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Herron TJ, Devaney E, Guerrero-Serna G, Mundada L, Metzger JM. Gene transfer of human cardiomyopathy β-MyHC mutant R403Q directly alters intact cardiac myocyte calcium homeostasis and causes hyper-contractility. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.31.605903. [PMID: 39211095 PMCID: PMC11361141 DOI: 10.1101/2024.07.31.605903] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/04/2024]
Abstract
The R403Q mutation of human cardiac β-myosin heavy chain was the first missense mutation of a sarcomeric protein identified as being causal for hypertrophic cardiomyopathy (HCM), in humans. The direct effect of the R403Q mutant myosin on intracellular calcium homeostasis and contractility is not fully known. Here we have used in vitro gene transfer of the R403Q mutant human β-myosin to study its direct effects on single intact adult cardiac myocyte contractility and calcium homeostasis. In the first experiments, adult cardiac myocytes transduced with the R403Q mutant myosin recombinant viral vectors were compared to myocytes transduced with wild-type human β-myosin (wtMYH7). Efficiency of gene transfer was high in both groups (>98%) and the degree of stoichiometric myofilament incorporation of either the mutant or normal myosin was comparable at ∼40% in quiescent myocytes in primary culture. Sarcomere structure and cellular morphology were unaffected by R403Q myosin expression and myofilament incorporation. Functionally, in electrically paced cardiac myocytes, the R403Q mutant myosin caused a significant increase in intracellular calcium concentration and myocyte hyper-contractility. At the sub-cellular myofilament level, the mutant myosin increased the calcium sensitivity of steady state isometric tension development and increased isometric cross-bridge cycling kinetics. R403Q myocytes became arrhythmic after β-adrenergic stimulation with spontaneous calcium transients and contractions in between electrical stimuli. These results indicate that human R403Q mutant myosin directly alters myofilament function and intracellular calcium cycling. Elevated calcium levels may provide a trigger for the ensuing hypertrophy and susceptibility to arrhythmia that are characteristic of HCM.
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2
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Bedada FB, Thompson BR, Mikkila JL, Chan SSK, Choi SH, Toso EA, Kyba M, Metzger JM. Inducing positive inotropy in human iPSC-derived cardiac muscle by gene editing-based activation of the cardiac α-myosin heavy chain. Sci Rep 2024; 14:3915. [PMID: 38365813 PMCID: PMC10873390 DOI: 10.1038/s41598-024-53395-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Accepted: 01/31/2024] [Indexed: 02/18/2024] Open
Abstract
Human induced pluripotent stem cells and their differentiation into cardiac myocytes (hiPSC-CMs) provides a unique and valuable platform for studies of cardiac muscle structure-function. This includes studies centered on disease etiology, drug development, and for potential clinical applications in heart regeneration/repair. Ultimately, for these applications to achieve success, a thorough assessment and physiological advancement of the structure and function of hiPSC-CMs is required. HiPSC-CMs are well noted for their immature and sub-physiological cardiac muscle state, and this represents a major hurdle for the field. To address this roadblock, we have developed a hiPSC-CMs (β-MHC dominant) experimental platform focused on directed physiological enhancement of the sarcomere, the functional unit of cardiac muscle. We focus here on the myosin heavy chain (MyHC) protein isoform profile, the molecular motor of the heart, which is essential to cardiac physiological performance. We hypothesized that inducing increased expression of α-MyHC in β-MyHC dominant hiPSC-CMs would enhance contractile performance of hiPSC-CMs. To test this hypothesis, we used gene editing with an inducible α-MyHC expression cassette into isogeneic hiPSC-CMs, and separately by gene transfer, and then investigated the direct effects of increased α-MyHC expression on hiPSC-CMs contractility and relaxation function. Data show improved cardiac functional parameters in hiPSC-CMs induced with α-MyHC. Positive inotropy and relaxation was evident in comparison to β-MyHC dominant isogenic controls both at baseline and during pacing induced stress. This approach should facilitate studies of hiPSC-CMs disease modeling and drug screening, as well as advancing fundamental aspects of cardiac function parameters for the optimization of future cardiac regeneration, repair and re-muscularization applications.
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Affiliation(s)
- Fikru B Bedada
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
- Present Address: Department of Clinical Laboratory Sciences, College of Nursing and Allied Health Sciences, Howard University, Washington, DC, USA
| | - Brian R Thompson
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Jennifer L Mikkila
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Sunny S-K Chan
- Lillehei Heart Institute, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Si Ho Choi
- Lillehei Heart Institute, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Erik A Toso
- Lillehei Heart Institute, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Michael Kyba
- Lillehei Heart Institute, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA
| | - Joseph M Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
- Lillehei Heart Institute, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN, 55455, USA.
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3
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Osten F, Weber N, Wendland M, Holler T, Piep B, Kröhn S, Teske J, Bodenschatz AK, Devadas SB, Menge KS, Chatterjee S, Schwanke K, Kosanke M, Montag J, Thum T, Zweigerdt R, Kraft T, Iorga B, Meissner JD. Myosin expression and contractile function are altered by replating stem cell-derived cardiomyocytes. J Gen Physiol 2023; 155:e202313377. [PMID: 37656049 PMCID: PMC10473967 DOI: 10.1085/jgp.202313377] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2023] [Revised: 06/16/2023] [Accepted: 07/19/2023] [Indexed: 09/02/2023] Open
Abstract
Myosin heavy chain (MyHC) is the main determinant of contractile function. Human ventricular cardiomyocytes (CMs) predominantly express the β-isoform. We previously demonstrated that ∼80% of human embryonic stem cell-derived cardiomyocytes (hESC-CMs) express exclusively β-MyHC after long-term culture on laminin-coated glass coverslips. Here, we investigated the impact of enzymatically detaching hESC-CMs after long-term culture and subsequently replating them for characterization of cellular function. We observed that force-related kinetic parameters, as measured in a micromechanical setup, resembled α- rather than β-MyHC-expressing myofibrils, as well as changes in calcium transients. Single-cell immunofluorescence analysis revealed that replating hESC-CMs led to rapid upregulation of α-MyHC, as indicated by increases in exclusively α-MyHC- and in mixed α/β-MyHC-expressing hESC-CMs. A comparable increase in heterogeneity of MyHC isoform expression was also found among individual human induced pluripotent stem cell (hiPSC)-derived CMs after replating. Changes in MyHC isoform expression and cardiomyocyte function induced by replating were reversible in the course of the second week after replating. Gene enrichment analysis based on RNA-sequencing data revealed changes in the expression profile of mechanosensation/-transduction-related genes and pathways, especially integrin-associated signaling. Accordingly, the integrin downstream mediator focal adhesion kinase (FAK) promoted β-MyHC expression on a stiff matrix, further validating gene enrichment analysis. To conclude, detachment and replating induced substantial changes in gene expression, MyHC isoform composition, and function of long-term cultivated human stem cell-derived CMs, thus inducing alterations in mechanosensation/-transduction, that need to be considered, particularly for downstream in vitro assays.
