1
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Gao Y, Peng L, Zhao C. MYH7 in cardiomyopathy and skeletal muscle myopathy. Mol Cell Biochem 2024; 479:393-417. [PMID: 37079208 DOI: 10.1007/s11010-023-04735-x] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2023] [Accepted: 04/07/2023] [Indexed: 04/21/2023]
Abstract
Myosin heavy chain gene 7 (MYH7), a sarcomeric gene encoding the myosin heavy chain (myosin-7), has attracted considerable interest as a result of its fundamental functions in cardiac and skeletal muscle contraction and numerous nucleotide variations of MYH7 are closely related to cardiomyopathy and skeletal muscle myopathy. These disorders display significantly inter- and intra-familial variability, sometimes developing complex phenotypes, including both cardiomyopathy and skeletal myopathy. Here, we review the current understanding on MYH7 with the aim to better clarify how mutations in MYH7 affect the structure and physiologic function of sarcomere, thus resulting in cardiomyopathy and skeletal muscle myopathy. Importantly, the latest advances on diagnosis, research models in vivo and in vitro and therapy for precise clinical application have made great progress and have epoch-making significance. All the great advance is discussed here.
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Affiliation(s)
- Yuan Gao
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Lu Peng
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China
| | - Cuifen Zhao
- Department of Pediatrics, Qilu Hospital of Shandong University, Jinan, 250012, China.
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2
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Liu T, Yao Y, Kang Y, Zhang Q. Same MYH7 gene mutation but different phenotypes of cardiomyopathy in one family. Kaohsiung J Med Sci 2023; 39:1052-1053. [PMID: 37615266 DOI: 10.1002/kjm2.12741] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2023] [Accepted: 07/12/2023] [Indexed: 08/25/2023] Open
Affiliation(s)
- Ting Liu
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
| | - Yuan Yao
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
- Department of Geriatric Medicine and Cardiology, West China School of Public Health and West China Fourth Hospital, Chengdu, China
| | - Yu Kang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
| | - Qing Zhang
- Department of Cardiology, West China Hospital, Sichuan University, Chengdu, China
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3
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Lehman SJ, Meller A, Solieva SO, Lotthammer JM, Greenberg L, Langer SJ, Greenberg MJ, Tardiff JC, Bowman GR, Leinwand L. Divergent Molecular Phenotypes in Point Mutations at the Same Residue in Beta-Myosin Heavy Chain Lead to Distinct Cardiomyopathies. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.03.547580. [PMID: 37461648 PMCID: PMC10349964 DOI: 10.1101/2023.07.03.547580] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 07/25/2023]
Abstract
In genetic cardiomyopathies, a frequently described phenomenon is how similar mutations in one protein can lead to discrete clinical phenotypes. One example is illustrated by two mutations in beta myosin heavy chain (β-MHC) that are linked to hypertrophic cardiomyopathy (HCM) (Ile467Val, I467V) and left ventricular non-compaction (LVNC) (Ile467Thr, I467T). To investigate how these missense mutations lead to independent diseases, we studied the molecular effects of each mutation using recombinant human β-MHC Subfragment 1 (S1) in in vitro assays. Both HCM-I467V and LVNC-I467T S1 mutations exhibited similar mechanochemical function, including unchanged ATPase and enhanced actin velocity but had opposing effects on the super-relaxed (SRX) state of myosin. HCM-I467V S1 showed a small reduction in the SRX state, shifting myosin to a more actin-available state that may lead to the "gain-of-function" phenotype commonly described in HCM. In contrast, LVNC-I467T significantly increased the population of myosin in the ultra-slow SRX state. Interestingly, molecular dynamics simulations reveal that I467T allosterically disrupts interactions between ADP and the nucleotide-binding pocket, which may result in an increased ADP release rate. This predicted change in ADP release rate may define the enhanced actin velocity measured in LVNC-I467T, but also describe the uncoupled mechanochemical function for this mutation where the enhanced ADP release rate may be sufficient to offset the increased SRX population of myosin. These contrasting molecular effects may lead to contractile dysregulation that initiates LVNC-associated signaling pathways that progress the phenotype. Together, analysis of these mutations provides evidence that phenotypic complexity originates at the molecular level and is critical to understanding disease progression and developing therapies.
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Affiliation(s)
- Sarah J Lehman
- University of Colorado, Molecular, Cellular, and Developmental Biology, Boulder, CO, USA
| | - Artur Meller
- Washington University in St. Louis, Department of Biochemistry and Molecular Biophysics, St. Louis, MO, USA
- Medical Scientist Training Program, Washington University in St. Louis, St. Louis, MO, USA
| | - Shahlo O Solieva
- University of Pennsylvania, Department of Biochemistry and Biophysics, Philadelphia, PA, USA
| | - Jeffrey M Lotthammer
- Washington University in St. Louis, Department of Biochemistry and Molecular Biophysics, St. Louis, MO, USA
| | - Lina Greenberg
- Washington University in St. Louis, Department of Biochemistry and Molecular Biophysics, St. Louis, MO, USA
| | - Stephen J Langer
- University of Colorado, Molecular, Cellular, and Developmental Biology, Boulder, CO, USA
| | - Michael J Greenberg
- Washington University in St. Louis, Department of Biochemistry and Molecular Biophysics, St. Louis, MO, USA
| | - Jil C Tardiff
- University of Arizona, Department of Biomedical Engineering, Tucson, AZ, USA
| | - Gregory R Bowman
- University of Pennsylvania, Department of Biochemistry and Biophysics, Philadelphia, PA, USA
| | - Leslie Leinwand
- University of Colorado, Molecular, Cellular, and Developmental Biology, Boulder, CO, USA
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4
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Abstract
Cardiomyopathies (CMPs) are a heterogeneous group of diseases, frequently genetic, affecting the heart muscle. The symptoms range from asymptomatic to dyspnea, arrhythmias, syncope, and sudden cardiac death. This study is focused on MYH7 (beta-myosin heavy chain), as this gene is commonly mutated in cardiomyopathy patients. Due to the high combined prevalence of MYH7 variants and severe health outcomes, it is one of the most frequently tested genes in clinical settings. We analyzed the clinical presentation and natural history of 48 patients with MYH7-related cardiomyopathy belonging to a cohort from a tertiary center at Helsinki University Hospital, Finland. We made special reference to three age subgroups (0–1, 1–12, and >12 years). Our results characterize a clinically significant MYH7 cohort, emphasizing the high variability of the CMP phenotype depending on age. We observed a subgroup of infants (0–1 years) with MYH7 associated severe DCM phenotype. We further demonstrate that patients under the age of 12 years have a similar symptom burden compared to older patients.
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5
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Crocini C, Gotthardt M. Cardiac sarcomere mechanics in health and disease. Biophys Rev 2021; 13:637-652. [PMID: 34745372 PMCID: PMC8553709 DOI: 10.1007/s12551-021-00840-7] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2021] [Accepted: 08/27/2021] [Indexed: 12/23/2022] Open
Abstract
The sarcomere is the fundamental structural and functional unit of striated muscle and is directly responsible for most of its mechanical properties. The sarcomere generates active or contractile forces and determines the passive or elastic properties of striated muscle. In the heart, mutations in sarcomeric proteins are responsible for the majority of genetically inherited cardiomyopathies. Here, we review the major determinants of cardiac sarcomere mechanics including the key structural components that contribute to active and passive tension. We dissect the molecular and structural basis of active force generation, including sarcomere composition, structure, activation, and relaxation. We then explore the giant sarcomere-resident protein titin, the major contributor to cardiac passive tension. We discuss sarcomere dynamics exemplified by the regulation of titin-based stiffness and the titin life cycle. Finally, we provide an overview of therapeutic strategies that target the sarcomere to improve cardiac contraction and filling.
