CARDIAC GROWTH REGULATION

描述 （摘自申请人摘要）心灵对各种事物的反应 血液动力学和体液刺激的变化，肌细胞的大小和功能。 左心室肥大，如高血压或瓣膜病引起的 疾病是一个敏感的预测发病率和死亡率， 心肌功能障碍 本研究的目的是检验 假设肌细胞收缩活动本身是 心肌细胞的生长和功能。 实验方法旨在 确定参与转导的分子机制， 向核发出收缩信号。 既往体外和体内试验数据 研究了α-肌球蛋白的转录调控， 重链（α-MHC）基因允许它们整合核变化 在血液动力学负荷变化的整体细胞反应中。 本申请解决了四个具体目的：（1）识别 转录因子，其在转录因子的-47bp处结合顺式作用元件。 α-MHC基因的转录起始位点，称为血流动力学 反应元件（HME），这是必要的，也足以赋予 心肌细胞对该启动子的收缩反应。 这 将从心肌细胞克隆核蛋白（命名为HRP 通过其与HME序列结合并与HME序列结合的能力， 激活α-MHC启动子;（2）研究其机制， 收缩刺激调节HRP的转录活性， 确定其活性是否受磷酸化调节，确定 它的DNA结合特性，以及它的二聚化特性， （3）研究心肌收缩诱导的信号转导 蛋白激酶C-zeta在磷酸化中起作用的途径 和激活HRP;和（4）通过测定HRP的体内功能， 使用病毒载体系统将基因递送到血流动力学的 未负载的异位移植心脏，经历萎缩， 减少α-MHC表达。 这些研究将推动 了解工作负荷调节心脏的分子途径 生长和功能，并可能导致新的基因疗法， 导致病理性肥大的心脏生长障碍。 (End的 摘要）

DESCRIPTION (Adapted from applicants' abstract) The heart responds to various hemodynamic and humoral stimuli by changes in myocyte size and function. Left ventricular hypertrophy such as arises from hypertension or valvular disease is a sensitive predictor for morbidity and mortality due to myocardial dysfunction. The purpose of the present study is test the hypothesis that myocyte contractile activity per se is a major stimulus of cardiomyocyte growth and function. The experimental approach is designed to identify the molecular mechanisms involved in the transduction of the contractile signal to the nucleus. Data from previous in vitro and in vivo studies that examined the transcriptional regulation of the alpha-myosin heavy chain (alpha-MHC) gene allow them to integrate the nuclear changes within the overall cellular response to the changes in hemodynamic load. This application addresses four specific aims: (1) identification of a transcription factor(s) that binds to a cis-acting element at -47 bp of the transcriptional start site of the alpha-MHC gene, designated hemodynamic response element (HME), that is both necessary and sufficient to confer contractile responsiveness to this promoter in cardiac myocytes. This nuclear protein (designated HRP) will be cloned from a cardiomyocyte expression library by its ability to bind to the HME sequence and to activate the alpha-MHC promoter; (2) study the mechanisms by which the contractile stimulus regulates the transcriptional activity of HRP by determining whether its activity is modulated by phosphorylation, determine its DNA binding characteristics, and its dimerization properties in response to the contractile stimulus; (3) study the contractile-induced signaling pathway in which protein kinase C-zeta plays a role in the phosphorylation and activation of HRP; and (4) determine the in vivo function of HRP by using viral vector systems to deliver the gene into the hemodynamically unloaded, heterotopically transplanted heart, that undergoes atrophy and decreased alpha-MHC expression. These studies will advance the understanding of the molecular pathways by which workload regulates cardiac growth and function, and potentially lead to novel genetic therapies of disorders of cardiac growth leading to pathologic hypertrophy. (End of Abstract)