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Affiliation(s)
- Felix Osten
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Natalie Weber
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany
| | - Meike Wendland
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Tim Holler
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Birgit Piep
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Simon Kröhn
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Jana Teske
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
| | - Alea K. Bodenschatz
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Santoshi Biswanath Devadas
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
| | - Kaja S. Menge
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany
| | - Shambhabi Chatterjee
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany
| | - Kristin Schwanke
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
| | - Maike Kosanke
- Research Core Unit Genomics, Hannover Medical School, Hannover, Germany
| | - Judith Montag
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Thomas Thum
- Institute of Molecular and Translational Therapeutic Strategies (IMTTS), Hannover Medical School, Hannover, Germany
- REBIRTH Center for Translational Regenerative Therapies, Hannover Medical School, Hannover, Germany
- Fraunhofer Institute for Toxicology and Experimental Medicine, Hannover, Germany
| | - Robert Zweigerdt
- Department of Cardiothoracic, Transplantation and Vascular Surgery, Leibniz Research Laboratories for Biotechnology and Artificial Organs (LEBAO), Hannover Medical School, Hannover, Germany
| | - Theresia Kraft
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
| | - Bogdan Iorga
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
- Department of Analytical Chemistry and Physical Chemistry, Faculty of Chemistry, University of Bucharest, Bucharest, Romania
| | - Joachim D. Meissner
- Institute of Molecular and Cell Physiology, Hannover Medical School, Hannover, Germany
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4
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Wiggs MP, Beaudry AG, Law ML. Cardiac Remodeling in Cancer-Induced Cachexia: Functional, Structural, and Metabolic Contributors. Cells 2022; 11:cells11121931. [PMID: 35741060 PMCID: PMC9221803 DOI: 10.3390/cells11121931] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Revised: 06/01/2022] [Accepted: 06/08/2022] [Indexed: 11/17/2022] Open
Abstract
Cancer cachexia is a syndrome of progressive weight loss and muscle wasting occurring in many advanced cancer patients. Cachexia significantly impairs quality of life and increases mortality. Cardiac atrophy and dysfunction have been observed in patients with cachexia, which may contribute to cachexia pathophysiology. However, relative to skeletal muscle, little research has been carried out to understand the mechanisms of cardiomyopathy in cachexia. Here, we review what is known clinically about the cardiac changes occurring in cachexia, followed by further discussion of underlying physiological and molecular mechanisms contributing to cachexia-induced cardiomyopathy. Impaired cardiac contractility and relaxation may be explained by a complex interplay of significant heart muscle atrophy and metabolic remodeling, including mitochondrial dysfunction. Because cardiac muscle has fundamental differences compared to skeletal muscle, understanding cardiac-specific effects of cachexia may bring light to unique therapeutic targets and ultimately improve clinical management for patients with cancer cachexia.
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Affiliation(s)
- Michael P. Wiggs
- Department of Health, Human Performance, and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, TX 76706, USA; (M.P.W.); (A.G.B.)
| | - Anna G. Beaudry
- Department of Health, Human Performance, and Recreation, Robbins College of Health and Human Sciences, Baylor University, Waco, TX 76706, USA; (M.P.W.); (A.G.B.)
| | - Michelle L. Law
- Department of Human Sciences and Design, Robbins College of Health and Human Sciences, Baylor University, Waco, TX 76706, USA
- Correspondence: ; Tel.: +1-(254)-710-6003
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5
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Cardiac myocyte intrinsic contractility and calcium handling deficits underlie heart organ dysfunction in murine cancer cachexia. Sci Rep 2021; 11:23627. [PMID: 34880268 PMCID: PMC8655071 DOI: 10.1038/s41598-021-02688-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2021] [Accepted: 11/02/2021] [Indexed: 12/11/2022] Open
Abstract
Cachexia is a muscle wasting syndrome occurring in many advanced cancer patients. Cachexia significantly increases cancer morbidity and mortality. Cardiac atrophy and contractility deficits have been observed in patients and in animal models with cancer cachexia, which may contribute to cachexia pathophysiology. However, underlying contributors to decreased in vivo cardiac contractility are not well understood. In this study, we sought to distinguish heart-intrinsic changes from systemic factors contributing to cachexia-associated cardiac dysfunction. We hypothesized that isolated heart and cardiac myocyte functional deficits underlie in vivo contractile dysfunction. To test this hypothesis, isolated heart and cardiac myocyte function was measured in the colon-26 adenocarcinoma murine model of cachexia. Ex vivo perfused hearts from cachectic animals exhibited marked contraction and relaxation deficits during basal and pacing conditions. Isolated myocytes displayed significantly decreased peak contraction and relaxation rates, which was accompanied by decreased peak calcium and decay rates. This study uncovers significant organ and cellular-level functional deficits in cachectic hearts outside of the catabolic in vivo environment, which is explained in part by impaired calcium cycling. These data provide insight into physiological mechanisms of cardiomyopathy in cachexia, which is critical for the ultimate development of effective treatments for patients.
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6
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Davis J, Chouman A, Creech J, Monteiro da Rocha A, Ponce-Balbuena D, Jimenez Vazquez EN, Nichols R, Lozhkin A, Madamanchi NR, Campbell KF, Herron TJ. In vitro model of ischemic heart failure using human induced pluripotent stem cell-derived cardiomyocytes. JCI Insight 2021; 6:134368. [PMID: 33878037 PMCID: PMC8262347 DOI: 10.1172/jci.insight.134368] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2019] [Accepted: 04/15/2021] [Indexed: 11/17/2022] Open
Abstract
Human induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) have been used extensively to model inherited heart diseases, but hiPSC-CM models of ischemic heart disease are lacking. Here, our objective was to generate an hiPSC-CM model of ischemic heart disease. To this end, hiPSCs were differentiated into functional hiPSC-CMs and then purified using either a simulated ischemia media or by using magnetic antibody-based purification targeting the nonmyocyte population for depletion from the cell population. Flow cytometry analysis confirmed that each purification approach generated hiPSC-CM cultures that had more than 94% cTnT+ cells. After purification, hiPSC-CMs were replated as confluent syncytial monolayers for electrophysiological phenotype analysis and protein expression by Western blotting. The phenotype of metabolic stress-selected hiPSC-CM monolayers recapitulated many of the functional and structural hallmarks of ischemic CMs, including elevated diastolic calcium, diminished calcium transient amplitude, prolonged action potential duration, depolarized resting membrane potential, hypersensitivity to chemotherapy-induced cardiotoxicity, depolarized mitochondrial membrane potential, depressed SERCA2a expression, reduced maximal oxygen consumption rate, and abnormal response to β1-adrenergic receptor stimulation. These findings indicate that metabolic selection of hiPSC-CMs generated cell populations with phenotype similar to what is well known to occur in the setting of ischemic heart failure and thus provide a opportunity for study of human ischemic heart disease.