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Affiliation(s)
- Claudia Crocini
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- BioFrontiers Institute & Department of Molecular and Cellular Development, University of Colorado Boulder, Boulder, USA
| | - Michael Gotthardt
- Max Delbrück Center for Molecular Medicine in the Helmholtz Association (MDC), Neuromuscular and Cardiovascular Cell Biology, Berlin, Germany
- German Center for Cardiovascular Research (DZHK) Partner Site Berlin, Berlin, Germany
- Charité-Universitätsmedizin Berlin, 10117 Berlin, Germany
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6
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Vander Roest AS, Liu C, Morck MM, Kooiker KB, Jung G, Song D, Dawood A, Jhingran A, Pardon G, Ranjbarvaziri S, Fajardo G, Zhao M, Campbell KS, Pruitt BL, Spudich JA, Ruppel KM, Bernstein D. Hypertrophic cardiomyopathy β-cardiac myosin mutation (P710R) leads to hypercontractility by disrupting super relaxed state. Proc Natl Acad Sci U S A 2021. [PMID: 34117120 DOI: 10.1073/pnas.2025030118/suppl_file/pnas.2025030118.sm02.avi] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/13/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited form of heart disease, associated with over 1,000 mutations, many in β-cardiac myosin (MYH7). Molecular studies of myosin with different HCM mutations have revealed a diversity of effects on ATPase and load-sensitive rate of detachment from actin. It has been difficult to predict how such diverse molecular effects combine to influence forces at the cellular level and further influence cellular phenotypes. This study focused on the P710R mutation that dramatically decreased in vitro motility velocity and actin-activated ATPase, in contrast to other MYH7 mutations. Optical trap measurements of single myosin molecules revealed that this mutation reduced the step size of the myosin motor and the load sensitivity of the actin detachment rate. Conversely, this mutation destabilized the super relaxed state in longer, two-headed myosin constructs, freeing more heads to generate force. Micropatterned human induced pluripotent derived stem cell (hiPSC)-cardiomyocytes CRISPR-edited with the P710R mutation produced significantly increased force (measured by traction force microscopy) compared with isogenic control cells. The P710R mutation also caused cardiomyocyte hypertrophy and cytoskeletal remodeling as measured by immunostaining and electron microscopy. Cellular hypertrophy was prevented in the P710R cells by inhibition of ERK or Akt. Finally, we used a computational model that integrated the measured molecular changes to predict the measured traction forces. These results confirm a key role for regulation of the super relaxed state in driving hypercontractility in HCM with the P710R mutation and demonstrate the value of a multiscale approach in revealing key mechanisms of disease.
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Affiliation(s)
- Alison Schroer Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Chao Liu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Makenna M Morck
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kristina Bezold Kooiker
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- School of Medicine, University of Washington, Seattle, WA 98109
| | - Gwanghyun Jung
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Dan Song
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Aminah Dawood
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Arnav Jhingran
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
| | - Gaspard Pardon
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Sara Ranjbarvaziri
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Giovanni Fajardo
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Mingming Zhao
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY 40536
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY 40536
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Mechanical and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - James A Spudich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kathleen M Ruppel
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Bernstein
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304;
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
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7
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Vander Roest AS, Liu C, Morck MM, Kooiker KB, Jung G, Song D, Dawood A, Jhingran A, Pardon G, Ranjbarvaziri S, Fajardo G, Zhao M, Campbell KS, Pruitt BL, Spudich JA, Ruppel KM, Bernstein D. Hypertrophic cardiomyopathy β-cardiac myosin mutation (P710R) leads to hypercontractility by disrupting super relaxed state. Proc Natl Acad Sci U S A 2021; 118:e2025030118. [PMID: 34117120 PMCID: PMC8214707 DOI: 10.1073/pnas.2025030118] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Hypertrophic cardiomyopathy (HCM) is the most common inherited form of heart disease, associated with over 1,000 mutations, many in β-cardiac myosin (MYH7). Molecular studies of myosin with different HCM mutations have revealed a diversity of effects on ATPase and load-sensitive rate of detachment from actin. It has been difficult to predict how such diverse molecular effects combine to influence forces at the cellular level and further influence cellular phenotypes. This study focused on the P710R mutation that dramatically decreased in vitro motility velocity and actin-activated ATPase, in contrast to other MYH7 mutations. Optical trap measurements of single myosin molecules revealed that this mutation reduced the step size of the myosin motor and the load sensitivity of the actin detachment rate. Conversely, this mutation destabilized the super relaxed state in longer, two-headed myosin constructs, freeing more heads to generate force. Micropatterned human induced pluripotent derived stem cell (hiPSC)-cardiomyocytes CRISPR-edited with the P710R mutation produced significantly increased force (measured by traction force microscopy) compared with isogenic control cells. The P710R mutation also caused cardiomyocyte hypertrophy and cytoskeletal remodeling as measured by immunostaining and electron microscopy. Cellular hypertrophy was prevented in the P710R cells by inhibition of ERK or Akt. Finally, we used a computational model that integrated the measured molecular changes to predict the measured traction forces. These results confirm a key role for regulation of the super relaxed state in driving hypercontractility in HCM with the P710R mutation and demonstrate the value of a multiscale approach in revealing key mechanisms of disease.
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Affiliation(s)
- Alison Schroer Vander Roest
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Chao Liu
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Makenna M Morck
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kristina Bezold Kooiker
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- School of Medicine, University of Washington, Seattle, WA 98109
| | - Gwanghyun Jung
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Dan Song
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Aminah Dawood
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Arnav Jhingran
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
| | - Gaspard Pardon
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Sara Ranjbarvaziri
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Giovanni Fajardo
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Mingming Zhao
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
| | - Kenneth S Campbell
- Department of Physiology, University of Kentucky, Lexington, KY 40536
- Division of Cardiovascular Medicine, University of Kentucky, Lexington, KY 40536
| | - Beth L Pruitt
- Department of Mechanical Engineering, Stanford University, Stanford, CA 94305
- Department of Bioengineering, School of Engineering and School of Medicine, Stanford University, Stanford, CA 94305
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Mechanical and Biomolecular Science and Engineering, University of California, Santa Barbara, CA 93106
| | - James A Spudich
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305;
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Kathleen M Ruppel
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305
| | - Daniel Bernstein
- Department of Pediatrics (Cardiology), Stanford University School of Medicine, Palo Alto, CA 94304;
- Stanford Cardiovascular Institute, Stanford University School of Medicine, Stanford, CA 94305
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Alsulami K, Marston S. Small Molecules acting on Myofilaments as Treatments for Heart and Skeletal Muscle Diseases. Int J Mol Sci 2020; 21:E9599. [PMID: 33339418 PMCID: PMC7767104 DOI: 10.3390/ijms21249599] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2020] [Revised: 12/11/2020] [Accepted: 12/11/2020] [Indexed: 01/10/2023] Open
Abstract
Hypertrophic cardiomyopathy (HCM) and dilated cardiomyopathy (DCM) are the most prevalent forms of the chronic and progressive pathological condition known as cardiomyopathy. These diseases have different aetiologies; however, they share the feature of haemodynamic abnormalities, which is mainly due to dysfunction in the contractile proteins that make up the contractile unit known as the sarcomere. To date, pharmacological treatment options are not disease-specific and rather focus on managing the symptoms, without addressing the disease mechanism. Earliest attempts at improving cardiac contractility by modulating the sarcomere indirectly (inotropes) resulted in unwanted effects. In contrast, targeting the sarcomere directly, aided by high-throughput screening systems, could identify small molecules with a superior therapeutic value in cardiac muscle disorders. Herein, an extensive literature review of 21 small molecules directed to five different targets was conducted. A simple scoring system was created to assess the suitability of small molecules for therapy by evaluating them in eight different criteria. Most of the compounds failed due to lack of target specificity or poor physicochemical properties. Six compounds stood out, showing a potential therapeutic value in HCM, DCM or heart failure (HF). Omecamtiv Mecarbil and Danicamtiv (myosin activators), Mavacamten, CK-274 and MYK-581 (myosin inhibitors) and AMG 594 (Ca2+-sensitiser) are all small molecules that allosterically modulate troponin or myosin. Omecamtiv Mecarbil showed limited efficacy in phase III GALACTIC-HF trial, while, results from phase III EXPLORER-HCM trial were recently published, indicating that Mavacamten reduced left ventricular outflow tract (LVOT) obstruction and diastolic dysfunction and improved the health status of patients with HCM. A novel category of small molecules known as "recouplers" was reported to target a phenomenon termed uncoupling commonly found in familial cardiomyopathies but has not progressed beyond preclinical work. In conclusion, the contractile apparatus is a promising target for new drug development.
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Affiliation(s)
- Khulud Alsulami
- Imperial Centre for Translational and Experimental Medicine, Cardiovascular Division, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK;
- National Centre for Pharmaceutical Technology, King Abdulaziz City for Science and Technology, Riyadh 11461, Saudi Arabia
| | - Steven Marston
- Imperial Centre for Translational and Experimental Medicine, Cardiovascular Division, National Heart and Lung Institute, Imperial College London, London W12 0NN, UK;
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9
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Parker F, Peckham M. Disease mutations in striated muscle myosins. Biophys Rev 2020; 12:887-894. [PMID: 32651905 PMCID: PMC7429545 DOI: 10.1007/s12551-020-00721-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/02/2020] [Indexed: 01/23/2023] Open
Abstract
Over 1000 disease-causing missense mutations have been found in human β-cardiac, α-cardiac, embryonic and adult fast myosin 2a myosin heavy chains. Most of these are found in human β-cardiac myosin heavy chain. Mutations in β-cardiac myosin cause hypertrophic cardiomyopathy predominantly, whereas those in α-cardiac are associated with many types of heart disease, of which the most common is dilated cardiomyopathy. Mutations in embryonic and fast myosin 2a affect skeletal muscle function. This review provides a short overview of the mutations in the different myosin isoforms and their disease-causing effects.
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Affiliation(s)
- Francine Parker
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK
| | - Michelle Peckham
- School of Molecular and Cellular Biology, Faculty of Biological Sciences, University of Leeds, Leeds, LS2 9JT, UK.
