1
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Rani DS, Kasala A, Dhandapany PS, Muthusami U, Kunnoth S, Rathinavel A, Ayapati DR, Thangaraj K. Novel MYBPC3 Mutations in Indian Population with Cardiomyopathies. Pharmgenomics Pers Med 2023; 16:883-893. [PMID: 37750083 PMCID: PMC10518145 DOI: 10.2147/pgpm.s407179] [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: 03/17/2023] [Accepted: 08/11/2023] [Indexed: 09/27/2023] Open
Abstract
Background Mutations in Myosin Binding Protein C (MYBPC3) are one of the most frequent causes of cardiomyopathies in the world, but not much data are available in India. Methods We carried out targeted direct sequencing of MYBPC3 in 115 hypertrophic (HCM) and 127 dilated (DCM) cardiomyopathies against 197 ethnically matched healthy controls from India. Results We detected 34 single nucleotide variations in MYBPC3, of which 19 were novel. We found a splice site mutation [(IVS6+2T) T>G] and 16 missense mutations in Indian cardiomyopathies [5 in HCM; E258K, T262S, H287L, R408M, V483A: 4 in DCM; T146N, V321L, A392T, E393K and 7 in both HCM and DCM; L104M, V158M, S236G, R272C, T290A, G522E, A626V], but those were absent in 197 normal healthy controls. Interestingly, we found 7 out of 16 missense mutations (V158M, E258K, R272C, A392T, V483A, G522E, and A626V) in MYBPC3 were altering the evolutionarily conserved native amino acids, accounted for 8.7% and 6.3% in HCM and DCM, respectively. The bioinformatic tools predicted that those 7 missense mutations were pathogenic. Moreover, the co-segregation of those 7 mutations in families further confirmed their pathogenicity. Remarkably, we also identified compound mutations within the MYBPC3 gene of 6 cardiomyopathy patients (5%) with more severe disease phenotype; of which, 3 were HCM (2.6%) [(1. K244K + E258K + (IVS6+2T) T>G); (2. L104M + G522E + A626V); (3. P186P + G522E + A626V]; and 3 were DCM (2.4%) [(1. 5'UTR + A392T; 2. V158M+G522E; and 3.V158M + T262T + A626V]. Conclusion The present comprehensive study on MYBPC3 has revealed both single and compound mutations in MYBPC3 and their association with disease in Indian Population with Cardiomyopathies. Our findings may perhaps help in initiating diagnostic strategies and eventually recognizing the targets for therapeutic interventions.
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Grants
- Rani DS has been supported by the CSIR-CCMB, Hyderabad, Telangana, India. K Thangaraj has been supported by the JC Bose Fellowship
- SERB, DST, and The Government of India. However, the funders had no role in designing the study, the collection of data, the analysis of sequence data, the decision to publish, or the preparation of the manuscript
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Affiliation(s)
- Deepa Selvi Rani
- Department of Population and Medical Genomics, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana, India
| | - Apoorva Kasala
- Department of Population and Medical Genomics, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana, India
| | - Perundurai S Dhandapany
- Department of Cardiovascular Biology and Medicine, Institute for Stem Cell Science and Regenerative Medicine, Bangalore, Karnataka, India
| | - Uthiralingam Muthusami
- Department of Advanced Zoology and Biotechnology, Loyola College, Chennai, Tamil Nadu, India
| | - Sreejith Kunnoth
- Department of Advanced Zoology and Biotechnology, Loyola College, Chennai, Tamil Nadu, India
| | - Andiappan Rathinavel
- Department of Cardiology, Government Rajaji Hospital, Madurai, Tamil Nadu, India
| | - Dharma Rakshak Ayapati
- Department of Cardiology, Nizam’s Institute of Medical Sciences, Hyderabad, Telangana, India
| | - Kumarasamy Thangaraj
- Department of Population and Medical Genomics, CSIR-Centre for Cellular and Molecular Biology, Hyderabad, Telangana, India
- DBT-Centre for DNA Fingerprinting and Diagnostics, Hyderabad, Telangana, India
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2
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Huang X, Torre I, Chiappi M, Yin Z, Vydyanath A, Cao S, Raschdorf O, Beeby M, Quigley B, de Tombe PP, Liu J, Morris EP, Luther PK. Cryo-electron tomography of intact cardiac muscle reveals myosin binding protein-C linking myosin and actin filaments. J Muscle Res Cell Motil 2023; 44:165-178. [PMID: 37115473 PMCID: PMC10542292 DOI: 10.1007/s10974-023-09647-3] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 03/29/2023] [Indexed: 04/29/2023]
Abstract
Myosin binding protein C (MyBP-C) is an accessory protein of the thick filament in vertebrate cardiac muscle arranged over 9 stripes of intervals of 430 Å in each half of the A-band in the region called the C-zone. Mutations in cardiac MyBP-C are a leading cause of hypertrophic cardiomyopathy the mechanism of which is unknown. It is a rod-shaped protein composed of 10 or 11 immunoglobulin- or fibronectin-like domains labelled C0 to C10 which binds to the thick filament via its C-terminal region. MyBP-C regulates contraction in a phosphorylation dependent fashion that may be through binding of its N-terminal domains with myosin or actin. Understanding the 3D organisation of MyBP-C in the sarcomere environment may provide new light on its function. We report here the fine structure of MyBP-C in relaxed rat cardiac muscle by cryo-electron tomography and subtomogram averaging of refrozen Tokuyasu cryosections. We find that on average MyBP-C connects via its distal end to actin across a disc perpendicular to the thick filament. The path of MyBP-C suggests that the central domains may interact with myosin heads. Surprisingly MyBP-C at Stripe 4 is different; it has weaker density than the other stripes which could result from a mainly axial or wavy path. Given that the same feature at Stripe 4 can also be found in several mammalian cardiac muscles and in some skeletal muscles, our finding may have broader implication and significance. In the D-zone, we show the first demonstration of myosin crowns arranged on a uniform 143 Å repeat.
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Affiliation(s)
- Xinrui Huang
- Department of Biochemistry and Biophysics, School of Basic Medical Sciences, Peking University, Beijing, 100191, China
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, 06516, USA
| | - Iratxe Torre
- National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Michele Chiappi
- National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Zhan Yin
- National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Anupama Vydyanath
- National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | - Shuangyi Cao
- National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
| | | | - Morgan Beeby
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Bonnie Quigley
- Department of Life Sciences, Imperial College London, London, SW7 2AZ, UK
| | - Pieter P de Tombe
- National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK
- Department of Physiology and Biophysics, University of Illinois at Chicago, 835 S. Wolcott Ave, Chicago, IL, 60612, USA
- Phymedexp, Université de Montpellier, Inserm, CNRS, Montpellier, France
| | - Jun Liu
- Department of Microbial Pathogenesis, Yale School of Medicine, New Haven, CT, 06516, USA
| | - Edward P Morris
- Division of Structural Biology, Institute of Cancer Research, London, SW3 6JB, UK
- School of Molecular Biosciences, University of Glasgow, Garscube Campus, Jarrett Building, 351, Bearsden Road, Glasgow, G61 1QH, UK
| | - Pradeep K Luther
- National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK.
- Cardiac Function Section, National Heart and Lung Institute, Imperial College London, London, SW7 2AZ, UK.
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3
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Barefield DY, Alvarez-Arce A, Araujo KN. Mechanisms of Sarcomere Protein Mutation-Induced Cardiomyopathies. Curr Cardiol Rep 2023; 25:473-484. [PMID: 37060436 PMCID: PMC11141690 DOI: 10.1007/s11886-023-01876-9] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 03/30/2023] [Indexed: 04/16/2023]
Abstract
PURPOSE OF REVIEW The pace of identifying cardiomyopathy-associated mutations and advances in our understanding of sarcomere function that underlies many cardiomyopathies has been remarkable. Here, we aim to synthesize how these advances have led to the promising new treatments that are being developed to treat cardiomyopathies. RECENT FINDINGS The genomics era has identified and validated many genetic causes of hypertrophic and dilated cardiomyopathies. Recent advances in our mechanistic understanding of sarcomere pathophysiology include high-resolution molecular models of sarcomere components and the identification of the myosin super-relaxed state. The advances in our understanding of sarcomere function have yielded several therapeutic agents that are now in development and clinical use to correct contractile dysfunction-mediated cardiomyopathy. New genes linked to cardiomyopathy include targets with limited clinical evidence and require additional investigation. Large portions of cardiomyopathy with family history remain genetically undiagnosed and may be due to polygenic disease.
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Affiliation(s)
- David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, 2160 S. 1st Ave, Maywood, IL, 60153, USA.
| | - Alejandro Alvarez-Arce
- Department of Cell and Molecular Physiology, Loyola University Chicago, 2160 S. 1st Ave, Maywood, IL, 60153, USA
| | - Kelly N Araujo
- Department of Cell and Molecular Physiology, Loyola University Chicago, 2160 S. 1st Ave, Maywood, IL, 60153, USA
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4
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Barefield DY. Is haploinsufficiency a sufficient mechanism for MYBPC3 truncating mutations? J Gen Physiol 2023; 155:e202313351. [PMID: 36946992 PMCID: PMC10072154 DOI: 10.1085/jgp.202313351] [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] [Indexed: 03/23/2023] Open
Abstract
Reduced expression of MYBPC3 causes early dysfunction in human cell culture models prior to reduced cMyBP-C levels.
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Affiliation(s)
- David Y. Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
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5
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Song T, Landim-Vieira M, Ozdemir M, Gott C, Kanisicak O, Pinto JR, Sadayappan S. Etiology of genetic muscle disorders induced by mutations in fast and slow skeletal MyBP-C paralogs. Exp Mol Med 2023; 55:502-509. [PMID: 36854776 PMCID: PMC10073172 DOI: 10.1038/s12276-023-00953-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2022] [Revised: 12/14/2022] [Accepted: 12/15/2022] [Indexed: 03/02/2023] Open
Abstract
Skeletal muscle, a highly complex muscle type in the eukaryotic system, is characterized by different muscle subtypes and functions associated with specific myosin isoforms. As a result, skeletal muscle is the target of numerous diseases, including distal arthrogryposes (DAs). Clinically, DAs are a distinct disorder characterized by variation in the presence of contractures in two or more distal limb joints without neurological issues. DAs are inherited, and up to 40% of patients with this condition have mutations in genes that encode sarcomeric protein, including myosin heavy chains, troponins, and tropomyosin, as well as myosin binding protein-C (MYBPC). Our research group and others are actively studying the specific role of MYBPC in skeletal muscles. The MYBPC family of proteins plays a critical role in the contraction of striated muscles. More specifically, three paralogs of the MYBPC gene exist, and these are named after their predominant expression in slow-skeletal, fast-skeletal, and cardiac muscle as sMyBP-C, fMyBP-C, and cMyBP-C, respectively, and encoded by the MYBPC1, MYBPC2, and MYBPC3 genes, respectively. Although the physiology of various types of skeletal muscle diseases is well defined, the molecular mechanism underlying the pathological regulation of DAs remains to be elucidated. In this review article, we aim to highlight recent discoveries involving the role of skeletal muscle-specific sMyBP-C and fMyBP-C as well as their expression profile, localization in the sarcomere, and potential role(s) in regulating muscle contractility. Thus, this review provides an overall summary of MYBPC skeletal paralogs, their potential roles in skeletal muscle function, and future research directions.
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Affiliation(s)
- Taejeong Song
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA.
| | - Maicon Landim-Vieira
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Mustafa Ozdemir
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Caroline Gott
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Onur Kanisicak
- Department of Pathology and Laboratory Medicine, College of Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA
| | - Jose Renato Pinto
- Department of Biomedical Sciences, Florida State University College of Medicine, Tallahassee, FL, 32306, USA
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, 45267, USA.
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6
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Yang Q, Berkman AM, Ezekian JE, Rosamilia M, Rosenfeld JA, Liu P, Landstrom AP. Determining the Likelihood of Disease Pathogenicity Among Incidentally Identified Genetic Variants in Rare Dilated Cardiomyopathy-Associated Genes. J Am Heart Assoc 2022; 11:e025257. [PMID: 36129056 DOI: 10.1161/jaha.122.025257] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Background As utilization of clinical exome sequencing (ES) has expanded, criteria for evaluating the diagnostic weight of incidentally identified variants are critical to guide clinicians and researchers. This is particularly important in genes associated with dilated cardiomyopathy (DCM), which can cause heart failure and sudden death. We sought to compare the frequency and distribution of incidentally identified variants in DCM-associated genes between a clinical referral cohort with those in control and known case cohorts to determine the likelihood of pathogenicity among those undergoing genetic testing for non-DCM indications. Methods and Results A total of 39 rare, non-TTN DCM-associated genes were identified and evaluated from a clinical ES testing referral cohort (n=14 005, Baylor Genetic Laboratories) and compared with a DCM case cohort (n=9442) as well as a control cohort of population variants (n=141 456) derived from the gnomAD database. Variant frequencies in each cohort were compared. Signal-to-noise ratios were calculated comparing the DCM and ES cohort with the gnomAD cohort. The likely pathogenic/pathogenic variant yield in the DCM cohort (8.2%) was significantly higher than in the ES cohort (1.9%). Based on signal-to-noise and correlation analysis, incidental variants found in FLNC, RBM20, MYH6, DSP, ABCC9, JPH2, and NEXN had the greatest chance of being DCM-associated. Conclusions The distribution of pathogenic variants between the ES cohort and the DCM case cohort was gene specific, and variants found in the ES cohort were similar to variants found in the control cohort. Incidentally identified variants in specific genes are more associated with DCM than others.
