, Tocchetti CG, Varricchi G, Bianco A, Sequeira V, Hilfiker-Kleiner D, Hamdani N, Leite-Moreira AF, Mayr M, Falcão-Pires I, Thum T, Dawson DK, Balligand JL, Heymans S. Metabolic changes in hypertrophic cardiomyopathies: scientific update from the Working Group of Myocardial Function of the European Society of Cardiology. Cardiovasc Res 2019; 114:1273-1280. [PMID: 29912308 PMCID: PMC6054261 DOI: 10.1093/cvr/cvy147] [Citation(s) in RCA: 57] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/18/2018] [Accepted: 06/13/2018] [Indexed: 12/20/2022] Open
Abstract
Disturbed metabolism as a consequence of obesity and diabetes may cause cardiac diseases (recently highlighted in the cardiovascular research spotlight issue on metabolic cardiomyopathies).1 In turn, the metabolism of the heart may also be disturbed in genetic and acquired forms of hypertrophic cardiac disease. Herein, we provide an overview of recent insights on metabolic changes in genetic hypertrophic cardiomyopathy and discuss several therapies, which may be explored to target disturbed metabolism and prevent onset of cardiac hypertrophy. This article is part of the Mini Review Series from the Varenna 2017 meeting of the Working Group of Myocardial Function of the European Society of Cardiology.
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Affiliation(s)
- Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands.,Netherlands Heart Institute, Utrecht, The Netherlands
| | - Carlo G Tocchetti
- Department of Translational Medical Sciences, Federico II University, Naples, NA, Italy
| | - Gilda Varricchi
- Department of Translational Medical Sciences, Federico II University, Naples, NA, Italy
| | - Anna Bianco
- Department of Translational Medical Sciences, Federico II University, Naples, NA, Italy.,Department of Cardiology, Maastricht University Medical Center & CARIM, Maastricht University, Maastricht, The Netherlands
| | - Vasco Sequeira
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, De Boelelaan 1117, 1081 HV Amsterdam, The Netherlands
| | - Denise Hilfiker-Kleiner
- Molecular Cardiology, Department of Cardiology and Angiology, Medical School Hannover, Germany
| | - Nazha Hamdani
- Department of Systems Physiology, Ruhr University Bochum, Bochum, Germany
| | - Adelino F Leite-Moreira
- Department of Surgery and Physiology, Faculty of Medicine, Cardiovascular Research Centre, University of Porto, Porto, Portugal
| | - Manuel Mayr
- The James Black Centre & King's British Heart Foundation Centre, King's College, University of London, London, UK
| | - Ines Falcão-Pires
- Department of Surgery and Physiology, Faculty of Medicine, Cardiovascular Research Centre, University of Porto, Porto, Portugal
| | - Thomas Thum
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany.,National Heart and Lung Institute, Imperial College London, London, UK.,REBIRTH Excellence Cluster, Hannover Medical School, Hannover, Germany
| | - Dana K Dawson
- School of Medicine & Dentistry, University of Aberdeen, Aberdeen AB25 2ZD, UK
| | - Jean-Luc Balligand
- Pole of Pharmacology and Therapeutics, Institut de Recherche Experimentale et Clinique (IREC), and Clinique Universitaire Saint-Luc, Université catholique de Louvain, Brussels, Belgium
| | - Stephane Heymans
- Netherlands Heart Institute, Utrecht, The Netherlands.,Department of Cardiology, Maastricht University Medical Center & CARIM, Maastricht University, Maastricht, The Netherlands.,Department of Cardiovascular Sciences, Leuven University, Leuven, Belgium
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26
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Wijnker PJ, Sequeira V, Kuster DW, van der Velden J. Hypertrophic Cardiomyopathy: A Vicious Cycle Triggered by Sarcomere Mutations and Secondary Disease Hits. Antioxid Redox Signal 2019; 31:318-358. [PMID: 29490477 PMCID: PMC6602117 DOI: 10.1089/ars.2017.7236] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/20/2017] [Revised: 02/23/2018] [Accepted: 02/25/2018] [Indexed: 02/06/2023]
Abstract
Significance: Hypertrophic cardiomyopathy (HCM) is a cardiac genetic disease characterized by left ventricular hypertrophy, diastolic dysfunction, and myocardial disarray. Disease onset occurs between 20 and 50 years of age, thus affecting patients in the prime of their life. HCM is caused by mutations in sarcomere proteins, the contractile building blocks of the heart. Despite increased knowledge of causal mutations, the exact path from genetic defect leading to cardiomyopathy is complex and involves additional disease hits. Recent Advances: Laboratory-based studies indicate that HCM development not only depends on the primary sarcomere impairment caused by the mutation but also on secondary disease-related alterations in the heart. Here we propose a vicious mutation-induced disease cycle, in which a mutation-induced energy depletion alters cellular metabolism with increased mitochondrial work, which triggers secondary disease modifiers that will worsen disease and ultimately lead to end-stage HCM. Critical Issues: Evidence shows excessive cellular reactive oxygen species (ROS) in HCM patients and HCM animal models. Oxidative stress markers are increased in the heart (oxidized proteins, DNA, and lipids) and serum of HCM patients. In addition, increased mitochondrial ROS production and changes in endogenous antioxidants are reported in HCM. Mutant sarcomeric protein may drive excessive levels of cardiac ROS via changes in cardiac efficiency and metabolism, mitochondrial activation and/or dysfunction, impaired protein quality control, and microvascular dysfunction. Future Directions: Interventions restoring metabolism, mitochondrial function, and improved ROS balance may be promising therapeutic approaches. We discuss the effects of current HCM pharmacological therapies and potential future therapies to prevent and reverse HCM. Antioxid. Redox Signal. 31, 318-358.
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Affiliation(s)
- Paul J.M. Wijnker
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Vasco Sequeira
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Diederik W.D. Kuster
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, The Netherlands
- Netherlands Heart Institute, Utrecht, The Netherlands
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27
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Dorsch LM, Schuldt M, dos Remedios CG, Schinkel AFL, de Jong PL, Michels M, Kuster DWD, Brundel BJJM, van der Velden J. Protein Quality Control Activation and Microtubule Remodeling in Hypertrophic Cardiomyopathy. Cells 2019; 8:E741. [PMID: 31323898 PMCID: PMC6678711 DOI: 10.3390/cells8070741] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2019] [Revised: 07/11/2019] [Accepted: 07/17/2019] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disorder. It is mainly caused by mutations in genes encoding sarcomere proteins. Mutant forms of these highly abundant proteins likely stress the protein quality control (PQC) system of cardiomyocytes. The PQC system, together with a functional microtubule network, maintains proteostasis. We compared left ventricular (LV) tissue of nine donors (controls) with 38 sarcomere mutation-positive (HCMSMP) and 14 sarcomere mutation-negative (HCMSMN) patients to define HCM and mutation-specific changes in PQC. Mutations in HCMSMP result in poison polypeptides or reduced protein levels (haploinsufficiency, HI). The main findings were 1) several key PQC players were more abundant in HCM compared to controls, 2) after correction for sex and age, stabilizing heat shock protein (HSP)B1, and refolding, HSPD1 and HSPA2 were increased in HCMSMP compared to controls, 3) α-tubulin and acetylated α-tubulin levels were higher in HCM compared to controls, especially in HCMHI, 4) myosin-binding protein-C (cMyBP-C) levels were inversely correlated with α-tubulin, and 5) α-tubulin levels correlated with acetylated α-tubulin and HSPs. Overall, carrying a mutation affects PQC and α-tubulin acetylation. The haploinsufficiency of cMyBP-C may trigger HSPs and α-tubulin acetylation. Our study indicates that proliferation of the microtubular network may represent a novel pathomechanism in cMyBP-C haploinsufficiency-mediated HCM.