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Affiliation(s)
- Justin Davis
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine
| | - Ahmad Chouman
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine
| | - Jeffery Creech
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine
| | - Andre Monteiro da Rocha
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine.,Center for Arrhythmia Research.,Department of Internal Medicine, Division of Cardiovascular Medicine
| | | | | | | | - Andrey Lozhkin
- Department of Internal Medicine, Division of Cardiovascular Medicine
| | | | - Katherine F Campbell
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine.,Center for Arrhythmia Research
| | - Todd J Herron
- Frankel Cardiovascular Regeneration Core Laboratory, Department of Internal Medicine, Division of Cardiovascular Medicine.,Center for Arrhythmia Research.,Department of Internal Medicine, Division of Cardiovascular Medicine.,Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, Michigan, USA
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7
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Scholman KT, Meijborg VMF, Gálvez-Montón C, Lodder EM, Boukens BJ. From Genome-Wide Association Studies to Cardiac Electrophysiology: Through the Maze of Biological Complexity. Front Physiol 2020; 11:557. [PMID: 32536879 PMCID: PMC7267057 DOI: 10.3389/fphys.2020.00557] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/04/2020] [Indexed: 12/19/2022] Open
Abstract
Genome Wide Association Studies (GWAS) have provided an enormous amount of data on genomic loci associated with cardiac electrophysiology and arrhythmias. Clinical relevance, however, remains unclear since GWAS do not provide a mechanistic explanation for this association. Determining the electrophysiological relevance of variants for arrhythmias would aid development of risk stratification models for patients with arrhythmias. In this review, we give an overview of genetic variants related to ECG intervals and arrhythmogenic pathologies and discuss how these variants may influence cardiac electrophysiology and the occurrence of arrhythmias.
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Affiliation(s)
- Koen T Scholman
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Veronique M F Meijborg
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Netherlands Heart Institute, Utrecht, Netherlands
| | - Carolina Gálvez-Montón
- ICREC Research Program, Germans Trias i Pujol Health Science Research Institute, Badalona, Spain.,CIBERCV, Instituto de Salud Carlos III, Madrid, Spain
| | - Elisabeth M Lodder
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
| | - Bastiaan J Boukens
- Department of Medical Biology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands.,Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, Netherlands
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8
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Biobank-driven genomic discovery yields new insight into atrial fibrillation biology. Nat Genet 2018; 50:1234-1239. [PMID: 30061737 DOI: 10.1038/s41588-018-0171-3] [Citation(s) in RCA: 489] [Impact Index Per Article: 81.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2018] [Accepted: 06/01/2018] [Indexed: 02/07/2023]
Abstract
To identify genetic variation underlying atrial fibrillation, the most common cardiac arrhythmia, we performed a genome-wide association study of >1,000,000 people, including 60,620 atrial fibrillation cases and 970,216 controls. We identified 142 independent risk variants at 111 loci and prioritized 151 functional candidate genes likely to be involved in atrial fibrillation. Many of the identified risk variants fall near genes where more deleterious mutations have been reported to cause serious heart defects in humans (GATA4, MYH6, NKX2-5, PITX2, TBX5)1, or near genes important for striated muscle function and integrity (for example, CFL2, MYH7, PKP2, RBM20, SGCG, SSPN). Pathway and functional enrichment analyses also suggested that many of the putative atrial fibrillation genes act via cardiac structural remodeling, potentially in the form of an 'atrial cardiomyopathy'2, either during fetal heart development or as a response to stress in the adult heart.
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9
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Hashem SI, Murphy AN, Divakaruni AS, Klos ML, Nelson BC, Gault EC, Rowland TJ, Perry CN, Gu Y, Dalton ND, Bradford WH, Devaney EJ, Peterson KL, Jones KL, Taylor MR, Chen J, Chi NC, Adler ED. Impaired mitophagy facilitates mitochondrial damage in Danon disease. J Mol Cell Cardiol 2017; 108:86-94. [DOI: 10.1016/j.yjmcc.2017.05.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/19/2017] [Revised: 05/14/2017] [Accepted: 05/15/2017] [Indexed: 12/27/2022]
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10
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Bedada FB, Martindale JJ, Arden E, Metzger JM. Molecular inotropy mediated by cardiac miR-based PDE4D/PRKAR1α/phosphoprotein signaling. Sci Rep 2016; 6:36803. [PMID: 27833092 PMCID: PMC5105063 DOI: 10.1038/srep36803] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2016] [Accepted: 10/21/2016] [Indexed: 01/05/2023] Open
Abstract
Molecular inotropy refers to cardiac contractility that can be modified to affect overall heart pump performance. Here we show evidence of a new molecular pathway for positive inotropy by a cardiac-restricted microRNA (miR). We report enhanced cardiac myocyte performance by acute titration of cardiac myosin-embedded miR-208a. The observed positive effect was independent of host gene myosin effects with evidence of negative regulation of cAMP-specific 3',5'-cyclic phosphodiesterase 4D (PDE4D) and the regulatory subunit of PKA (PRKAR1α) content culminating in PKA-site dependent phosphorylation of cardiac troponin I (cTnI) and phospholamban (PLN). Further, acute inhibition of miR-208a in adult myocytes in vitro increased PDE4D expression causing reduced isoproterenol-mediated phosphorylation of cTnI and PLN. Next, rAAV-mediated miR-208a gene delivery enhanced heart contractility and relaxation parameters in vivo. Finally, acute inducible increases in cardiac miR-208a in vivo reduced PDE4D and PRKAR1α, with evidence of increased content of several complementary miRs harboring the PDE4D recognition sequence. Physiologically, this resulted in significant cardiac cTnI and PLN phosphorylation and improved heart performance in vivo. As phosphorylation of cTnI and PLN is critical to myocyte function, titration of miR-208a represents a potential new mechanism to enhance myocardial performance via the PDE4D/PRKAR1α/PKA phosphoprotein signaling pathway.
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Affiliation(s)
- Fikru B. Bedada
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455 USA
| | - Joshua J. Martindale
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455 USA
| | - Erik Arden
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455 USA
| | - Joseph M. Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, 6-125 Jackson Hall, 321 Church Street SE, Minneapolis, MN 55455 USA
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11
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Monteiro da Rocha A, Guerrero-Serna G, Helms A, Luzod C, Mironov S, Russell M, Jalife J, Day SM, Smith GD, Herron TJ. Deficient cMyBP-C protein expression during cardiomyocyte differentiation underlies human hypertrophic cardiomyopathy cellular phenotypes in disease specific human ES cell derived cardiomyocytes. J Mol Cell Cardiol 2016; 99:197-206. [PMID: 27620334 PMCID: PMC5609478 DOI: 10.1016/j.yjmcc.2016.09.004] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2016] [Revised: 08/18/2016] [Accepted: 09/08/2016] [Indexed: 02/07/2023]
Abstract
AIMS Mutations of cardiac sarcomere genes have been identified to cause HCM, but the molecular mechanisms that lead to cardiomyocyte hypertrophy and risk for sudden death are uncertain. The aim of this study was to examine HCM disease mechanisms at play during cardiac differentiation of human HCM specific pluripotent stem cells. METHODS AND RESULTS We generated a human embryonic stem cell (hESC) line carrying a naturally occurring mutation of MYPBC3 (c.2905 +1 G >A) to study HCM pathogenesis during cardiac differentiation. HCM-specific hESC-derived cardiomyocytes (hESC-CMs) displayed hallmark aspects of HCM including sarcomere disarray, hypertrophy and impaired calcium impulse propagation. HCM hESC-CMs presented a transient haploinsufficiency of cMyBP-C during cardiomyocyte differentiation, but by day 30 post-differentiation cMyBP-C levels were similar to control hESC-CMs. Gene transfer of full-length MYBPC3 during differentiation prevented hypertrophy, sarcomere disarray and improved calcium impulse propagation in HCM hESC-CMs. CONCLUSION(S) These findings point to the critical role of MYBPC3 during sarcomere assembly in cardiac myocyte differentiation and suggest developmental influences of MYBPC3 truncating mutations on the mature hypertrophic phenotype.