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Affiliation(s)
- Qixin Yang
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC.,Department of Cardiology The First Affiliated Hospital, College of Medicine, Zhejiang University Hangzhou China
| | - Amy M Berkman
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC
| | - Jordan E Ezekian
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC
| | - Michael Rosamilia
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC
| | - Jill A Rosenfeld
- Department of Molecular and Human Genetics Baylor College of Medicine and Baylor Genetics Laboratories Houston TX
| | - Pengfei Liu
- Department of Molecular and Human Genetics Baylor College of Medicine and Baylor Genetics Laboratories Houston TX
| | - Andrew P Landstrom
- Department of Pediatrics, Division of Cardiology Duke University School of Medicine Durham NC.,Department of Cell Biology Duke University School of Medicine Durham NC
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7
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Desai DA, Rao VJ, Jegga AG, Dhandapany PS, Sadayappan S. Heterogeneous Distribution of Genetic Mutations in Myosin Binding Protein-C Paralogs. Front Genet 2022; 13:896117. [PMID: 35832193 PMCID: PMC9272480 DOI: 10.3389/fgene.2022.896117] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 06/07/2022] [Indexed: 11/29/2022] Open
Abstract
Myosin binding protein-C (MyBP-C) is a sarcomeric protein which regulates the force of contraction in striated muscles. Mutations in the MYBPC family of genes, including slow skeletal (MYBPC1), fast skeletal (MYBPC2) and cardiac (MYBPC3), can result in cardiac and skeletal myopathies. Nonetheless, their evolutionary pattern, pathogenicity and impact on MyBP-C protein structure remain to be elucidated. Therefore, the present study aimed to systematically assess the evolutionarily conserved and epigenetic patterns of MYBPC family mutations. Leveraging a machine learning (ML) approach, the Genome Aggregation Database (gnomAD) provided variants in MYBPC1, MYBPC2, and MYBPC3 genes. This was followed by an analysis with Ensembl’s variant effect predictor (VEP), resulting in the identification of 8,618, 3,871, and 3,071 variants in MYBPC1, MYBPC2, and MYBPC3, respectively. Missense variants comprised 61%–66% of total variants in which the third nucleotide positions in the codons were highly altered. Arginine was the most mutated amino acid, important because most disease-causing mutations in MyBP-C proteins are arginine in origin. Domains C5 and C6 of MyBP-C were found to be hotspots for most mutations in the MyBP-C family of proteins. A high percentage of truncated mutations in cMyBP-C cause cardiomyopathies. Arginine and glutamate were the top hits in fMyBP-C and cMyBP-C, respectively, and tryptophan and tyrosine were the most common among the three paralogs changing to premature stop codons and causing protein truncations at the carboxyl terminus. A heterogeneous epigenetic pattern was identified among the three MYBP-C paralogs. Overall, it was shown that databases using computational approaches can facilitate diagnosis and drug discovery to treat muscle disorders caused by MYBPC mutations.
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Affiliation(s)
- Darshini A. Desai
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH, United States
| | - Vinay J. Rao
- Cardiovascular Biology and Disease Theme, Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
| | - Anil G. Jegga
- Division of Biomedical Informatics, Cincinnati Children’s Hospital Medical Center, Cincinnati, OH, United States
- Department of Pediatrics, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Perundurai S. Dhandapany
- Cardiovascular Biology and Disease Theme, Institute for Stem Cell Science and Regenerative Medicine, Bangalore, India
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, United States
| | - Sakthivel Sadayappan
- Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH, United States
- *Correspondence: Sakthivel Sadayappan,
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8
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Touma AM, Tang W, Rasicci DV, Vang D, Rai A, Previs SB, Warshaw DM, Yengo CM, Sivaramakrishnan S. Nanosurfer Assay Dissects β-Cardiac Myosin and Cardiac Myosin-Binding Protein C Interactions. Biophys J 2022; 121:2449-2460. [PMID: 35591788 DOI: 10.1016/j.bpj.2022.05.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Revised: 04/13/2022] [Accepted: 05/13/2022] [Indexed: 11/02/2022] Open
Abstract
Cardiac myosin-binding protein C (cMyBP-C) modulates cardiac contractility through putative interactions with the myosin S2 tail and/or the thin filament. The relative contribution of these binding-partner interactions to cMyBP-C modulatory function remains unclear. Hence, we developed a "nanosurfer" assay as a model system to interrogate these cMyBP-C binding-partner interactions. Synthetic thick filaments were generated using recombinant human β-cardiac myosin subfragments (HMM or S1) attached to DNA nanotubes, with 14 or 28 nm spacing, corresponding to the 14.3 nm myosin spacing in native thick filaments. The nanosurfer assay consists of DNA nanotubes added to the in vitro motility assay so that myosins on the motility surface effectively deliver thin filaments to the DNA nanotubes, enhancing thin filament gliding probability on the DNA nanotubes. Thin filament velocities on nanotubes with either 14 or 28 nm myosin spacing were no different. We then characterized the effects of cMyBP-C on thin filament motility by alternating HMM and cMyBP-C N-terminal fragments (C0-C2 or C1-C2) on nanotubes every 14 nm. Both C0-C2 and C1-C2 reduced thin filament velocity 4-6 fold relative to HMM alone. Similar inhibition occurred using the myosin S1 construct, which lacks the myosin S2 region proposed to interact with cMyBP-C, suggesting that the cMyBP-C N-terminus must interact with other myosin head domains and/or actin to slow thin filament velocity. Thin filament velocity was unaffected by the C0-C1f fragment, which lacks the majority of the M-domain, supporting the importance of this domain for inhibitory interaction(s). A C0-C2 fragment with phosphomimetic replacement in the M-domain showed markedly less inhibition of thin filament velocity compared to its phosphonull counterpart, highlighting the modulatory role of M-domain phosphorylation on cMyBP-C function. Therefore, the nanosurfer assay provides a platform to precisely manipulate spatially dependent cMyBP-C binding partner interactions, shedding light on the molecular regulation of β-cardiac myosin contractility.
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Affiliation(s)
- Anja M Touma
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Wanjian Tang
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - David V Rasicci
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Duha Vang
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Ashim Rai
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA
| | - Samantha B Previs
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT
| | - David M Warshaw
- Department of Molecular Physiology and Biophysics, Cardiovascular Research Institute, University of Vermont, Burlington, VT
| | - Christopher M Yengo
- Department of Cellular and Molecular Physiology, Penn State College of Medicine, Hershey, Pennsylvania, USA
| | - Sivaraj Sivaramakrishnan
- Department of Genetics, Cell Biology, and Development, University of Minnesota, Minneapolis, MN, USA.
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9
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Torrado M, Maneiro E, Lamounier Junior A, Fernández-Burriel M, Sánchez Giralt S, Martínez-Carapeto A, Cazón L, Santiago E, Ochoa JP, McKenna WJ, Santomé L, Monserrat L. Identification of an elusive spliceogenic MYBPC3 variant in an otherwise genotype-negative hypertrophic cardiomyopathy pedigree. Sci Rep 2022; 12:7284. [PMID: 35508642 PMCID: PMC9068804 DOI: 10.1038/s41598-022-11159-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2021] [Accepted: 04/13/2022] [Indexed: 11/10/2022] Open
Abstract
The finding of a genotype-negative hypertrophic cardiomyopathy (HCM) pedigree with several affected members indicating a familial origin of the disease has driven this study to discover causative gene variants. Genetic testing of the proband and subsequent family screening revealed the presence of a rare variant in the MYBPC3 gene, c.3331−26T>G in intron 30, with evidence supporting cosegregation with the disease in the family. An analysis of potential splice-altering activity using several splicing algorithms consistently yielded low scores. Minigene expression analysis at the mRNA and protein levels revealed that c.3331−26T>G is a spliceogenic variant with major splice-altering activity leading to undetectable levels of properly spliced transcripts or the corresponding protein. Minigene and patient mRNA analyses indicated that this variant induces complete and partial retention of intron 30, which was expected to lead to haploinsufficiency in carrier patients. As most spliceogenic MYBPC3 variants, c.3331−26T>G appears to be non-recurrent, since it was identified in only two additional unrelated probands in our large HCM cohort. In fact, the frequency analysis of 46 known splice-altering MYBPC3 intronic nucleotide substitutions in our HCM cohort revealed 9 recurrent and 16 non-recurrent variants present in a few probands (≤ 4), while 21 were not detected. The identification of non-recurrent elusive MYBPC3 spliceogenic variants that escape detection by in silico algorithms represents a challenge for genetic diagnosis of HCM and contributes to solving a fraction of genotype-negative HCM cases.
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Affiliation(s)
- Mario Torrado
- Cardiovascular Research Group, University of A Coruña, Campus de Oza, Building Fortín, 15006, A Coruña, Spain. .,Biomedical Research Institute of A Coruña, A Coruña, Spain.
| | - Emilia Maneiro
- Biomedical Research Institute of A Coruña, A Coruña, Spain. .,Cardiovascular Genetics, Health in Code, Business Center Marineda, Avenida de Arteixo 43, Local 1A, 15008, A Coruña, Spain.
| | - Arsonval Lamounier Junior
- Cardiovascular Research Group, University of A Coruña, Campus de Oza, Building Fortín, 15006, A Coruña, Spain.,Biomedical Research Institute of A Coruña, A Coruña, Spain.,Cardiovascular Genetics, Health in Code, Business Center Marineda, Avenida de Arteixo 43, Local 1A, 15008, A Coruña, Spain.,Medical School, Universidade Vale do Rio Doce, Governador Valadares, MG, Brazil
| | | | | | | | - Laura Cazón
- Cardiovascular Genetics, Health in Code, Business Center Marineda, Avenida de Arteixo 43, Local 1A, 15008, A Coruña, Spain
| | - Elisa Santiago
- Cardiovascular Genetics, Health in Code, Business Center Marineda, Avenida de Arteixo 43, Local 1A, 15008, A Coruña, Spain
| | - Juan Pablo Ochoa
- Biomedical Research Institute of A Coruña, A Coruña, Spain.,Cardiovascular Genetics, Health in Code, Business Center Marineda, Avenida de Arteixo 43, Local 1A, 15008, A Coruña, Spain
| | - William J McKenna
- Cardiovascular Research Group, University of A Coruña, Campus de Oza, Building Fortín, 15006, A Coruña, Spain.,Biomedical Research Institute of A Coruña, A Coruña, Spain.,Institute of Cardiovascular Science, University College London, London, UK
| | - Luis Santomé
- Cardiovascular Genetics, Health in Code, Business Center Marineda, Avenida de Arteixo 43, Local 1A, 15008, A Coruña, Spain
| | - Lorenzo Monserrat
- Biomedical Research Institute of A Coruña, A Coruña, Spain.,Cardiovascular Genetics, Health in Code, Business Center Marineda, Avenida de Arteixo 43, Local 1A, 15008, A Coruña, Spain
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10
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Sepp R, Hategan L, Csányi B, Borbás J, Tringer A, Pálinkás ED, Nagy V, Takács H, Latinovics D, Nyolczas N, Pálinkás A, Faludi R, Rábai M, Szabó GT, Czuriga D, Balogh L, Halmosi R, Borbély A, Habon T, Hegedűs Z, Nagy I. The Genetic Architecture of Hypertrophic Cardiomyopathy in Hungary: Analysis of 242 Patients with a Panel of 98 Genes. Diagnostics (Basel) 2022; 12:diagnostics12051132. [PMID: 35626289 PMCID: PMC9139509 DOI: 10.3390/diagnostics12051132] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2022] [Revised: 04/24/2022] [Accepted: 04/29/2022] [Indexed: 12/03/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a primary disease of the myocardium most commonly caused by mutations in sarcomeric genes. We aimed to perform a nationwide large-scale genetic analysis of a previously unreported, representative HCM cohort in Hungary. A total of 242 consecutive HCM index patients (127 men, 44 ± 11 years) were studied with next generation sequencing using a custom-designed gene-panel comprising 98 cardiomyopathy-related genes. A total of 90 patients (37%) carried pathogenic/likely pathogenic (P/LP) variants. The percentage of patients with P/LP variants in genes with definitive evidence for HCM association was 93%. Most of the patients with P/LP variants had mutations in MYBPC3 (55 pts, 61%) and in MYH7 (21 pts, 23%). Double P/LP variants were present in four patients (1.7%). P/LP variants in other genes could be detected in ≤3% of patients. Of the patients without P/LP variants, 46 patients (19%) carried a variant of unknown significance. Non-HCM P/LP variants were identified in six patients (2.5%), with two in RAF1 (p.Leu633Val, p.Ser257Leu) and one in DES (p.Arg406Trp), FHL1 (p.Glu96Ter), TTN (p.Lys23480fs), and in the mitochondrial genome (m.3243A>G). Frameshift, nonsense, and splice-variants made up 82% of all P/LP MYBPC3 variants. In all the other genes, missense mutations were the dominant form of variants. The MYBPC3 p.Gln1233Ter, the MYBPC3 p.Pro955ArgfsTer95, and the MYBPC3 p.Ser593ProfsTer11 variants were identified in 12, 7, and 13 patients, respectively. These three variants made up 36% of all patients with identified P/LP variants, raising the possibility of a possible founder effect for these mutations. Similar to other HCM populations, the MYBPC3 and the MYH7 genes seemed to be the most frequently affected genes in Hungarian HCM patients. The high prevalence of three MYBPC3 mutations raises the possibility of a founder effect in our HCM cohort.
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Affiliation(s)
- Róbert Sepp
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
- Correspondence: ; Tel.: +36-30-267-5845; Fax: +36-62-545-820
| | - Lidia Hategan
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
| | - Beáta Csányi
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
| | - János Borbás
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
| | - Annamária Tringer
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
| | - Eszter Dalma Pálinkás
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
| | - Viktória Nagy
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
| | - Hedvig Takács
- Division of Non-Invasive Cardiology, Department of Internal Medicine, Faculty of Medicine, University of Szeged, Semmelweis u. 8, H-6725 Szeged, Hungary; (L.H.); (B.C.); (J.B.); (A.T.); (E.D.P.); (V.N.); (H.T.)
| | - Dóra Latinovics
- SeqOmics Biotechnology Ltd., Vállalkozók útja 7, H-6782 Mórahalom, Hungary; (D.L.); (I.N.)
| | - Noémi Nyolczas
- Gottsegen National Cardiovascular Center, Haller u. 29, H-1096 Budapest, Hungary;
- Military Hospital-State Health Center, Róbert Károly körút 44, H-1134 Budapest, Hungary
| | - Attila Pálinkás
- Elisabeth Hospital, Dr. Imre József u. 9, H-6800 Hódmezővásárhely, Hungary;
| | - Réka Faludi
- Heart Institute, Medical School, University of Pécs, Ifjúság útja 13, H-7624 Pécs, Hungary;
| | - Miklós Rábai
- Division of Cardiology, First Department of Medicine, Medical School, University of Pécs, Ifjúság útja 13, H-7624 Pécs, Hungary; (M.R.); (R.H.); (T.H.)
| | - Gábor Tamás Szabó
- Division of Cardiology and Division of Clinical Physiology, Department of Cardiology, University of Debrecen, Móricz Zsigmond körút 22, H-4032 Debrecen, Hungary; (G.T.S.); (D.C.); (L.B.); (A.B.)
| | - Dániel Czuriga
- Division of Cardiology and Division of Clinical Physiology, Department of Cardiology, University of Debrecen, Móricz Zsigmond körút 22, H-4032 Debrecen, Hungary; (G.T.S.); (D.C.); (L.B.); (A.B.)
| | - László Balogh
- Division of Cardiology and Division of Clinical Physiology, Department of Cardiology, University of Debrecen, Móricz Zsigmond körút 22, H-4032 Debrecen, Hungary; (G.T.S.); (D.C.); (L.B.); (A.B.)
| | - Róbert Halmosi
- Division of Cardiology, First Department of Medicine, Medical School, University of Pécs, Ifjúság útja 13, H-7624 Pécs, Hungary; (M.R.); (R.H.); (T.H.)