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10
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Hirono K, Hata Y, Miyao N, Okabe M, Takarada S, Nakaoka H, Ibuki K, Ozawa S, Yoshimura N, Nishida N, Ichida F. Left Ventricular Noncompaction and Congenital Heart Disease Increases the Risk of Congestive Heart Failure. J Clin Med 2020; 9:jcm9030785. [PMID: 32183154 PMCID: PMC7141335 DOI: 10.3390/jcm9030785] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 02/28/2020] [Accepted: 03/09/2020] [Indexed: 12/21/2022] Open
Abstract
BACKGROUND Left ventricular noncompaction (LVNC) is a hereditary cardiomyopathy that is associated with high morbidity and mortality rates. Recently, LVNC was classified into several phenotypes including congenital heart disease (CHD). However, although LVNC and CHD are frequently observed, the role and clinical significance of genetics in these cardiomyopathies has not been fully evaluated. Therefore, we aimed to evaluate the impact on the perioperative outcomes of children with concomitant LVNC and CHD using next-generation sequencing (NGS). METHODS From May 2000 to August 2018, 53 Japanese probands with LVNC (25 males and 28 females) were enrolled and we screened 182 cardiomyopathy-associated genes in these patients using NGS. RESULTS The age at diagnosis of the enrolled patients ranged from 0 to 14 years (median: 0.3 months). A total of 23 patients (43.4%) were diagnosed with heart failure, 14 with heart murmur (26.4%), and 6 with cyanosis (11.3%). During the observation period, 31 patients (58.5%) experienced heart failure and 13 (24.5%) developed arrhythmias such as ventricular tachycardia, supraventricular tachycardia, and atrioventricular block. Moreover, 29 patients (54.7%) had ventricular septal defects (VSDs), 17 (32.1%) had atrial septal defects, 10 had patent ductus arteriosus (PDA), and 7 (13.2%) had Ebstein's anomaly and double outlet right ventricle. Among the included patients, 30 underwent surgery, 19 underwent biventricular repair, and 2 underwent pulmonary artery banding, bilateral pulmonary artery banding, and PDA ligation. Overall, 30 genetic variants were identified in 28 patients with LVNC and CHD. Eight variants were detected in MYH7 and two in TPM1. Echocardiography showed lower ejection fractions and more thickened trabeculations in the left ventricle in patients with LVNC and CHD than in age-matched patients with VSDs. During follow-up, 4 patients died and the condition of 8 worsened postoperatively. The multivariable proportional hazards model showed that heart failure, LV ejection fraction of < 24%, LV end-diastolic diameter z-score of > 8.56, and noncompacted-to-compacted ratio of the left ventricular apex of > 8.33 at the last visit were risk factors for survival. CONCLUSIONS LVNC and CHD are frequently associated with genetic abnormalities. Knowledge of the association between CHD and LVNC is important for the awareness of clinical implications during the preoperative and postoperative periods to identify the populations who are at an increased risk of additional morbidity.
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Affiliation(s)
- Keiichi Hirono
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
- Correspondence: ; Tel.: +81-76-434-7313; Fax: +81-76-434-5029
| | - Yukiko Hata
- Legal Medicine, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (Y.H.); (N.N.)
| | - Nariaki Miyao
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Mako Okabe
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Shinya Takarada
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Hideyuki Nakaoka
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Keijiro Ibuki
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Sayaka Ozawa
- Department of Pediatrics, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (N.M.); (M.O.); (S.T.); (H.N.); (K.I.); (S.O.)
| | - Naoki Yoshimura
- First Department of Surgery, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan;
| | - Naoki Nishida
- Legal Medicine, Graduate School of Medicine, University of Toyama, Toyama 930-0194, Japan; (Y.H.); (N.N.)
| | - Fukiko Ichida
- Department of Pediatrics, International University of Health and Welfare, Tokyo 107-0052, Japan;
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11
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Mamelona J, Filice L, Oussedik Y, Crapoulet N, Ouellette RJ, Marrero A. A novel missense mutation in the MYH7 gene causes an uncharacteristic phenotype of myosin storage myopathy: a case report. BMC MEDICAL GENETICS 2019; 20:78. [PMID: 31068177 PMCID: PMC6507130 DOI: 10.1186/s12881-019-0804-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Accepted: 04/09/2019] [Indexed: 11/10/2022]
Abstract
BACKGROUND Few manuscripts have reported phenotypes of skeletal muscle myopathies caused by mutations in the head region of slow/cardiac beta-myosin heavy chain (MyHCI). Among the patients, some of them showed the phenotype of skeletal muscle weakness with the obvious clinical features of cardiomyopathy while others showed pure skeletal muscle weakness with no symptoms of cardiac involvement. Genotype-phenotype relationship regarding the effect of a mutation on MyHCI is complex. Questions regarding why some mutations cause cardiomyopathy or skeletal muscle disorders alone or a combination of both still need to be answered. More findings in genetic variation are needed to extend knowledge of mutations in the MYH7 gene linked to skeletal muscle disorders. CASE PRESENTATION Here we present a female adult patient with a phenotype of childhood onset of muscular disorders and predominant involvement of thigh muscles with biopsy showing intrasarcoplasmic inclusion bodies. Whole exome sequencing showed that variant c.1370 T > G (p.Ile457Arg) in the MYH7 gene is a missense mutation possibly linked to the clinical findings. Our patient likely shows an uncharacteristic myosin storage myopathy associated with respiratory and cardiac involvement linked to a missense mutation in the head of MyHCI. CONCLUSIONS Given this mutation is located within the motor domain of MyHCI, this might affect the regulation of myosin mechano-chemical activity during the contractile cycle. Consequently, this potentially damaging effect can be easily amplified within the network of ~ 300-myosin molecules forming the thick filament and therefore become cumulatively deleterious, affecting, in turn, the overall organization and performance of sarcomere.
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Affiliation(s)
- Jean Mamelona
- Department of Neurology, Dr.-Georges-L.-Dumont University Hospital Center, 330 University Avenue, Moncton, NB, E1C 2Z3, Canada
| | - Louisa Filice
- Centre de Formation Médicale du Nouveau-Brunswick, 100 Des Aboiteaux Street, Moncton, NB, E1A 7R1, Canada
| | - Youcef Oussedik
- Department of Pathology, Dr.-Georges-L.-Dumont University Hospital Center, 330 University Avenue, Moncton, NB, E1C 2Z3, Canada
| | - Nicolas Crapoulet
- Molecular Genetics, Dr.-Alfred-Bastarche Laboratory, 37 Providence Street, Moncton, NB, E1C 8X3, Canada
| | - Rodney J Ouellette
- Molecular Genetics, Dr.-Alfred-Bastarche Laboratory, 37 Providence Street, Moncton, NB, E1C 8X3, Canada
| | - Alier Marrero
- Department of Neurology, Dr.-Georges-L.-Dumont University Hospital Center, 330 University Avenue, Moncton, NB, E1C 2Z3, Canada. .,Centre de Formation Médicale du Nouveau-Brunswick, 100 Des Aboiteaux Street, Moncton, NB, E1A 7R1, Canada.
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12
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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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13
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Bell KM, Kronert WA, Huang A, Bernstein SI, Swank DM. The R249Q hypertrophic cardiomyopathy myosin mutation decreases contractility in Drosophila by impeding force production. J Physiol 2019; 597:2403-2420. [PMID: 30950055 DOI: 10.1113/jp277333] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2018] [Accepted: 03/06/2019] [Indexed: 12/18/2022] Open
Abstract
KEY POINTS Hypertrophic cardiomyopathy (HCM) is a genetic disease that causes thickening of the heart's ventricular walls and is a leading cause of sudden cardiac death. HCM is caused by missense mutations in muscle proteins including myosin, but how these mutations alter muscle mechanical performance in largely unknown. We investigated the disease mechanism for HCM myosin mutation R249Q by expressing it in the indirect flight muscle of Drosophila melanogaster and measuring alterations to muscle and flight performance. Muscle mechanical analysis revealed R249Q decreased muscle power production due to slower muscle kinetics and decreased force production; force production was reduced because fewer mutant myosin cross-bridges were bound simultaneously to actin. This work does not support the commonly proposed hypothesis that myosin HCM mutations increase muscle contractility, or causes a gain in function; instead, it suggests that for some myosin HCM mutations, hypertrophy is a compensation for decreased contractility. ABSTRACT Hypertrophic cardiomyopathy (HCM) is an inherited disease that causes thickening of the heart's ventricular walls. A generally accepted hypothesis for this phenotype is that myosin heavy chain HCM mutations increase muscle contractility. To test this hypothesis, we expressed an HCM myosin mutation, R249Q, in Drosophila indirect flight muscle (IFM) and assessed myofibril structure, skinned fibre mechanical properties, and flight ability. Mechanics experiments were performed on fibres dissected from 2-h-old adult flies, prior to degradation of IFM myofilament structure, which started at 2 days old and increased with age. Homozygous and heterozygous R249Q fibres showed decreased maximum power generation by 67% and 44%, respectively. Decreases in force and work and slower overall muscle kinetics caused homozygous fibres to produce less power. While heterozygous fibres showed no overall slowing of muscle kinetics, active force and work production dropped by 68% and 47%, respectively, which hindered power production. The muscle apparent rate constant 2πb decreased 33% for homozygous but increased for heterozygous fibres. The apparent rate constant 2πc was greater for homozygous fibres. This indicates that R249Q myosin is slowing attachment while speeding up detachment from actin, resulting in less time bound. Decreased IFM power output caused 43% and 33% decreases in Drosophila flight ability and 19% and 6% drops in wing beat frequency for homozygous and heterozygous flies, respectively. Overall, our results do not support the increased contractility hypothesis. Instead, our results suggest the ventricular hypertrophy for human R249Q mutation is a compensatory response to decreases in heart muscle power output.