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Affiliation(s)
- Andre Monteiro da Rocha
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States; Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, United States
| | - Guadalupe Guerrero-Serna
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Adam Helms
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Carly Luzod
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Sergey Mironov
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Mark Russell
- Department of Pediatrics, University of Michigan, Ann Arbor, MI 48109, United States
| | - José Jalife
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Sharlene M Day
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States
| | - Gary D Smith
- Department of Obstetrics and Gynecology, University of Michigan, Ann Arbor, MI 48109, United States.
| | - Todd J Herron
- Department of Internal Medicine, Center for Arrhythmia Research, University of Michigan, Ann Arbor, MI 48109, United States.
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12
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Han P, Li W, Yang J, Shang C, Lin CH, Cheng W, Hang CT, Cheng HL, Chen CH, Wong J, Xiong Y, Zhao M, Drakos SG, Ghetti A, Li DY, Bernstein D, Chen HSV, Quertermous T, Chang CP. Epigenetic response to environmental stress: Assembly of BRG1-G9a/GLP-DNMT3 repressive chromatin complex on Myh6 promoter in pathologically stressed hearts. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1772-81. [PMID: 26952936 DOI: 10.1016/j.bbamcr.2016.03.002] [Citation(s) in RCA: 36] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/06/2016] [Revised: 03/01/2016] [Accepted: 03/03/2016] [Indexed: 02/07/2023]
Abstract
Chromatin structure is determined by nucleosome positioning, histone modifications, and DNA methylation. How chromatin modifications are coordinately altered under pathological conditions remains elusive. Here we describe a stress-activated mechanism of concerted chromatin modification in the heart. In mice, pathological stress activates cardiomyocytes to express Brg1 (nucleosome-remodeling factor), G9a/Glp (histone methyltransferase), and Dnmt3 (DNA methyltransferase). Once activated, Brg1 recruits G9a and then Dnmt3 to sequentially assemble repressive chromatin-marked by H3K9 and CpG methylation-on a key molecular motor gene (Myh6), thereby silencing Myh6 and impairing cardiac contraction. Disruption of Brg1, G9a or Dnmt3 erases repressive chromatin marks and de-represses Myh6, reducing stress-induced cardiac dysfunction. In human hypertrophic hearts, BRG1-G9a/GLP-DNMT3 complex is also activated; its level correlates with H3K9/CpG methylation, Myh6 repression, and cardiomyopathy. Our studies demonstrate a new mechanism of chromatin assembly in stressed hearts and novel therapeutic targets for restoring Myh6 and ventricular function. The stress-induced Brg1-G9a-Dnmt3 interactions and sequence of repressive chromatin assembly on Myh6 illustrates a molecular mechanism by which the heart epigenetically responds to environmental signals. This article is part of a Special Issue entitled: Cardiomyocyte Biology: Integration of Developmental and Environmental Cues in the Heart edited by Marcus Schaub and Hughes Abriel.
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Affiliation(s)
- Pei Han
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Wei Li
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Jin Yang
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Ching Shang
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Chiou-Hong Lin
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Wei Cheng
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA
| | - Calvin T Hang
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Hsiu-Ling Cheng
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Chen-Hao Chen
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Johnson Wong
- Del E. Webb Neuroscience, Aging & Stem Cell Research Center, Sanford/Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Yiqin Xiong
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Mingming Zhao
- Division of Cardiovascular Medicine, Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
| | - Stavros G Drakos
- Cardiovascular Department and Utah Artificial Heart Program, Intermountain Medical Center, Salt Lake City, UT 84112, USA
| | - Andrea Ghetti
- AnaBios Corporation, 3030 Bunker Hill St., San Diego, CA 92109, USA
| | - Dean Y Li
- Cardiovascular Department and Utah Artificial Heart Program, Intermountain Medical Center, Salt Lake City, UT 84112, USA
| | - Daniel Bernstein
- Division of Cardiovascular Medicine, Department of Pediatrics, Stanford University, Stanford, CA 94305, USA
| | - Huei-Sheng Vincent Chen
- Del E. Webb Neuroscience, Aging & Stem Cell Research Center, Sanford/Burnham Medical Research Institute, La Jolla, CA 92037, USA
| | - Thomas Quertermous
- Division of Cardiovascular Medicine, Department of Medicine, Stanford University, Stanford, CA 94305, USA
| | - Ching-Pin Chang
- Krannert Institute of Cardiology and Division of Cardiology, Department of Medicine, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Krannert Institute of Cardiology and Division of Cardiology, Department of Biochemistry and Molecular Biology, Indiana University School of Medicine, Indianapolis, IN 46202, USA; Krannert Institute of Cardiology and Division of Cardiology, Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN 46202, USA.
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13
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Herron TJ. Calcium and voltage mapping in hiPSC-CM monolayers. Cell Calcium 2016; 59:84-90. [PMID: 26922095 DOI: 10.1016/j.ceca.2016.02.004] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2015] [Revised: 02/04/2016] [Accepted: 02/10/2016] [Indexed: 01/18/2023]
Abstract
The advent of induced pluripotent stem cell derived cardiomyocytes (hiPSC-CMs) has revolutionized the cardiovascular research field. Now it is possible to generate a virtually unlimited supply of patient specific pluripotent stem cells and cardiomyocytes that can be used for research purposes, drug toxicity testing and/or regenerative medicine therapies. The most immediate application for this technology is in vitro disease modeling and in vitro drug toxicity testing. To date the majority of disease modeling and drug toxicity testing has been performed on single hiPSC-CMs in culture. However, the study of complex cardiac arrhythmia mechanisms requires a more physiological model system of electrically and mechanically connected hiPSC-CMs that function as a syncytium-like the cardiomyocytes of the adult heart. This review focuses on the work that has been performed recently using hiPSC-CM 2D monolayers for the study of cardiac electrical impulse propagation.
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Affiliation(s)
- Todd J Herron
- North Campus Research Complex, Bldg 26, Room 223N, 2800 Plymouth Road, Ann Arbor, MI 48109-2800, United States.