- Szentágothai Research Centre, University of Pécs, Ifjúság útja 20, H-7624 Pécs, Hungary
| | - Attila Borbély
- Division of Cardiology and Division of Clinical Physiology, Department of Cardiology, University of Debrecen, Móricz Zsigmond körút 22, H-4032 Debrecen, Hungary; (G.T.S.); (D.C.); (L.B.); (A.B.)
| | - Tamás Habon
- Division of Cardiology, First Department of Medicine, Medical School, University of Pécs, Ifjúság útja 13, H-7624 Pécs, Hungary; (M.R.); (R.H.); (T.H.)
| | - Zoltán Hegedűs
- Institute of Biophysics, Biological Research Centre, Eötvös Loránd Research Network, Temesvári krt. 62, H-6726 Szeged, Hungary;
- Department of Biochemistry and Medical Chemistry, Medical School, University of Pécs, Szigeti út 12, H-7624 Pécs, Hungary
| | - István Nagy
- SeqOmics Biotechnology Ltd., Vállalkozók útja 7, H-6782 Mórahalom, Hungary; (D.L.); (I.N.)
- Institute of Biochemistry, Biological Research Center, Eötvös Loránd Research Network, Temesvári krt. 62, H-6726 Szeged, Hungary
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11
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Liu Z, Chen X. Whole-exome sequencing establishes a diagnosis of Alstrom syndrome: a case report. Transl Pediatr 2022; 11:589-594. [PMID: 35558979 PMCID: PMC9085958 DOI: 10.21037/tp-21-623] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2021] [Accepted: 03/14/2022] [Indexed: 11/06/2022] Open
Abstract
BACKGROUND Alstrom syndrome (ALMS) is a rare genetic disorder. ALMS is characterized by progressive bilateral sensorineural hearing impairment, cone-rod dystrophy, infantile-onset cardiomyopathy, hypertriglyceridemia, accelerated non-alcoholic fatty liver disease, renal dysfunction and insulin-resistant diabetes mellitus (DM). DM typically develop in childhood or adolescence. Dilated cardiomyopathy may arise in infancy. Clinical symptoms appear with great variability and severity. Several cases have been reported worldwide; however, diagnosis remains challenging. CASE DESCRIPTION We report an 8-year-and-11-month-old female diagnosed with ALMS who had a long history of obesity and amblyopia from infancy. We found high levels of alanine aminotransferase (ALT) and aspartate aminotransferase (AST) in this patient. She showed no hearing disfunction. Recently, she presented with sudden-onset insulin-resistant DM. Genetic analysis revealed the heterozygous mutations c.8366delT, p.L2789* and c.6829C>T, p.R2277*. c.8366delT, which results in premature protein termination, has not been reported previously in ALMS1. Although the patient's two sisters died of acute heart failure following infection at 4 and 14 months respectively, she showed no signs of cardiomyopathy until now. CONCLUSIONS This case provides an unusual cause of genetic syndrome associated with diabetes. A detailed medical history, physical examination and appropriate gene analysis are critical for diagnosis. Our case identifies a novel ALMS1 mutation and reaffirms the great clinical variation of this disease even within families.
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Affiliation(s)
- Ziqin Liu
- Department of Endocrinology, Children's Hospital Capital Institute of Pediatrics, Beijing, China
| | - Xiaobo Chen
- Department of Endocrinology, Children's Hospital Capital Institute of Pediatrics, Beijing, China
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12
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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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13
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Bazrafshan S, Sibilia R, Girgla S, Viswanathan SK, Puckelwartz MJ, Sangha KS, Singh RR, Kakroo M, Jandarov R, Harris DM, Rubinstein J, Becker RC, McNally EM, Sadayappan S. South Asian-Specific MYBPC3 Δ25bp Deletion Carriers Display Hypercontraction and Impaired Diastolic Function Under Exercise Stress. Front Cardiovasc Med 2021; 8:766339. [PMID: 35004883 PMCID: PMC8733148 DOI: 10.3389/fcvm.2021.766339] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2021] [Accepted: 11/22/2021] [Indexed: 11/13/2022] Open
Abstract
Background: A 25-base pair (25bp) intronic deletion in the MYBPC3 gene enriched in South Asians (SAs) is a risk allele for late-onset left ventricular (LV) dysfunction, hypertrophy, and heart failure (HF) with several forms of cardiomyopathy. However, the effect of this variant on exercise parameters has not been evaluated. Methods: As a pilot study, 10 asymptomatic SA carriers of the MYBPC3 Δ25bp variant (52.9 ± 2.14 years) and 10 age- and gender-matched non-carriers (NCs) (50.1 ± 2.7 years) were evaluated at baseline and under exercise stress conditions using bicycle exercise echocardiography and continuous cardiac monitoring. Results: Baseline echocardiography parameters were not different between the two groups. However, in response to exercise stress, the carriers of Δ25bp had significantly higher LV ejection fraction (%) (CI: 4.57 ± 1.93; p < 0.0001), LV outflow tract peak velocity (m/s) (CI: 0.19 ± 0.07; p < 0.0001), and higher aortic valve (AV) peak velocity (m/s) (CI: 0.103 ± 0.08; p = 0.01) in comparison to NCs, and E/A ratio, a marker of diastolic compliance, was significantly lower in Δ25bp carriers (CI: 0.107 ± 0.102; p = 0.038). Interestingly, LV end-diastolic diameter (LVIDdia) was augmented in NCs in response to stress, while it did not increase in Δ25bp carriers (CI: 0.239 ± 0.125; p = 0.0002). Further, stress-induced right ventricular systolic excursion velocity s' (m/s), as a marker of right ventricle function, increased similarly in both groups, but tricuspid annular plane systolic excursion increased more in carriers (slope: 0.008; p = 0.0001), suggesting right ventricle functional differences between the two groups. Conclusions: These data support that MYBPC3 Δ25bp is associated with LV hypercontraction under stress conditions with evidence of diastolic impairment.
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Affiliation(s)
- Sholeh Bazrafshan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Robert Sibilia
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Saavia Girgla
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Shiv Kumar Viswanathan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Megan J. Puckelwartz
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Kiranpal S. Sangha
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Rohit R. Singh
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Mashhood Kakroo
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Roman Jandarov
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - David M. Harris
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Jack Rubinstein
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Richard C. Becker
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
| | - Elizabeth M. McNally
- Center for Genetic Medicine, Feinberg School of Medicine, Northwestern University, Chicago, IL, United States
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, College of Medicine, University of Cincinnati, Cincinnati, OH, United States
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14
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Pradeep R, Akram A, Proute MC, Kothur NR, Georgiou P, Serhiyenia T, Shi W, Kerolos ME, Mostafa JA. Understanding the Genetic and Molecular Basis of Familial Hypertrophic Cardiomyopathy and the Current Trends in Gene Therapy for Its Management. Cureus 2021; 13:e17548. [PMID: 34646605 PMCID: PMC8481153 DOI: 10.7759/cureus.17548] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/28/2021] [Indexed: 01/16/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a genetically acquired disease of cardiac myocytes. Studies show that 70% of this disease is a result of different mutations in various sarcomere genes. This review aims to discuss several genetic mutations, epigenetic factors, and signal transduction pathways leading to the development of HCM. In addition, this article elaborates on recent advances in gene therapies and their implications for managing this condition. We start by discussing the founding mutations in HCM and their effect on power stroke generation. The less explored field of epigenetics including methylation, acetylation, and the role of different micro RNAs in the development of cardiac muscle hypertrophy has been highlighted in this article. The signal transduction pathways that lead to gene transcription, which in turn lead to increased protein synthesis of cardiac muscle fibers are elaborated. Finally, the microscopic events leading to the pathophysiologic macro events of cardiac failure, and the current experimental trials of gene therapy models, and the clustered regularly interspaced short palindromic repeats (CRISPR) type 2 system proteins, are discussed. We have concluded our discussion by emphasizing the need for more studies on epigenomics and experimental designs for gene therapy in HCM patients. This review focuses on the process of HCM from initial mutation to the development of phenotypic expression and various points of intervention in cardiac myocardial hypertrophy development.
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Affiliation(s)
- Roshini Pradeep
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Aqsa Akram
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Matthew C Proute
- Family Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Nageshwar R Kothur
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Petros Georgiou
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Tatsiana Serhiyenia
- Internal Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Wangpan Shi
- Pathology, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Mina E Kerolos
- Medicine, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Jihan A Mostafa
- Psychiatry/Cognitive Behavioural Psychotherapy, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
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15
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Suay-Corredera C, Pricolo MR, Herrero-Galán E, Velázquez-Carreras D, Sánchez-Ortiz D, García-Giustiniani D, Delgado J, Galano-Frutos JJ, García-Cebollada H, Vilches S, Domínguez F, Molina MS, Barriales-Villa R, Frisso G, Sancho J, Serrano L, García-Pavía P, Monserrat L, Alegre-Cebollada J. Protein haploinsufficiency drivers identify MYBPC3 variants that cause hypertrophic cardiomyopathy. J Biol Chem 2021; 297:100854. [PMID: 34097875 PMCID: PMC8260873 DOI: 10.1016/j.jbc.2021.100854] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2021] [Revised: 05/21/2021] [Accepted: 06/03/2021] [Indexed: 02/06/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited cardiac disease. Variants in MYBPC3, the gene encoding cardiac myosin-binding protein C (cMyBP-C), are the leading cause of HCM. However, the pathogenicity status of hundreds of MYBPC3 variants found in patients remains unknown, as a consequence of our incomplete understanding of the pathomechanisms triggered by HCM-causing variants. Here, we examined 44 nontruncating MYBPC3 variants that we classified as HCM-linked or nonpathogenic according to cosegregation and population genetics criteria. We found that around half of the HCM-linked variants showed alterations in RNA splicing or protein stability, both of which can lead to cMyBP-C haploinsufficiency. These protein haploinsufficiency drivers associated with HCM pathogenicity with 100% and 94% specificity, respectively. Furthermore, we uncovered that 11% of nontruncating MYBPC3 variants currently classified as of uncertain significance in ClinVar induced one of these molecular phenotypes. Our strategy, which can be applied to other conditions induced by protein loss of function, supports the idea that cMyBP-C haploinsufficiency is a fundamental pathomechanism in HCM.
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Affiliation(s)
| | - Maria Rosaria Pricolo
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy
| | | | | | | | | | - Javier Delgado
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain
| | - Juan José Galano-Frutos
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain; Biocomputation and Complex Systems Physics Institute (BIFI). Joint Units BIFI-IQFR (CSIC) and GBs-CSIC, Universidad de Zaragoza, Zaragoza, Spain
| | - Helena García-Cebollada
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain; Biocomputation and Complex Systems Physics Institute (BIFI). Joint Units BIFI-IQFR (CSIC) and GBs-CSIC, Universidad de Zaragoza, Zaragoza, Spain
| | - Silvia Vilches
- Heart Failure and Inherited Cardiac Diseases Unit. Department of Cardiology. Hospital Universitario Puerta de Hierro, Madrid, Spain; European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-HEART), Madrid, Spain
| | - Fernando Domínguez
- Centro Nacional de Investigaciones Cardiovasculares (CNIC), Madrid, Spain; Heart Failure and Inherited Cardiac Diseases Unit. Department of Cardiology. Hospital Universitario Puerta de Hierro, Madrid, Spain; European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-HEART), Madrid, Spain; Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain
| | - María Sabater Molina
- European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-HEART), Madrid, Spain; Hospital C. Universitario Virgen de la Arrixaca, El Palmar, Murcia, Spain
| | - Roberto Barriales-Villa
- Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain; Unidad de Cardiopatías Familiares, Instituto de Investigación Biomédica de A Coruña (INIBIC), Complexo Hospitalario Universitario de A Coruña, Servizo Galego de Saúde (SERGAS), Universidade da Coruña, A Coruña, Spain
| | - Giulia Frisso
- Dipartimento di Medicina Molecolare e Biotecnologie Mediche, Università di Napoli Federico II, Naples, Italy; CEINGE Biotecnologie Avanzate, scarl, Naples, Italy
| | - Javier Sancho
- Departamento de Bioquímica y Biología Molecular y Celular, Facultad de Ciencias, Universidad de Zaragoza, Zaragoza, Spain; Biocomputation and Complex Systems Physics Institute (BIFI). Joint Units BIFI-IQFR (CSIC) and GBs-CSIC, Universidad de Zaragoza, Zaragoza, Spain; Aragon Health Research Institute (IIS Aragón), Zaragoza, Spain
| | - Luis Serrano
- EMBL/CRG Systems Biology Research Unit, Centre for Genomic Regulation (CRG), The Barcelona Institute of Science and Technology, Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Barcelona, Spain; Universitat Pompeu Fabra (UPF), Barcelona, Spain
| | - Pablo García-Pavía
- Heart Failure and Inherited Cardiac Diseases Unit. Department of Cardiology. Hospital Universitario Puerta de Hierro, Madrid, Spain; European Reference Network for Rare and Low Prevalence Complex Diseases of the Heart (ERN GUARD-HEART), Madrid, Spain; Centro de Investigación Biomédica en Red en Enfermedades Cardiovasculares (CIBERCV), Madrid, Spain; Universidad Francisco de Vitoria (UFV), Pozuelo de Alarcón, Madrid, Spain
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16
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Complex functionality of protein phosphatase 1 isoforms in the heart. Cell Signal 2021; 85:110059. [PMID: 34062239 DOI: 10.1016/j.cellsig.2021.110059] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2021] [Revised: 05/21/2021] [Accepted: 05/28/2021] [Indexed: 02/04/2023]
Abstract
Protein phosphatase 1(PP1) is a key regulator of cardiac function through dephosphorylating serine/threonine residues within target proteins to oppose the function of protein kinases. Studies from failing hearts of animal models and human patients have demonstrated significant increase of PP1 activity in myocardium, while elevated PP1 activity in transgenic mice leads to cardiac dysfunction, suggesting that PP1 might be a therapeutic target to ameliorate cardiac dysfunction in failing hearts. In fact, cardiac overexpression of inhibitor 1, the endogenous inhibitor of PP1, increases cardiac contractility and suppresses heart failure progression. However, this notion of PP1 inhibition for heart failure treatment has been challenged by recent studies on the isoform-specific roles of PP1 in the heart. PP1 is a holoenzyme composed of catalytic subunits (PP1α, PP1β, or PP1γ) and regulatory proteins that target them to distinct subcellular locations for functional specificity. This review will summarize how PP1 regulates phosphorylation of some of the key cardiac proteins involved in Ca2+ handling and cardiac contraction, and the potential role of PP1 isoforms in controlling cardiac physiology and pathophysiology.