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Affiliation(s)
- Kaylyn M Bell
- Department of Biological Sciences & Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - William A Kronert
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA, USA
| | - Alice Huang
- Department of Biological Sciences & Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
| | - Sanford I Bernstein
- Department of Biology, Molecular Biology Institute and Heart Institute, San Diego State University, San Diego, CA, USA
| | - Douglas M Swank
- Department of Biological Sciences & Biomedical Engineering, Center for Biotechnology and Interdisciplinary Studies, Rensselaer Polytechnic Institute, Troy, NY, USA
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14
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Hershkovitz T, Kurolap A, Ruhrman-Shahar N, Monakier D, DeChene ET, Peretz-Amit G, Funke B, Zucker N, Hirsch R, Tan WH, Baris Feldman H. Clinical diversity of MYH7-related cardiomyopathies: Insights into genotype-phenotype correlations. Am J Med Genet A 2018; 179:365-372. [PMID: 30588760 DOI: 10.1002/ajmg.a.61017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2018] [Revised: 11/15/2018] [Accepted: 11/20/2018] [Indexed: 12/21/2022]
Abstract
MYH7-related disease (MRD) is the most common hereditary primary cardiomyopathy (CM), with pathogenic MYH7 variants accounting for approximately 40% of familial hypertrophic CMs. MRDs may also present as skeletal myopathies, with or without CM. Since pathogenic MYH7 variants result in highly variable clinical phenotypes, from mild to fatal forms of cardiac and skeletal myopathies, genotype-phenotype correlations are not always apparent, and translation of the genetic findings to clinical practice can be complicated. Data on genotype-phenotype correlations can help facilitate more specific and personalized decisions on treatment strategies, surveillance, and genetic counseling. We present a series of six MRD pedigrees with rare genotypes, encompassing various clinical presentations and inheritance patterns. This study provides new insights into the spectrum of MRD that is directly translatable to clinical practice.
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Affiliation(s)
- Tova Hershkovitz
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel
| | - Alina Kurolap
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel.,Rappaport School of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
| | - Noa Ruhrman-Shahar
- The Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Daniel Monakier
- Department of Cardiology, Rabin Medical Center, Beilinson Hospital, Petah Tikva and the Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Elizabeth T DeChene
- Division of Genomic Diagnostics, Children's Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Gabriela Peretz-Amit
- The Raphael Recanati Genetics Institute, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Birgit Funke
- Department of Pathology, Massachusetts General Hospital, and Harvard Medical School, Boston, Massachusetts
| | - Nili Zucker
- Pediatric Cardiology Unit, Schneider Children's Medical Center, Petah Tikva, Israel
| | - Rafael Hirsch
- Institute of Cardiology, Rabin Medical Center, Beilinson Hospital, Petah Tikva, Israel
| | - Wen-Hann Tan
- Division of Genetics and Genomics, Boston Children's Hospital, and Harvard Medical School, Boston, Massachusetts
| | - Hagit Baris Feldman
- The Genetics Institute, Rambam Health Care Campus, Haifa, Israel.,Rappaport School of Medicine, Technion - Israel Institute of Technology, Haifa, Israel
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15
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Philipson DJ, DePasquale EC, Yang EH, Baas AS. Emerging pharmacologic and structural therapies for hypertrophic cardiomyopathy. Heart Fail Rev 2018; 22:879-888. [PMID: 28856513 DOI: 10.1007/s10741-017-9648-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Hypertrophic cardiomyopathy is the most common inherited heart disease. Although it was first described over 50 years ago, there has been little in the way of novel disease-specific therapeutic development for these patients. Current treatment practice largely aims at symptomatic control using old drugs made for other diseases and does little to modify the disease course. Septal reduction by surgical myectomy or percutaneous alcohol septal ablation are well-established treatments for pharmacologic-refractory left ventricular outflow tract obstruction in hypertrophic cardiomyopathy patients. In recent years, there has been a relative surge in the development of innovative therapeutics, which aim to target the complex molecular pathophysiology and resulting hemodynamics that underlie hypertrophic cardiomyopathy. Herein, we review the new and emerging therapeutics for hypertrophic cardiomyopathy, which include pharmacologic attenuation of sarcomeric calcium sensitivity, allosteric inhibition of cardiac myosin, myocardial metabolic modulation, and renin-angiotensin-aldosterone system inhibition, as well as structural intervention by percutaneous mitral valve plication and endocardial radiofrequency ablation of septal hypertrophy. In conclusion, while further development of these therapeutic strategies is ongoing, they each mark a significant and promising advancement in treatment for hypertrophic cardiomyopathy patients.
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Affiliation(s)
- Daniel J Philipson
- Department of Medicine, UCLA, 200 UCLA Medical Plaza Suite 420, Los Angeles, CA, 90095, USA.
| | - Eugene C DePasquale
- Ahmanson-UCLA Cardiomyopathy Center, Division of Cardiology, Department of Medicine, UCLA, Los Angeles, CA, USA
| | - Eric H Yang
- Division of Cardiology, Department of Medicine, UCLA, Los Angeles, CA, USA
| | - Arnold S Baas
- Ahmanson-UCLA Cardiomyopathy Center, Division of Cardiology, Department of Medicine, UCLA, Los Angeles, CA, USA
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16
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Trivedi DV, Adhikari AS, Sarkar SS, Ruppel KM, Spudich JA. Hypertrophic cardiomyopathy and the myosin mesa: viewing an old disease in a new light. Biophys Rev 2017; 10:27-48. [PMID: 28717924 PMCID: PMC5803174 DOI: 10.1007/s12551-017-0274-6] [Citation(s) in RCA: 105] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2017] [Accepted: 06/12/2017] [Indexed: 12/15/2022] Open
Abstract
The sarcomere is an exquisitely designed apparatus that is capable of generating force, which in the case of the heart results in the pumping of blood throughout the body. At the molecular level, an ATP-dependent interaction of myosin with actin drives the contraction and force generation of the sarcomere. Over the past six decades, work on muscle has yielded tremendous insights into the workings of the sarcomeric system. We now stand on the cusp where the acquired knowledge of how the sarcomere contracts and how that contraction is regulated can be extended to an understanding of the molecular mechanisms of sarcomeric diseases, such as hypertrophic cardiomyopathy (HCM). In this review we present a picture that combines current knowledge of the myosin mesa, the sequestered state of myosin heads on the thick filament, known as the interacting-heads motif (IHM), their possible interaction with myosin binding protein C (MyBP-C) and how these interactions can be abrogated leading to hyper-contractility, a key clinical manifestation of HCM. We discuss the structural and functional basis of the IHM state of the myosin heads and identify HCM-causing mutations that can directly impact the equilibrium between the 'on state' of the myosin heads (the open state) and the IHM 'off state'. We also hypothesize a role of MyBP-C in helping to maintain myosin heads in the IHM state on the thick filament, allowing release in a graded manner upon adrenergic stimulation. By viewing clinical hyper-contractility as the result of the destabilization of the IHM state, our aim is to view an old disease in a new light.
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Affiliation(s)
- Darshan V Trivedi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Arjun S Adhikari
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Saswata S Sarkar
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA. .,Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA, 94305, USA.
| | - James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA, 94305, USA.
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17
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The myosin mesa and the basis of hypercontractility caused by hypertrophic cardiomyopathy mutations. Nat Struct Mol Biol 2017; 24:525-533. [PMID: 28481356 DOI: 10.1038/nsmb.3408] [Citation(s) in RCA: 149] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2016] [Accepted: 04/05/2017] [Indexed: 12/12/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is primarily caused by mutations in β-cardiac myosin and myosin-binding protein-C (MyBP-C). Changes in the contractile parameters of myosin measured so far do not explain the clinical hypercontractility caused by such mutations. We propose that hypercontractility is due to an increase in the number of myosin heads (S1) that are accessible for force production. In support of this hypothesis, we demonstrate myosin tail (S2)-dependent functional regulation of actin-activated human β-cardiac myosin ATPase. In addition, we show that both S2 and MyBP-C bind to S1 and that phosphorylation of either S1 or MyBP-C weakens these interactions. Importantly, the S1-S2 interaction is also weakened by four myosin HCM-causing mutations but not by two other mutations. To explain these experimental results, we propose a working structural model involving multiple interactions, including those with myosin's own S2 and MyBP-C, that hold myosin in a sequestered state.
