Cytoskeletal-Associated Proteins and Cardiomyopathy

描述（由申请人提供）：壁压力的慢性增加在心肌病和相关心力衰竭的发生和发展中起关键作用。实验和人体研究指出了细胞骨架缺陷的关键作用，包括编码Z盘成分的基因突变的聚类及其与titin和titin相关蛋白的相互作用。人类titin， telthonin和肌肉LIM结构域蛋白（MLP, Cypher）的突变现在已经明确地与人类心肌病的发病有关。此外，Z盘蛋白和titin复合物最近被确定为心肌细胞生物力学拉伸传感器的重要组成部分，这表明细胞骨骼依赖性应激信号通路的缺陷可能与人类DCM的发生和发展有关。将导致人类心力衰竭的复杂Z盘和titin相关蛋白进行机械连接将变得至关重要。我们已经发现了一些新的心脏细胞骨骼相关蛋白，它们与肌动蛋白、肌动蛋白和心脏拉伸介导反应的其他成分相互作用。该提案将利用这些新的细胞骨架相关蛋白，这些基因的新小鼠敲除，新的体外和体内检测系统，这些系统将允许精确评估将它们连接到关键端点的上游和下游信号通路，以及最先进的转录分析和生物信息学来识别下游靶基因。通过在培养细胞、完整乳头状肌和原位心脏中使用新的检测系统来评估它们在拉伸介导反应中的作用，可以直接评估它们在确定拉伸介导反应因果关系中的机制作用。因此，本提案的具体目的是：1)确定gp130依赖性，生物力学应力诱导的细胞骨架相关蛋白（SprMA）与心肌细胞肥大和存活途径之间的机制联系；2)描述titin相关的应激诱导蛋白（CARP）在生物力学应激下心脏肥厚下游信号转导中的作用；3)确定CARP-titin复合物的肌肉限制性成分myopalladin在生物力学应力诱导的心肌肥厚和心肌病通路中的作用。

DESCRIPTION (provided by applicant): Chronic increases in wall stress play a pivotal role in the initiation and progression of cardiomyopathy and associated heart failure. Experimental and human studies point to a critical role of cytoskeletal defects, with a clustering of mutations in genes encoding components of the Z disc and their interaction with titin and titin-associated proteins. Human mutations in titin, telethonin, and muscle LIM domain proteins (MLP, Cypher), have now been clearly implicated in the onset of human cardiomyopathy. In addition, Z disc proteins and the titin complex have recently been identified as an essential part of the cardiomyocyte biomechanical stretch sensor, suggesting that defects in cytoskeletal-dependent stress signaling pathways may be linked to the initiation and progression of human DCM. It will become critical to mechanistically link the complex Z disc and titin associated proteins that contribute to human heart failure. We have uncovered a number of new cardiac cytoskeletal-associated proteins that physically interact with titin, actin, and other components of the cardiac-stretch mediated responses. This proposal will capitalize on these novel cytoskeletal associated proteins, new mouse knockouts of these genes, new in vitro and in vivo assay systems that will allow a precise evaluation of the upstream and downstream signaling pathways that link them to key endpoints, and state-of-the-art transcriptional profiling and bioinformatics to identify downstream target genes. A direct evaluation of their mechanistic role in exacting a cause-effect relationship with stretch mediated responses will be evaluated by capitalizing on new assay systems in cultured cells, intact papillary muscle, and in the in situ heart to evaluate the role of these in stretch mediated responses. Accordingly, the Specific Aims of this proposal are: 1) To identify the mechanistic links between a gp130 dependent, biomechanical stress-inducible cytoskeletal associated protein (SprMA) and pathways for cardiomyocyte hypertrophy and survival; 2) To delineate the role of a titin-associated, stress inducible protein (CARP) in the transduction of downstream signals for cardiac hypertrophy during biomechanical stress; and 3) To define the role of myopalladin, a muscle restricted component of the CARP-titin complex, in biomechanical stress induced pathways for cardiac hypertrophy and cardiomyopathy.