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17
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Sweeney NM, Nahas SA, Chowdhury S, Batalov S, Clark M, Caylor S, Cakici J, Nigro JJ, Ding Y, Veeraraghavan N, Hobbs C, Dimmock D, Kingsmore SF. Rapid whole genome sequencing impacts care and resource utilization in infants with congenital heart disease. NPJ Genom Med 2021; 6:29. [PMID: 33888711 PMCID: PMC8062477 DOI: 10.1038/s41525-021-00192-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 03/19/2021] [Indexed: 11/09/2022] Open
Abstract
Congenital heart disease (CHD) is the most common congenital anomaly and a major cause of infant morbidity and mortality. While morbidity and mortality are highest in infants with underlying genetic conditions, molecular diagnoses are ascertained in only ~20% of cases using widely adopted genetic tests. Furthermore, cost of care for children and adults with CHD has increased dramatically. Rapid whole genome sequencing (rWGS) of newborns in intensive care units with suspected genetic diseases has been associated with increased rate of diagnosis and a net reduction in cost of care. In this study, we explored whether the clinical utility of rWGS extends to critically ill infants with structural CHD through a retrospective review of rWGS study data obtained from inpatient infants < 1 year with structural CHD at a regional children's hospital. rWGS diagnosed genetic disease in 46% of the enrolled infants. Moreover, genetic disease was identified five times more frequently with rWGS than microarray ± gene panel testing in 21 of these infants (rWGS diagnosed 43% versus 10% with microarray ± gene panels, p = 0.02). Molecular diagnoses ranged from syndromes affecting multiple organ systems to disorders limited to the cardiovascular system. The average daily hospital spending was lower in the time period post blood collection for rWGS compared to prior (p = 0.003) and further decreased after rWGS results (p = 0.000). The cost was not prohibitive to rWGS implementation in the care of this cohort of infants. rWGS provided timely actionable information that impacted care and there was evidence of decreased hospital spending around rWGS implementation.
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Affiliation(s)
- Nathaly M Sweeney
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA.
- Rady Children's Hospital, San Diego, CA, USA.
- Department of Pediatrics, University of California San Diego, La Jolla, CA, USA.
| | - Shareef A Nahas
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Shimul Chowdhury
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Sergey Batalov
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Michelle Clark
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Sara Caylor
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - Julie Cakici
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
- Department of Family Medicine and Public Health, University of California San Diego, La Jolla, CA, USA
| | - John J Nigro
- Rady Children's Hospital, San Diego, CA, USA
- Department of Surgery, University of California San Diego, La Jolla, CA, USA
| | - Yan Ding
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | | | - Charlotte Hobbs
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
| | - David Dimmock
- Rady Children's Institute for Genomic Medicine, San Diego, CA, USA
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18
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Duran J, Nickel L, Estrada M, Backs J, van den Hoogenhof MMG. CaMKIIδ Splice Variants in the Healthy and Diseased Heart. Front Cell Dev Biol 2021; 9:644630. [PMID: 33777949 PMCID: PMC7991079 DOI: 10.3389/fcell.2021.644630] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 02/22/2021] [Indexed: 01/16/2023] Open
Abstract
RNA splicing has been recognized in recent years as a pivotal player in heart development and disease. The Ca2+/calmodulin dependent protein kinase II delta (CaMKIIδ) is a multifunctional Ser/Thr kinase family and generates at least 11 different splice variants through alternative splicing. This enzyme, which belongs to the CaMKII family, is the predominant family member in the heart and functions as a messenger toward adaptive or detrimental signaling in cardiomyocytes. Classically, the nuclear CaMKIIδB and cytoplasmic CaMKIIδC splice variants are described as mediators of arrhythmias, contractile function, Ca2+ handling, and gene transcription. Recent findings also put CaMKIIδA and CaMKIIδ9 as cardinal players in the global CaMKII response in the heart. In this review, we discuss and summarize the new insights into CaMKIIδ splice variants and their (proposed) functions, as well as CaMKII-engineered mouse phenotypes and cardiac dysfunction related to CaMKIIδ missplicing. We also discuss RNA splicing factors affecting CaMKII splicing. Finally, we discuss the translational perspective derived from these insights and future directions on CaMKIIδ splicing research in the healthy and diseased heart.
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Affiliation(s)
- Javier Duran
- Institute of Experimental Cardiology, Heidelberg University, Heidelberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Lennart Nickel
- Institute of Experimental Cardiology, Heidelberg University, Heidelberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Manuel Estrada
- Faculty of Medicine, Institute of Biomedical Sciences, University of Chile, Santiago, Chile
| | - Johannes Backs
- Institute of Experimental Cardiology, Heidelberg University, Heidelberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
| | - Maarten M G van den Hoogenhof
- Institute of Experimental Cardiology, Heidelberg University, Heidelberg, Germany.,German Center for Cardiovascular Research (DZHK), Partner Site Heidelberg/Mannheim, Heidelberg, Germany
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19
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Hypertrophic Cardiomyopathy: Diverse Pathophysiology Revealed by Genetic Research, Toward Future Therapy. Keio J Med 2020; 69:77-87. [PMID: 32224552 DOI: 10.2302/kjm.2019-0012-oa] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is an intractable disease that causes heart failure mainly due to unexplained severe cardiac hypertrophy and diastolic dysfunction. HCM, which occurs in 0.2% of the general population, is the most common cause of sudden cardiac death in young people. HCM has been studied extensively using molecular genetic approaches. Genes encoding cardiac β-myosin heavy chain, cardiac myosin-binding protein C, and troponin complex, which were originally identified as causative genes, were subsequently reported to be frequently implicated in HCM. Indeed, HCM has been considered a disease of sarcomere gene mutations. However, fewer than half of patients with HCM have mutations in sarcomere genes. The others have been documented to have mutations in cardiac proteins in various other locations, including the Z disc, sarcoplasmic reticulum, plasma membrane, nucleus, and mitochondria. Next-generation sequencing makes it possible to detect mutations at high throughput, and it has become increasingly common to identify multiple cardiomyopathy-causing gene mutations in a single HCM patient. Elucidating how mutations in different genes contribute to the disease pathophysiology will be a challenge. In studies using animal models, sarcomere mutations generally tend to increase myocardial Ca2+ sensitivity, and some mutations increase the activity of myosin ATPase. Clinical trials of drugs to treat HCM are ongoing, and further new therapies based on pathophysiological analyses of the causative genes are eagerly anticipated.
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20
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Cibi DM, Bi-Lin KW, Shekeran SG, Sandireddy R, Tee N, Singh A, Wu Y, Srinivasan DK, Kovalik JP, Ghosh S, Seale P, Singh MK. Prdm16 Deficiency Leads to Age-Dependent Cardiac Hypertrophy, Adverse Remodeling, Mitochondrial Dysfunction, and Heart Failure. Cell Rep 2020; 33:108288. [PMID: 33086060 DOI: 10.1016/j.celrep.2020.108288] [Citation(s) in RCA: 32] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 03/23/2020] [Accepted: 09/29/2020] [Indexed: 01/09/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a well-established risk factor for cardiovascular mortality worldwide. Although hypertrophy is traditionally regarded as an adaptive response to physiological or pathological stress, prolonged hypertrophy can lead to heart failure. Here we demonstrate that Prdm16 is dispensable for cardiac development. However, it is required in the adult heart to preserve mitochondrial function and inhibit hypertrophy with advanced age. Cardiac-specific deletion of Prdm16 results in cardiac hypertrophy, excessive ventricular fibrosis, mitochondrial dysfunction, and impaired metabolic flexibility, leading to heart failure. We demonstrate that Prdm16 and euchromatic histone-lysine N-methyltransferase factors (Ehmts) act together to reduce expression of fetal genes reactivated in pathological hypertrophy by inhibiting the functions of the pro-hypertrophic transcription factor Myc. Although young Prdm16 knockout mice show normal cardiac function, they are predisposed to develop heart failure in response to metabolic stress. Our study demonstrates that Prdm16 protects the heart against age-dependent cardiac hypertrophy and heart failure.
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Affiliation(s)
- Dasan Mary Cibi
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857
| | - Kathleen Wung Bi-Lin
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857
| | - Shamini Guna Shekeran
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857
| | - Reddemma Sandireddy
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857
| | - Nicole Tee
- National Heart Research Institute Singapore, National Heart Center Singapore, Singapore 169609
| | - Anamika Singh
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857
| | - Yajun Wu
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117594
| | - Dinesh Kumar Srinivasan
- Department of Anatomy, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 117594
| | - Jean-Paul Kovalik
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857
| | - Sujoy Ghosh
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857
| | - Patrick Seale
- Institute for Diabetes, Obesity, and Metabolism, Department of Cell and Developmental Biology, Perelman School of Medicine at the University of Pennsylvania, Smilow Center for Translational Research, 3400 Civic Center Boulevard, Philadelphia, PA 19104, USA
| | - Manvendra K Singh
- Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore 169857; National Heart Research Institute Singapore, National Heart Center Singapore, Singapore 169609.
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21
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Arif M, Nabavizadeh P, Song T, Desai D, Singh R, Bazrafshan S, Kumar M, Wang Y, Gilbert RJ, Dhandapany PS, Becker RC, Kranias EG, Sadayappan S. Genetic, clinical, molecular, and pathogenic aspects of the South Asian-specific polymorphic MYBPC3 Δ25bp variant. Biophys Rev 2020; 12:1065-1084. [PMID: 32656747 PMCID: PMC7429610 DOI: 10.1007/s12551-020-00725-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 07/03/2020] [Indexed: 02/06/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is a cardiac genetic disease characterized by ventricular enlargement, diastolic dysfunction, and increased risk for sudden cardiac death. Sarcomeric genetic defects are the predominant known cause of HCM. In particular, mutations in the myosin-binding protein C gene (MYBPC3) are associated with ~ 40% of all HCM cases in which a genetic basis has been established. A decade ago, our group reported a 25-base pair deletion in intron 32 of MYBPC3 (MYBPC3Δ25bp) that is uniquely prevalent in South Asians and is associated with autosomal dominant cardiomyopathy. Although our studies suggest that this deletion results in left ventricular dysfunction, cardiomyopathies, and heart failure, the precise mechanism by which this variant predisposes to heart disease remains unclear. Increasingly appreciated, however, is the contribution of secondary risk factors, additional mutations, and lifestyle choices in augmenting or modifying the HCM phenotype in MYBPC3Δ25bp carriers. Therefore, the goal of this review article is to summarize the current research dedicated to understanding the molecular pathophysiology of HCM in South Asians with the MYBPC3Δ25bp variant. An emphasis is to review the latest techniques currently applied to explore the MYBPC3Δ25bp pathogenesis and to provide a foundation for developing new diagnostic strategies and advances in therapeutics.
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Affiliation(s)
- Mohammed Arif
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA.
| | - Pooneh Nabavizadeh
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Taejeong Song
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Darshini Desai
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Rohit Singh
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Sholeh Bazrafshan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Mohit Kumar
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Yigang Wang
- Department of Pathology and Laboratory Medicine, University of Cincinnati, College of Medicine, Cincinnati, OH, 45267, USA
| | - Richard J Gilbert
- Research Service, Providence VA Medical Center, Providence, RI, 02908, USA
| | - Perundurai S Dhandapany
- Centre for Cardiovascular Biology and Disease, Institute for Stem Cell Biology and Regenerative Medicine (inStem), Bangalore, India
- The Knight Cardiovascular Institute, Oregon Health and Science University, Portland, OR, USA
- Department of Medicine, Oregon Health and Science University, Portland, OR, USA
- Department of Molecular and Medical Genetics, Oregon Health and Science University, Portland, OR, USA
| | - Richard C Becker
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati, College of Medicine, Cincinnati, OH, 45267, USA
| | - Sakthivel Sadayappan
- Division of Cardiovascular Health and Disease, Department of Internal Medicine, Heart, Lung and Vascular Institute, University of Cincinnati, College of Medicine, 231 Albert Sabin Way, Cincinnati, OH, 45267-0575, USA
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22
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Kumar M, Haghighi K, Kranias EG, Sadayappan S. Phosphorylation of cardiac myosin-binding protein-C contributes to calcium homeostasis. J Biol Chem 2020; 295:11275-11291. [PMID: 32554466 DOI: 10.1074/jbc.ra120.013296] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2020] [Revised: 06/17/2020] [Indexed: 12/13/2022] Open
Abstract
Cardiac myosin-binding protein-C (cMyBP-C) is highly phosphorylated under basal conditions. However, its phosphorylation level is decreased in individuals with heart failure. The necessity of cMyBP-C phosphorylation for proper contractile function is well-established, but the physiological and pathological consequences of decreased cMyBP-C phosphorylation in the heart are not clear. Herein, using intact adult cardiomyocytes from mouse models expressing phospho-ablated (AAA) and phosphomimetic (DDD) cMyBP-C as well as controls, we found that cMyBP-C dephosphorylation is sufficient to reduce contractile parameters and calcium kinetics associated with prolonged decay time of the calcium transient and increased diastolic calcium levels. Isoproterenol stimulation reversed the depressive contractile and Ca2+-kinetic parameters. Moreover, caffeine-induced calcium release yielded no difference between AAA/DDD and controls in calcium content of the sarcoplasmic reticulum. On the other hand, sodium-calcium exchanger function and phosphorylation levels of calcium-handling proteins were significantly decreased in AAA hearts compared with controls. Stress conditions caused increases in both spontaneous aftercontractions in AAA cardiomyocytes and the incidence of arrhythmias in vivo compared with the controls. Treatment with omecamtiv mecarbil, a positive cardiac inotropic drug, rescued the contractile deficit in AAA cardiomyocytes, but not the calcium-handling abnormalities. These findings indicate a cascade effect whereby cMyBP-C dephosphorylation causes contractile defects, which then lead to calcium-cycling abnormalities, resulting in aftercontractions and increased incidence of cardiac arrhythmias under stress conditions. We conclude that improvement of contractile deficits alone without improving calcium handling may be insufficient for effective management of heart failure.