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14
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Mamidi R, Gresham KS, Li A, dos Remedios CG, Stelzer JE. Molecular effects of the myosin activator omecamtiv mecarbil on contractile properties of skinned myocardium lacking cardiac myosin binding protein-C. J Mol Cell Cardiol 2015; 85:262-72. [PMID: 26100051 DOI: 10.1016/j.yjmcc.2015.06.011] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 05/28/2015] [Accepted: 06/15/2015] [Indexed: 01/03/2023]
Abstract
Decreased expression of cardiac myosin binding protein-C (cMyBP-C) in the myocardium is thought to be a contributing factor to hypertrophic cardiomyopathy in humans, and the initial molecular defect is likely abnormal cross-bridge (XB) function which leads to impaired force generation, decreased contractile performance, and hypertrophy in vivo. The myosin activator omecamtiv mecarbil (OM) is a pharmacological drug that specifically targets the myosin XB and recent evidence suggests that OM induces a significant decrease in the in vivo motility velocity and an increase in the XB duty cycle. Thus, the molecular effects of OM maybe beneficial in improving contractile function in skinned myocardium lacking cMyBP-C because absence of cMyBP-C in the sarcomere accelerates XB kinetics and enhances XB turnover rate, which presumably reduces contractile efficiency. Therefore, parameters of XB function were measured in skinned myocardium lacking cMyBP-C prior to and following OM incubation. We measured ktr, the rate of force redevelopment as an index of XB transition from both the weakly- to strongly-bound state and from the strongly- to weakly-bound states and performed stretch activation experiments to measure the rates of XB detachment (krel) and XB recruitment (kdf) in detergent-skinned ventricular preparations isolated from hearts of wild-type (WT) and cMyBP-C knockout (KO) mice. Samples from donor human hearts were also used to assess the effects of OM in cardiac muscle expressing a slow β-myosin heavy chain (β-MHC). Incubation of skinned myocardium with OM produced large enhancements in steady-state force generation which were most pronounced at low levels of [Ca(2+)] activations, suggesting that OM cooperatively recruits additional XB's into force generating states. Despite a large increase in steady-state force generation following OM incubation, parallel accelerations in XB kinetics as measured by ktr were not observed, and there was a significant OM-induced decrease in krel which was more pronounced in the KO skinned myocardium compared to WT skinned myocardium (58% in WT vs. 76% in KO at pCa 6.1), such that baseline differences in krel between KO and WT skinned myocardium were no longer apparent following OM-incubation. A significant decrease in the kdf was also observed following OM incubation in all groups, which may be related to the increase in the number of cooperatively recruited XB's at low Ca(2+)-activations which slows the overall rate of force generation. Our results indicate that OM may be a useful pharmacological approach to normalize hypercontractile XB kinetics in myocardium with decreased cMyBP-C expression due to its molecular effects on XB behavior.
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Affiliation(s)
- Ranganath Mamidi
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Kenneth S Gresham
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA
| | - Amy Li
- Muscle Research Unit, Bosch Institute, University of Sydney, Sydney Australia
| | | | - Julian E Stelzer
- Department of Physiology and Biophysics, School of Medicine, Case Western Reserve University, Cleveland, OH 44106 USA.
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15
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Abstract
Various human diseases can disrupt the balance between muscle contraction and relaxation. Sarcomeric modulators can be used to readjust this balance either indirectly by intervening in signalling pathways or directly through interaction with the muscle proteins that control contraction. Such agents represent a novel approach to treating any condition in which striated muscle function is compromised, including heart failure, cardiomyopathies, skeletal myopathies and a wide range of neuromuscular conditions. Here, we review agents that modulate the mechanical function of the sarcomere, focusing on emerging compounds that target myosin or the troponin complex.
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16
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Abstract
Traditional methods for DNA transfection are often inefficient and toxic for terminally differentiated cells, such as cardiac myocytes. Vector-based gene transfer is an efficient approach for introducing exogenous cDNA into these types of primary cell cultures. In this chapter, separate protocols for adult rat cardiac myocyte isolation and gene transfer with recombinant adenovirus are provided and are routinely utilized for studying the effects of sarcomeric proteins on myofilament function.
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17
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Zarzoso M, Mironov S, Guerrero-Serna G, Willis BC, Pandit SV. Ventricular remodelling in rabbits with sustained high-fat diet. Acta Physiol (Oxf) 2014; 211:36-47. [PMID: 24304486 DOI: 10.1111/apha.12185] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Revised: 09/02/2013] [Accepted: 10/19/2013] [Indexed: 12/23/2022]
Abstract
AIM Excess weight gain and obesity are one of the most serious health problems in the western societies. These conditions enhance risk of cardiac disease and have been linked with increased prevalence for cardiac arrhythmias and sudden death. Our goal was to study the ventricular remodelling occurring in rabbits fed with high-fat diet (HFD) and its potential arrhythmogenic mechanisms. METHODS We used 15 NZW rabbits that were randomly assigned to a control (n = 7) or HFD group (n = 8) for 18 weeks. In vivo studies included blood glucose, electrocardiographic, and echocardiographic measurements. Optical mapping was performed in Langendorff-perfused isolated hearts. RESULTS Body weight (3.69 ± 0.31 vs. 2.94 ± 0.18 kg, P < 0.001) and blood glucose levels (230 ± 61 vs. 141 ± 14 mg dL(-1) , P < 0.05) were higher in the HFD group vs. controls. The rate-corrected QT interval and its dispersion were increased in HFD rabbits vs. controls (169 ± 10 vs. 146 ± 13 ms and 37 ± 11 vs. 9 ± 2 ms, respectively; P < 0.05). Echocardiographic analysis showed morphological and functional alterations in HFD rabbits indicative of left ventricle (LV) hypertrophy. Isolated heart studies revealed no changes in repolarization and propagation properties under conditions of normal extracellular K(+) , suggesting that extrinsic factors could underlie those electrocardiographic modifications. There were no differences in the dynamics of ventricular fibrillation (frequency, wave breaks) in the presence of isoproterenol. However, HFD rabbits showed a small reduction in action potential duration and an increased incidence of arrhythmias during hyperkalaemia. CONCLUSION High-fat feeding during 18 weeks in rabbits induced a type II diabetes phenotype, LV hypertrophy, abnormalities in repolarization and susceptibility to arrhythmias during hyperkalaemia.
