Pathogenesis and in vivo suppression of thin filament based cardiomyopathies

基于细丝的心肌病的发病机制和体内抑制

基本信息

批准号：
8884895
负责人：
Anthony Cammarato
金额：
$ 36.67万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2015
资助国家：
美国
起止时间：
2015-09-01 至 2019-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8884895
关键词：
Actins Actomyosin Affect Alleles Amino Acids Animal Model Animals Atomic Force Microscopy Binding Binding Sites Biological Models Cardiac Cardiomyopathies Charge Clinical Communication Complex Comprehension Computer Simulation Data Defect Development Disease Drosophila genus Drosophila melanogaster Electron Microscopy Elements Environmental Risk Factor F-Actin Face Figs - dietary Functional disorder Genetic Genetic Suppression Genotype Goals Heart Diseases Human Hypertrophic Cardiomyopathy Image Imaging Techniques In Vitro Individual Inherited Investigation Laboratories Lead Lesion Life Light Location Mechanics Mediating Missense Mutation Modality Modeling Modification Molecular Molecular Genetics Movement Muscle Muscle Contraction Mutation Myocardial dysfunction Myocardium Myopathy Myosin ATPase N-terminal Pathogenesis Pathologic Processes Pathology Performance Phenotype Physiological Positioning Attribute Process Production Proteins Regulation Relative (related person)Restrictive Cardiomyopathy Role Running Signal Transduction Site Skeletal Muscle Speed Striated Muscles Structure Suppressor Mutations Surface System Testing Therapeutic Thin Filament Time Tissues Transgenic Animals Tropomyosin Troponin Troponin T Variant Work base design disease-causing mutation fly improved in vivo innovation insight molecular mechanics novel prevent public health relevance research study response skeletal tool treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Striated muscle contraction involves highly dynamic processes that require coordinated communication among, and relative movement of, individual thin filament components. The goal of this application is to understand how human cardiomyopathy mutations located at conserved interfaces between thin filament subunits lead to disease. Drosophila melanogaster, the fruit fly, benefits from robust experimental tools that permit efficient tissue-specific expression of disease alleles in cardiac or skeletal muscle and relatively rapid genetic interaction screens. The fly represents a powerful in vivo system to scrutinize the most proximal consequences of thin filament lesions to facilitate our effort to discern the molecular basis of contractile regulation and, importantly, of myopathic responses in humans. A remarkably integrative approach will be employed that relies upon several new Drosophila models of actin and troponin T (TnT)-based cardiomyopathies. Animal models do not currently exist for five of the six mutations under investigation here, minimizing our comprehension of the pathological effects of these disease alleles in the physiological context of muscle. Using a unique combination of imaging techniques that includes high-speed live video, confocal, atomic force and electron microscopy we will define, for the first time, the structural and functional effects of the cardiomyopathy mutations from the tissue to the molecular level. The studies will involve pioneering strategies to evaluate Drosophila systolic and diastolic molecular mechanics in vivo. Aim 1 will focus on multiple hypertrophic cardiomyopathy (HCM) models that express one of three a-cardiac actin missense mutations. We will test the hypothesis that the HCM actin variants induce similar cardiac and skeletal pathology in flies due to equivalently disturbed tropomyosin (Tm)-based contractile regulation that leads to excessive contractile activity. For Aim 2 the hierarchical effects of several TnT cardiomyopathy mutations will be delineated. We will test the hypothesis that the mutations differentially influence TnT-Tm interaction, which distinctly affects the extent of contractile inhibition and consequently prompts diverse cardiac remodeling in flies. For Aim 3 "second-site" actin mutations will be used to improve cardiac dysfunction initiated by aberrant TnT, in vivo and in vitro. Using Drosophila we identified specific actin lesions that suppress TnT-mediated skeletal myopathy. We will now test the hypothesis that, when co-expressed, these second-site actin mutations can ameliorate TnT-based cardiomyopathies in our fly models. Overall this work is significant since it will provide critical structural-functional information necessary to better comprehend how the thin filament machine functions normally and during disease. Additionally, our efforts will yield genotype-phenotype information in a less complex model system that limits genetic modifiers and environmental factors to help establish paradigms and treatment strategies for pathological processes involved in cardiac remodeling.

描述（应用程序提供）：横纹肌肉收缩涉及高度动态的过程，这些过程需要在单个薄丝成分之间进行协调的和相对运动。该应用的目的是了解薄丝亚基之间构成界面的人类心肌病突变如何导致疾病。果蝇果蝇（果蝇）受益于强大的实验工具，该工具允许心脏或骨骼肌中疾病等位基因的有效组织特异性表达以及相对较快的遗传相互作用筛查。苍蝇代表了一个强大的体内系统，可以仔细检查薄丝细丝病变的最近端后果，以促进我们的能量辨别收缩调控的分子基础，以及重要的是，人类的肌病反应。将采用一种非常集成的方法，依赖于肌动蛋白和肌钙蛋白T（TNT）基于心肌病的几种新的果蝇模型。目前，在此处研究的六个突变中，动物模型目前尚不存在，从而最大程度地减少了我们对这些疾病等位基因的病理影响的理解。使用成像技术的独特组合，包括高速实时视频，共聚焦，原子力和电子显微镜，我们将首次定义从组织到分子水平的心肌病变突变的结构和功能效应。这些研究将涉及在体内评估果蝇收缩和舒张分子机制的开创性策略。 AIM 1将集中于多种肥厚的心肌病（HCM）模型，这些模型表达了三个A-核肌动蛋白错义突变之一。我们将检验以下假设：HCM肌动蛋白变体由于同样受干扰的肌动菌素（TM）基于基于的收缩调节而引起的苍蝇中相似的心脏和骨骼病理，从而导致过度的收缩活性。对于目标2，将描绘出几个TNT心肌病突变的分层效应。我们将检验以下假设，即突变会影响TNT-TM相互作用，这明显影响收缩抑制的程度，因此提示了。苍蝇的多样化心脏重塑。对于AIM 3“第二位”肌动蛋白突变将用于改善异常TNT，体内和体外引发的心脏功能障碍。我们使用果蝇确定了抑制TNT介导的骨骼肌病的特定肌动蛋白病变。现在，我们将测试以下假设：当共表达这些第二个位点肌动蛋白突变时，可以在我们的飞蝇模型中改善基于TNT的心肌病。总体而言，这项工作很重要，因为它将提供必要的关键结构功能信息，以更好地理解细丝机在疾病期间的正常功能。此外，我们的努力将在不太复杂的模型系统中产生基因型 - 表型信息，该系统限制了遗传修饰符和环境因素，以帮助建立涉及心脏重塑的病理过程的范式和治疗策略。