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Pathogenic mechanisms of myosin binding protein C missense variants within hypertrophic cardiomyopathy

肥厚型心肌病中肌球蛋白结合蛋白C错义变异的致病机制

基本信息

批准号：
10610423
负责人：
Andrea Dooley Thompson
金额：
$ 16.74万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-07-01 至 2027-06-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10610423
关键词：
Acceleration Accounting Affect Affinity Affinity Chromatography Amino Acids Arrhythmia Bar Codes Binding Binding Proteins Biological Biological Assay Biological Models Biology Cardiac Cardiac Myocytes Cardiac Myosins Cardiomyopathies Cell model Cells Chemicals Classification Clinical Clinical Data Clinical Trials Data Data Analyses Development Diagnostic Disease Disease model Electrostatics Eligibility Determination Exhibits Experimental Genetics Failure Familial Hypertrophic Cardiomyopathy Functional disorder Future Generations Genes Genetic Genetic Diseases Genetic Screening Genetic Techniques Goals Green Fluorescent Proteins Half-Life Heart Atrium Heart Diseases Heart failure Hypertrophic Cardiomyopathy Individual Knock-in Mouse Knowledge Label Lead Learning Left Left Ventricular Hypertrophy Length Libraries Mass Spectrum Analysis Mentorship Methods Modeling Myofibrils Myosin ATPase Nature Nonmuscle Myosin Type IIA Nonsense Codon Outcome Pathogenicity Patient Care Patients Persons Phenotype Physicians Physiology Property Protein Inhibition Proteins Relative Risks Research Personnel Sarcomeres Scientist Surface Techniques Testing Therapeutic Thermodynamics Tissues Training Training Activity United States Variant Work experience genetic testing human disease improved inherited cardiomyopathy innovation insight loss of function mouse model mutant myosin-binding protein C novel personalized medicine prognostication protein folding protein misfolding skills sudden cardiac death targeted treatment tool variant of unknown significance

项目摘要

PROJECT SUMMARY/ABSTRACT Hypertrophic cardiomyopathy (HCM) is a common genetic disease, affecting ~ 1:500 people, with substantial clinical burden including heart failure, arrhythmia and sudden cardiac death. The most commonly affected protein is myosin binding protein C3 (MYBPC3). Defining a MYBPC3 variant as pathogenic enables clinical prognostication and genetic screening in at-risk relatives. Truncating variants of MYBPC3 cause a premature stop codon resulting in loss of function. However, missense variants in MYBPC3, often classified as variants of uncertain significance, are difficult to interpret as proteins may tolerate the substitution of one amino acid for another. Prior cellular and structural data suggest that pathogenic missense variants may lead to HCM via two distinct mechanisms. Some pathogenic missense variants normally incorporate into myofibrils and Dr. Thompson hypothesizes that these variants lead to HCM via inhibition of protein binding. To evaluate this hypothesis, in aim 1, Dr. Thompson will study alterations in protein binding caused by pathogenic missense variants using affinity mass spectrometry. Further, she will characterize a patient-derived cellular model and a knock-in mouse model of the most common pathogenic missense variant predicted to work via this mechanism, R502W, which accounts for 2.4% of HCM cases. These models will evaluate if HCM phenotypes can be reversed by expression of wild-type MYBPC3, suggesting a similar targeted therapeutic approach can be utilized for this common missense variant and truncating variants. Other pathogenic missense variants are rapidly cleared from the cell, similar to truncating variants, and Dr. Thompson hypothesizes that these variants lead to HCM via thermodynamic instability. Supporting this hypothesis, her prior computational work demonstrated that patients with HCM and a MYBPC3 VUS computationally predicted to cause subdomain misfolding exhibited higher rates of adverse clinical outcomes, similar to patients with HCM and known MYBPC3 pathogenic variant. In aim 2, she will evaluate if a step-wise experimental approach, which characterizes variants first in a high-throughput manner within individual subdomains and then within cardiomyocytes using full-length MYBPC3, will enable accelerated identification of variants which cause protein misfolding. Taken together, this work should provide novel biologic insight into the pathogenic mechanism(s) of MYBPC3 missense variants, enable improved clinical prognostication for patients with HCM and at-risk relatives, and inform personalized targeted therapeutic approaches to treat HCM. This proposal is distinct from Dr. Thompson’s prior experience in chemical biology and will provide her with valuable training in disease models of cardiomyopathy, cardiac physiology, and advanced experimental genetics. This work, her mentorship team, and the training activities described will facilitate Dr. Thompson’s development toward her ultimate goal of becoming an academic physician-scientist and independent investigator.

项目总结/摘要肥厚型心肌病（HCM）是一种常见的遗传性疾病，影响约1：500人，严重的临床负担，包括心力衰竭、心律失常和心源性猝死。最常见的受影响的蛋白是肌球蛋白结合蛋白C3（MYBPC 3）。将MYBPC 3变体定义为致病性使得能够在高危亲属中进行临床诊断和遗传筛查。MYBPC 3的截短变体导致提前终止密码子导致功能丧失。然而，MYBPC 3中的错义变体，通常被归类为不确定意义的变体，很难解释，因为蛋白质可以容忍一个氨基的取代，酸为另一种。先前的细胞和结构数据表明致病性错义变异可能导致HCM 通过两种不同的机制。一些致病性错义变异体通常并入肌原纤维。 Thompson假设这些变异通过抑制蛋白结合导致HCM。评价这一假设，在目标1中，汤普森博士将研究致病性错义引起的蛋白质结合的改变使用亲和质谱分析变体。此外，她将表征患者来源的细胞模型和最常见的致病性错义变体的敲入小鼠模型预测通过这种方式起作用。机制，R502 W，占HCM病例的2.4%。这些模型将评估HCM表型可以通过表达野生型MYBPC 3逆转，这表明类似的靶向治疗方法可以用于这种常见的错义变体和截短变体。其他致病性错义变体是迅速从细胞中清除，类似于截短变体，汤普森博士假设这些变体通过热力学不稳定导致HCM。支持这一假设，她先前的计算工作表明HCM患者和MYBPC 3 VUS计算预测引起亚结构域错误折叠表现出更高的不良临床结局率，与HCM患者相似， MYBPC 3致病性变体。在目标2中，她将评估一种逐步的实验方法，首先在单个子域内以高通量方式表征变体，然后在使用全长MYBPC 3的心肌细胞，将能够加速鉴定导致心肌细胞凋亡的变异体。蛋白质错误折叠总之，这项工作应该提供新的生物学见解的致病性 MYBPC 3错义变体的机制能够改善HCM患者的临床预后和有风险的亲属，并告知个性化的靶向治疗方法来治疗HCM。这项建议是与汤普森博士先前在化学生物学方面的经验不同，将为她提供宝贵的培训，心肌病、心脏生理学和先进的实验遗传学的疾病模型。这项工作，她导师团队，所描述的培训活动将促进汤普森博士的发展，她最终目标是成为一名学术物理学家，科学家和独立调查员。