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Affiliation(s)
- Larissa M Dorsch
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands.
| | - Maike Schuldt
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Cristobal G dos Remedios
- Sydney Heart Bank, Discipline of Anatomy, Bosch Institute, University of Sydney, Sydney 2006, Australia
| | - Arend F L Schinkel
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Peter L de Jong
- Department of Cardiothoracic Surgery, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Michelle Michels
- Department of Cardiology, Thoraxcenter, Erasmus Medical Center, 3015 GD Rotterdam, The Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Bianca J J M Brundel
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, 1081 HV Amsterdam, The Netherlands
- Netherlands Heart Institute, 3511 EP Utrecht, The Netherlands
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28
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Nijenkamp LLAM, Bollen IAE, van Velzen HG, Regan JA, van Slegtenhorst M, Niessen HWM, Schinkel AFL, Krüger M, Poggesi C, Ho CY, Kuster DWD, Michels M, van der Velden J. Sex Differences at the Time of Myectomy in Hypertrophic Cardiomyopathy. Circ Heart Fail 2019; 11:e004133. [PMID: 29853478 DOI: 10.1161/circheartfailure.117.004133] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2017] [Accepted: 04/19/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND One of the first clinically detectable alterations in heart function in hypertrophic cardiomyopathy (HCM) is a decline in diastolic function. Diastolic dysfunction is caused by changes in intrinsic properties of cardiomyocytes or an increase in fibrosis. We investigated whether clinical and cellular parameters of diastolic function are different between male and female patients with HCM at the time of myectomy. METHODS AND RESULTS Cardiac tissue from the interventricular septum of patients with HCM (27 women and 44 men) was obtained during myectomy preceded by echocardiography. At myectomy, female patients were 7 years older than male patients and showed more advanced diastolic dysfunction than men evident from significantly higher values for E/e' ratio, left ventricular filling pattern, tricuspid regurgitation velocity, and left atrial diameter indexed for body surface. Whereas most male patients (56%) showed mild (grade I) diastolic dysfunction, 50% of female patients showed grade III diastolic dysfunction. Passive tension in HCM cardiomyocytes was comparable with controls, and myofilament calcium sensitivity was higher in HCM compared with controls, but no sex differences were observed in myofilament function. In female patients with HCM, titin was more compliant, and more fibrosis was present compared with men. Differences between female and male patients with HCM remained significant after correction for age. CONCLUSIONS Female patients with HCM are older at the time of myectomy and show greater impairment of diastolic function. Furthermore, left ventricular and left atrial remodeling is increased in women when corrected for body surface area. At a cellular level, HCM women showed increased compliant titin and a larger degree of interstitial fibrosis.
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Affiliation(s)
| | - Ilse A E Bollen
- Department of Physiology (L.L.A.M.N., I.A.E.B., J.A.R., D.W.D.K., J.v.d.V.)
| | - Hannah G van Velzen
- VU University Medical Center, Amsterdam, The Netherlands. Department of Cardiology (H.G.v.V., A.F.L.S., M.M.)
| | - Jessica A Regan
- Department of Physiology (L.L.A.M.N., I.A.E.B., J.A.R., D.W.D.K., J.v.d.V.)
| | | | - Hans W M Niessen
- Department of Pathology and Cardiac Surgery, Amsterdam Cardiovascular Sciences (H.W.M.N.)
| | - Arend F L Schinkel
- VU University Medical Center, Amsterdam, The Netherlands. Department of Cardiology (H.G.v.V., A.F.L.S., M.M.)
| | - Martina Krüger
- Erasmus MC, Rotterdam, The Netherlands. Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Germany (M.K.)
| | - Corrado Poggesi
- Dipartimento di Medicina Sperimentale e Clinica, Università degli Studi di Firenze, Italy (C.P.)
| | - Carolyn Y Ho
- Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA (C.Y.H.)
| | | | - Michelle Michels
- VU University Medical Center, Amsterdam, The Netherlands. Department of Cardiology (H.G.v.V., A.F.L.S., M.M.)
| | - Jolanda van der Velden
- Department of Physiology (L.L.A.M.N., I.A.E.B., J.A.R., D.W.D.K., J.v.d.V.) .,Netherlands Heart Institute, Utrecht (J.v.d.V.)
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29
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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] [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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30
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Kraft T, Montag J. Altered force generation and cell-to-cell contractile imbalance in hypertrophic cardiomyopathy. Pflugers Arch 2019; 471:719-733. [PMID: 30740621 PMCID: PMC6475633 DOI: 10.1007/s00424-019-02260-9] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2018] [Accepted: 01/20/2019] [Indexed: 01/18/2023]
Abstract
Hypertrophic cardiomyopathy (HCM) is mainly caused by mutations in sarcomeric proteins. Thirty to forty percent of identified mutations are found in the ventricular myosin heavy chain (β-MyHC). A common mechanism explaining how numerous mutations in several different proteins induce a similar HCM-phenotype is unclear. It was proposed that HCM-mutations cause hypercontractility, which for some mutations is thought to result from mutation-induced unlocking of myosin heads from a so-called super-relaxed state (SRX). The SRX was suggested to be related to the "interacting head motif," i.e., pairs of myosin heads folded back onto their S2-region. Here, we address these structural states of myosin in context of earlier work on weak binding cross-bridges. However, not all HCM-mutations cause hypercontractility and/or are involved in the interacting head motif. But most likely, all mutations alter the force generating mechanism, yet in different ways, possibly including inhibition of SRX. Such functional-hyper- and hypocontractile-changes are the basis of our previously proposed concept stating that contractile imbalance due to unequal fractions of mutated and wildtype protein among individual cardiomyocytes over time will induce cardiomyocyte disarray and fibrosis, hallmarks of HCM. Studying β-MyHC-mutations, we found substantial contractile variability from cardiomyocyte to cardiomyocyte within a patient's myocardium, much higher than in controls. This was paralleled by a similarly variable fraction of mutant MYH7-mRNA (cell-to-cell allelic imbalance), due to random, burst-like transcription, independent for mutant and wildtype MYH7-alleles. Evidence suggests that HCM-mutations in other sarcomeric proteins follow the same disease mechanism.
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Affiliation(s)
- Theresia Kraft
- Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany
| | - Judith Montag
- Molecular and Cell Physiology, Hannover Medical School, Carl-Neuberg-Str. 1, 30625, Hannover, Germany.
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31
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Sewanan LR, Campbell SG. Modelling sarcomeric cardiomyopathies with human cardiomyocytes derived from induced pluripotent stem cells. J Physiol 2019; 598:2909-2922. [PMID: 30624779 DOI: 10.1113/jp276753] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Accepted: 12/06/2018] [Indexed: 12/22/2022] Open
Abstract
Cardiomyocytes derived from human induced pluripotent stem cells (iPSCs) provide a unique opportunity to understand the pathophysiological effects of genetic cardiomyopathy mutations. In particular, these cells hold the potential to unmask the effects of mutations on contractile behaviour in vitro, providing new insights into genotype-phenotype relationships. With this goal in mind, several groups have established iPSC lines that contain sarcomeric gene mutations linked to cardiomyopathy in patient populations. Their studies have employed diverse systems and methods for performing mechanical measurements of contractility, ranging from single cell techniques to multicellular tissue-like constructs. Here, we review published results to date within the growing field of iPSC-based sarcomeric cardiomyopathy disease models. We devote special attention to the methods of mechanical characterization selected in each case, and how these relate to the paradigms of classical muscle mechanics. An appreciation of these somewhat subtle paradigms can inform efforts to compare the results of different studies and possibly reconcile discrepancies. Although more work remains to be done to improve and possibly standardize methods for producing, maturing, and mechanically interrogating iPSC-derived cardiomyocytes, the initial results indicate that this approach to modelling cardiomyopathies will continue to provide critical insights into these devastating diseases.