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Affiliation(s)
- Mohit Kumar
- Heart, Lung, and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA.,Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Kobra Haghighi
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Evangelia G Kranias
- Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
| | - Sakthivel Sadayappan
- Heart, Lung, and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, USA .,Department of Pharmacology and Systems Physiology, University of Cincinnati, Cincinnati, Ohio, USA
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23
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Hossain MB, Elbeck Z, Siga H, Knöll R. Myosin binding protein-C and hypertrophic cardiomyopathy: role of altered C10 domain. Cardiovasc Res 2020; 115:1943-1945. [PMID: 31263890 DOI: 10.1093/cvr/cvz167] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Affiliation(s)
- Mohammad Bakhtiar Hossain
- Research & Early Development, Cardiovascular, Renal and Metabolic Diseases (CVRM), Biopharmaceuticals R&D, AstraZeneca, 431 83 Mölndal, Sweden.,Integrated Cardio Metabolic Center (ICMC), Department of Medicine, Karolinska Institutet, 141 57 Huddinge, Sweden
| | - Zaher Elbeck
- Integrated Cardio Metabolic Center (ICMC), Department of Medicine, Karolinska Institutet, 141 57 Huddinge, Sweden
| | - Humam Siga
- Integrated Cardio Metabolic Center (ICMC), Department of Medicine, Karolinska Institutet, 141 57 Huddinge, Sweden
| | - Ralph Knöll
- Research & Early Development, Cardiovascular, Renal and Metabolic Diseases (CVRM), Biopharmaceuticals R&D, AstraZeneca, 431 83 Mölndal, Sweden.,Integrated Cardio Metabolic Center (ICMC), Department of Medicine, Karolinska Institutet, 141 57 Huddinge, Sweden
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24
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Kaier TE, Alaour B, Marber M. Cardiac Myosin-Binding Protein C-From Bench to Improved Diagnosis of Acute Myocardial Infarction. Cardiovasc Drugs Ther 2020; 33:221-230. [PMID: 30617437 PMCID: PMC6509074 DOI: 10.1007/s10557-018-6845-3] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Chest pain is responsible for 6-10% of all presentations to acute healthcare providers. Triage is inherently difficult and heavily reliant on the quantification of cardiac Troponin (cTn), as a minority of patients with an ultimate diagnosis of acute myocardial infarction (AMI) present with clear diagnostic features such as ST-elevation on the electrocardiogram. Owing to slow release and disappearance of cTn, many patients require repeat blood testing or present with stable but elevated concentrations of the best available biomarker and are thus caught at the interplay of sensitivity and specificity.We identified cardiac myosin-binding protein C (cMyC) in coronary venous effluent and developed a high-sensitivity assay by producing an array of monoclonal antibodies and choosing an ideal pair based on affinity and epitope maps. Compared to high-sensitivity cardiac Troponin (hs-cTn), we demonstrated that cMyC appears earlier and rises faster following myocardial necrosis. In this review, we discuss discovery and structure of cMyC, as well as the migration from a comparably insensitive to a high-sensitivity assay facilitating first clinical studies. This assay was subsequently used to describe relative abundance of the protein, compare sensitivity to two high-sensitivity cTn assays and test diagnostic performance in over 1900 patients presenting with chest pain and suspected AMI. A standout feature was cMyC's ability to more effectively triage patients. This distinction is likely related to the documented greater abundance and more rapid release profile, which could significantly improve the early triage of patients with suspected AMI.
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Affiliation(s)
- Thomas E Kaier
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, 4th Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK.
| | - Bashir Alaour
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, 4th Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK
| | - Michael Marber
- King's College London BHF Centre, The Rayne Institute, St Thomas' Hospital, 4th Floor Lambeth Wing, Westminster Bridge Road, London, SE1 7EH, UK
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25
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Abstract
The heart is an extraordinarily versatile pump, finely tuned to respond to a multitude of demands. Given the heart pumps without rest for decades its efficiency is particularly relevant. Although many proteins in the heart are essential for viability, the non-essential components can attract numerous mutations which can cause disease, possibly through alterations in pumping efficiency. Of these, myosin binding protein C is strongly over-represented with ~ 40% of all known mutations in hypertrophic cardiomyopathy. Therefore, a complete understanding of its molecular function in the cardiac sarcomere is warranted. In this review, we revisit contemporary and classical literature to clarify both the current standing of this fast-moving field and frame future unresolved questions. To date, much effort has been directed at understanding MyBP-C function on either thick or thin filaments. Here we aim to focus questions on how MyBP-C functions at a molecular level in the context of both the thick and thin filaments together. A concept that emerges is MyBP-C acts to govern interactions on two levels; controlling myosin access to the thin filament by sequestration on the thick filament, and controlling the activation state and access of myosin to its binding sites on the thin filament. Such affects are achieved through directed interactions mediated by phosphorylation (of MyBP-C and other sarcomeric components) and calcium.
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26
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Boese EA, Tollefson MR, Schnieders MJ, Darbro BW, Alward WLM, Fingert JH. Novel Intragenic PAX6 Deletion in a Pedigree with Aniridia, Morbid Obesity, and Diabetes. Curr Eye Res 2020; 45:91-96. [PMID: 31361967 PMCID: PMC10413309 DOI: 10.1080/02713683.2019.1649704] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/03/2019] [Revised: 07/18/2019] [Accepted: 07/20/2019] [Indexed: 10/26/2022]
Abstract
Purpose: Aniridia is a rare congenital eye disease, characterized by a constellation of symptoms including hypoplastic irides, foveal hypoplasia, early cataract, corneal stem cell deficiency, and glaucoma. Large chromosomal deletions spanning the PAX6 gene cause WAGR syndrome (Wilms tumor, aniridia, genitourinary anomalies, and intellectual disability [formerly called mental retardation]). We describe clinical and genetic studies of a three-generation pedigree with aniridia along with additional systemic conditions (morbid obesity, diabetes) suggesting the possibility of a contiguous-gene syndrome like WAGR.Methods: Clinical records were obtained and DNA was prepared from blood samples from three of the four patients and tested for mutations in the coding sequences of the PAX6 gene. The index patient also had cardiomyopathy and was tested for known cardiomyopathy genetic mutations using a next-generation DNA sequencing assay.Results: We discovered a novel intragenic PAX6 mutation, a 16 bp heterozygous deletion c.203delCCAGGGCAATCGGTGG, with Sanger sequencing that is the likely cause of autosomal dominant aniridia in this pedigree. This PAX6 deletion causes a frameshift in predicted protein translation and a subsequent premature termination, p.Pro68Leufs*6. The PAX6 deletion was detected in all three available family members with aniridia, the index patient, his mother, and his maternal aunt but was not observed in the Exome Aggregation Consortium (ExAC) database. Targeted sequencing of known cardiomyopathy genes in the index patient identified a second mutation, a 1.7 Mp deletion that spans the MYBPC3 gene.Conclusions: We report a pedigree with aniridia and other systemic abnormalities that were initially suspicious for a contiguous-gene syndrome like WAGR. However, genetic analysis of the pedigree revealed two independent genetic abnormalities on chromosome 11p: 1) a novel PAX6 mutation, and 2) a large chromosome deletion spanning MYBPC3, a known cardiomyopathy gene. It is unclear if morbid obesity and type II diabetes mellitus have a related genetic cause.
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Affiliation(s)
- Erin A Boese
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Mallory R Tollefson
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Michael J Schnieders
- Department of Biochemistry, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Benjamin W Darbro
- Department of Pediatrics, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - Wallace L M Alward
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
| | - John H Fingert
- Department of Ophthalmology and Visual Sciences, Carver College of Medicine, University of Iowa, Iowa City, IA, USA
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27
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Kuster DWD, Lynch TL, Barefield DY, Sivaguru M, Kuffel G, Zilliox MJ, Lee KH, Craig R, Namakkal-Soorappan R, Sadayappan S. Altered C10 domain in cardiac myosin binding protein-C results in hypertrophic cardiomyopathy. Cardiovasc Res 2019; 115:1986-1997. [PMID: 31050699 PMCID: PMC6872972 DOI: 10.1093/cvr/cvz111] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/20/2018] [Revised: 04/04/2019] [Accepted: 04/25/2019] [Indexed: 12/12/2022] Open
Abstract
AIMS A 25-base pair deletion in the cardiac myosin binding protein-C (cMyBP-C) gene (MYBPC3), proposed to skip exon 33, modifies the C10 domain (cMyBP-CΔC10mut) and is associated with hypertrophic cardiomyopathy (HCM) and heart failure, affecting approximately 100 million South Asians. However, the molecular mechanisms underlying the pathogenicity of cMyBP-CΔC10mutin vivo are unknown. We hypothesized that expression of cMyBP-CΔC10mut exerts a poison polypeptide effect leading to improper assembly of cardiac sarcomeres and the development of HCM. METHODS AND RESULTS To determine whether expression of cMyBP-CΔC10mut is sufficient to cause HCM and contractile dysfunction in vivo, we generated transgenic (TG) mice having cardiac-specific protein expression of cMyBP-CΔC10mut at approximately half the level of endogenous cMyBP-C. At 12 weeks of age, significant hypertrophy was observed in TG mice expressing cMyBP-CΔC10mut (heart weight/body weight ratio: 4.43 ± 0.11 mg/g non-transgenic (NTG) vs. 5.34 ± 0.25 mg/g cMyBP-CΔC10mut, P < 0.05). Furthermore, haematoxylin and eosin, Masson's trichrome staining, as well as second-harmonic generation imaging revealed the presence of significant fibrosis and a greater relative nuclear area in cMyBP-CΔC10mut hearts compared with NTG controls. M-mode echocardiography analysis revealed hypercontractile hearts (EF: 53.4%±2.9% NTG vs. 66.4% ± 4.7% cMyBP-CΔC10mut; P < 0.05) and early diastolic dysfunction (E/E': 28.7 ± 3.7 NTG vs. 46.3 ± 8.4 cMyBP-CΔC10mut; P < 0.05), indicating the presence of an HCM phenotype. To assess whether these changes manifested at the myofilament level, contractile function of single skinned cardiomyocytes was measured. Preserved maximum force generation and increased Ca2+-sensitivity of force generation were observed in cardiomyocytes from cMyBP-CΔC10mut mice compared with NTG controls (EC50: 3.6 ± 0.02 µM NTG vs. 2.90 ± 0.01 µM cMyBP-CΔC10mut; P < 0.0001). CONCLUSION Expression of cMyBP-C protein with a modified C10 domain is sufficient to cause contractile dysfunction and HCM in vivo.
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MESH Headings
- Animals
- Calcium Signaling
- Cardiomyopathy, Hypertrophic/genetics
- Cardiomyopathy, Hypertrophic/metabolism
- Cardiomyopathy, Hypertrophic/pathology
- Cardiomyopathy, Hypertrophic/physiopathology
- Carrier Proteins/genetics
- Carrier Proteins/metabolism
- Disease Models, Animal
- Fibrosis
- Gene Expression Regulation
- Gene Regulatory Networks
- Genetic Predisposition to Disease
- Mice, Transgenic
- Mutation
- Myocardial Contraction
- Myocytes, Cardiac/metabolism
- Myocytes, Cardiac/pathology
- Protein Domains
- Sarcomeres/genetics
- Sarcomeres/metabolism
- Sarcomeres/pathology
- Ventricular Dysfunction, Left/genetics
- Ventricular Dysfunction, Left/metabolism
- Ventricular Dysfunction, Left/pathology
- Ventricular Dysfunction, Left/physiopathology
- Ventricular Remodeling
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Affiliation(s)
- Diederik W D Kuster
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
- Department of Physiology, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, Netherlands
| | - Thomas L Lynch
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
| | - David Y Barefield
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
- Center for Genetic Medicine, Northwestern University, Chicago, IL, USA
| | - Mayandi Sivaguru
- Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Champaign, IL, USA
| | - Gina Kuffel
- Public Health Sciences, Loyola University Chicago, Maywood, IL, USA
| | | | - Kyoung Hwan Lee
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Roger Craig
- Division of Cell Biology and Imaging, Department of Radiology, University of Massachusetts Medical School, Worcester, MA, USA
| | - Rajasekaran Namakkal-Soorappan
- Molecular and Cellular Pathology, Department of Pathology, School of Medicine, The University of Alabama at Birmingham, Birmingham, AL, USA
| | - Sakthivel Sadayappan
- Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
- Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, 231 Albert Sabin Way, Cincinnati, OH, USA
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28
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Pinto YM, Reckman YJ. Formins Emerge as a Cause of Hypertrophic Cardiomyopathy: New Genes for Thick Hearts. J Am Coll Cardiol 2019; 72:2468-2470. [PMID: 30442289 DOI: 10.1016/j.jacc.2018.09.026] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/03/2018] [Accepted: 09/08/2018] [Indexed: 10/27/2022]
Affiliation(s)
- Yigal M Pinto
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands.
| | - Yolan J Reckman
- Department of Experimental Cardiology, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam Cardiovascular Sciences, Amsterdam, the Netherlands
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29
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Spudich JA. Three perspectives on the molecular basis of hypercontractility caused by hypertrophic cardiomyopathy mutations. Pflugers Arch 2019; 471:701-717. [PMID: 30767072 PMCID: PMC6475635 DOI: 10.1007/s00424-019-02259-2] [Citation(s) in RCA: 104] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2018] [Revised: 01/11/2019] [Accepted: 01/20/2019] [Indexed: 01/10/2023]
Abstract
Several lines of evidence suggest that the primary effect of hypertrophic cardiomyopathy mutations in human β-cardiac myosin is hypercontractility of the heart, which leads to subsequent hypertrophy, fibrosis, and myofilament disarray. Here, I describe three perspectives on the molecular basis of this hypercontractility. The first is that hypercontractility results from changes in the fundamental parameters of the actin-activated β-cardiac myosin chemo-mechanical ATPase cycle. The second considers that hypercontractility results from an increase in the number of functionally accessible heads in the sarcomere for interaction with actin. The final and third perspective is that load dependence of contractility is affected by cardiomyopathy mutations and small-molecule effectors in a manner that changes the power output of cardiac contraction. Experimental approaches associated with each perspective are described along with concepts of therapeutic approaches that could prove valuable in treating hypertrophic cardiomyopathy.