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18
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Spudich JA, Aksel T, Bartholomew SR, Nag S, Kawana M, Yu EC, Sarkar SS, Sung J, Sommese RF, Sutton S, Cho C, Adhikari AS, Taylor R, Liu C, Trivedi D, Ruppel KM. Effects of hypertrophic and dilated cardiomyopathy mutations on power output by human β-cardiac myosin. ACTA ACUST UNITED AC 2016; 219:161-7. [PMID: 26792326 DOI: 10.1242/jeb.125930] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Hypertrophic cardiomyopathy is the most frequently occurring inherited cardiovascular disease, with a prevalence of more than one in 500 individuals worldwide. Genetically acquired dilated cardiomyopathy is a related disease that is less prevalent. Both are caused by mutations in the genes encoding the fundamental force-generating protein machinery of the cardiac muscle sarcomere, including human β-cardiac myosin, the motor protein that powers ventricular contraction. Despite numerous studies, most performed with non-human or non-cardiac myosin, there is no clear consensus about the mechanism of action of these mutations on the function of human β-cardiac myosin. We are using a recombinantly expressed human β-cardiac myosin motor domain along with conventional and new methodologies to characterize the forces and velocities of the mutant myosins compared with wild type. Our studies are extending beyond myosin interactions with pure actin filaments to include the interaction of myosin with regulated actin filaments containing tropomyosin and troponin, the roles of regulatory light chain phosphorylation on the functions of the system, and the possible roles of myosin binding protein-C and titin, important regulatory components of both cardiac and skeletal muscles.
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Affiliation(s)
- James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Tural Aksel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sadie R Bartholomew
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Suman Nag
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Masataka Kawana
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Elizabeth Choe Yu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Saswata S Sarkar
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Jongmin Sung
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Ruth F Sommese
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Shirley Sutton
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Carol Cho
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Arjun S Adhikari
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Rebecca Taylor
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Chao Liu
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Darshan Trivedi
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Kathleen M Ruppel
- Department of Biochemistry, Stanford University School of Medicine, Stanford, CA 94305, USA Department of Pediatrics (Cardiology), Stanford University School of Medicine, Stanford, CA 94305, USA
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19
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Multidimensional structure-function relationships in human β-cardiac myosin from population-scale genetic variation. Proc Natl Acad Sci U S A 2016; 113:6701-6. [PMID: 27247418 DOI: 10.1073/pnas.1606950113] [Citation(s) in RCA: 80] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Myosin motors are the fundamental force-generating elements of muscle contraction. Variation in the human β-cardiac myosin heavy chain gene (MYH7) can lead to hypertrophic cardiomyopathy (HCM), a heritable disease characterized by cardiac hypertrophy, heart failure, and sudden cardiac death. How specific myosin variants alter motor function or clinical expression of disease remains incompletely understood. Here, we combine structural models of myosin from multiple stages of its chemomechanical cycle, exome sequencing data from two population cohorts of 60,706 and 42,930 individuals, and genetic and phenotypic data from 2,913 patients with HCM to identify regions of disease enrichment within β-cardiac myosin. We first developed computational models of the human β-cardiac myosin protein before and after the myosin power stroke. Then, using a spatial scan statistic modified to analyze genetic variation in protein 3D space, we found significant enrichment of disease-associated variants in the converter, a kinetic domain that transduces force from the catalytic domain to the lever arm to accomplish the power stroke. Focusing our analysis on surface-exposed residues, we identified a larger region significantly enriched for disease-associated variants that contains both the converter domain and residues on a single flat surface on the myosin head described as the myosin mesa. Notably, patients with HCM with variants in the enriched regions have earlier disease onset than patients who have HCM with variants elsewhere. Our study provides a model for integrating protein structure, large-scale genetic sequencing, and detailed phenotypic data to reveal insight into time-shifted protein structures and genetic disease.
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20
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Korkmaz EN, Taylor KC, Andreas MP, Ajay G, Heinze NT, Cui Q, Rayment I. A composite approach towards a complete model of the myosin rod. Proteins 2016; 84:172-189. [PMID: 26573747 PMCID: PMC4715562 DOI: 10.1002/prot.24964] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2015] [Revised: 10/23/2015] [Accepted: 11/09/2015] [Indexed: 12/17/2022]
Abstract
Sarcomeric myosins have the remarkable ability to form regular bipolar thick filaments that, together with actin thin filaments, constitute the fundamental contractile unit of skeletal and cardiac muscle. This has been established for over 50 years and yet a molecular model for the thick filament has not been attained. In part this is due to the lack of a detailed molecular model for the coiled-coil that constitutes the myosin rod. The ability to self-assemble resides in the C-terminal section of myosin known as light meromyosin (LMM) which exhibits strong salt-dependent aggregation that has inhibited structural studies. Here we evaluate the feasibility of generating a complete model for the myosin rod by combining overlapping structures of five sections of coiled-coil covering 164 amino acid residues which constitute 20% of LMM. Each section contains ∼ 7-9 heptads of myosin. The problem of aggregation was overcome by incorporating the globular folding domains, Gp7 and Xrcc4 which enhance crystallization. The effect of these domains on the stability and conformation of the myosin rod was examined through biophysical studies and overlapping structures. In addition, a computational approach was developed to combine the sections into a contiguous model. The structures were aligned, trimmed to form a contiguous model, and simulated for >700 ns to remove the discontinuities and achieve an equilibrated conformation that represents the native state. This experimental and computational strategy lays the foundation for building a model for the entire myosin rod.
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Affiliation(s)
- E. Nihal Korkmaz
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, WI 53706, USA
| | - Keenan C. Taylor
- Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706, USA
| | - Michael P. Andreas
- Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706, USA
| | - Guatam Ajay
- Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706, USA
| | - Nathan T. Heinze
- Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706, USA
| | - Qiang Cui
- Department of Chemistry and Theoretical Chemistry Institute, University of Wisconsin, Madison, WI 53706, USA
| | - Ivan Rayment
- Department of Biochemistry, University of Wisconsin, 433 Babcock Drive, Madison, WI 53706, USA
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21
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The myosin mesa and a possible unifying hypothesis for the molecular basis of human hypertrophic cardiomyopathy. Biochem Soc Trans 2015; 43:64-72. [PMID: 25619247 DOI: 10.1042/bst20140324] [Citation(s) in RCA: 94] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
No matter how many times one explores the structure of the myosin molecule, there is always something new to discover. Here, I describe the myosin mesa, a structural feature of the motor domain that has the characteristics of a binding domain for another protein, possibly myosin-binding protein C (MyBP-C). Interestingly, many well-known hypertrophic cardiomyopathy (HCM) mutations lie along this surface and may affect the putative interactions proposed here. A potential unifying hypothesis for the molecular basis of human hypertrophic cardiomyopathy is discussed here. It involves increased power output of the cardiac muscle as a result of HCM mutations causing the release of inhibition by myosin binding protein C.
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22
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Colegrave M, Peckham M. Structural implications of β-cardiac myosin heavy chain mutations in human disease. Anat Rec (Hoboken) 2015; 297:1670-80. [PMID: 25125180 DOI: 10.1002/ar.22973] [Citation(s) in RCA: 82] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2014] [Revised: 04/09/2014] [Accepted: 04/09/2014] [Indexed: 12/11/2022]
Abstract
Over 500 disease-causing point mutations have been found in the human β-cardiac myosin heavy chain, many quite recently with modern sequencing techniques. This review shows that clusters of these mutations occur at critical points in the sequence and investigates whether the many studies on these mutants reveal information about the function of this protein.
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Affiliation(s)
- Melanie Colegrave
- Faculty of Biological Sciences, School of Molecular and Cellular Biology, University of Leeds, Leeds LS2 9JT, United Kingdom
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23
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Spudich JA. Hypertrophic and dilated cardiomyopathy: four decades of basic research on muscle lead to potential therapeutic approaches to these devastating genetic diseases. Biophys J 2014; 106:1236-49. [PMID: 24655499 PMCID: PMC3985504 DOI: 10.1016/j.bpj.2014.02.011] [Citation(s) in RCA: 198] [Impact Index Per Article: 19.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2013] [Revised: 01/30/2014] [Accepted: 02/04/2014] [Indexed: 01/10/2023] Open
Abstract
With the advent of technologies to obtain the complete sequence of the human genome in a cost-effective manner, this decade and those to come will see an exponential increase in our understanding of the underlying genetics that lead to human disease. And where we have a deep understanding of the biochemical and biophysical basis of the machineries and pathways involved in those genetic changes, there are great hopes for the development of modern therapeutics that specifically target the actual machinery and pathways altered by individual mutations. Prime examples of such a genetic disease are those classes of hypertrophic and dilated cardiomyopathy that result from single amino-acid substitutions in one of several of the proteins that make up the cardiac sarcomere or from the truncation of myosin binding protein C. Hypertrophic cardiomyopathy alone affects ∼1 in 500 individuals, and it is the leading cause of sudden cardiac death in young adults. Here I describe approaches to understand the molecular basis of the alterations in power output that result from these mutations. Small molecules binding to the mutant sarcomeric protein complex should be able to mitigate the effects of hypertrophic and dilated cardiomyopathy mutations at their sources, leading to possible new therapeutic approaches for these genetic diseases.
