Allele-Specific Effects of Single Amino Acid Exchange in cTnT

cTnT 中单个氨基酸交换的等位基因特异性效应

• 批准号: 7792343
• 负责人: Jil C Tardiff
• 金额: $ 41.94万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2012-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7792343
• 关键词: Actins; Actomyosin; Address; Adrenergic Agents; Adrenergic Antagonists; Alleles; Amino Acid Substitution; Amino Acids; Animal Model; Animals; Binding; Biological Assay; Biophysics; Cardiac; Cardiomyopathies; Cardiovascular system; Cell physiology; Clinical; Complex; Computer Simulation; Cost Measures; Development; Disease; Dobutamine; Evaluation; Exhibits; Familial Hypertrophic Cardiomyopathy; Funding; Genes; Genotype; Goals; Grant; Head; Heart; Heart Diseases; Homeostasis; In Vitro; Individual; Infusion procedures; Isoproterenol; Lead; Link; Malignant - descriptor; Measures; Mechanics; Mediating; Methodology; Microfilaments; Modeling; Molecular; Motion; Mus; Muscle Contraction; Mutation; Myosin ATPase; Organ; Pathogenesis; Pattern; Peptides; Phenotype; Phosphorylation; Physiological; Physiology; Property; Protein Dynamics; Protein Isoforms; Proteins; Regulation; Research; Research Design; Research Project Grants; Resolution; Sarcomeres; Signal Pathway; Structure; Therapeutic; Thin Filament; Transgenic Model; Tropomyosin; Troponin; Troponin T; Work; adapter protein; adrenergic; base; cell motility; clinical phenotype; cost; disease-causing mutation; flexibility; in vivo; insight; malignant phenotype; model development; molecular dynamics; molecular phenotype; mouse model; mutant; programs; response; sudden cardiac death; tool

DESCRIPTION (provided by applicant): The long-term goal of the research program outlined in this application is to establish the mechanisms that link structural mutations in thin filament proteins to the development of Familial Hypertrophic Cardiomyopathy (FHC). During the original granting period we established that independent disease mutations at Residue 92 of cTnT (R92Q, R92W and R92L) result in discrete, mutation-specific alterations in cTnT structure and protein dynamics, energetics and contractile reserve, -adrenergic responsiveness and myocellular Ca2+ homeostasis. Moreover, many of these downstream cellular processes exhibit mutation-specific temporal changes that determine the progression of the resultant cardiomyopathy. Independent amino acid substitutions at a single residue of cTnT are thus sufficient to cause disparate physiologic phenotypes, and these phenotypes are the eventual result of specific changes in biophysical properties of the cTnT molecule. We have now developed the molecular, computational, cellular and whole-heart based tools to directly address this hypothesis and they define an integrative approach to establishing and eventually modifying the mechanistic link between mutations in cTnT and the malignant clinical course of FHC. These proposed studies are designed to both further our understanding of the pathogenesis of FHC and to provide new insights into the fundamental physiology and biophysics of the thin filament. In order to complete this research program we will implement the following three Specific Aims: Aim 1: To identify, evaluate and functionally }rank} the effects of known TNT1 mutations on the flexibility and structure of the 70-170 peptide around the critical }hinge} residue 104. Aim 2: To determine whether reducing the cost of contraction rescues the mutation-specific energetic-mechanical phenotypes of R92Q, R92L and R92W cTnT mutant hearts. Aim 3: To determine the mechanism(s) underlying the observed alterations in -adrenergic responsiveness in the R92 cTnT mutant hearts at the myofilament level. The completion of the studies will extend our understanding of how mutations in cTnT are mechanistically linked to their complex, malignant phenotype at the level of protein dynamics, cost of contraction, and energy reserve and the crucial myofilament response to -adrenergic stimulation. Moreover, we believe that these studies will both establish a new computational-functional paradigm for the study of thin filament cardiomyopathies and further expand our understanding of myofilament activation at the level of the cardiac sarcomere. Familial Hypertrophic Cardiomyopathy is one of the most common causes of sudden cardiac death in young people and the form of the disease caused by mutations in the thin filament protein cardiac Troponin T comprises a particularly malignant subset. The goal of this research project is to develop a integrated approach that utilizes computational modeling, development of rigorous genotype-molecular phenotype correlations and eventual whole-heart studies in animal models. The end result will be a better understanding of how these individual mutations in sarcomere proteins lead to severe cardiac disease and eventually lead to genotype-specific therapeutics for this currently untreatable disorder.

描述（由申请人提供）：本申请中概述的研究计划的长期目标是建立将细丝蛋白的结构突变与家族性肥厚性心肌病（FHC）的发展联系起来的机制。在最初的授权期间，我们确定 cTnT 残基 92（R92Q、R92W 和 R92L）的独立疾病突变会导致 cTnT 结构和蛋白质动力学、能量学和收缩储备、β-肾上腺素能反应性和肌细胞 Ca2+ 稳态的离散、突变特异性改变。此外，许多下游细胞过程表现出突变特异性的时间变化，决定了由此产生的心肌病的进展。因此，cTnT 单个残基上的独立氨基酸取代足以引起不同的生理表型，并且这些表型是 cTnT 分子生物物理特性特定变化的最终结果。我们现在已经开发了基于分子、计算、细胞和全心脏的工具来直接解决这一假设，并且它们定义了一种综合方法来建立并最终修改 cTnT 突变与 FHC 恶性临床过程之间的机制联系。这些拟议的研究旨在进一步了解 FHC 的发病机制，并为细丝的基础生理学和生物物理学提供新的见解。为了完成这项研究计划，我们将实现以下三个具体目标： 目标 1：识别、评估和功能性地“排序”已知 TNT1 突变对关键“铰链”残基 104 周围 70-170 肽的灵活性和结构的影响。目标 2：确定降低收缩成本是否可以挽救 R92Q、R92L 和 R92L 的突变特异性能量机械表型。 R92W cTnT 突变心脏。目标 3：确定 R92 cTnT 突变体心脏中肌丝水平上观察到的 β-肾上腺素能反应性变化背后的机制。这些研究的完成将加深我们对 cTnT 突变如何在蛋白质动力学、收缩成本、能量储备以及对 β-肾上腺素能刺激的关键肌丝反应水平上与其复杂的恶性表型机械相关的理解。此外，我们相信这些研究将为细丝心肌病的研究建立一个新的计算功能范式，并进一步扩大我们对心脏肌节水平的肌丝激活的理解。 家族性肥厚型心肌病是年轻人心源性猝死的最常见原因之一，由细丝蛋白心肌肌钙蛋白 T 突变引起的疾病形式包括一个特别恶性的亚型。该研究项目的目标是开发一种综合方法，利用计算模型、开发严格的基因型-分子表型相关性以及最终在动物模型中进行全心脏研究。最终结果将是更好地了解肌节蛋白中的这些个体突变如何导致严重的心脏病，并最终导致针对这种目前无法治疗的疾病的基因型特异性疗法。