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Affiliation(s)
- James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.
- Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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30
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Li CJ, Chen CS, Yiang GT, Tsai APY, Liao WT, Wu MY. Advanced Evolution of Pathogenesis Concepts in Cardiomyopathies. J Clin Med 2019; 8:jcm8040520. [PMID: 30995779 PMCID: PMC6518034 DOI: 10.3390/jcm8040520] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2019] [Revised: 04/12/2019] [Accepted: 04/12/2019] [Indexed: 12/15/2022] Open
Abstract
Cardiomyopathy is a group of heterogeneous cardiac diseases that impair systolic and diastolic function, and can induce chronic heart failure and sudden cardiac death. Cardiomyopathy is prevalent in the general population, with high morbidity and mortality rates, and contributes to nearly 20% of sudden cardiac deaths in younger individuals. Genetic mutations associated with cardiomyopathy play a key role in disease formation, especially the mutation of sarcomere encoding genes and ATP kinase genes, such as titin, lamin A/C, myosin heavy chain 7, and troponin T1. Pathogenesis of cardiomyopathy occurs by multiple complex steps involving several pathways, including the Ras-Raf-mitogen-activated protein kinase-extracellular signal-activated kinase pathway, G-protein signaling, mechanotransduction pathway, and protein kinase B/phosphoinositide 3-kinase signaling. Excess biomechanical stress induces apoptosis signaling in cardiomyocytes, leading to cell loss, which can induce myocardial fibrosis and remodeling. The clinical features and pathophysiology of cardiomyopathy are discussed. Although several basic and clinical studies have investigated the mechanism of cardiomyopathy, the detailed pathophysiology remains unclear. This review summarizes current concepts and focuses on the molecular mechanisms of cardiomyopathy, especially in the signaling from mutation to clinical phenotype, with the aim of informing the development of therapeutic interventions.
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Affiliation(s)
- Chia-Jung Li
- Department of Obstetrics and Gynecology, Kaohsiung Veterans General Hospital, Kaohsiung 813, Taiwan.
| | - Chien-Sheng Chen
- Department of Emergency Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei 231, Taiwan.
- Department of Emergency Medicine, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
| | - Giou-Teng Yiang
- Department of Emergency Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei 231, Taiwan.
- Department of Emergency Medicine, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
| | - Andy Po-Yi Tsai
- Department of Medical Research, Buddhist Tzu Chi General Hospital, Hualien 970, Taiwan.
| | - Wan-Ting Liao
- Institute of Medicine, Chung Shan Medical University, Taichung 402, Taiwan.
- Chinese Medicine Department, Show Chwan Memorial Hospital, Changhua 500, Taiwan.
| | - Meng-Yu Wu
- Department of Emergency Medicine, Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei 231, Taiwan.
- Department of Emergency Medicine, School of Medicine, Tzu Chi University, Hualien 970, Taiwan.
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31
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Role of intrinsic disorder in muscle sarcomeres. PROGRESS IN MOLECULAR BIOLOGY AND TRANSLATIONAL SCIENCE 2019; 166:311-340. [PMID: 31521234 DOI: 10.1016/bs.pmbts.2019.03.014] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The role and utility of intrinsically disordered regions (IDRs) is reviewed for two groups of sarcomeric proteins, such as members of tropomodulin/leiomodin (Tmod/Lmod) protein homology group and myosin binding protein C (MyBP-C). These two types of sarcomeric proteins represent very different but strongly interdependent functions, being responsible for maintaining structure and operation of the muscle sarcomere. The role of IDRs in the formation of complexes between thin filaments and Tmods/Lmods is discussed within the framework of current understanding of the thin filament length regulation. For MyBP-C, the function of IDRs is discussed in the context of MYBP-C-dependent sarcomere contraction and actomyosin activation.
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32
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Barefield DY, McNamara JW, Lynch TL, Kuster DWD, Govindan S, Haar L, Wang Y, Taylor EN, Lorenz JN, Nieman ML, Zhu G, Luther PK, Varró A, Dobrev D, Ai X, Janssen PML, Kass DA, Jones WK, Gilbert RJ, Sadayappan S. Ablation of the calpain-targeted site in cardiac myosin binding protein-C is cardioprotective during ischemia-reperfusion injury. J Mol Cell Cardiol 2019; 129:236-246. [PMID: 30862451 PMCID: PMC7222036 DOI: 10.1016/j.yjmcc.2019.03.006] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2018] [Revised: 03/07/2019] [Accepted: 03/08/2019] [Indexed: 12/31/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) phosphorylation is essential for normal heart function and protects the heart from ischemia-reperfusion (I/R) injury. It is known that protein kinase-A (PKA)-mediated phosphorylation of cMyBP-C prevents I/R-dependent proteolysis, whereas dephosphorylation of cMyBP-C at PKA sites correlates with its degradation. While sites on cMyBP-C associated with phosphorylation and proteolysis co-localize, the mechanisms that link cMyBP-C phosphorylation and proteolysis during cardioprotection are not well understood. Therefore, we aimed to determine if abrogation of cMyBP-C proteolysis in association with calpain, a calcium-activated protease, confers cardioprotection during I/R injury. Calpain is activated in both human ischemic heart samples and ischemic mouse myocardium where cMyBP-C is dephosphorylated and undergoes proteolysis. Moreover, cMyBP-C is a substrate for calpain proteolysis and cleaved by calpain at residues 272-TSLAGAGRR-280, a domain termed as the calpain-target site (CTS). Cardiac-specific transgenic (Tg) mice in which the CTS motif was ablated were bred into a cMyBP-C null background. These Tg mice were conclusively shown to possess a normal basal structure and function by analysis of histology, electron microscopy, immunofluorescence microscopy, Q-space MRI of tissue architecture, echocardiography, and hemodynamics. However, the genetic ablation of the CTS motif conferred resistance to calpain-mediated proteolysis of cMyBP-C. Following I/R injury, the loss of the CTS reduced infarct size compared to non-transgenic controls. Collectively, these findings demonstrate the physiological significance of calpain-targeted cMyBP-C proteolysis and provide a rationale for studying inhibition of calpain-mediated proteolysis of cMyBP-C as a therapeutic target for cardioprotection.
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Affiliation(s)
- David Y Barefield
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA; Center for Genetic Medicine, Northwestern University, Chicago, IL, USA.
| | - James W McNamara
- Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA
| | - Thomas L Lynch
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA; Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Maywood, IL, USA
| | - Diederik W D Kuster
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA; Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands
| | - Suresh Govindan
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA
| | - Lauren Haar
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Maywood, IL, USA
| | - Yang Wang
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Maywood, IL, USA
| | - Erik N Taylor
- Department of Physiology and Biophysics, Boston University, Boston, MA, USA
| | - John N Lorenz
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Michelle L Nieman
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | - Guangshuo Zhu
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Pradeep K Luther
- Molecular Medicine Section, National Heart and Lung Institute, Imperial College London, London, UK
| | - Andras Varró
- Department of Pharmacology and Pharmacotherapy, Faculty of Medicine, University of Szeged, Szeged, Hungary
| | - Dobromir Dobrev
- Institute of Pharmacology, West German Heart and Vascular Center, University Duisburg-Essen, Essen, Germany
| | - Xun Ai
- Department of Physiology and Biophysics, Rush University, Chicago, IL, USA
| | - Paul M L Janssen
- Department of Physiology and Cell Biology, The Ohio State University College of Medicine, Columbus, OH, USA
| | - David A Kass
- Division of Cardiology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, MD, USA
| | - Walter Keith Jones
- Department of Molecular Pharmacology and Therapeutics, Loyola University Chicago, Maywood, IL, USA
| | - Richard J Gilbert
- Research Service, Providence VA Medical Center and Brown University, Providence, RI, USA
| | - Sakthivel Sadayappan
- Department of Cell and Molecular Physiology, Loyola University Chicago, Maywood, IL, USA; Heart, Lung and Vascular Institute, Division of Cardiovascular Health and Disease, Department of Internal Medicine, University of Cincinnati, Cincinnati, OH, USA.
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33
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McNamara JW, Sadayappan S. Skeletal myosin binding protein-C: An increasingly important regulator of striated muscle physiology. Arch Biochem Biophys 2018; 660:121-128. [PMID: 30339776 DOI: 10.1016/j.abb.2018.10.007] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2018] [Revised: 10/07/2018] [Accepted: 10/11/2018] [Indexed: 12/22/2022]
Abstract
The Myosin Binding Protein-C (MyBP-C) family is a group of sarcomeric proteins important for striated muscle structure and function. Comprising approximately 2% of the myofilament mass, MyBP-C has important roles in both contraction and relaxation. Three paralogs of MyBP-C are encoded by separate genes with distinct expression profiles in striated muscle. In mammals, cardiac MyBP-C is limited to the heart, and it is the most extensively studied owing to its involvement in cardiomyopathies. However, the roles of two skeletal paralogs, slow and fast, in muscle biology remain poorly characterized. Nonetheless, both have been recently implicated in the development of skeletal myopathies. This calls for a better understanding of their function in the pathophysiology of distal arthrogryposis. This review characterizes MyBP-C as a whole and points out knowledge gaps that still remain with respect to skeletal MyBP-C.
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Affiliation(s)
- James W McNamara
- Heart, Lung and Vascular Institute, Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH 45236, USA
| | - Sakthivel Sadayappan
- Heart, Lung and Vascular Institute, Department of Internal Medicine, Division of Cardiovascular Health and Disease, University of Cincinnati, Cincinnati, OH 45236, USA.
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34
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Wang L, Geist J, Grogan A, Hu LYR, Kontrogianni-Konstantopoulos A. Thick Filament Protein Network, Functions, and Disease Association. Compr Physiol 2018; 8:631-709. [PMID: 29687901 PMCID: PMC6404781 DOI: 10.1002/cphy.c170023] [Citation(s) in RCA: 48] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Sarcomeres consist of highly ordered arrays of thick myosin and thin actin filaments along with accessory proteins. Thick filaments occupy the center of sarcomeres where they partially overlap with thin filaments. The sliding of thick filaments past thin filaments is a highly regulated process that occurs in an ATP-dependent manner driving muscle contraction. In addition to myosin that makes up the backbone of the thick filament, four other proteins which are intimately bound to the thick filament, myosin binding protein-C, titin, myomesin, and obscurin play important structural and regulatory roles. Consistent with this, mutations in the respective genes have been associated with idiopathic and congenital forms of skeletal and cardiac myopathies. In this review, we aim to summarize our current knowledge on the molecular structure, subcellular localization, interacting partners, function, modulation via posttranslational modifications, and disease involvement of these five major proteins that comprise the thick filament of striated muscle cells. © 2018 American Physiological Society. Compr Physiol 8:631-709, 2018.
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Affiliation(s)
- Li Wang
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Janelle Geist
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Alyssa Grogan
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
| | - Li-Yen R. Hu
- Department of Biochemistry and Molecular Biology, University of Maryland, Baltimore, Maryland, USA
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35
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Abstract
Dilated cardiomyopathy (DCM) affects approximately 1 in 250 individuals and is the leading indication for heart transplantation. DCM is often familial, and the most common genetic predisposition is a truncating variation in the giant sarcomeric protein, titin, which occurs in up to 15% of ambulant patients with DCM and 25% of end-stage or familial cases. In this article, we review the evidence for the role of titin truncation in the pathogenesis of DCM and our understanding of the molecular mechanisms and pathophysiological consequences of variation in the gene encoding titin (TTN). Such variation is common in the general population (up to 1% of individuals), and we consider key features that discriminate variants with disease-causing potential from those that are benign. We summarize strategies for clinical interpretation of genetic variants for use in the diagnosis of patients and the evaluation of their relatives. Finally, we consider the contemporary and potential future role for genetic stratification in cardiomyopathy and in the general population, evaluating titin variation as a predictor of outcome and treatment response for precision medicine.
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Affiliation(s)
- James S Ware
- National Heart and Lung Institute, Imperial College London, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.,Medical Research College (MRC) London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK
| | - Stuart A Cook
- National Heart and Lung Institute, Imperial College London, Royal Brompton Hospital, Sydney Street, London SW3 6NP, UK.,Medical Research College (MRC) London Institute of Medical Sciences, Du Cane Road, London W12 0NN, UK.,Duke-National University of Singapore (Duke-NUS) Medical School and National Heart Centre Singapore, 8 College Road, 169857, Singapore
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36
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Viswanathan SK, Sanders HK, McNamara JW, Jagadeesan A, Jahangir A, Tajik AJ, Sadayappan S. Hypertrophic cardiomyopathy clinical phenotype is independent of gene mutation and mutation dosage. PLoS One 2017; 12:e0187948. [PMID: 29121657 PMCID: PMC5679632 DOI: 10.1371/journal.pone.0187948] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2017] [Accepted: 10/27/2017] [Indexed: 12/27/2022] Open
Abstract
Over 1,500 gene mutations are known to cause hypertrophic cardiomyopathy (HCM). Previous studies suggest that cardiac β-myosin heavy chain (MYH7) gene mutations are commonly associated with a more severe phenotype, compared to cardiac myosin binding protein-C (MYBPC3) gene mutations with milder phenotype, incomplete penetrance and later age of onset. Compound mutations can worsen the phenotype. This study aimed to validate these comparative differences in a large cohort of individuals and families with HCM. We performed genome-phenome correlation among 80 symptomatic HCM patients, 35 asymptomatic carriers and 35 non-carriers, using an 18-gene clinical diagnostic HCM panel. A total of 125 mutations were identified in 14 genes. MYBPC3 and MYH7 mutations contributed to 50.0% and 24.4% of the HCM patients, respectively, suggesting that MYBPC3 mutations were the most frequent cause of HCM in our cohort. Double mutations were found in only nine HCM patients (7.8%) who were phenotypically indistinguishable from single-mutation carriers. Comparisons of clinical parameters of MYBPC3 and MYH7 mutants were not statistically significant, but asymptomatic carriers had high left ventricular ejection fraction and diastolic dysfunction when compared to non-carriers. The presence of double mutations increases the risk for symptomatic HCM with no change in severity, as determined in this study subset. The pathologic effects of MYBPC3 and MYH7 were found to be independent of gene mutation location. Furthermore, HCM pathology is independent of protein domain disruption in both MYBPC3 and MYH7. These data provide evidence that MYBPC3 mutations constitute the preeminent cause of HCM and that they are phenotypically indistinguishable from HCM caused by MYH7 mutations.