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Affiliation(s)
- M. Zarzoso
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
- Department of Physiotherapy; Universitat de València; Valencia Spain
| | - S. Mironov
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
| | - G. Guerrero-Serna
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
| | - B. Cicero Willis
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
| | - S. V. Pandit
- Center for Arrhythmia Research; University of Michigan; Ann Arbor MI USA
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18
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Martindale JJ, Metzger JM. Uncoupling of increased cellular oxidative stress and myocardial ischemia reperfusion injury by directed sarcolemma stabilization. J Mol Cell Cardiol 2014; 67:26-37. [PMID: 24362314 PMCID: PMC3920738 DOI: 10.1016/j.yjmcc.2013.12.008] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/01/2013] [Revised: 12/09/2013] [Accepted: 12/11/2013] [Indexed: 12/31/2022]
Abstract
Myocardial ischemia/reperfusion (I/R) injury is a major clinical problem leading to cardiac dysfunction and myocyte death. It is widely held that I/R causes damage to membrane phospholipids, and is a significant mechanism of cardiac I/R injury. Molecular dissection of sarcolemmal damage in I/R, however, has been difficult to address experimentally. We studied here cardiac I/R injury under conditions targeting gain- or loss-of sarcolemma integrity. To implement gain-in-sarcolemma integrity during I/R, synthetic copolymer-based sarcolemmal stabilizers (CSS), including Poloxamer 188 (P188), were used as a tool to directly stabilize the sarcolemma. Consistent with the hypothesis of sarcolemmal stabilization, cellular markers of necrosis and apoptosis evident in untreated myocytes were fully blocked in sarcolemma stabilized myocytes. Unexpectedly, sarcolemmal stabilization of adult cardiac myocytes did not affect the status of myocyte-generated oxidants or lipid peroxidation in two independent assays. We also investigated the loss of sarcolemmal integrity using two independent genetic mouse models, dystrophin-deficient mdx or dysferlin knockout (Dysf KO) mice. Both models of sarcolemmal loss-of-function were severely affected by I/R injury ex vivo, and this was lessened by CSS. In vivo studies also showed that infarct size was significantly reduced in CSS-treated hearts. Mechanistically, these findings support a model whereby I/R-mediated increased myocyte oxidative stress is uncoupled from myocyte injury. Because the sarcolemma stabilizers used here do not transit across the myocyte membrane this is evidence that intracellular targets of oxidants are not sufficiently altered to affect cell death when sarcolemma integrity is preserved by synthetic stabilizers. These findings, in turn, suggest that sarcolemma destabilization, and consequent Ca(2+) mishandling, as a focal initiating mechanism underlying myocardial I/R injury.
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Affiliation(s)
- Joshua J Martindale
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA
| | - Joseph M Metzger
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, MN, USA.
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19
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Cardiac myosin binding protein-C: a novel sarcomeric target for gene therapy. Pflugers Arch 2013; 466:225-30. [PMID: 24310821 DOI: 10.1007/s00424-013-1412-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2013] [Revised: 11/22/2013] [Accepted: 11/26/2013] [Indexed: 01/19/2023]
Abstract
Through its ability to interact with both the thick and thin filament proteins within the sarcomere, cardiac myosin binding protein-C (cMyBP-C) regulates the contractile properties of the myocardium. The central regulatory role of cMyBP-C in heart function is emphasized by the fact that a large proportion of inherited hypertrophic cardiomyopathy cases in humans are caused by mutations in cMyBP-C. The primary dysfunction in cMyBP-C-related cardiomyopathies is likely to be abnormal myofilament contractile function; however, currently, there are no effective therapies for ameliorating these contractile defects. Thus, there is a compelling need to design novel therapies to restore normal contractile function in cMyBP-C-related cardiomyopathies. To this end, concepts gleaned from various structural, functional, and biochemical studies can now be utilized to engineer cMyBP-C proteins that, when incorporated into the sarcomere, can significantly improve contractile function. In this review, we discuss the rationale for cMyBP-C-based gene therapies that can be utilized to treat contractile dysfunction in inherited and acquired cardiomyopathies.
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20
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Wang W, Barnabei MS, Asp ML, Heinis FI, Arden E, Davis J, Braunlin E, Li Q, Davis JP, Potter JD, Metzger JM. Noncanonical EF-hand motif strategically delays Ca2+ buffering to enhance cardiac performance. Nat Med 2013; 19:305-12. [PMID: 23396207 DOI: 10.1038/nm.3079] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 12/21/2012] [Indexed: 12/26/2022]
Abstract
EF-hand proteins are ubiquitous in cell signaling. Parvalbumin (Parv), the archetypal EF-hand protein, is a high-affinity Ca(2+) buffer in many biological systems. Given the centrality of Ca(2+) signaling in health and disease, EF-hand motifs designed to have new biological activities may have widespread utility. Here, an EF-hand motif substitution that had been presumed to destroy EF-hand function, that of glutamine for glutamate at position 12 of the second cation binding loop domain of Parv (ParvE101Q), markedly inverted relative cation affinities: Mg(2+) affinity increased, whereas Ca(2+) affinity decreased, forming a new ultra-delayed Ca(2+) buffer with favorable properties for promoting cardiac relaxation. In therapeutic testing, expression of ParvE101Q fully reversed the severe myocyte intrinsic contractile defect inherent to expression of native Parv and corrected abnormal myocardial relaxation in diastolic dysfunction disease models in vitro and in vivo. Strategic design of new EF-hand motif domains to modulate intracellular Ca(2+) signaling could benefit many biological systems with abnormal Ca(2+) handling, including the diseased heart.
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Affiliation(s)
- Wang Wang
- Department of Integrative Biology and Physiology, University of Minnesota Medical School, Minneapolis, Minnesota, USA
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21
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Deacon JC, Bloemink MJ, Rezavandi H, Geeves MA, Leinwand LA. Erratum to: Identification of functional differences between recombinant human α and β cardiac myosin motors. Cell Mol Life Sci 2012; 69:4239-55. [PMID: 23001010 PMCID: PMC3685716 DOI: 10.1007/s00018-012-1111-5] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The myosin isoform composition of the heart is dynamic in health and disease and has been shown to affect contractile velocity and force generation. While different mammalian species express different proportions of α and β myosin heavy chain, healthy human heart ventricles express these isoforms in a ratio of about 1:9 (α:β) while failing human ventricles express no detectable α-myosin. We report here fast-kinetic analysis of recombinant human α and β myosin heavy chain motor domains. This represents the first such analysis of any human muscle myosin motor and the first of α-myosin from any species. Our findings reveal substantial isoform differences in individual kinetic parameters, overall contractile character, and predicted cycle times. For these parameters, α-subfragment 1 (S1) is far more similar to adult fast skeletal muscle myosin isoforms than to the slow β isoform despite 91% sequence identity between the motor domains of α- and β-myosin. Among the features that differentiate α- from β-S1: the ATP hydrolysis step of α-S1 is ~ten-fold faster than β-S1, α-S1 exhibits ~five-fold weaker actin affinity than β-S1, and actin·α-S1 exhibits rapid ADP release, which is >ten-fold faster than ADP release for β-S1. Overall, the cycle times are ten-fold faster for α-S1 but the portion of time each myosin spends tightly bound to actin (the duty ratio) is similar. Sequence analysis points to regions that might underlie the basis for this finding.