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Affiliation(s)
- James A Spudich
- Department of Biochemistry, Stanford University School of Medicine, Stanford, California.
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24
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Bloemink M, Deacon J, Langer S, Vera C, Combs A, Leinwand L, Geeves MA. The hypertrophic cardiomyopathy myosin mutation R453C alters ATP binding and hydrolysis of human cardiac β-myosin. J Biol Chem 2013; 289:5158-67. [PMID: 24344137 PMCID: PMC3931073 DOI: 10.1074/jbc.m113.511204] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The human hypertrophic cardiomyopathy mutation R453C results in one of the more severe forms of the myopathy. Arg-453 is found in a conserved surface loop of the upper 50-kDa domain of the myosin motor domain and lies between the nucleotide binding pocket and the actin binding site. It connects to the cardiomyopathy loop via a long α-helix, helix O, and to Switch-2 via the fifth strand of the central β-sheet. The mutation is, therefore, in a position to perturb a wide range of myosin molecular activities. We report here the first detailed biochemical kinetic analysis of the motor domain of the human β-cardiac myosin carrying the R453C mutation. A recent report of the same mutation (Sommese, R. F., Sung, J., Nag, S., Sutton, S., Deacon, J. C., Choe, E., Leinwand, L. A., Ruppel, K., and Spudich, J. A. (2013) Proc. Natl. Acad. Sci. U.S.A. 110, 12607-12612) found reduced ATPase and in vitro motility but increased force production using an optical trap. Surprisingly, our results show that the mutation alters few biochemical kinetic parameters significantly. The exceptions are the rate constants for ATP binding to the motor domain (reduced by 35%) and the ATP hydrolysis step/recovery stroke (slowed 3-fold), which could be the rate-limiting step for the ATPase cycle. Effects of the mutation on the recovery stroke are consistent with a perturbation of Switch-2 closure, which is required for the recovery stroke and the subsequent ATP hydrolysis.
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Affiliation(s)
- Marieke Bloemink
- From the School of Biosciences, University of Kent, Canterbury CT2 7NJ, United Kingdom and
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Li M, Zheng W. All-atom molecular dynamics simulations of actin-myosin interactions: a comparative study of cardiac α myosin, β myosin, and fast skeletal muscle myosin. Biochemistry 2013; 52:8393-405. [PMID: 24224850 DOI: 10.1021/bi4006896] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Myosins are a superfamily of actin-binding motor proteins with significant variations in kinetic properties (such as actin binding affinity) between different isoforms. It remains unknown how such kinetic variations arise from the structural and dynamic tuning of the actin-myosin interface at the amino acid residue level. To address this key issue, we have employed molecular modeling and simulations to investigate, with atomistic details, the isoform dependence of actin-myosin interactions in the rigor state. By combining electron microscopy-based docking with homology modeling, we have constructed three all-atom models for human cardiac α and β and rabbit fast skeletal muscle myosin in complex with three actin subunits in the rigor state. Starting from these models, we have performed extensive all-atom molecular dynamics (MD) simulations (total of 100 ns per system) and then used the MD trajectories to calculate actin-myosin binding free energies with contributions from both electrostatic and nonpolar forces. Our binding calculations are in good agreement with the experimental finding of isoform-dependent differences in actin binding affinity between these myosin isoforms. Such differences are traced to changes in actin-myosin electrostatic interactions (i.e., hydrogen bonds and salt bridges) that are highly dynamic and involve several flexible actin-binding loops. By partitioning the actin-myosin binding free energy to individual myosin residues, we have also identified key myosin residues involved in the actin-myosin interactions, some of which were previously validated experimentally or implicated in cardiomyopathy mutations, and the rest make promising targets for future mutational experiments.
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Affiliation(s)
- Minghui Li
- Physics Department, University at Buffalo , Buffalo, New York 14260, United States
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Moore JR, Leinwand L, Warshaw DM. Understanding cardiomyopathy phenotypes based on the functional impact of mutations in the myosin motor. Circ Res 2012; 111:375-85. [PMID: 22821910 DOI: 10.1161/circresaha.110.223842] [Citation(s) in RCA: 147] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Hypertrophic (HCM) and dilated (DCM) cardiomyopathies are inherited diseases with a high incidence of death due to electric abnormalities or outflow tract obstruction. In many of the families afflicted with either disease, causative mutations have been identified in various sarcomeric proteins. In this review, we focus on mutations in the cardiac muscle molecular motor, myosin, and its associated light chains. Despite the >300 identified mutations, there is still no clear understanding of how these mutations within the same myosin molecule can lead to the dramatically different clinical phenotypes associated with HCM and DCM. Localizing mutations within myosin's molecular structure provides insight into the potential consequence of these perturbations to key functional domains of the motor. Review of biochemical and biophysical data that characterize the functional capacities of these mutant myosins suggests that mutant myosins with enhanced contractility lead to HCM, whereas those displaying reduced contractility lead to DCM. With gain and loss of function potentially being the primary consequence of a specific mutation, how these functional changes trigger the hypertrophic response and lead to the distinct HCM and DCM phenotypes will be the future investigative challenge.
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Affiliation(s)
- Jeffrey R Moore
- Department of Physiology and Biophysics, Boston University School of Medicine, Boston, MA 02118, USA.
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Golbus JR, Puckelwartz MJ, Fahrenbach JP, Dellefave-Castillo LM, Wolfgeher D, McNally EM. Population-based variation in cardiomyopathy genes. ACTA ACUST UNITED AC 2012; 5:391-9. [PMID: 22763267 DOI: 10.1161/circgenetics.112.962928] [Citation(s) in RCA: 115] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
BACKGROUND Hypertrophic cardiomyopathy and dilated cardiomyopathy arise from mutations in genes encoding sarcomere proteins including MYH7, MYBPC3, and TTN. Genetic diagnosis of cardiomyopathy relies on complete sequencing of the gene coding regions, and most pathogenic variation is rare. The 1000 Genomes Project is an ongoing consortium designed to deliver whole genome sequence information from an ethnically diverse population and, therefore, is a rich source to determine both common and rare genetic variants. METHODS AND RESULTS We queried the 1000 Genomes Project database of 1092 individuals for exonic variants within 3 sarcomere genes MHY7, MYBPC3, and TTN. We focused our analysis on protein-altering variation, including nonsynonymous single nucleotide polymorphisms, insertion/deletion polymorphisms, or splice site altering variants. We identified known and predicted pathogenic variation in MYBPC3 and MYH7 at a higher frequency than what would be expected based on the known prevalence of cardiomyopathy. We also found substantial variation, including protein-disrupting sequences, in TTN. CONCLUSIONS Cardiomyopathy is a genetically heterogeneous disorder caused by mutations in multiple genes. The frequency of predicted pathogenic protein-altering variation in cardiomyopathy genes suggests that many of these variants may be insufficient to cause disease on their own but may modify phenotype in a genetically susceptible host. This is suggested by the high prevalence of TTN insertion/deletions in the 1000 Genomes Project cohort. Given the possibility of additional genetic variants that modify the phenotype of a primary driver mutation, broad-based genetic testing should be employed.
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Affiliation(s)
- Jessica R Golbus
- Department of Medicine and Department of Human Genetics, The University of Chicago, Chicago, IL 60637, USA
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Thompson RC, Buvoli M, Buvoli A, Leinwand LA. Myosin filament assembly requires a cluster of four positive residues located in the rod domain. FEBS Lett 2012; 586:3008-12. [PMID: 22728135 DOI: 10.1016/j.febslet.2012.06.019] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2012] [Revised: 06/04/2012] [Accepted: 06/05/2012] [Indexed: 11/30/2022]
Abstract
Myosin has an intrinsic ability to organize into ordered thick filaments that mediate muscle contraction. Here, we use surface plasmon resonance and light scattering analysis to further characterize the molecular determinants that guide myosin filament assembly. Both assays identify a cluster of lysine and arginine residues as important for myosin polymerization in vitro. Moreover, in cardiomyocytes, replacement of these charged residues by alanine severely affects the incorporation of myosin into the distal ends of the sarcomere. Our findings show that a novel assembly element with a distinct charge profile is present at the C-terminus of sarcomeric myosins.