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Affiliation(s)
- Lorenzo R Sewanan
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA
| | - Stuart G Campbell
- Department of Biomedical Engineering, Yale University, New Haven, CT, USA.,Department of Cellular and Molecular Physiology, Yale School of Medicine, New Haven, CT, USA
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32
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van der Velden J, Stienen GJM. Cardiac Disorders and Pathophysiology of Sarcomeric Proteins. Physiol Rev 2019; 99:381-426. [PMID: 30379622 DOI: 10.1152/physrev.00040.2017] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The sarcomeric proteins represent the structural building blocks of heart muscle, which are essential for contraction and relaxation. During recent years, it has become evident that posttranslational modifications of sarcomeric proteins, in particular phosphorylation, tune cardiac pump function at rest and during exercise. This delicate, orchestrated interaction is also influenced by mutations, predominantly in sarcomeric proteins, which cause hypertrophic or dilated cardiomyopathy. In this review, we follow a bottom-up approach starting from a description of the basic components of cardiac muscle at the molecular level up to the various forms of cardiac disorders at the organ level. An overview is given of sarcomere changes in acquired and inherited forms of cardiac disease and the underlying disease mechanisms with particular reference to human tissue. A distinction will be made between the primary defect and maladaptive/adaptive secondary changes. Techniques used to unravel functional consequences of disease-induced protein changes are described, and an overview of current and future treatments targeted at sarcomeric proteins is given. The current evidence presented suggests that sarcomeres not only form the basis of cardiac muscle function but also represent a therapeutic target to combat cardiac disease.
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Affiliation(s)
- Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
| | - Ger J M Stienen
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam , The Netherlands ; and Department of Physiology, Kilimanjaro Christian Medical University College, Moshi, Tanzania
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33
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Piroddi N, Witjas-Paalberends ER, Ferrara C, Ferrantini C, Vitale G, Scellini B, Wijnker PJM, Sequiera V, Dooijes D, Dos Remedios C, Schlossarek S, Leung MC, Messer A, Ward DG, Biggeri A, Tesi C, Carrier L, Redwood CS, Marston SB, van der Velden J, Poggesi C. The homozygous K280N troponin T mutation alters cross-bridge kinetics and energetics in human HCM. J Gen Physiol 2018; 151:18-29. [PMID: 30578328 PMCID: PMC6314385 DOI: 10.1085/jgp.201812160] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Accepted: 11/29/2018] [Indexed: 01/24/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is caused by mutations in sarcomeric proteins, but the pathogenic mechanism is unclear. Piroddi et al. find impairment of cross-bridge kinetics and energetics in human sarcomeres with a TNNT2 mutation, suggesting that HCM involves inefficient ATP utilization. Hypertrophic cardiomyopathy (HCM) is a genetic form of left ventricular hypertrophy, primarily caused by mutations in sarcomere proteins. The cardiac remodeling that occurs as the disease develops can mask the pathogenic impact of the mutation. Here, to discriminate between mutation-induced and disease-related changes in myofilament function, we investigate the pathogenic mechanisms underlying HCM in a patient carrying a homozygous mutation (K280N) in the cardiac troponin T gene (TNNT2), which results in 100% mutant cardiac troponin T. We examine sarcomere mechanics and energetics in K280N-isolated myofibrils and demembranated muscle strips, before and after replacement of the endogenous troponin. We also compare these data to those of control preparations from donor hearts, aortic stenosis patients (LVHao), and HCM patients negative for sarcomeric protein mutations (HCMsmn). The rate constant of tension generation following maximal Ca2+ activation (kACT) and the rate constant of isometric relaxation (slow kREL) are markedly faster in K280N myofibrils than in all control groups. Simultaneous measurements of maximal isometric ATPase activity and Ca2+-activated tension in demembranated muscle strips also demonstrate that the energy cost of tension generation is higher in the K280N than in all controls. Replacement of mutant protein by exchange with wild-type troponin in the K280N preparations reduces kACT, slow kREL, and tension cost close to control values. In donor myofibrils and HCMsmn demembranated strips, replacement of endogenous troponin with troponin containing the K280N mutant increases kACT, slow kREL, and tension cost. The K280N TNNT2 mutation directly alters the apparent cross-bridge kinetics and impairs sarcomere energetics. This result supports the hypothesis that inefficient ATP utilization by myofilaments plays a central role in the pathogenesis of the disease.
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Affiliation(s)
- Nicoletta Piroddi
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - E Rosalie Witjas-Paalberends
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Claudia Ferrara
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Cecilia Ferrantini
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy.,LENS, Sesto Fiorentino (Firenze), Florence, Italy
| | - Giulia Vitale
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Beatrice Scellini
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Paul J M Wijnker
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Vasco Sequiera
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Dennis Dooijes
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,Clinical Genetics, University Medical Center, Utrecht, Netherlands
| | - Cristobal Dos Remedios
- Department of Anatomy and Histology, Bosch Institute, The University of Sydney, Sydney, Australia
| | - Saskia Schlossarek
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | - Man Ching Leung
- National Heart and Lung Institute, Imperial College, London, England, UK
| | - Andrew Messer
- National Heart and Lung Institute, Imperial College, London, England, UK
| | - Douglas G Ward
- Institute of Cancer and Genomic Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham, UK
| | | | - Chiara Tesi
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany.,German Centre for Cardiovascular Research (DZHK), partner site Hamburg/Kiel/Lübeck, Germany
| | | | - Steven B Marston
- National Heart and Lung Institute, Imperial College, London, England, UK
| | - Jolanda van der Velden
- Amsterdam UMC, Vrije Universiteit Amsterdam, Physiology, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands.,Clinical Genetics, University Medical Center, Utrecht, Netherlands.,ICIN-Netherlands, Heart Institute, Utrecht, Netherlands
| | - Corrado Poggesi
- Dipartimento di Medicina Sperimentale e Clinica, Università di Firenze, Florence, Italy .,LENS, Sesto Fiorentino (Firenze), Florence, Italy
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Allelic imbalance and haploinsufficiency in MYBPC3-linked hypertrophic cardiomyopathy. Pflugers Arch 2018; 471:781-793. [PMID: 30456444 DOI: 10.1007/s00424-018-2226-9] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2018] [Revised: 10/04/2018] [Accepted: 10/17/2018] [Indexed: 01/04/2023]
Abstract
Mutations in cardiac myosin binding protein C (MYBPC3) represent the most frequent cause of familial hypertrophic cardiomyopathy (HCM), making up approximately 50% of identified HCM mutations. MYBPC3 is distinct among other sarcomere genes associated with HCM in that truncating mutations make up the vast majority, whereas nontruncating mutations predominant in other sarcomere genes. Several studies using myocardial tissue from HCM patients have found reduced abundance of wild-type MYBPC3 compared to control hearts, suggesting haploinsufficiency of full-length MYBPC3. Further, decreased mutant versus wild-type mRNA and lack of truncated mutant MYBPC3 protein has been demonstrated, highlighting the presence of allelic imbalance. In this review, we will begin by introducing allelic imbalance and haploinsufficiency, highlighting the broad role each plays within the spectrum of human disease. We will subsequently focus on the roles allelic imbalance and haploinsufficiency play within MYBPC3-linked HCM. Finally, we will explore the implications of these findings on future directions of HCM research. An improved understanding of allelic imbalance and haploinsufficiency may help us better understand genotype-phenotype relationships in HCM and develop novel targeted therapies, providing exciting future research opportunities.