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Affiliation(s)
- John C. Deacon
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
| | | | - Heresh Rezavandi
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | | | - Leslie A. Leinwand
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
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22
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Zhang J, Klos M, Wilson GF, Herman AM, Lian X, Raval KK, Barron MR, Hou L, Soerens AG, Yu J, Palecek SP, Lyons GE, Thomson JA, Herron TJ, Jalife J, Kamp TJ. Extracellular matrix promotes highly efficient cardiac differentiation of human pluripotent stem cells: the matrix sandwich method. Circ Res 2012; 111:1125-36. [PMID: 22912385 DOI: 10.1161/circresaha.112.273144] [Citation(s) in RCA: 340] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
RATIONALE Cardiomyocytes (CMs) differentiated from human pluripotent stem cells (PSCs) are increasingly being used for cardiovascular research, including disease modeling, and hold promise for clinical applications. Current cardiac differentiation protocols exhibit variable success across different PSC lines and are primarily based on the application of growth factors. However, extracellular matrix is also fundamentally involved in cardiac development from the earliest morphogenetic events, such as gastrulation. OBJECTIVE We sought to develop a more effective protocol for cardiac differentiation of human PSCs by using extracellular matrix in combination with growth factors known to promote cardiogenesis. METHODS AND RESULTS PSCs were cultured as monolayers on Matrigel, an extracellular matrix preparation, and subsequently overlayed with Matrigel. The matrix sandwich promoted an epithelial-to-mesenchymal transition as in gastrulation with the generation of N-cadherin-positive mesenchymal cells. Combining the matrix sandwich with sequential application of growth factors (Activin A, bone morphogenetic protein 4, and basic fibroblast growth factor) generated CMs with high purity (up to 98%) and yield (up to 11 CMs/input PSC) from multiple PSC lines. The resulting CMs progressively matured over 30 days in culture based on myofilament expression pattern and mitotic activity. Action potentials typical of embryonic nodal, atrial, and ventricular CMs were observed, and monolayers of electrically coupled CMs modeled cardiac tissue and basic arrhythmia mechanisms. CONCLUSIONS Dynamic extracellular matrix application promoted epithelial-mesenchymal transition of human PSCs and complemented growth factor signaling to enable robust cardiac differentiation.
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Affiliation(s)
- Jianhua Zhang
- Department of Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, WI, USA
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23
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Deacon JC, Bloemink MJ, Rezavandi H, Geeves MA, Leinwand LA. Identification of functional differences between recombinant human α and β cardiac myosin motors. Cell Mol Life Sci 2012; 69:2261-77. [PMID: 22349210 PMCID: PMC3375423 DOI: 10.1007/s00018-012-0927-3] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2011] [Revised: 12/29/2011] [Accepted: 01/19/2012] [Indexed: 11/24/2022]
Abstract
The myosin isoform composition of the heart is dynamic in health and disease and has been shown to affect contractile velocity and force generation. While different mammalian species express different proportions of α and β myosin heavy chain, healthy human heart ventricles express these isoforms in a ratio of about 1:9 (α:β) while failing human ventricles express no detectable α-myosin. We report here fast-kinetic analysis of recombinant human α and β myosin heavy chain motor domains. This represents the first such analysis of any human muscle myosin motor and the first of α-myosin from any species. Our findings reveal substantial isoform differences in individual kinetic parameters, overall contractile character, and predicted cycle times. For these parameters, α-subfragment 1 (S1) is far more similar to adult fast skeletal muscle myosin isoforms than to the slow β isoform despite 91% sequence identity between the motor domains of α- and β-myosin. Among the features that differentiate α- from β-S1: the ATP hydrolysis step of α-S1 is ~ten-fold faster than β-S1, α-S1 exhibits ~five-fold weaker actin affinity than β-S1, and actin·α-S1 exhibits rapid ADP release, which is >ten-fold faster than ADP release for β-S1. Overall, the cycle times are ten-fold faster for α-S1 but the portion of time each myosin spends tightly bound to actin (the duty ratio) is similar. Sequence analysis points to regions that might underlie the basis for this finding.
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Affiliation(s)
- John C. Deacon
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
| | | | - Heresh Rezavandi
- School of Biosciences, University of Kent, Canterbury, CT2 7NJ UK
| | | | - Leslie A. Leinwand
- Department of Molecular, Cellular and Developmental Biology and Biofrontiers Institute, University of Colorado, MCDB, UCB 347, Boulder, CO 80309 USA
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24
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Hwang H, Robinson DA, Stevenson TK, Wu HC, Kampert SE, Pagani FD, Dyke DB, Martin JL, Sadayappan S, Day SM, Westfall MV. PKCβII modulation of myocyte contractile performance. J Mol Cell Cardiol 2012; 53:176-86. [PMID: 22587992 DOI: 10.1016/j.yjmcc.2012.05.001] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/29/2011] [Revised: 05/03/2012] [Accepted: 05/04/2012] [Indexed: 12/26/2022]
Abstract
Significant up-regulation of the protein kinase Cβ(II) (PKCβ(II)) develops during heart failure and yet divergent functional outcomes are reported in animal models. The goal here is to investigate PKCβ(II) modulation of contractile function and gain insights into downstream targets in adult cardiac myocytes. Increased PKCβ(II) protein expression and phosphorylation developed after gene transfer into adult myocytes while expression remained undetectable in controls. The PKCβ(II) was distributed in a peri-nuclear pattern and this expression resulted in diminished rates and amplitude of shortening and re-lengthening compared to controls and myocytes expressing dominant negative PKCβ(II) (PKCβDN). Similar decreases were observed in the Ca(2+) transient and the Ca(2+) decay rate slowed in response to caffeine in PKCβ(II)-expressing myocytes. Parallel phosphorylation studies indicated PKCβ(II) targets phosphatase activity to reduce phospholamban (PLB) phosphorylation at residue Thr17 (pThr17-PLB). The PKCβ inhibitor, LY379196 (LY) restored pThr17-PLB to control levels. In contrast, myofilament protein phosphorylation was enhanced by PKCβ(II) expression, and individually, LY and the phosphatase inhibitor, calyculin A each failed to block this response. Further work showed PKCβ(II) increased Ca(2+)-activated, calmodulin-dependent kinase IIδ (CaMKIIδ) expression and enhanced both CaMKIIδ and protein kinase D (PKD) phosphorylation. Phosphorylation of both signaling targets also was resistant to acute inhibition by LY. These later results provide evidence PKCβ(II) modulates contractile function via intermediate downstream pathway(s) in cardiac myocytes.
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Affiliation(s)
- Hyosook Hwang
- Dept. of Surgery, Cardiac Surgery Section, University of Michigan, Ann Arbor, MI 48109, USA
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25
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Upregulation of cardiomyocyte ribonucleotide reductase increases intracellular 2 deoxy-ATP, contractility, and relaxation. J Mol Cell Cardiol 2011; 51:894-901. [PMID: 21925507 PMCID: PMC3208740 DOI: 10.1016/j.yjmcc.2011.08.026] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2011] [Revised: 08/22/2011] [Accepted: 08/25/2011] [Indexed: 11/22/2022]
Abstract
We have previously demonstrated that substitution of ATP with 2 deoxy-ATP
(dATP) increased the magnitude and rate of force production at all levels of
Ca2+-mediated activation in demembranated cardiac muscle.
In the current study we hypothesized that cellular [dATP] could
be increased by viral-mediated over expression of the ribonucleotide reductase
(Rrm1 and Rrm2) complex, which would increase contractility of adult rat
cardiomyocytes. Cell length and ratiometric (fura2) Ca2+
fluorescence were monitored by video microscopy. At 0.5 Hz stimulation, the
extent of shortening was increased ~40% and maximal rate of shortening
was increased ~80% in cardiomyocytes overexpressing Rrm1+Rrm2 as
compared to non-transduced cardiomyocytes. The maximal rate of relaxation was
also increased ~150% with Rrm1+Rrm2 over expression, resulting
in decreased time to 50% relaxation over non-transduced cardiomyocytes.