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Affiliation(s)
- Robert C Thompson
- Department of Molecular, Cellular, and Developmental Biology and BioFrontiers Institute, University of Colorado, Boulder, CO 80303, United States
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Kuang SQ, Kwartler CS, Byanova KL, Pham J, Gong L, Prakash SK, Huang J, Kamm KE, Stull JT, Sweeney HL, Milewicz DM. Rare, nonsynonymous variant in the smooth muscle-specific isoform of myosin heavy chain, MYH11, R247C, alters force generation in the aorta and phenotype of smooth muscle cells. Circ Res 2012; 110:1411-22. [PMID: 22511748 DOI: 10.1161/circresaha.111.261743] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/04/2023]
Abstract
RATIONALE Mutations in myosin heavy chain (MYH11) cause autosomal dominant inheritance of thoracic aortic aneurysms and dissections. At the same time, rare, nonsynonymous variants in MYH11 that are predicted to disrupt protein function but do not cause inherited aortic disease are common in the general population and the vascular disease risk associated with these variants is unknown. OBJECTIVE To determine the consequences of the recurrent MYH11 rare variant, R247C, through functional studies in vitro and analysis of a knock-in mouse model with this specific variant, including assessment of aortic contraction, response to vascular injury, and phenotype of primary aortic smooth muscle cells (SMCs). METHODS AND RESULTS The steady state ATPase activity (actin-activated) and the rates of phosphate and ADP release were lower for the R247C mutant myosin than for the wild-type, as was the rate of actin filament sliding in an in vitro motility assay. Myh11(R247C/R247C) mice exhibited normal growth, reproduction, and aortic histology but decreased aortic contraction. In response to vascular injury, Myh11(R247C/R247C) mice showed significantly increased neointimal formation due to increased SMC proliferation when compared with the wild-type mice. Primary aortic SMCs explanted from the Myh11(R247C/R247C) mice were dedifferentiated compared with wild-type SMCs based on increased proliferation and reduced expression of SMC contractile proteins. The mutant SMCs also displayed altered focal adhesions and decreased Rho activation, associated with decreased nuclear localization of myocardin-related transcription factor-A. Exposure of the Myh11(R247C/R247C) SMCs to a Rho activator rescued the dedifferentiated phenotype of the SMCs. CONCLUSIONS These results indicate that a rare variant in MYH11, R247C, alters myosin contractile function and SMC phenotype, leading to increased proliferation in vitro and in response to vascular injury.
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Affiliation(s)
- Shao-Qing Kuang
- Department of Internal Medicine, The University of Texas Medical School at Houston, Houston, TX 77030, USA
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Cappola TP, Dorn GW. Clinical considerations of heritable factors in common heart failure. ACTA ACUST UNITED AC 2012; 4:701-9. [PMID: 22187448 DOI: 10.1161/circgenetics.110.959379] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Affiliation(s)
- Thomas P Cappola
- Department of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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Capek P, Vondrasek J, Skvor J, Brdicka R. Hypertrophic cardiomyopathy: from mutation to functional analysis of defective protein. Croat Med J 2012; 52:384-91. [PMID: 21674835 PMCID: PMC3118724 DOI: 10.3325/cmj.2011.52.384] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Aim To analyze the genesis of hypertrophic cardiomyopathy on a large cohort of patients from molecular genetics point of view and perform the functional analysis of the 3D molecular model of defective myosin-7 protein in silico. Methods The study enrolled 153 patients with diagnosed hypertrophic cardiomyopathy from different parts of the Czech Republic. DNA samples were analyzed for mutations in exons 21 and 22 of the MYH7 gene, which have been associated with high mutation clustering. The 3D model of human myosin-7 was built using the x-ray structure of nucleotide-free scallop myosin S1 as the structural template. We performed de novo structure prediction of mutant and wild type peptides spanning the 769-788 amino acids region of the myosin-7 protein. Results The Arg870His and Asp778Val amino acid alterations were found in 2 unrelated patients with a severe form of hypertrophic cardiomyopathy. The Asp778Val variation was chosen for subsequent 3D molecular modeling in silico. The mutation of the Asp by Val not only changes the character of the interaction pattern with other amino acids or ions but Val, being a small hydrophobic amino acid, can also completely change the stability of the region. Conclusion Mutation location in the MYH7 gene and changes in amino acid composition may have a crucial negative impact on the outcome of the disease in patients with hypertrophic cardiomyopathy. In addition, a mutation that changes the charge of the amino acid is more likely to affect protein function than a conservative mutation.
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Affiliation(s)
- Pavel Capek
- Department of Anthropology and Human Genetics, Charles University, Prague, Czech Republic.
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Abstract
The heart exhibits remarkable adaptive responses to a wide array of genetic and extrinsic factors to maintain contractile function. When compensatory responses are not sustainable, cardiac dysfunction occurs, leading to cardiomyopathy. The many forms of cardiomyopathy exhibit a set of overlapping phenotypes reflecting the limited range of compensatory responses that the heart can use. These include cardiac hypertrophy, induction of genes normally expressed during development, fibrotic deposits that replace necrotic and apoptotic cardiomyocytes, and metabolic disturbances. The compensatory responses are mediated by signaling pathways that initially serve to maintain normal contractility; however, persistent activation of these pathways leads to cardiac dysfunction. Current research focuses on ways to target these specific pathways therapeutically.
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Affiliation(s)
- Pamela A Harvey
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado at Boulder, USA
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Moawad HA, Sinanan ACM, Lewis MP, Hunt NP. Grouping patients for masseter muscle genotype-phenotype studies. Angle Orthod 2011; 82:261-6. [PMID: 21859331 DOI: 10.2319/122810-750.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVES To use various facial classifications, including either/both vertical and horizontal facial criteria, to assess their effects on the interpretation of masseter muscle (MM) gene expression. MATERIALS AND METHODS Fresh MM biopsies were obtained from 29 patients (age, 16-36 years) with various facial phenotypes. Based on clinical and cephalometric analysis, patients were grouped using three different classifications: (1) basic vertical, (2) basic horizontal, and (3) combined vertical and horizontal. Gene expression levels of the myosin heavy chain genes MYH1, MYH2, MYH3, MYH6, MYH7, and MYH8 were recorded using quantitative reverse transcriptase polymerase chain reaction (RT-PCR) and were related to the various classifications. The significance level for statistical analysis was set at P ≤ .05. RESULTS Using classification 1, none of the MYH genes were found to be significantly different between long face (LF) patients and the average vertical group. Using classification 2, MYH3, MYH6, and MYH7 genes were found to be significantly upregulated in retrognathic patients compared with prognathic and average horizontal groups. Using classification 3, only the MYH7 gene was found to be significantly upregulated in retrognathic LF compared with prognathic LF, prognathic average vertical faces, and average vertical and horizontal groups. CONCLUSION The use of basic vertical or basic horizontal facial classifications may not be sufficient for genetics-based studies of facial phenotypes. Prognathic and retrognathic facial phenotypes have different MM gene expressions; therefore, it is not recommended to combine them into one single group, even though they may have a similar vertical facial phenotype.
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Zheng DD, Yang JH, Tao Q, Geng M, Lin J, Yang XJ, Song JP, Li HX, Han LH, Jiang WP. Mutations in the beta-myosin heavy chain gene in southern Chinese families with hypertrophic cardiomyopathy. J Int Med Res 2010; 38:810-20. [PMID: 20819418 DOI: 10.1177/147323001003800308] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
In this study, 14 unrelated hypertrophic cardiomyopathy (HCM) probands were scanned by polymerase chain reaction-single-strand conformation polymorphism analysis and DNA sequencing. Three mis-sense mutations of the beta-myosin heavy chain gene, MYH7, were found: valine (Val) 606 methionine (Met), arginine (Arg) 694 leucine (Leu), and Arg 723 glycine (Gly). All are reported here for the first time in Chinese subjects. The results showed that: Val606Met is an intermediate malignancy mutation; Arg694Leu is a novel mutation with a benign phenotype; and the Arg723Gly mutation is linked to malignancy - it can lead not only to HCM but also to dilated cardiomyopathy at various ages. The clinical symptoms associated with Arg723Gly emerged early and caused more severe clinical manifestation and poorer prognosis in females than in males. Mis-sense mutations were not detected in the myosin binding protein C, cardiac, cardiac troponin T type 2, or cardiac troponin I type 3 genes. The MYH7 gene may be an HCM mutation hotspot in the Chinese and have unique features in this study population.
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Affiliation(s)
- D D Zheng
- Department of Cardiology, First Affiliated Hospital of Soochow University, Suzhou, Jiangsu, China
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Armel TZ, Leinwand LA. A mutation in the beta-myosin rod associated with hypertrophic cardiomyopathy has an unexpected molecular phenotype. Biochem Biophys Res Commun 2009; 391:352-6. [PMID: 19913502 DOI: 10.1016/j.bbrc.2009.11.062] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2009] [Accepted: 11/09/2009] [Indexed: 10/20/2022]
Abstract
Hypertrophic cardiomyopathy (HCM) is a common, autosomal dominant disorder primarily characterized by left ventricular hypertrophy and is the leading cause of sudden cardiac death in youth. HCM is caused by mutations in several sarcomeric proteins, with mutations in MYH7, encoding beta-MyHC, being the most common. While many mutations in the globular head region of the protein have been reported and studied, analysis of HCM-causing mutations in the beta-MyHC rod domain has not yet been reported. To address this question, we performed an array of biochemical and biophysical assays to determine how the HCM-causing E1356K mutation affects the structure, stability, and function of the beta-MyHC rod. Surprisingly, the E1356K mutation appears to thermodynamically destabilize the protein, rather than alter the charge profile know to be essential for muscle filament assembly. This thermodynamic instability appears to be responsible for the decreased ability of the protein to form filaments and may be responsible for the HCM phenotype seen in patients.