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35
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Eschenhagen T, Carrier L. Cardiomyopathy phenotypes in human-induced pluripotent stem cell-derived cardiomyocytes-a systematic review. Pflugers Arch 2018; 471:755-768. [PMID: 30324321 PMCID: PMC6475632 DOI: 10.1007/s00424-018-2214-0] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2018] [Revised: 09/19/2018] [Accepted: 10/02/2018] [Indexed: 12/12/2022]
Abstract
Human-induced pluripotent stem cells (hiPSC) can be differentiated to cardiomyocytes at high efficiency and are increasingly used to study cardiac disease in a human context. This review evaluated 38 studies on hypertrophic (HCM) and dilated cardiomyopathy (DCM) of different genetic causes asking to which extent published data allow the definition of an in vitro HCM/DCM hiPSC-CM phenotype. The data are put in context with the prevailing hypotheses on HCM/DCM dysfunction and pathophysiology. Relatively consistent findings in HCM not reported in DCM were larger cell size (156 ± 85%, n = 15), more nuclear localization of nuclear factor of activated T cells (NFAT; 175 ± 65%, n = 3), and higher β-myosin heavy chain gene expression levels (500 ± 547%, n = 8) than respective controls. Conversely, DCM lines showed consistently less force development than controls (47 ± 23%, n = 9), while HCM forces scattered without clear trend. Both HCM and DCM lines often showed sarcomere disorganization, higher NPPA/NPPB expression levels, and arrhythmic beating behaviour. The data have to be taken with the caveat that reporting frequencies of the various parameters (e.g. cell size, NFAT expression) differ widely between HCM and DCM lines, in which data scatter is large and that only 9/38 studies used isogenic controls. Taken together, the current data provide interesting suggestions for disease-specific phenotypes in HCM/DCM hiPSC-CM but indicate that the field is still in its early days. Systematic, quantitative comparisons and robust, high content assays are warranted to advance the field.
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Affiliation(s)
- Thomas Eschenhagen
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. .,Partner Site Hamburg/Kiel/Lübeck, DZHK (German Centre for Cardiovascular Research), Hamburg, Germany.
| | - Lucie Carrier
- Institute of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany. .,Partner Site Hamburg/Kiel/Lübeck, DZHK (German Centre for Cardiovascular Research), Hamburg, Germany.
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Mamidi R, Li J, Doh CY, Verma S, Stelzer JE. Impact of the Myosin Modulator Mavacamten on Force Generation and Cross-Bridge Behavior in a Murine Model of Hypercontractility. J Am Heart Assoc 2018; 7:e009627. [PMID: 30371160 PMCID: PMC6201428 DOI: 10.1161/jaha.118.009627] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 07/27/2018] [Indexed: 01/09/2023]
Abstract
Background Recent studies suggest that mavacamten (Myk461), a small myosin-binding molecule, decreases hypercontractility in myocardium expressing hypertrophic cardiomyopathy-causing missense mutations in myosin heavy chain. However, the predominant feature of most mutations in cardiac myosin binding protein-C ( cMyBPC ) that cause hypertrophic cardiomyopathy is reduced total cMyBPC expression, and the impact of Myk461 on cMyBPC -deficient myocardium is currently unknown. Methods and Results We measured the impact of Myk461 on steady-state and dynamic cross-bridge ( XB ) behavior in detergent-skinned mouse wild-type myocardium and myocardium lacking cMyBPC (knockout (KO)). KO myocardium exhibited hypercontractile XB behavior as indicated by significant accelerations in rates of XB detachment (krel) and recruitment (kdf) at submaximal Ca2+ activations. Incubation of KO and wild-type myocardium with Myk461 resulted in a dose-dependent force depression, and this impact was more pronounced at low Ca2+ activations. Interestingly, Myk461-induced force depressions were less pronounced in KO myocardium, especially at low Ca2+ activations, which may be because of increased acto-myosin XB formation and potential disruption of super-relaxed XB s in KO myocardium. Additionally, Myk461 slowed krel in KO myocardium but not in wild-type myocardium, indicating increased XB " on" time. Furthermore, the greater degree of Myk461-induced slowing in kdf and reduction in XB recruitment magnitude in KO myocardium normalized the XB behavior back to wild-type levels. Conclusions This is the first study to demonstrate that Myk461-induced force depressions are modulated by cMyBPC expression levels in the sarcomere, and emphasizes that clinical use of Myk461 may need to be optimized based on the molecular trigger that underlies the hypertrophic cardiomyopathy phenotype.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
| | - Jiayang Li
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
| | - Chang Yoon Doh
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
| | - Sujeet Verma
- Department of Horticulture SciencesIFAS, Gulf Coast Research and Education CenterUniversity of FloridaWimauma
| | - Julian E. Stelzer
- Department of Physiology and BiophysicsSchool of MedicineCase Western Reserve UniversityClevelandOH
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37
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Kraft T, Montag J, Radocaj A, Brenner B. Hypertrophic Cardiomyopathy: Cell-to-Cell Imbalance in Gene Expression and Contraction Force as Trigger for Disease Phenotype Development. Circ Res 2018; 119:992-995. [PMID: 27737944 DOI: 10.1161/circresaha.116.309804] [Citation(s) in RCA: 40] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Affiliation(s)
- Theresia Kraft
- From the Institute of Molecular and Cell Physiology, Hannover Medical School, Germany.
| | - Judith Montag
- From the Institute of Molecular and Cell Physiology, Hannover Medical School, Germany
| | - Ante Radocaj
- From the Institute of Molecular and Cell Physiology, Hannover Medical School, Germany
| | - Bernhard Brenner
- From the Institute of Molecular and Cell Physiology, Hannover Medical School, Germany
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38
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Vikhorev PG, Vikhoreva NN. Cardiomyopathies and Related Changes in Contractility of Human Heart Muscle. Int J Mol Sci 2018; 19:ijms19082234. [PMID: 30065175 PMCID: PMC6121228 DOI: 10.3390/ijms19082234] [Citation(s) in RCA: 39] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2018] [Revised: 07/22/2018] [Accepted: 07/27/2018] [Indexed: 02/07/2023] Open
Abstract
About half of hypertrophic and dilated cardiomyopathies cases have been recognized as genetic diseases with mutations in sarcomeric proteins. The sarcomeric proteins are involved in cardiomyocyte contractility and its regulation, and play a structural role. Mutations in non-sarcomeric proteins may induce changes in cell signaling pathways that modify contractile response of heart muscle. These facts strongly suggest that contractile dysfunction plays a central role in initiation and progression of cardiomyopathies. In fact, abnormalities in contractile mechanics of myofibrils have been discovered. However, it has not been revealed how these mutations increase risk for cardiomyopathy and cause the disease. Much research has been done and still much is being done to understand how the mechanism works. Here, we review the facts of cardiac myofilament contractility in patients with cardiomyopathy and heart failure.
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Affiliation(s)
- Petr G Vikhorev
- National Heart and Lung Institute, Imperial College London, London W12 0NN, UK.
| | - Natalia N Vikhoreva
- Heart Science Centre, Magdi Yacoub Institute, Harefield Hospital, London UB9 6JH, UK.
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39
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Glazier AA, Hafeez N, Mellacheruvu D, Basrur V, Nesvizhskii AI, Lee LM, Shao H, Tang V, Yob JM, Gestwicki JE, Helms AS, Day SM. HSC70 is a chaperone for wild-type and mutant cardiac myosin binding protein C. JCI Insight 2018; 3:99319. [PMID: 29875314 PMCID: PMC6124431 DOI: 10.1172/jci.insight.99319] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 05/01/2018] [Indexed: 11/17/2022] Open
Abstract
Cardiac myosin binding protein C (MYBPC3) is the most commonly mutated gene associated with hypertrophic cardiomyopathy (HCM). Haploinsufficiency of full-length MYBPC3 and disruption of proteostasis have both been proposed as central to HCM disease pathogenesis. Discriminating the relative contributions of these 2 mechanisms requires fundamental knowledge of how turnover of WT and mutant MYBPC3 proteins is regulated. We expressed several disease-causing mutations in MYBPC3 in primary neonatal rat ventricular cardiomyocytes. In contrast to WT MYBPC3, mutant proteins showed reduced expression and failed to localize to the sarcomere. In an unbiased coimmunoprecipitation/mass spectrometry screen, we identified HSP70-family chaperones as interactors of both WT and mutant MYBPC3. Heat shock cognate 70 kDa (HSC70) was the most abundant chaperone interactor. Knockdown of HSC70 significantly slowed degradation of both WT and mutant MYBPC3, while pharmacologic activation of HSC70 and HSP70 accelerated degradation. HSC70 was expressed in discrete striations in the sarcomere. Expression of mutant MYBPC3 did not affect HSC70 localization, nor did it induce a protein folding stress response or ubiquitin proteasome dysfunction. Together these data suggest that WT and mutant MYBPC3 proteins are clients for HSC70, and that the HSC70 chaperone system plays a major role in regulating MYBPC3 protein turnover.
