Dissecting the mechanism of how dominant negative MYH7 mutations lead to genetic cardiomyopathies

剖析 MYH7 显性失活突变导致遗传性心肌病的机制

• 批准号: 10045499
• 负责人: Kai-Chun Daniel Yang
• 金额: --
• 依托单位: VA PUGET SOUND HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2019
• 资助国家: 美国
• 起止时间: 2019-10-01 至 2024-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/10045499
• 关键词: Accounting; Address; Affect; American; Award; Biological Assay; Cardiac Myocytes; Cardiac Myosins; Cardiomyopathies; Caring; Cells; Clinical; Co-Immunoprecipitations; Data; Diagnosis; Dilated Cardiomyopathy; Disease; Disease model; Dominant-Negative Mutation; EFRAC; Emotional; Functional disorder; Future; General Population; Genetic; Genetic Databases; Genomics; Goals; Guidelines; Healthcare; Healthcare Systems; Heart failure; Human; Hypertrophic Cardiomyopathy; Impairment; Induced Mutation; Intervention; Knock-out; Lead; Mammalian Cell; Medical; Methods; Modeling; Morbidity - disease rate; Muscle; Mutagenesis; Mutation; Myosin ATPase; Myosin Heavy Chains; Pathogenesis; Pathogenicity; Patients; Play; Process; Protein Isoforms; Proteins; Research; Ring Finger Domain; Risk; Rodent; Role; Techniques; Testing; Therapeutic Intervention; Thick Filament; Training; Two-Hybrid System Techniques; Up-Regulation; Variant; Veterans; Work; Yeasts; base; cardiac tissue engineering; cardiogenesis; cellular engineering; clinically relevant; experimental study; familial dilated cardiomyopathy; gain of function; genetic testing; heart cell; high throughput screening; human disease; improved; induced pluripotent stem cell; inherited cardiomyopathy; innovation; loss of function; mortality; mutant; myosin-binding protein C; new therapeutic target; novel; overexpression; precision medicine; preservation; protein degradation; protein protein interaction; ubiquitin-protein ligase; variant of unknown significance; yeast two hybrid system

Dilated and “burnt out” hypertrophic cardiomyopathies are common genetic cardiomyopathies that lead to heart failure. Currently over 115,000 Veterans annually receive care for heart failure from the VA Health Care System. Despite efforts to implement guideline-directed medical therapy, the overall 5 year mortality is ~50% after diagnosis, so clearly this is a disease important to not only Veterans but also the general population. Myosin heavy chain 7 (MYH7) mutations are common causes of hypertrophic and dilated cardiomyopathies. Genetic testing for MYH7 variants have been limited by frequent identification of variants of unknown significance and the lack of disease-modifying therapies when pathogenic variants are identified. This proposal will identify MYH7 variants that will cause contractile dysfunction, the first step to the development of heart failure, and study the disease pathogenesis in human induced pluripotent stem cell-derived cardiomyocytes. Mutations in either the MYH7 S2 domain or the C1C2 domain of cardiac myosin binding protein C (cMyBPC) that disrupt the normal protein-protein interaction between S2/C1C2 have recently been shown to induce heart failure with reduced ejection fraction. This leads to the hypothesis that a subset of MYH7 mutation-induced cardiomyopathies are due to impaired interaction between these two proteins. The proposed work uses saturation mutagenesis and high-throughput modified yeast two-hybrid assays to identify nearly all mutations in the MYH7 S2 domain that disrupt normal protein-protein interaction with the C1C2 domain of cMyBPC. This will assist in identifying all clinically relevant MYH7 S2 variants that are susceptible to developing heart failure and generate a “look up” table that would enable the confident identification of patients that could benefit from therapeutic intervention (Aim 1). Abnormally functioning mutant MYH7 protein raises the possibility of increased myosin degradation. This is supported by recent work demonstrating an upregulation of muscle RING-finger protein-1 (MuRF1), an E3 ligase that targets MYH7 and other sarcomeric proteins for degradation, in human induced pluripotent stem cell-derived cardiomyocytes expressing the pathogenic MYH7 E848G variant. This leads to the hypothesis that MuRF1 upregulation in MYH7 mutation-induced cardiomyopathies contributes to systolic dysfunction and that reducing MuRF1 levels will increase contractility. The proposed work will use gain-of-function and loss-of-function experiments to elucidate the role of MuRF1 in MYH7 mutation-induced cardiomyopathies (Aim 2). If successful it will determine if MuRF1 can be a novel therapeutic target for these genetic cardiomyopathies. The proposed work uses several innovative techniques. It combines cutting-edge high-throughput functional assays with mechanistic studies in genetically-edited human induced pluripotent stem cell-derived cardiomyocytes to identify patients with MYH7 mutations that are at risk of developing heart failure and then determines the suitability of a potential novel disease-modifying intervention. The high-throughput assays will integrate well with the proposed training in computational genomics. The method in Aim 1 can later be applied to interactions between MYH7 and other sarcomeric proteins to potentially identify all clinically relevant MYH7 variants. The mechanistic studies in human induced pluripotent stem cells in Aim 2 will help elucidate the pathogenesis of MYH7 mutation-induced cardiomyopathies and together with Aim 1 will form the basis for a future Merit Award proposal during the 4th year of the CDA2 award. Overall, the CDA2 will provide the additional training necessary for the nominee to use iPSC-based disease modeling with computational genomics to discover new disease-modifying therapies with precision medicine approaches.

扩张型和“燃尽型”肥厚性心肌病是常见的遗传性心肌病