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Affiliation(s)
- Shiv Kumar Viswanathan
- Heart Lung Vascular Institute, Division of Cardiology, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Cell and Molecular Physiology, Center for Translational Research and Education, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Heather K. Sanders
- Aurora Cardiovascular Services, St. Luke’s Medical Center, Milwaukee, Wisconsin, United States of America
- Center for Integrative Research on Cardiovascular Aging (CIRCA), Aurora Health Care, Milwaukee, Wisconsin, United States of America
| | - James W. McNamara
- Heart Lung Vascular Institute, Division of Cardiology, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Cell and Molecular Physiology, Center for Translational Research and Education, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Aravindakshan Jagadeesan
- Department of Cell and Molecular Physiology, Center for Translational Research and Education, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, United States of America
| | - Arshad Jahangir
- Aurora Cardiovascular Services, St. Luke’s Medical Center, Milwaukee, Wisconsin, United States of America
- Center for Integrative Research on Cardiovascular Aging (CIRCA), Aurora Health Care, Milwaukee, Wisconsin, United States of America
| | - A. Jamil Tajik
- Aurora Cardiovascular Services, St. Luke’s Medical Center, Milwaukee, Wisconsin, United States of America
- Center for Integrative Research on Cardiovascular Aging (CIRCA), Aurora Health Care, Milwaukee, Wisconsin, United States of America
| | - Sakthivel Sadayappan
- Heart Lung Vascular Institute, Division of Cardiology, Department of Internal Medicine, University of Cincinnati, Cincinnati, Ohio, United States of America
- Department of Cell and Molecular Physiology, Center for Translational Research and Education, Health Sciences Division, Loyola University Chicago, Maywood, Illinois, United States of America
- * E-mail:
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37
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Barefield DY, Puckelwartz MJ, Kim EY, Wilsbacher LD, Vo AH, Waters EA, Earley JU, Hadhazy M, Dellefave-Castillo L, Pesce LL, McNally EM. Experimental Modeling Supports a Role for MyBP-HL as a Novel Myofilament Component in Arrhythmia and Dilated Cardiomyopathy. Circulation 2017; 136:1477-1491. [PMID: 28778945 DOI: 10.1161/circulationaha.117.028585] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2017] [Accepted: 07/21/2017] [Indexed: 12/23/2022]
Abstract
BACKGROUND Cardiomyopathy and arrhythmias are under significant genetic influence. Here, we studied a family with dilated cardiomyopathy and associated conduction system disease in whom prior clinical cardiac gene panel testing was unrevealing. METHODS Whole-genome sequencing and induced pluripotent stem cells were used to examine a family with dilated cardiomyopathy and atrial and ventricular arrhythmias. We also characterized a mouse model with heterozygous and homozygous deletion of Mybphl. RESULTS Whole-genome sequencing identified a premature stop codon, R255X, in the MYBPHL gene encoding MyBP-HL (myosin-binding protein-H like), a novel member of the myosin-binding protein family. MYBPHL was found to have high atrial expression with low ventricular expression. We determined that MyBP-HL protein was myofilament associated in the atria, and truncated MyBP-HL protein failed to incorporate into the myofilament. Human cell modeling demonstrated reduced expression from the mutant MYBPHL allele. Echocardiography of Mybphl heterozygous and null mouse hearts exhibited a 36% reduction in fractional shortening and an increased diastolic ventricular chamber size. Atria weight normalized to total heart weight was significantly increased in Mybphl heterozygous and null mice. Using a reporter system, we detected robust expression of Mybphl in the atria, and in discrete puncta throughout the right ventricular wall and septum, as well. Telemetric electrocardiogram recordings in Mybphl mice revealed cardiac conduction system abnormalities with aberrant atrioventricular conduction and an increased rate of arrhythmia in heterozygous and null mice. CONCLUSIONS The findings of reduced ventricular function and conduction system defects in Mybphl mice support that MYBPHL truncations may increase risk for human arrhythmias and cardiomyopathy.
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Affiliation(s)
- David Y Barefield
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Megan J Puckelwartz
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Ellis Y Kim
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Lisa D Wilsbacher
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Andy H Vo
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Emily A Waters
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Judy U Earley
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Michele Hadhazy
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Lisa Dellefave-Castillo
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Lorenzo L Pesce
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.)
| | - Elizabeth M McNally
- From Center for Genetic Medicine, Northwestern University Feinberg School of Medicine, Chicago, IL (D.Y.B., M.J.P., J.U.E., M.H., L.D.-C., E.M.M.); Molecular Pathogenesis and Molecular Medicine, University of Chicago, IL (E.Y.K.); Feinberg Cardiovascular Institute, Northwestern University Feinberg School of Medicine, Chicago, IL (L.D.W.); Committee on Development, Regeneration and Stem Cell Biology, University of Chicago, IL (A.H.V.); Northwestern University Center for Advanced Molecular Imaging, Evanston, IL (E.A.W.); and Computation Institute, University of Chicago, IL (L.L.P.).
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38
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Burke MA, Cook SA, Seidman JG, Seidman CE. Clinical and Mechanistic Insights Into the Genetics of Cardiomyopathy. J Am Coll Cardiol 2017; 68:2871-2886. [PMID: 28007147 DOI: 10.1016/j.jacc.2016.08.079] [Citation(s) in RCA: 198] [Impact Index Per Article: 28.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2016] [Revised: 08/01/2016] [Accepted: 08/02/2016] [Indexed: 12/19/2022]
Abstract
Over the last quarter-century, there has been tremendous progress in genetics research that has defined molecular causes for cardiomyopathies. More than a thousand mutations have been identified in many genes with varying ontologies, therein indicating the diverse molecules and pathways that cause hypertrophic, dilated, restrictive, and arrhythmogenic cardiomyopathies. Translation of this research to the clinic via genetic testing can precisely group affected patients according to molecular etiology, and identify individuals without evidence of disease who are at high risk for developing cardiomyopathy. These advances provide insights into the earliest manifestations of cardiomyopathy and help to define the molecular pathophysiological basis for cardiac remodeling. Although these efforts remain incomplete, new genomic technologies and analytic strategies provide unparalleled opportunities to fully explore the genetic architecture of cardiomyopathies. Such data hold the promise that mutation-specific pathophysiology will uncover novel therapeutic targets, and herald the beginning of precision therapy for cardiomyopathy patients.
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Affiliation(s)
- Michael A Burke
- Division of Cardiology, Emory University School of Medicine, Atlanta, Georgia; Department of Genetics, Harvard Medical School, Boston, Massachusetts
| | - Stuart A Cook
- National Heart & Lung Institute, Imperial College London, London, United Kingdom; National Heart Centre Singapore, Singapore; Duke-National University of Singapore, Singapore
| | | | - Christine E Seidman
- Department of Genetics, Harvard Medical School, Boston, Massachusetts; Division of Cardiovascular Medicine, Brigham and Women's Hospital, Boston, Massachusetts; Howard Hughes Medical Institute, Chevy Chase, Maryland.
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MYBPC3 mutations are associated with a reduced super-relaxed state in patients with hypertrophic cardiomyopathy. PLoS One 2017; 12:e0180064. [PMID: 28658286 PMCID: PMC5489194 DOI: 10.1371/journal.pone.0180064] [Citation(s) in RCA: 87] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2017] [Accepted: 06/08/2017] [Indexed: 11/23/2022] Open
Abstract
The “super-relaxed state” (SRX) of myosin represents a ‘reserve’ of motors in the heart. Myosin heads in the SRX are bound to the thick filament and have a very low ATPase rate. Changes in the SRX are likely to modulate cardiac contractility. We previously demonstrated that the SRX is significantly reduced in mouse cardiomyocytes lacking cardiac myosin binding protein–C (cMyBP-C). Here, we report the effect of mutations in the cMyBP-C gene (MYBPC3) using samples from human patients with hypertrophic cardiomyopathy (HCM). Left ventricular (LV) samples from 11 HCM patients were obtained following myectomy surgery to relieve LV outflow tract obstruction. HCM samples were genotyped as either MYBPC3 mutation positive (MYBPC3mut) or negative (HCMsmn) and were compared to eight non-failing donor hearts. Compared to donors, only MYBPC3mut samples display a significantly diminished SRX, characterised by a decrease in both the number of myosin heads in the SRX and the lifetime of ATP turnover. These changes were not observed in HCMsmn samples. There was a positive correlation (p < 0.01) between the expression of cMyBP-C and the proportion of myosin heads in the SRX state, suggesting cMyBP-C modulates and maintains the SRX. Phosphorylation of the myosin regulatory light chain in MYBPC3mut samples was significantly decreased compared to the other groups, suggesting a potential mechanism to compensate for the diminished SRX. We conclude that by altering both contractility and sarcomeric energy requirements, a reduced SRX may be an important disease mechanism in patients with MYBPC3 mutations.
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40
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Sohn DW, Kim HK, Kim YJ, Oh S, Seong MW, Park SS. Cardiomyopathies with Mixed and Inapparent Morphological Features in Cardiac Troponin I3 Mutation. Korean Circ J 2017; 47:413-417. [PMID: 28567093 PMCID: PMC5449537 DOI: 10.4070/kcj.2016.0302] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2016] [Revised: 10/20/2016] [Accepted: 10/25/2016] [Indexed: 11/29/2022] Open
Abstract
The fact that different types of cardiomyopathies can be manifested by the same sarcomere protein gene mutation in a single family is well known. However, mixed features of different types of cardiomyopathies in a single patient have not been well appreciated. We identified a novel mutation in cardiac troponin I3 (Arg186Gly) in the present case, and two of the family members showed mixed morphologic features of hypertrophic cardiomyopathy and left ventricular non-compaction. Moreover, both the features of cardiomyopathies were not apparent for each type of cardiomyopathy. In the patient's family, four other members had unexpected deaths before the age of 30.
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Affiliation(s)
- Dae-Won Sohn
- Division of Cardiology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Hyung-Kwan Kim
- Division of Cardiology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Yong-Jin Kim
- Division of Cardiology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Seil Oh
- Division of Cardiology, Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Moon-Woo Seong
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sung-Sup Park
- Department of Laboratory Medicine, Seoul National University College of Medicine, Seoul, Korea
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41
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Simpson S, Rutland P, Rutland CS. Genomic Insights into Cardiomyopathies: A Comparative Cross-Species Review. Vet Sci 2017; 4:E19. [PMID: 29056678 PMCID: PMC5606618 DOI: 10.3390/vetsci4010019] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/27/2016] [Revised: 03/15/2017] [Accepted: 03/15/2017] [Indexed: 12/19/2022] Open
Abstract
In the global human population, the leading cause of non-communicable death is cardiovascular disease. It is predicted that by 2030, deaths attributable to cardiovascular disease will have risen to over 20 million per year. This review compares the cardiomyopathies in both human and non-human animals and identifies the genetic associations for each disorder in each species/taxonomic group. Despite differences between species, advances in human medicine can be gained by utilising animal models of cardiac disease; likewise, gains can be made in animal medicine from human genomic insights. Advances could include undertaking regular clinical checks in individuals susceptible to cardiomyopathy, genetic testing prior to breeding, and careful administration of breeding programmes (in non-human animals), further development of treatment regimes, and drugs and diagnostic techniques.
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Affiliation(s)
- Siobhan Simpson
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
| | - Paul Rutland
- Great Ormond Street Institute of Child Health, University College London, 30 Guilford Street, London WC1N 1EH, UK.
| | - Catrin Sian Rutland
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington Campus, Loughborough LE12 5RD, UK.
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42
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Ceyhan-Birsoy O, Machini K, Lebo MS, Yu TW, Agrawal PB, Parad RB, Holm IA, McGuire A, Green RC, Beggs AH, Rehm HL. A curated gene list for reporting results of newborn genomic sequencing. Genet Med 2017; 19:809-818. [PMID: 28079900 DOI: 10.1038/gim.2016.193] [Citation(s) in RCA: 73] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2016] [Accepted: 10/26/2016] [Indexed: 12/20/2022] Open
Abstract
PURPOSE Genomic sequencing (GS) for newborns may enable detection of conditions for which early knowledge can improve health outcomes. One of the major challenges hindering its broader application is the time it takes to assess the clinical relevance of detected variants and the genes they impact so that disease risk is reported appropriately. METHODS To facilitate rapid interpretation of GS results in newborns, we curated a catalog of genes with putative pediatric relevance for their validity based on the ClinGen clinical validity classification framework criteria, age of onset, penetrance, and mode of inheritance through systematic evaluation of published evidence. Based on these attributes, we classified genes to guide the return of results in the BabySeq Project, a randomized, controlled trial exploring the use of newborn GS (nGS), and used our curated list for the first 15 newborns sequenced in this project. RESULTS Here, we present our curated list for 1,514 gene-disease associations. Overall, 954 genes met our criteria for return in nGS. This reference list eliminated manual assessment for 41% of rare variants identified in 15 newborns. CONCLUSION Our list provides a resource that can assist in guiding the interpretive scope of clinical GS for newborns and potentially other populations.Genet Med advance online publication 12 January 2017.