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Affiliation(s)
| | | | | | | | | | - Lap Man Lee
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Hao Shao
- Institute for Neurodegenerative Diseases, UCSF, San Francisco, California, USA
| | - Vi Tang
- Department of Molecular and Integrative Physiology
| | | | - Jason E. Gestwicki
- Institute for Neurodegenerative Diseases, UCSF, San Francisco, California, USA
| | | | - Sharlene M. Day
- Department of Molecular and Integrative Physiology
- Department of Internal Medicine
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40
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Reda SM, Chandra M. Cardiomyopathy mutation (F88L) in troponin T abolishes length dependency of myofilament Ca 2+ sensitivity. J Gen Physiol 2018; 150:809-819. [PMID: 29776992 PMCID: PMC5987878 DOI: 10.1085/jgp.201711974] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2017] [Revised: 03/09/2018] [Accepted: 04/24/2018] [Indexed: 01/14/2023] Open
Abstract
The F88L mutation in cardiac troponin T (TnTF88L) is associated with hypertrophic cardiomyopathy. Reda and Chandra reveal that it abolishes length-mediated increase in myofilament Ca2+ sensitivity and attenuates cooperative mechanisms governing length-dependent activation. Recent clinical studies have revealed a new hypertrophic cardiomyopathy–associated mutation (F87L) in the central region of human cardiac troponin T (TnT). However, despite its implication in several incidences of sudden cardiac death in young and old adults, whether F87L is associated with cardiac contractile dysfunction is unknown. Because the central region of TnT is important for modulating the muscle length–mediated recruitment of new force-bearing cross-bridges (XBs), we hypothesize that the F87L mutation causes molecular changes that are linked to the length-dependent activation of cardiac myofilaments. Length-dependent activation is important because it contributes significantly to the Frank–Starling mechanism, which enables the heart to vary stroke volume as a function of changes in venous return. We measured steady-state and dynamic contractile parameters in detergent-skinned guinea pig cardiac muscle fibers reconstituted with recombinant guinea pig wild-type TnT (TnTWT) or the guinea pig analogue (TnTF88L) of the human mutation at two different sarcomere lengths (SLs): short (1.9 µm) and long (2.3 µm). TnTF88L increases pCa50 (−log [Ca2+]free required for half-maximal activation) to a greater extent at short SL than at long SL; for example, pCa50 increases by 0.25 pCa units at short SL and 0.17 pCa units at long SL. The greater increase in pCa50 at short SL leads to the abolishment of the SL-dependent increase in myofilament Ca2+ sensitivity (ΔpCa50) in TnTF88L fibers, ΔpCa50 being 0.10 units in TnTWT fibers but only 0.02 units in TnTF88L fibers. Furthermore, at short SL, TnTF88L attenuates the negative impact of strained XBs on force-bearing XBs and augments the magnitude of muscle length–mediated recruitment of new force-bearing XBs. Our findings suggest that the TnTF88L-mediated effects on cardiac thin filaments may lead to a negative impact on the Frank–Starling mechanism.
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Affiliation(s)
- Sherif M Reda
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA
| | - Murali Chandra
- Department of Integrative Physiology and Neuroscience, Washington State University, Pullman, WA
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41
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Point mutations in the tri-helix bundle of the M-domain of cardiac myosin binding protein-C influence systolic duration and delay cardiac relaxation. J Mol Cell Cardiol 2018; 119:116-124. [PMID: 29729251 DOI: 10.1016/j.yjmcc.2018.05.001] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2017] [Revised: 04/06/2018] [Accepted: 05/01/2018] [Indexed: 11/23/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) is an essential regulatory protein required for proper systolic contraction and diastolic relaxation. We previously showed that N'-terminal domains of cMyBP-C stimulate contraction by binding to actin and activating the thin filament in vitro. In principle, thin filament activating effects of cMyBP-C could influence contraction and relaxation rates, or augment force amplitude in vivo. cMyBP-C binding to actin could also contribute to an internal load that slows muscle shortening velocity as previously hypothesized. However, the functional significance of cMyBP-C binding to actin has not yet been established in vivo. We previously identified an actin binding site in the regulatory M-domain of cMyBP-C and described two missense mutations that either increased (L348P) or decreased (E330K) binding affinity of recombinant cMyBP-C N'-terminal domains for actin in vitro. Here we created transgenic mice with either the L348P or E330K mutations to determine the functional significance of cMyBP-C binding to actin in vivo. Results showed that enhanced binding of cMyBP-C to actin in L348P-Tg mice prolonged the time to end-systole and slowed relaxation rates. Reduced interactions between cMyBP-C and actin in E330K-Tg mice had the opposite effect and significantly shortened the duration of ejection. Neither mouse model displayed overt systolic dysfunction, but L348P-Tg mice showed diastolic dysfunction presumably resulting from delayed relaxation. We conclude that cMyBP-C binding to actin contributes to sustained thin filament activation at the end of systole and during isovolumetric relaxation. These results provide the first functional evidence that cMyBP-C interactions with actin influence cardiac function in vivo.
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42
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Martin-Garrido A, Biesiadecki BJ, Salhi HE, Shaifta Y, Dos Remedios CG, Ayaz-Guner S, Cai W, Ge Y, Avkiran M, Kentish JC. Monophosphorylation of cardiac troponin-I at Ser-23/24 is sufficient to regulate cardiac myofibrillar Ca 2+ sensitivity and calpain-induced proteolysis. J Biol Chem 2018; 293:8588-8599. [PMID: 29669813 PMCID: PMC5986213 DOI: 10.1074/jbc.ra117.001292] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Revised: 04/04/2018] [Indexed: 01/03/2023] Open
Abstract
The acceleration of myocardial relaxation produced by β-adrenoreceptor stimulation is mediated in part by protein kinase A (PKA)-mediated phosphorylation of cardiac troponin-I (cTnI), which decreases myofibrillar Ca2+ sensitivity. Previous evidence suggests that phosphorylation of both Ser-23 and Ser-24 in cTnI is required for this Ca2+ desensitization. PKA-mediated phosphorylation also partially protects cTnI from proteolysis by calpain. Here we report that protein kinase D (PKD) phosphorylates only one serine of cTnI Ser-23/24. To explore the functional consequences of this monophosphorylation, we examined the Ca2+ sensitivity of force production and susceptibility of cTnI to calpain-mediated proteolysis when Ser-23/24 of cTnI in mouse cardiac myofibrils was nonphosphorylated, mono-phosphorylated, or bisphosphorylated (using sequential incubations in λ-phosphatase, PKD, and PKA, respectively). Phos-tag gels, Western blotting, and high-resolution MS revealed that PKD produced >90% monophosphorylation of cTnI, primarily at Ser-24, whereas PKA led to cTnI bisphosphorylation exclusively. PKD markedly decreased the Ca2+ sensitivity of force production in detergent-permeabilized ventricular trabeculae, whereas subsequent incubation with PKA produced only a small further fall of Ca2+ sensitivity. Unlike PKD, PKA also substantially phosphorylated myosin-binding protein-C and significantly accelerated cross-bridge kinetics (ktr). After phosphorylation by PKD or PKA, cTnI in isolated myofibrils was partially protected from calpain-mediated degradation. We conclude that cTnI monophosphorylation at Ser-23/24 decreases myofibrillar Ca2+ sensitivity and partially protects cTnI from calpain-induced proteolysis. In healthy cardiomyocytes, the basal monophosphorylation of cTnI may help tonically regulate myofibrillar Ca2+ sensitivity.