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Affiliation(s)
- Thomas Z Armel
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, CO 80309, USA
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Armel TZ, Leinwand LA. Mutations at the same amino acid in myosin that cause either skeletal or cardiac myopathy have distinct molecular phenotypes. J Mol Cell Cardiol 2009; 48:1007-13. [PMID: 19854198 DOI: 10.1016/j.yjmcc.2009.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/10/2009] [Revised: 10/05/2009] [Accepted: 10/08/2009] [Indexed: 11/29/2022]
Abstract
To date, more than 230 disease-causing mutations have been linked to the slow/cardiac muscle myosin gene, beta-MyHC (MYH7). Most of these mutations are located in the globular head region of the protein and result in cardiomyopathies. Recently, however, a number of novel disease-causing mutations have been described in the long, alpha-helical, coiled coil tail region of the beta-MyHC protein. Mutations in this region are of particular interest because they are associated with a multitude of human diseases, including both cardiac and skeletal myopathies. Here, we attempt to dissect the mechanism(s) by which mutations in the rod region of beta-MyHC can cause a variety of diseases by analyzing two mutations at a single amino acid (R1500P and R1500W) which cause two distinct diseases (Laing-type early-onset distal myopathy and dilated cardiomyopathy, respectively). For diseases linked to the R1500 residue, we find that each mutation displays distinct structural, thermodynamic, and functional properties. Both R1500P and R1500W cause a decrease in thermodynamic stability, although the R1500W phenotype is more severe. Both mutations also affect filament assembly, with R1500P causing an additional decrease in filament stability. In addition to furthering our understanding of the mechanism of pathogenesis for each of these diseases, these data also suggest how the variance in molecular phenotype may be associated with the variance in clinical phenotype present with mutations in the beta-MyHC rod.
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Affiliation(s)
- Thomas Z Armel
- Department of Molecular, Cellular, and Developmental Biology, 347 UCB, University of Colorado, Boulder, CO 80309, USA
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Greaser ML. Stressing the giant: a new approach to understanding dilated cardiomyopathy. J Mol Cell Cardiol 2009; 47:347-9. [PMID: 19555694 DOI: 10.1016/j.yjmcc.2009.06.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Accepted: 06/12/2009] [Indexed: 11/29/2022]
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Gurnett CA, Alaee F, Desruisseau D, Boehm S, Dobbs MB. Skeletal muscle contractile gene (TNNT3, MYH3, TPM2) mutations not found in vertical talus or clubfoot. Clin Orthop Relat Res 2009; 467:1195-200. [PMID: 19142688 PMCID: PMC2664426 DOI: 10.1007/s11999-008-0694-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/18/2008] [Accepted: 12/18/2008] [Indexed: 01/31/2023]
Abstract
UNLABELLED Arthrogryposis presents with lower limb contractures that resemble clubfoot and/or vertical talus. Recently, mutations in skeletal muscle contractile genes MYH3 (myosin heavy chain 3), TNNT3 (troponin T3), and TPM2 (tropomyosin 2) were identified in patients with distal arthrogryposis DA2A (Freeman-Sheldon syndrome) or DA2B (Sheldon-Hall syndrome). We asked whether the contractile genes responsible for distal arthrogryposis are also responsible for cases of familial clubfoot or vertical talus. We determined the frequency of MYH3, TNNT3, and TPM2 mutations in patients with idiopathic clubfoot, vertical talus, and distal arthrogryposis type 1 (DA1). We resequenced the coding exons of the MYH3, TNNT3, and TPM2 genes in 31 patients (five with familial vertical talus, 20 with familial clubfoot, and six with DA1). Variants were evaluated for segregation with disease in additional family members, and the frequency of identified variants was determined in a control population. In one individual with DA1, we identified a de novo TNNT3 mutation (R63H) previously identified in an individual with DA2B. No other causative mutations were identified, though we found several previously undescribed single-nucleotide polymorphisms of unknown importance. Although mutations in MYH3, TNNT3, and TPM2 are frequently associated with distal arthrogryposis syndromes, they were not present in patients with familial vertical talus or clubfoot. The TNNT3 R63H recurrent mutation identified in two unrelated individuals may be associated with either DA1 or DA2B. LEVEL OF EVIDENCE Level II, prospective study. See the Guidelines for Authors for a complete description of levels of evidence.
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Affiliation(s)
- Christina A. Gurnett
- Department of Neurology,
Washington University School of Medicine, St Louis, MO USA
,Department of Pediatrics,
Washington University School of Medicine,
St Louis, MO
USA ,Department of Orthopaedic Surgery, Washington University School of Medicine, One Children’s Place, St Louis, MO 63110 USA
| | - Farhang Alaee
- Department of Orthopaedic Surgery, Washington University School of Medicine, One Children’s Place, Suite 4S20, St Louis, MO 63110 USA
| | - David Desruisseau
- Department of Orthopaedic Surgery, Washington University School of Medicine, One Children’s Place, Suite 4S20, St Louis, MO 63110 USA
| | - Stephanie Boehm
- Department of Orthopaedic Surgery, Washington University School of Medicine, One Children’s Place, Suite 4S20, St Louis, MO 63110 USA
| | - Matthew B. Dobbs
- Department of Orthopaedic Surgery, Washington University School of Medicine, One Children’s Place, Suite 4S60, St Louis, MO 63110 USA ,St Louis Shriners Hospital for Children, St Louis, MO USA
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Mutations in the beta-myosin rod cause myosin storage myopathy via multiple mechanisms. Proc Natl Acad Sci U S A 2009; 106:6291-6. [PMID: 19336582 DOI: 10.1073/pnas.0900107106] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Myosin storage myopathy (MSM) is a congenital myopathy characterized by the presence of subsarcolemmal inclusions of myosin in the majority of type I muscle fibers, and has been linked to 4 mutations in the slow/cardiac muscle myosin, beta-MyHC (MYH7). Although the majority of the >230 disease causing mutations in MYH7 are located in the globular head region of the molecule, those responsible for MSM are part of a subset of MYH7 mutations that are located in the alpha-helical coiled-coil tail. Mutations in the myosin head are thought to affect the ATPase and actin-binding properties of the molecule. To date, however, there are no reports of the molecular mechanism of pathogenesis for mutations in the rod region of muscle myosins. Here, we present analysis of 4 mutations responsible for MSM: L1793P, R1845W, E1886K, and H1901L. We show that each MSM mutation has a different molecular phenotype, suggesting that there are multiple mechanisms by which MSM can be caused. These mechanisms range from thermodynamic and functional irregularities of individual proteins (L1793P), to varying defects in the assembly and stability of filaments formed from the proteins (R1845W, E1886K, and H1901L). In addition to furthering our understanding of MSM, these observations provide the first insight into how mutations affect the rod region of muscle myosins, and provide a framework for future studies of disease-causing mutations in this region of the molecule.
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Caporaso JG, Smit S, Easton BC, Hunter L, Huttley GA, Knight R. Detecting coevolution without phylogenetic trees? Tree-ignorant metrics of coevolution perform as well as tree-aware metrics. BMC Evol Biol 2008; 8:327. [PMID: 19055758 PMCID: PMC2637866 DOI: 10.1186/1471-2148-8-327] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2008] [Accepted: 12/03/2008] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Identifying coevolving positions in protein sequences has myriad applications, ranging from understanding and predicting the structure of single molecules to generating proteome-wide predictions of interactions. Algorithms for detecting coevolving positions can be classified into two categories: tree-aware, which incorporate knowledge of phylogeny, and tree-ignorant, which do not. Tree-ignorant methods are frequently orders of magnitude faster, but are widely held to be insufficiently accurate because of a confounding of shared ancestry with coevolution. We conjectured that by using a null distribution that appropriately controls for the shared-ancestry signal, tree-ignorant methods would exhibit equivalent statistical power to tree-aware methods. Using a novel t-test transformation of coevolution metrics, we systematically compared four tree-aware and five tree-ignorant coevolution algorithms, applying them to myoglobin and myosin. We further considered the influence of sequence recoding using reduced-state amino acid alphabets, a common tactic employed in coevolutionary analyses to improve both statistical and computational performance. RESULTS Consistent with our conjecture, the transformed tree-ignorant metrics (particularly Mutual Information) often outperformed the tree-aware metrics. Our examination of the effect of recoding suggested that charge-based alphabets were generally superior for identifying the stabilizing interactions in alpha helices. Performance was not always improved by recoding however, indicating that the choice of alphabet is critical. CONCLUSION The results suggest that t-test transformation of tree-ignorant metrics can be sufficient to control for patterns arising from shared ancestry.
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Affiliation(s)
- J Gregory Caporaso
- Department of Chemistry and Biochemistry, University of Colorado at Boulder, Boulder, CO, USA.
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