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Affiliation(s)
- Ozge Ceyhan-Birsoy
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Kalotina Machini
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Matthew S Lebo
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA
| | - Tim W Yu
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts, USA.,Department of Neurology, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Pankaj B Agrawal
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts, USA.,Division of Newborn Medicine, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Richard B Parad
- Harvard Medical School, Boston, Massachusetts, USA.,Department of Pediatric Newborn Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA
| | - Ingrid A Holm
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Amy McGuire
- Center for Medical Ethics and Health Policy, Baylor College of Medicine, Houston, Texas, USA
| | - Robert C Green
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Genetics, Department of Medicine, Brigham and Women's Hospital, Boston, Massachusetts, USA.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
| | - Alan H Beggs
- Harvard Medical School, Boston, Massachusetts, USA.,Division of Genetics and Genomics, Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, Massachusetts, USA
| | - Heidi L Rehm
- Laboratory for Molecular Medicine, Partners HealthCare Personalized Medicine, Cambridge, Massachusetts, USA.,Department of Pathology, Brigham and Women's Hospital, Boston, Massachusetts, USA.,Harvard Medical School, Boston, Massachusetts, USA.,The Broad Institute of MIT and Harvard, Cambridge, Massachusetts, USA
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43
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Li M, Andersson-Lendahl M, Sejersen T, Arner A. Knockdown of fast skeletal myosin-binding protein C in zebrafish results in a severe skeletal myopathy. ACTA ACUST UNITED AC 2016; 147:309-22. [PMID: 27022191 PMCID: PMC4810067 DOI: 10.1085/jgp.201511452] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 02/26/2016] [Indexed: 12/30/2022]
Abstract
MyBPC: A muscle protein for all seasons. Myosin-binding protein C (MyBPC) in the muscle sarcomere interacts with several contractile and structural proteins. Mutations in the cardiac isoform (MyBPC-3) in humans, or animal knockout, are associated with cardiomyopathy. Function of the fast skeletal isoform (MyBPC-2) in living muscles is less understood. This question was addressed using zebrafish models, combining gene expression data with functional analysis of contractility and small-angle x-ray diffraction measurements of filament structure. Fast skeletal MyBPC-2B, the major isoform, was knocked down by >50% using morpholino antisense nucleotides. These morphants exhibited a skeletal myopathy with elevated apoptosis and up-regulation of factors associated with muscle protein degradation. Morphant muscles had shorter sarcomeres with a broader length distribution, shorter actin filaments, and a wider interfilament spacing compared with controls, suggesting that fast skeletal MyBPC has a role in sarcomere assembly. Active force was reduced more than expected from the decrease in muscle size, suggesting that MyBPC-2 is required for optimal force generation at the cross-bridge level. The maximal shortening velocity was significantly increased in the MyBPC-2 morphants, but when related to the sarcomere length, the difference was smaller, reflecting that the decrease in MyBPC-2B content and the resulting myopathy were accompanied by only a minor influence on filament shortening kinetics. In the controls, equatorial patterns from small-angle x-ray scattering revealed that comparatively few cross-bridges are attached (as evaluated by the intensity ratio of the 11 and 10 equatorial reflections) during active contraction. X-ray scattering data from relaxed and contracting morphants were not significantly different from those in controls. However, the increase in the 11:10 intensity ratio in rigor was lower compared with that in controls, possibly reflecting effects of MyBPC on the cross-bridge interactions. In conclusion, lack of MyBPC-2 results in a severe skeletal myopathy with structural changes and muscle weakness.
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Affiliation(s)
- Mei Li
- Department of Physiology and Pharmacology, Department of Cell and Molecular Biology, and Department of Women's and Children's Health, Karolinska Institutet, SE 171 77 Stockholm, Sweden
| | - Monika Andersson-Lendahl
- Department of Physiology and Pharmacology, Department of Cell and Molecular Biology, and Department of Women's and Children's Health, Karolinska Institutet, SE 171 77 Stockholm, Sweden
| | - Thomas Sejersen
- Department of Physiology and Pharmacology, Department of Cell and Molecular Biology, and Department of Women's and Children's Health, Karolinska Institutet, SE 171 77 Stockholm, Sweden
| | - Anders Arner
- Department of Physiology and Pharmacology, Department of Cell and Molecular Biology, and Department of Women's and Children's Health, Karolinska Institutet, SE 171 77 Stockholm, Sweden
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44
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Nguyen S, Siu R, Dewey S, Cui Z, Gomes AV. Amino Acid Changes at Arginine 204 of Troponin I Result in Increased Calcium Sensitivity of Force Development. Front Physiol 2016; 7:520. [PMID: 27895589 PMCID: PMC5108889 DOI: 10.3389/fphys.2016.00520] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2016] [Accepted: 10/20/2016] [Indexed: 11/26/2022] Open
Abstract
Mutations in human cardiac troponin I (cTnI) have been associated with restrictive, dilated, and hypertrophic cardiomyopathies. The most commonly occurring residue on cTnI associated with familial hypertrophic cardiomyopathy (FHC) is arginine (R), which is also the most common residue at which multiple mutations occur. Two FHC mutations are known to occur at cTnI arginine 204, R204C and R204H, and both are associated with poor clinical prognosis. The R204H mutation has also been associated with restrictive cardiomyopathy (RCM). To characterize the effects of different mutations at the same residue (R204) on the physiological function of cTnI, six mutations at R204 (C, G, H, P, Q, W) were investigated in skinned fiber studies. Skinned fiber studies showed that all tested mutations at R204 caused significant increases in Ca2+ sensitivity of force development (ΔpCa50 = 0.22–0.35) when compared to wild-type (WT) cTnI. Investigation of the interactions between the cTnI mutants and WT cardiac troponin C (cTnC) or WT cardiac troponin T (cTnT) showed that all the mutations investigated, except R204G, affected either or both cTnI:cTnT and cTnI:cTnC interactions. The R204H mutation affected both cTnI:cTnT and cTnI:cTnC interactions while the R204C mutation affected only the cTnI:cTnC interaction. These results suggest that different mutations at the same site on cTnI could have varying effects on thin filament interactions. A mutation in fast skeletal TnI (R174Q, homologous to cTnI R204Q) also significantly increased Ca2+ sensitivity of force development (ΔpCa50 = 0.16). Our studies indicate that known cTnI mutations associated with poor prognosis (R204C and R204H) exhibit large increases in Ca2+ sensitivity of force development. Therefore, other R204 mutations that cause similar increases in Ca2+ sensitivity are also likely to have poor prognoses.
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Affiliation(s)
- Susan Nguyen
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis Davis, CA, USA
| | - Rylie Siu
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis Davis, CA, USA
| | - Shannamar Dewey
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis Davis, CA, USA
| | - Ziyou Cui
- Department of Neurobiology, Physiology, and Behavior, University of California, Davis Davis, CA, USA
| | - Aldrin V Gomes
- Department of Neurobiology, Physiology, and Behavior, University of California, DavisDavis, CA, USA; Department of Physiology and Membrane Biology, University of California, DavisDavis, CA, USA
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45
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The genetic basis of hypertrophic cardiomyopathy in cats and humans. J Vet Cardiol 2016; 17 Suppl 1:S53-73. [PMID: 26776594 DOI: 10.1016/j.jvc.2015.03.001] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2014] [Revised: 01/16/2015] [Accepted: 03/16/2015] [Indexed: 12/19/2022]
Abstract
Mutations in genes that encode for muscle sarcomeric proteins have been identified in humans and two breeds of domestic cats with hypertrophic cardiomyopathy (HCM). This article reviews the history, genetics, and pathogenesis of HCM in the two species in order to give veterinarians a perspective on the genetics of HCM. Hypertrophic cardiomyopathy in people is a genetic disease that has been called a disease of the sarcomere because the preponderance of mutations identified that cause HCM are in genes that encode for sarcomeric proteins (Maron and Maron, 2013). Sarcomeres are the basic contractile units of muscle and thus sarcomeric proteins are responsible for the strength, speed, and extent of muscle contraction. In people with HCM, the two most common genes affected by HCM mutations are the myosin heavy chain gene (MYH7), the gene that encodes for the motor protein β-myosin heavy chain (the sarcomeric protein that splits ATP to generate force), and the cardiac myosin binding protein-C gene (MYBPC3), a gene that encodes for the closely related structural and regulatory protein, cardiac myosin binding protein-C (cMyBP-C). To date, the two mutations linked to HCM in domestic cats (one each in Maine Coon and Ragdoll breeds) also occur in MYBPC3 (Meurs et al., 2005, 2007). This is a review of the genetics of HCM in both humans and domestic cats that focuses on the aspects of human genetics that are germane to veterinarians and on all aspects of feline HCM genetics.
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46
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Mirtschink P, Krek W. Hypoxia-driven glycolytic and fructolytic metabolic programs: Pivotal to hypertrophic heart disease. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2016; 1863:1822-8. [DOI: 10.1016/j.bbamcr.2016.02.011] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/10/2015] [Revised: 01/28/2016] [Accepted: 02/13/2016] [Indexed: 01/21/2023]
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47
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Cheng Y, Regnier M. Cardiac troponin structure-function and the influence of hypertrophic cardiomyopathy associated mutations on modulation of contractility. Arch Biochem Biophys 2016; 601:11-21. [PMID: 26851561 PMCID: PMC4899195 DOI: 10.1016/j.abb.2016.02.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2015] [Revised: 01/30/2016] [Accepted: 02/02/2016] [Indexed: 11/29/2022]
Abstract
Cardiac troponin (cTn) acts as a pivotal regulator of muscle contraction and relaxation and is composed of three distinct subunits (cTnC: a highly conserved Ca(2+) binding subunit, cTnI: an actomyosin ATPase inhibitory subunit, and cTnT: a tropomyosin binding subunit). In this mini-review, we briefly summarize the structure-function relationship of cTn and its subunits, its modulation by PKA-mediated phosphorylation of cTnI, and what is known about how these properties are altered by hypertrophic cardiomyopathy (HCM) associated mutations of cTnI. This includes recent work using computational modeling approaches to understand the atomic-based structural level basis of disease-associated mutations. We propose a viewpoint that it is alteration of cTnC-cTnI interaction (rather than the Ca(2+) binding properties of cTn) per se that disrupt the ability of PKA-mediated phosphorylation at cTnI Ser-23/24 to alter contraction and relaxation in at least some HCM-associated mutations. The combination of state of the art biophysical approaches can provide new insight on the structure-function mechanisms of contractile dysfunction resulting cTnI mutations and exciting new avenues for the diagnosis, prevention, and even treatment of heart diseases.
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Affiliation(s)
- Yuanhua Cheng
- University of Washington, Department of Bioengineering, Seattle, WA, USA
| | - Michael Regnier
- University of Washington, Department of Bioengineering, Seattle, WA, USA.
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48
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McNamara JW, Li A, Smith NJ, Lal S, Graham RM, Kooiker KB, van Dijk SJ, Remedios CGD, Harris SP, Cooke R. Ablation of cardiac myosin binding protein-C disrupts the super-relaxed state of myosin in murine cardiomyocytes. J Mol Cell Cardiol 2016; 94:65-71. [PMID: 27021517 DOI: 10.1016/j.yjmcc.2016.03.009] [Citation(s) in RCA: 101] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/08/2016] [Revised: 03/17/2016] [Accepted: 03/19/2016] [Indexed: 11/24/2022]
Abstract
Cardiac myosin binding protein-C (cMyBP-C) is a structural and regulatory component of cardiac thick filaments. It is observed in electron micrographs as seven to nine transverse stripes in the central portion of each half of the A band. Its C-terminus binds tightly to the myosin rod and contributes to thick filament structure, while the N-terminus can bind both myosin S2 and actin, influencing their structure and function. Mutations in the MYBPC3 gene (encoding cMyBP-C) are commonly associated with hypertrophic cardiomyopathy (HCM). In cardiac cells there exists a population of myosin heads in the super-relaxed (SRX) state, which are bound to the thick filament core with a highly inhibited ATPase activity. This report examines the role cMyBP-C plays in regulating the population of the SRX state of cardiac myosin by using an assay that measures single ATP turnover of myosin. We report a significant decrease in the proportion of myosin heads in the SRX state in homozygous cMyBP-C knockout mice, however heterozygous cMyBP-C knockout mice do not significantly differ from the wild type. A smaller, non-significant decrease is observed when thoracic aortic constriction is used to induce cardiac hypertrophy in mutation negative mice. These results support the proposal that cMyBP-C stabilises the thick filament and that the loss of cMyBP-C results in an untethering of myosin heads. This results in an increased myosin ATP turnover, further consolidating the relationship between thick filament structure and the myosin ATPase.
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Affiliation(s)
- James W McNamara
- Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia.
| | - Amy Li
- Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia
| | - Nicola J Smith
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Sean Lal
- Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia
| | - Robert M Graham
- Molecular Cardiology Program, Victor Chang Cardiac Research Institute, Darlinghurst, NSW 2010, Australia
| | - Kristina Bezold Kooiker
- Department of Pediatrics (Cardiology), Cardiovascular Institute, Stanford University, CA 94304, USA
| | - Sabine J van Dijk
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - Cristobal G Dos Remedios
- Discipline of Anatomy & Histology, Bosch Institute, University of Sydney, Sydney, NSW 2006, Australia
| | - Samantha P Harris
- Department of Cellular and Molecular Medicine, University of Arizona, Tucson, AZ 85721, USA
| | - Roger Cooke
- Department of Biochemistry & Biophysics, Cardiovascular Research Institute, University of California, San Francisco, CA 94158-2517, USA
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49
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The electrical heart: 25 years of discovery in cardiac electrophysiology, arrhythmias and sudden death. Cardiovasc Pathol 2016; 25:149-57. [DOI: 10.1016/j.carpath.2015.11.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/25/2015] [Revised: 11/23/2015] [Accepted: 11/26/2015] [Indexed: 12/16/2022] Open
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50
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Abstract
RNA splicing represents a post-transcriptional mechanism to generate multiple functional RNAs or proteins from a single transcript. The evolution of RNA splicing is a prime example of the Darwinian function follows form concept. A mutation that leads to a new mRNA (form) that encodes for a new functional protein (function) is likely to be retained, and this way, the genome has gradually evolved to encode for genes with multiple isoforms, thereby creating an enormously diverse transcriptome. Advances in technologies to characterize RNA populations have led to a better understanding of RNA processing in health and disease. In the heart, alternative splicing is increasingly being recognized as an important layer of post-transcriptional gene regulation. Moreover, the recent identification of several cardiac splice factors, such as RNA-binding motif protein 20 and SF3B1, not only provided important insight into the mechanisms underlying alternative splicing but also revealed how these splicing factors impact functional properties of the heart. Here, we review our current knowledge of alternative splicing in the heart, with a particular focus on the major and minor spliceosome, the factors controlling RNA splicing, and the role of alternative splicing in cardiac development and disease.
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Affiliation(s)
- Maarten M.G. van den Hoogenhof
- From the Department of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Yigal M. Pinto
- From the Department of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
| | - Esther E. Creemers
- From the Department of Experimental Cardiology, Academic Medical Center, University of Amsterdam, Amsterdam, The Netherlands
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