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Affiliation(s)
- Abel Martin-Garrido
- From the King's College London British Heart Foundation Centre of Excellence, School of Cardiovascular Medicine and Sciences, London SE1 7EH, United Kingdom
| | - Brandon J Biesiadecki
- the Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio 43210
| | - Hussam E Salhi
- the Department of Physiology and Cell Biology, Davis Heart and Lung Research Institute, Ohio State University, Columbus, Ohio 43210
| | - Yasin Shaifta
- From the King's College London British Heart Foundation Centre of Excellence, School of Cardiovascular Medicine and Sciences, London SE1 7EH, United Kingdom
| | - Cristobal G Dos Remedios
- the Bosch Institute, Discipline of Anatomy and Histology, University of Sydney, New South Wales 2006, Australia, and
| | | | - Wenxuan Cai
- the Departments of Cell and Regenerative Biology and.,Molecular and Cellular Pharmacology Training Program, and
| | - Ying Ge
- the Departments of Cell and Regenerative Biology and.,Human Proteomics Program, University of Wisconsin, Madison, Wisconsin 53705.,Chemistry
| | - Metin Avkiran
- From the King's College London British Heart Foundation Centre of Excellence, School of Cardiovascular Medicine and Sciences, London SE1 7EH, United Kingdom,
| | - Jonathan C Kentish
- From the King's College London British Heart Foundation Centre of Excellence, School of Cardiovascular Medicine and Sciences, London SE1 7EH, United Kingdom,
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43
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Montag J, Kowalski K, Makul M, Ernstberger P, Radocaj A, Beck J, Becker E, Tripathi S, Keyser B, Mühlfeld C, Wissel K, Pich A, van der Velden J, Dos Remedios CG, Perrot A, Francino A, Navarro-López F, Brenner B, Kraft T. Burst-Like Transcription of Mutant and Wildtype MYH7-Alleles as Possible Origin of Cell-to-Cell Contractile Imbalance in Hypertrophic Cardiomyopathy. Front Physiol 2018; 9:359. [PMID: 29686627 PMCID: PMC5900384 DOI: 10.3389/fphys.2018.00359] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/22/2018] [Indexed: 12/28/2022] Open
Abstract
Hypertrophic Cardiomyopathy (HCM) has been related to many different mutations in more than 20 different, mostly sarcomeric proteins. While development of the HCM-phenotype is thought to be triggered by the different mutations, a common mechanism remains elusive. Studying missense-mutations in the ventricular beta-myosin heavy chain (β-MyHC, MYH7) we hypothesized that significant contractile heterogeneity exists among individual cardiomyocytes of HCM-patients that results from cell-to-cell variation in relative expression of mutated vs. wildtype β-MyHC. To test this hypothesis, we measured force-calcium-relationships of cardiomyocytes isolated from myocardium of heterozygous HCM-patients with either β-MyHC-mutation Arg723Gly or Arg200Val, and from healthy controls. From the myocardial samples of the HCM-patients we also obtained cryo-sections, and laser-microdissected single cardiomyocytes for quantification of mutated vs. wildtype MYH7-mRNA using a single cell RT-qPCR and restriction digest approach. We characterized gene transcription by visualizing active transcription sites by fluorescence in situ hybridization of intronic and exonic sequences of MYH7-pre-mRNA. For both mutations, cardiomyocytes showed large cell-to-cell variation in Ca++-sensitivity. Interestingly, some cardiomyocytes were essentially indistinguishable from controls what might indicate that they had no mutant β-MyHC while others had highly reduced Ca++-sensitivity suggesting substantial fractions of mutant β-MyHC. Single-cell MYH7-mRNA-quantification in cardiomyocytes of the same patients revealed high cell-to-cell variability of mutated vs. wildtype mRNA, ranging from essentially pure mutant to essentially pure wildtype MYH7-mRNA. We found 27% of nuclei without active transcription sites which is inconsistent with continuous gene transcription but suggests burst-like transcription of MYH7. Model simulations indicated that burst-like, stochastic on/off-switching of MYH7 transcription, which is independent for mutant and wildtype alleles, could generate the observed cell-to-cell variation in the fraction of mutant vs. wildtype MYH7-mRNA, a similar variation in β-MyHC-protein, and highly heterogeneous Ca++-sensitivity of individual cardiomyocytes. In the long run, such contractile imbalance in the myocardium may well induce progressive structural distortions like cellular and myofibrillar disarray and interstitial fibrosis, as they are typically observed in HCM.
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Affiliation(s)
- Judith Montag
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Kathrin Kowalski
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Mirza Makul
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Pia Ernstberger
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Ante Radocaj
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Julia Beck
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Edgar Becker
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Snigdha Tripathi
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Britta Keyser
- Hannover Medical School, Institute of Human Genetics, Hannover, Germany
| | - Christian Mühlfeld
- Hannover Medical School, Institute of Functional and Applied Anatomy, Hannover, Germany
| | - Kirsten Wissel
- Clinic for Laryngology, Rhinology and Otology, Hannover Medical School, Hannover, Germany
| | - Andreas Pich
- Hannover Medical School, Institute of Toxicology, Hannover, Germany
| | - Jolanda van der Velden
- Department of Physiology, Institute for Cardiovascular Research, VU University, Amsterdam, Netherlands
| | | | - Andreas Perrot
- Cardiovascular Genetics, Experimental and Clinical Research Center, Charité-Universitätsmedizin Berlin, Berlin, Germany
| | - Antonio Francino
- Hospital Clinic/IDIBAPS, University of Barcelona, Barcelona, Spain
| | | | - Bernhard Brenner
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
| | - Theresia Kraft
- Hannover Medical School, Institute of Molecular and Cell Physiology, Hannover, Germany
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44
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Bollen IAE, van der Meulen M, de Goede K, Kuster DWD, Dalinghaus M, van der Velden J. Cardiomyocyte Hypocontractility and Reduced Myofibril Density in End-Stage Pediatric Cardiomyopathy. Front Physiol 2017; 8:1103. [PMID: 29312005 PMCID: PMC5743800 DOI: 10.3389/fphys.2017.01103] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2017] [Accepted: 12/13/2017] [Indexed: 12/25/2022] Open
Abstract
Dilated cardiomyopathy amongst children (pediatric cardiomyopathy, pediatric CM) is associated with a high morbidity and mortality. Because little is known about the pathophysiology of pediatric CM, treatment is largely based on adult heart failure therapy. The reason for high morbidity and mortality is largely unknown as well as data on cellular pathomechanisms is limited. Here, we assessed cardiomyocyte contractility and protein expression to define cellular pathomechanisms in pediatric CM. Explanted heart tissue of 11 pediatric CM patients and 18 controls was studied. Contractility was measured in single membrane-permeabilized cardiomyocytes and protein expression was assessed with gel electrophoresis and western blot analysis. We observed increased Ca2+-sensitivity of myofilaments which was due to hypophosphorylation of cardiac troponin I, a feature commonly observed in adult DCM. We also found a significantly reduced maximal force generating capacity of pediatric CM cardiomyocytes, as well as a reduced passive force development over a range of sarcomere lengths. Myofibril density was reduced in pediatric CM compared to controls. Correction of maximal force and passive force for myofibril density normalized forces in pediatric CM cardiomyocytes to control values. This implies that the hypocontractility was caused by the reduction in myofibril density. Unlike in adult DCM we did not find an increase in compliant titin isoform expression in end-stage pediatric CM. The limited ability of pediatric CM patients to maintain myofibril density might have contributed to their early disease onset and severity.
