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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：
10426667
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/10426667
关键词：
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 Clinical Clinical Data Clinical Trials Data Data Analyses Development Diagnostic Disease Disease model Electrostatics 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 Play Property Protein Inhibition Proteins Relative Risks Research Personnel Role Sarcomeres Scientist Surface Techniques Testing Therapeutic Thermodynamics Training Training Activity United States Variant Work base 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.

项目概要/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，其中严重的临床负担，包括心力衰竭、心律失常和心源性猝死。最常见的是受影响的蛋白是肌球蛋白结合蛋白 C3 (MYBPC3)。将 MYBPC3 变体定义为致病性启用高危亲属的临床预测和基因筛查。 MYBPC3 的截断变体会导致过早终止密码子导致功能丧失。然而，MYBPC3 中的错义变体，通常被归类为意义不确定的变体很难解释，因为蛋白质可能容忍一个氨基酸的取代酸为另一个。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通常会融入肌原纤维中，并且博士。 Thompson 推测这些变异通过抑制蛋白质结合导致 HCM。为了评价这一点假设，在目标 1 中，Thompson 博士将研究由致病性错义引起的蛋白质结合的改变使用亲和质谱法的变体。此外，她还将描述源自患者的细胞模型和最常见致病错义变异的敲入小鼠模型预计通过此发挥作用 R502W 机制，占 HCM 病例的 2.4%。这些模型将评估 HCM 表型是否可以通过野生型 MYBPC3 的表达来逆转，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断变体。其他致病性错义变异是与截短变体类似，迅速从细胞中清除，汤普森博士假设这些变体通过热力学不稳定性导致 HCM。她之前的计算工作支持了这一假设证明患有 HCM 和 MYBPC3 VUS 的患者经计算预测会导致子域错误折叠表现出较高的不良临床结果发生率，与肥厚型心肌病患者相似并且已知 MYBPC3 致病变异。在目标 2 中，她将评估是否采用逐步实验方法，该方法首先在各个子域内以高通量方式表征变体，然后在使用全长 MYBPC3 的心肌细胞将能够加速识别导致蛋白质错误折叠。总而言之，这项工作应该为致病性提供新的生物学见解 MYBPC3 错义变异的机制可改善 HCM 患者的临床预后和高危亲属，并告知治疗 HCM 的个性化靶向治疗方法。这个提议是与汤普森博士之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、心脏生理学和高级实验遗传学的疾病模型。这部作品，她导师团队，所描述的培训活动将促进汤普森博士的发展最终目标是成为一名学术医师科学家和独立研究者。