These differences were even more dramatic when compared to cardiomyocytes
expressing GFP-only. Interestingly, Rrm1+Rrm2 over expression had no
effect on minimal or maximal intracellular
[Ca2+] (Fura2 fluorescence), indicating
increased contractility is primarily due to increased myofilament activity
without altering Ca2+ release from the sarcoplasmic
reticulum. Additionally, functional potentiation was maintained with
Rrm1+Rrm2 over expression as stimulation frequency was increased (1 Hz
and 2 Hz). HPLC analysis indicated cellular [dATP] was increased
by approximately 10-fold following transduction, becoming ~1.5% of the
adenine nucleotide pool. Furthermore, 2% dATP was sufficient to
significantly increase crossbridge binding and contractile force during
sub-maximal Ca2+ activation in demembranated cardiac muscle.
These experiments demonstrate the feasibility of directly targeting the
actin-myosin chemomechanical crossbridge cycle to enhance cardiac contractility
and relaxation without affecting minimal or maximal Ca2+.
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Stein AB, Jones TA, Herron TJ, Patel SR, Day SM, Noujaim SF, Milstein ML, Klos M, Furspan PB, Jalife J, Dressler GR. Loss of H3K4 methylation destabilizes gene expression patterns and physiological functions in adult murine cardiomyocytes. J Clin Invest 2011; 121:2641-50. [PMID: 21646717 DOI: 10.1172/jci44641] [Citation(s) in RCA: 100] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Accepted: 04/13/2011] [Indexed: 11/17/2022] Open
Abstract
Histone H3 lysine 4 (H3K4me) methyltransferases and their cofactors are essential for embryonic development and the establishment of gene expression patterns in a cell-specific and heritable manner. However, the importance of such epigenetic marks in maintaining gene expression in adults and in initiating human disease is unclear. Here, we addressed this question using a mouse model in which we could inducibly ablate PAX interacting (with transcription-activation domain) protein 1 (PTIP), a key component of the H3K4me complex, in cardiac cells. Reducing H3K4me3 marks in differentiated cardiomyocytes was sufficient to alter gene expression profiles. One gene regulated by H3K4me3 was Kv channel-interacting protein 2 (Kcnip2), which regulates a cardiac repolarization current that is downregulated in heart failure and functions in arrhythmogenesis. This regulation led to a decreased sodium current and action potential upstroke velocity and significantly prolonged action potential duration (APD). The prolonged APD augmented intracellular calcium and in vivo systolic heart function. Treatment with isoproterenol and caffeine in this mouse model resulted in the generation of premature ventricular beats, a harbinger of lethal ventricular arrhythmias. These results suggest that the maintenance of H3K4me3 marks is necessary for the stability of a transcriptional program in differentiated cells and point to an essential function for H3K4me3 epigenetic marks in cellular homeostasis.
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Affiliation(s)
- Adam B Stein
- Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan, USA.
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Locher MR, Razumova MV, Stelzer JE, Norman HS, Moss RL. Effects of low-level α-myosin heavy chain expression on contractile kinetics in porcine myocardium. Am J Physiol Heart Circ Physiol 2011; 300:H869-78. [PMID: 21217059 DOI: 10.1152/ajpheart.00452.2010] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Myosin heavy chain (MHC) isoforms are principal determinants of work capacity in mammalian ventricular myocardium. The ventricles of large mammals including humans normally express ∼10% α-MHC on a predominantly β-MHC background, while in failing human ventricles α-MHC is virtually eliminated, suggesting that low-level α-MHC expression in normal myocardium can accelerate the kinetics of contraction and augment systolic function. To test this hypothesis in a model similar to human myocardium we determined composite rate constants of cross-bridge attachment (f(app)) and detachment (g(app)) in porcine myocardium expressing either 100% α-MHC or 100% β-MHC in order to predict the MHC isoform-specific effect on twitch kinetics. Right atrial (∼100% α-MHC) and left ventricular (∼100% β-MHC) tissue was used to measure myosin ATPase activity, isometric force, and the rate constant of force redevelopment (k(tr)) in solutions of varying Ca(2+) concentration. The rate of ATP utilization and k(tr) were approximately ninefold higher in atrial compared with ventricular myocardium, while tension cost was approximately eightfold greater in atrial myocardium. From these values, we calculated f(app) to be ∼10-fold higher in α- compared with β-MHC, while g(app) was 8-fold higher in α-MHC. Mathematical modeling of an isometric twitch using these rate constants predicts that the expression of 10% α-MHC increases the maximal rate of rise of force (dF/dt(max)) by 92% compared with 0% α-MHC. These results suggest that low-level expression of α-MHC significantly accelerates myocardial twitch kinetics, thereby enhancing systolic function in large mammalian myocardium.
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Affiliation(s)
- Matthew R Locher
- 1Department of Physiology, University of Wisconsin School of Medicine and Public Health, Madison, Wisconsin 53711, USA.
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Chen Y, Somji A, Yu X, Stelzer JE. Altered in vivo left ventricular torsion and principal strains in hypothyroid rats. Am J Physiol Heart Circ Physiol 2010; 299:H1577-87. [PMID: 20729398 DOI: 10.1152/ajpheart.00406.2010] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The twisting and untwisting motions of the left ventricle (LV) lead to efficient ejection of blood during systole and filling of the ventricle during diastole. Global LV mechanical performance is dependent on the contractile properties of cardiac myocytes; however, it is not known how changes in contractile protein expression affect the pattern and timing of LV rotation. At the myofilament level, contractile performance is largely dependent on the isoforms of myosin heavy chain (MHC) that are expressed. Therefore, in this study, we used MRI to examine the in vivo mechanical consequences of altered MHC isoform expression by comparing the contractile properties of hypothyroid rats, which expressed only the slow β-MHC isoform, and euthyroid rats, which predominantly expressed the fast α-MHC isoform. Unloaded shortening velocity (V(o)) and apparent rate constants of force development (k(tr)) were measured in the skinned ventricular myocardium isolated from euthyroid and hypothyroid hearts. Increased expression of β-MHC reduced LV torsion and fiber strain and delayed the development of peak torsion and strain during systole. Depressed in vivo mechanical performance in hypothyroid rats was related to slowed cross-bridge performance, as indicated by significantly slower V(o) and k(tr), compared with euthyroid rats. Dobutamine infusion in hypothyroid hearts produced smaller increases in torsion and strain and aberrant transmural torsion patterns, suggesting that the myocardial response to β-adrenergic stress is compromised. Thus, increased expression of β-MHC alters the pattern and decreases the magnitude of LV rotation, contributing to reduced mechanical performance during systole, especially in conditions of increased workload.
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Affiliation(s)
- Yong Chen
- Department of Biomedical Engineering, School of Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA
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