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Affiliation(s)
- Ilse A E Bollen
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, Netherlands
| | - Marijke van der Meulen
- Department of Pediatric Cardiology, Erasmus Medical Center, Erasmus University Rotterdam, Rotterdam, Netherlands
| | - Kyra de Goede
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, Netherlands
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, Netherlands
| | - Michiel Dalinghaus
- Department of Pediatric Cardiology, Erasmus Medical Center, Erasmus University Rotterdam, Rotterdam, Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, Netherlands.,Netherlands Heart Institute, Utrecht, Netherlands
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45
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Soetkamp D, Raedschelders K, Mastali M, Sobhani K, Bairey Merz CN, Van Eyk J. The continuing evolution of cardiac troponin I biomarker analysis: from protein to proteoform. Expert Rev Proteomics 2017; 14:973-986. [PMID: 28984473 DOI: 10.1080/14789450.2017.1387054] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
INTRODUCTION The troponin complex consists of three proteins that fundamentally couple excitation with contraction. Circulating cardiac-specific Troponin I (cTnI) serves as diagnostic biomarker tools for risk stratification of acute coronary syndromes and acute myocardial infarction (MI). Within the heart, cTnI oscillates between inactive and active conformations to either block or disinhibit actinomyosin formation. This molecular mechanism is fine-tuned through extensive protein modifications whose profiles are maladaptively altered with co-morbidities including hypertrophic cardiomyopathy, diabetes, and heart failure. Technological advances in analytical platforms over the last decade enable routine baseline cTnI analysis in patients without cardiovascular complications, and hold potential to expand cTnI readouts that include modified cTnI proteoforms. Areas covered: This review covers the current state, advances, and prospects of analytical platforms that now enable routine baseline cTnI analysis in patients. In parallel, improved mass spectrometry instrumentation and workflows already reveal an array of modified cTnI proteoforms with promising diagnostic implications. Expert commentary: New analytical capabilities provide clinicians and researchers with an opportunity to address important questions surrounding circulating cTnI in the improved diagnosis of specific patient cohorts. These techniques also hold considerable promise for new predictive and prescriptive applications for individualized profiling and improve patient care.
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Affiliation(s)
- Daniel Soetkamp
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Koen Raedschelders
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Mitra Mastali
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Kimia Sobhani
- b Pathology and Laboratory Medicine , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - C Noel Bairey Merz
- c Women's Heart Center , Cedars-Sinai Medical Center , Los Angeles , CA , USA
| | - Jennifer Van Eyk
- a Heart Institute , Cedars-Sinai Medical Center , Los Angeles , CA , USA
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46
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Bollen IAE, Ehler E, Fleischanderl K, Bouwman F, Kempers L, Ricke-Hoch M, Hilfiker-Kleiner D, Dos Remedios CG, Krüger M, Vink A, Asselbergs FW, van Spaendonck-Zwarts KY, Pinto YM, Kuster DWD, van der Velden J. Myofilament Remodeling and Function Is More Impaired in Peripartum Cardiomyopathy Compared with Dilated Cardiomyopathy and Ischemic Heart Disease. THE AMERICAN JOURNAL OF PATHOLOGY 2017; 187:2645-2658. [PMID: 28935576 DOI: 10.1016/j.ajpath.2017.08.022] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 08/21/2017] [Accepted: 08/24/2017] [Indexed: 01/09/2023]
Abstract
Peripartum cardiomyopathy (PPCM) and dilated cardiomyopathy (DCM) show similarities in clinical presentation. However, although DCM patients do not recover and slowly deteriorate further, PPCM patients show either a fast cardiac deterioration or complete recovery. The aim of this study was to assess if underlying cellular changes can explain the clinical similarities and differences in the two diseases. We, therefore, assessed sarcomeric protein expression, modification, titin isoform shift, and contractile behavior of cardiomyocytes in heart tissue of PPCM and DCM patients and compared these with nonfailing controls. Heart samples from ischemic heart disease (ISHD) patients served as heart failure control samples. Passive force was only increased in PPCM samples compared with controls, whereas PPCM, DCM, and ISHD samples all showed increased myofilament Ca2+ sensitivity. Length-dependent activation was significantly impaired in PPCM compared with controls, no impairment was observed in ISHD samples, and DCM samples showed an intermediate response. Contractile impairments were caused by impaired protein kinase A (PKA)-mediated phosphorylation because exogenous PKA restored all parameters to control levels. Although DCM samples showed reexpression of EH-myomesin, an isoform usually only expressed in the heart before birth, PPCM and ISHD did not. The lack of EH-myomesin, combined with low PKA-mediated phosphorylation of myofilament proteins and increased compliant titin isoform, may explain the increase in passive force and blunted length-dependent activation of myofilaments in PPCM samples.
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Affiliation(s)
- Ilse A E Bollen
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands.
| | - Elisabeth Ehler
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Karin Fleischanderl
- Randall Division of Cell and Molecular Biophysics and Cardiovascular Division, British Heart Foundation Centre of Research Excellence, King's College London, London, United Kingdom
| | - Floor Bouwman
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Lanette Kempers
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands
| | - Melanie Ricke-Hoch
- Department of Cardiology and Angiology, Hannover Medical School, Hannover, Germany
| | | | - Cristobal G Dos Remedios
- Bosch Institute, Discipline of Anatomy and Histology, University of Sydney, Sydney, New South Wales, Australia
| | - Martina Krüger
- Institute of Cardiovascular Physiology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
| | - Aryan Vink
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Folkert W Asselbergs
- Division Heart and Lungs, Department of Cardiology, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands; Durrer Center for Cardiogenetic Research, Netherlands Heart Institute, Utrecht, the Netherlands; Institute of Cardiovascular Science, Faculty of Population Health Sciences, University College London, London, United Kingdom
| | - Karin Y van Spaendonck-Zwarts
- Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands; Department of Clinical Genetics, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, the Netherlands
| | - Yigal M Pinto
- Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands; Amsterdam Medical Center Heart Center, Department of Clinical and Experimental Cardiology, Academic Medical Center Amsterdam, University of Amsterdam, Amsterdam, the Netherlands
| | - Diederik W D Kuster
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, VU University Medical Center, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands; Netherlands Heart Institute, Utrecht, the Netherlands
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47
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Gollapudi SK, Reda SM, Chandra M. Omecamtiv Mecarbil Abolishes Length-Mediated Increase in Guinea Pig Cardiac Myofiber Ca 2+ Sensitivity. Biophys J 2017; 113:880-888. [PMID: 28834724 DOI: 10.1016/j.bpj.2017.07.002] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2017] [Revised: 06/19/2017] [Accepted: 07/05/2017] [Indexed: 01/14/2023] Open
Abstract
Omecamtiv mecarbil (OM) is a pharmacological agent that augments cardiac contractile function by enhancing myofilament Ca2+ sensitivity. Given that interventions that increase myofilament Ca2+ sensitivity have the potential to alter length-dependent activation (LDA) of cardiac myofilaments, we tested the influence of OM on this fundamental property of the heart. This is significant not only because LDA is prominent in cardiac muscle but also because it contributes to the Frank-Starling law, a mechanism by which the heart increases stroke volume in response to an increase in venous return. We measured steady-state and dynamic contractile indices in detergent-skinned guinea pig (Cavia porcellus) cardiac muscle fibers in the absence and presence of 0.3 and 3.0 μM OM at two different sarcomere lengths (SLs), short SL (1.9 μm) and long SL (2.3 μm). Myofilament Ca2+ sensitivity, as measured by pCa50 (-log of [Ca2+]free concentration required for half-maximal activation), increased significantly at both short and long SLs in OM-treated fibers when compared to untreated fibers; however, the magnitude of increase in pCa50 was twofold greater at short SL than at long SL. A consequence of this greater increase in pCa50 at short SL was that pCa50 did not increase any further at long SL, suggesting that OM abolished the SL dependency of pCa50. Furthermore, the SL dependency of rate constants of cross-bridge distortion dynamics (c) and force redevelopment (ktr) was abolished in 0.3-μM-OM-treated fibers. The negative impact of OM on the SL dependency of pCa50, c, and ktr was also observed in 3.0-μM-OM-treated fibers, indicating that cooperative mechanisms linked to LDA were altered by the OM-mediated effects on cardiac myofilaments.
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Affiliation(s)
- Sampath K Gollapudi
- Department of Integrative Physiology and Neuroscience (IPN), Washington State University, Pullman, Washington
| | - Sherif M Reda
- Department of Integrative Physiology and Neuroscience (IPN), Washington State University, Pullman, Washington
| | - Murali Chandra
- Department of Integrative Physiology and Neuroscience (IPN), Washington State University, Pullman, Washington.
