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：
8903521
负责人：
Anthony Cammarato
金额：
$ 38.27万
依托单位：
JOHNS HOPKINS UNIVERSITY
依托单位国家：
美国
项目类别：
财政年份：
2014
资助国家：
美国
起止时间：
2014-09-01 至 2015-08-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8903521
关键词：
Actins 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 Disease Drosophila genus Drosophila melanogaster Electron Microscopy Elements Environmental Risk Factor Event F-Actin Figs - dietary Genetic Genetic Suppression Genotype Goals Health 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 Myocardium Myopathy Myosin ATPase N-terminal Pathogenesis Pathologic Processes Pathology Performance Phenotype Physiological Positioning Attribute Process Production Proteins Regulation Relative (related person)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 fly improved in vivo innovation insight molecular mechanics novel prevent research study response skeletal tool treatment strategy

项目摘要

DESCRIPTION (provided by applicant): Striated muscle contraction is dependent upon highly dynamic processes that rely on 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 events caused by thin filament lesions to facilitate our effort to understand 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 six of the seven 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 rely on multiple hypertrophic cardiomyopathy (HCM) models that express one of three α-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 contractile regulation and activity and consequently prompts diverse cardiac remodeling in flies. For Aim 3 "second-site" actin mutations will be used to improve cardiac pathology initiated by aberrant TnT, in vivo. Using Drosophila we identified specific actin lesions that suppress troponin-mediated skeletal myopathy. We will now test the hypothesis that 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（由申请人提供）：横纹肌收缩依赖于高度动态的过程，该过程依赖于各个细丝成分之间的协调通信和相对运动。本申请的目标是了解人类心肌病突变如何位于之间的保守界面处。细丝亚基导致疾病，果蝇受益于强大的实验工具，这些工具允许疾病等位基因在心脏或骨骼肌中有效的组织特异性表达以及相对快速的遗传相互作用。果蝇代表了一个强大的体内系统，可以检查细丝损伤引起的最近事件，以促进我们了解收缩调节的分子基础，更重要的是，将采用一种独特的综合方法。依赖于几种新的基于肌动蛋白和肌钙蛋白 T (TnT) 的心肌病的果蝇模型，目前尚不存在正在研究的七种突变中的六种动物模型，从而最大限度地减少了我们对这种心肌病的理解。通过使用高速实时视频、共聚焦、原子力和电子显微镜等独特的成像技术组合，我们将首次定义这些疾病等位基因在肌肉生理背景下的结构和功能效应。该研究将涉及评估果蝇体内收缩和舒张分子力学的开创性策略，目标 1 将依赖于多种肥厚型心肌病 (HCM) 模型。我们将测试以下假设：HCM 肌动蛋白变异体在果蝇中诱导类似的心脏和骨骼病理，这是由于基于原肌球蛋白 (Tm) 的收缩调节受到同样的干扰，从而导致过度的收缩活动。目标 2 将描述几种 TnT 心肌病突变的分层效应，我们将检验突变对 TnT-Tm 相互作用有不同影响的假设，这种相互作用明显影响收缩调节和活性。因此，Aim 3“第二位点”肌动蛋白突变将用于改善由异常 TnT 引发的心脏病理学，我们将在体内使用果蝇鉴定出抑制肌钙蛋白介导的骨骼肌病的特定肌动蛋白损伤。现在测试这些第二位点肌动蛋白突变可以改善我们的果蝇模型中基于 TnT 的心肌病的假设，总的来说，这项工作意义重大，因为它将提供必要的关键结构功能信息。此外，我们的努力将在一个不太复杂的模型系统中产生基因型-表型信息，该系统限制遗传修饰剂和环境因素，以帮助建立涉及心脏重塑的病理过程的范例和治疗策略。。