Cytoskeletal-Associated Proteins and Cardiomyopathy

说明(申请人提供)：室壁应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着关键作用。实验和人体研究指出了细胞骨架缺陷的关键作用，即Z盘编码成分的基因突变及其与肌动蛋白和肌动蛋白相关蛋白的相互作用。人类肌动蛋白、端粒素和肌肉LIM结构域蛋白(MLP、Cypher)的突变，现在已被明确地与人类心肌病的发病有关。此外，Z-Disc蛋白和肌动蛋白复合体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，提示细胞骨架依赖的应激信号通路中的缺陷可能与人类扩张型心肌病的发生和发展有关。将导致人类心力衰竭的复杂Z盘和肌动蛋白相关蛋白机械地联系起来将变得至关重要。我们已经发现了一些新的心脏细胞骨架相关蛋白，它们与肌动蛋白、肌动蛋白和心脏拉伸介导的反应的其他成分物理上相互作用。这项提议将利用这些新的细胞骨架相关蛋白、新的小鼠敲除这些基因、新的体外和体内测试系统(将允许精确评估将它们与关键终点连接的上游和下游信号通路)以及最先进的转录图谱和生物信息学来识别下游目标基因。通过在培养细胞、完整的乳头肌和原位心脏中利用新的检测系统来评估这些检测系统在牵张介导的反应中的作用，将直接评估它们在牵拉介导的反应中的机制作用。因此，这项建议的具体目的是：1)确定依赖于gp130的生物力学应激诱导细胞骨架相关蛋白(SprMA)与心肌细胞肥大和存活途径之间的机制联系；2)描述Titin相关应激诱导蛋白(CARP)在生物机械应激过程中心肌肥大下游信号转导中的作用；以及3)确定肌肉限制成分myopalladin在生物力学应激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.