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48
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Stücker S, Kresin N, Carrier L, Friedrich FW. Nebivolol Desensitizes Myofilaments of a Hypertrophic Cardiomyopathy Mouse Model. Front Physiol 2017; 8:558. [PMID: 28824454 PMCID: PMC5539082 DOI: 10.3389/fphys.2017.00558] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2017] [Accepted: 07/17/2017] [Indexed: 01/19/2023] Open
Abstract
Background: Hypertrophic cardiomyopathy (HCM) patients often present with diastolic dysfunction and a normal to supranormal systolic function. To counteract this hypercontractility, guideline therapies advocate treatment with beta-adrenoceptor and Ca2+ channel blockers. One well established pathomechanism for the hypercontractile phenotype frequently observed in HCM patients and several HCM mouse models is an increased myofilament Ca2+ sensitivity. Nebivolol, a commonly used beta-adrenoceptor antagonist, has been reported to lower maximal force development and myofilament Ca2+ sensitivity in rabbit and human heart tissues. The aim of this study was to evaluate the effect of nebivolol in cardiac muscle strips of an established HCM Mybpc3 mouse model. Furthermore, we investigated actions of nebivolol and epigallocatechin-gallate, which has been shown to desensitize myofilaments for Ca2+ in mouse and human HCM models, in cardiac strips of HCM patients with a mutation in the most frequently mutated HCM gene MYBPC3. Methods and Results: Nebivolol effects were tested on contractile parameters and force-Ca2+ relationship of skinned ventricular muscle strips isolated from Mybpc3-targeted knock-in (KI), wild-type (WT) mice and cardiac strips of three HCM patients with MYBPC3 mutations. At baseline, KI strips showed no difference in maximal force development compared to WT mouse heart strips. Neither 1 nor 10 μM nebivolol had an effect on maximal force development in both genotypes. 10 μM nebivolol induced myofilament Ca2+ desensitization in WT strips and to a greater extent in KI strips. Neither 1 nor 10 μM nebivolol had an effect on Ca2+ sensitivity in cardiac muscle strips of three HCM patients with MYBPC3 mutations, whereas epigallocatechin-gallate induced a right shift in the force-Ca2+ curve. Conclusion: Nebivolol induced a myofilament Ca2+ desensitization in both WT and KI strips, which was more pronounced in KI muscle strips. In human cardiac muscle strips of three HCM patients nebivolol had no effect on myofilament Ca2+ sensitivity.
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Affiliation(s)
- Sabrina Stücker
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-EppendorfHamburg, Germany.,German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
| | - Nico Kresin
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-EppendorfHamburg, Germany.,German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
| | - Lucie Carrier
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-EppendorfHamburg, Germany.,German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
| | - Felix W Friedrich
- Department of Experimental Pharmacology and Toxicology, Cardiovascular Research Center, University Medical Center Hamburg-EppendorfHamburg, Germany.,German Centre for Cardiovascular Research (DZHK)Hamburg, Germany
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49
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Bollen IAE, Schuldt M, Harakalova M, Vink A, Asselbergs FW, Pinto JR, Krüger M, Kuster DWD, van der Velden J. Genotype-specific pathogenic effects in human dilated cardiomyopathy. J Physiol 2017; 595:4677-4693. [PMID: 28436080 PMCID: PMC5509872 DOI: 10.1113/jp274145] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Accepted: 04/18/2017] [Indexed: 01/09/2023] Open
Abstract
KEY POINTS Mutations in genes encoding cardiac troponin I (TNNI3) and cardiac troponin T (TNNT2) caused altered troponin protein stoichiometry in patients with dilated cardiomyopathy. TNNI3p.98trunc resulted in haploinsufficiency, increased Ca2+ -sensitivity and reduced length-dependent activation. TNNT2p.K217del caused increased passive tension. A mutation in the gene encoding Lamin A/C (LMNAp.R331Q ) led to reduced maximal force development through secondary disease remodelling in patients suffering from dilated cardiomyopathy. Our study shows that different gene mutations induce dilated cardiomyopathy via diverse cellular pathways. ABSTRACT Dilated cardiomyopathy (DCM) can be caused by mutations in sarcomeric and non-sarcomeric genes. In this study we defined the pathogenic effects of three DCM-causing mutations: the sarcomeric mutations in genes encoding cardiac troponin I (TNNI3p.98truncation ) and cardiac troponin T (TNNT2p.K217deletion ; also known as the p.K210del) and the non-sarcomeric gene mutation encoding lamin A/C (LMNAp.R331Q ). We assessed sarcomeric protein expression and phosphorylation and contractile behaviour in single membrane-permeabilized cardiomyocytes in human left ventricular heart tissue. Exchange with recombinant troponin complex was used to establish the direct pathogenic effects of the mutations in TNNI3 and TNNT2. The TNNI3p.98trunc and TNNT2p.K217del mutation showed reduced expression of troponin I to 39% and 51%, troponin T to 64% and 53%, and troponin C to 73% and 97% of controls, respectively, and altered stoichiometry between the three cardiac troponin subunits. The TNNI3p.98trunc showed pure haploinsufficiency, increased Ca2+ -sensitivity and impaired length-dependent activation. The TNNT2p.K217del mutation showed a significant increase in passive tension that was not due to changes in titin isoform composition or phosphorylation. Exchange with wild-type troponin complex corrected troponin protein levels to 83% of controls in the TNNI3p.98trunc sample. Moreover, upon exchange all functional deficits in the TNNI3p.98trunc and TNNT2p.K217del samples were normalized to control values confirming the pathogenic effects of the troponin mutations. The LMNAp.R331Q mutation resulted in reduced maximal force development due to disease remodelling. Our study shows that different gene mutations induce DCM via diverse cellular pathways.
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Affiliation(s)
- Ilse A E Bollen
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands
| | - Maike Schuldt
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands
| | - Magdalena Harakalova
- Department of Cardiology, Division of Heart and Lungs, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Aryan Vink
- Department of Pathology, University Medical Center Utrecht, Utrecht, the Netherlands
| | - Folkert W Asselbergs
- Department of Cardiology, Division of Heart and Lungs, University of Utrecht, University Medical Center Utrecht, Utrecht, the Netherlands.,Durrer Center for Cardiogenetic Research, ICIN-Netherlands Heart Institute, Utrecht, the Netherlands.,Institute of Cardiovascular Science, Faculty of Population Health Sciences, University College London, London, UK
| | - Jose R Pinto
- Department of Biomedical Sciences, College of Medicine, Florida State University, Tallahassee, FL, USA
| | - Martina Krüger
- Institute of Cardiovascular Physiology, Heinrich Heine University Düsseldorf, Düsseldorf, Germany
| | - Diederik W D Kuster
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands
| | - Jolanda van der Velden
- Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands.,Netherlands Heart Institute, Utrecht, the Netherlands
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50
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FRET biosensor uncovers cAMP nano-domains at β-adrenergic targets that dictate precise tuning of cardiac contractility. Nat Commun 2017; 8:15031. [PMID: 28425435 PMCID: PMC5411486 DOI: 10.1038/ncomms15031] [Citation(s) in RCA: 146] [Impact Index Per Article: 20.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 02/21/2017] [Indexed: 12/18/2022] Open
Abstract
Compartmentalized cAMP/PKA signalling is now recognized as important for physiology and pathophysiology, yet a detailed understanding of the properties, regulation and function of local cAMP/PKA signals is lacking. Here we present a fluorescence resonance energy transfer (FRET)-based sensor, CUTie, which detects compartmentalized cAMP with unprecedented accuracy. CUTie, targeted to specific multiprotein complexes at discrete plasmalemmal, sarcoplasmic reticular and myofilament sites, reveals differential kinetics and amplitudes of localized cAMP signals. This nanoscopic heterogeneity of cAMP signals is necessary to optimize cardiac contractility upon adrenergic activation. At low adrenergic levels, and those mimicking heart failure, differential local cAMP responses are exacerbated, with near abolition of cAMP signalling at certain locations. This work provides tools and fundamental mechanistic insights into subcellular adrenergic signalling in normal and pathological cardiac function.
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