REGULATION OF CARDIOMYOCYTE SURVIVAL

心力衰竭(HF)是一种常见的儿童期事件，发病率和死亡率都很高。当前的研究 提示心肌细胞凋亡可能在心力衰竭的发生发展中起重要作用。我们有 最近证明ROCK1(Rho相关的，包含蛋白激酶1的卷曲卷曲)是一个关键 在新生儿心肌细胞中，将促凋亡刺激与凋亡联系起来的介体。我们的结果表明 低水平激活的caspase 3直接切割并激活ROCK1；激活的ROCK1在 TURN放大caspase3的激活，导致心肌细胞凋亡的显著放大。重要的是，这 在衰竭的人心脏中存在ROCK1激活和Caspase 3激活之间的机制关系， 提示该通路是一个有效的治疗靶点。项目2中提出的实验将进一步 验证ROCK1中介的重要性，并建立其机制基础 心肌细胞凋亡。特定目标1将表征ROCK1激活在心肌细胞中的作用 细胞凋亡。初步实验将确定caspase 3依赖的ROCK1激活在 心脏毒性药物治疗后的心肌细胞存活和心力衰竭进展 童年心力衰竭。其他研究将验证这样的假设，即ROCK1的激活足以扩增caspase 3 在活体内激活并诱导心肌细胞凋亡。在具体目标2中提出的实验将 建立活化的ROCK1诱导心肌细胞凋亡的分子机制。首字母 研究将验证激活的ROCK1通过线粒体后放大caspase 3激活的假设 监管。其他研究将确定以TAT为基础的抗凋亡蛋白的传递是否可以减弱 在体外激活ROCK1诱导的心肌细胞凋亡，如果有必要，在体内也可以。总体而言， 项目2中提出的实验将检验ROCK1介导的caspase 3扩增的假设 激活在心肌细胞凋亡中起关键作用，并将进一步确立ROCK1的作用 对导致儿童心衰的获得性心肌损伤作出反应的信号。该项目还将 确定是否可以利用对ROCK1信号的操纵来治疗抑制心肌细胞 后天获得性心衰小鼠模型中的细胞凋亡。

Heart Failure (HF) is a common event in childhood with significant morbidity and mortality. Current research indicates that cardiomyocyte apoptosis may contribute significantly to the development of HF. We have recently demonstrated that ROCK1 (Rho-associated, coiled-coil containing protein kinase 1) is a key mediator which links pro-apoptotic stimuli to apoptosis in neonatal cardiomyocytes. Our results suggest a model wherein low levels of activated caspase 3 directly cleave and activate ROCK1; activated ROCK1 in turn amplifies caspase 3 activation, resulting in a marked amplification of cardiac apoptosis. Importantly, this mechanistic relationship between ROCK1 activation and caspase 3 activation occurs in failing human hearts, suggesting that this pathway is a valid therapeutic target. The experiments proposed in Project 2 will further validate the importance of, as well as establish the mechanistic underpinnings of, ROCK1-mediated cardiomyocyte apoptosis. Specific Aim 1 will characterize the role of ROCK1 activation in cardiomyocyte apoptosis. Initial experiments will establish the importance of caspase 3-dependent ROCK1 activation on cardiomyocyte survival and HF progression following treatment with cardiotoxic drugs which induce childhood HF. Other studies will test the hypothesis that ROCK1 activation is sufficient to amplify caspase 3 activation and induce cardiomyocyte apoptosis in vivo. Experiments proposed in Specific Aim 2 will establish the molecular mechanism by which activated ROCK1 induces cardiomyocyte apoptosis. Initial studies will test the hypothesis that activated ROCK1 amplifies caspase 3 activation via post-mitochondrial regulation. Other studies will determine if TAT-based delivery of anti-apoptotic proteins can attenuate activated ROCK1-induced cardiomyocyteapoptosis in vitro, and if warranted, in vivo. Collectively, the experiments proposed in Project 2 will test the hypothesis that ROCK1-mediated amplification of caspase 3 activation plays a critical role in cardiomyocyte apoptosis, and furthermore will establish the role of ROCK1 signaling in response to acquired myocardial injuries which lead to childhood HF. This project will also determine if manipulation of ROCK1 signaling can be exploited to therapeutically inhibit cardiomyocyte apoptosis in a mouse model of acquired postnatal HF.