PROTEASE-ACTIVATED RECEPTOR ACTIONS IN CARDIOMYOCYTES

描述（来自申请人摘要的逐字记录）： 应用是基于蛋白酶激活受体的证据， （PAR）对心肌细胞产生深远的影响;对PAR的反应包括 钙的强烈变化和肥大生长程序的诱导。 我们的初步数据表明，心肌细胞表达至少两种PAR （PAR-1和PAR-2）具有相似（但不相同）的信号传导 性质和PAR诱导一种形式的肥大， （与原型Gq偶联α 1-肾上腺素能受体引起的不同） 受体。不同的肥大程序的分子基础， 对PAR和α 1-AR激活的反应尚不清楚，但PAR- vs 1 α-肾上腺素能受体-G蛋白偶联和几种 在初步数据中鉴定了重要的信号分子， 可能是贡献。总的来说，这些结果强调， 靶向PAR的药物可能具有重要的心脏后果。这 应用程序将解决与PAR行动机制有关的一般问题 以及关于表达和详细说明的具体问题， 心肌细胞中单个PAR的偶联/功能特性， 这些研究在很大程度上被忽视了。具体目标是（一） 研究PAR与下游信号通路和生长反应的联系; 这些研究将确定和区分肥大的机制， PAR与α 1-肾上腺素能受体的信号传导，（II）使用新的分子 描述个体信号传导的G蛋白依赖性的技术 途径，并确定其对PAR-1肥大信号传导的贡献， (III)使用PAR-1基因敲除小鼠来确定PAR-1在细胞凋亡中的功能作用。 完整小鼠心脏的综合反应。通过跨越细胞培养， 完整的动物模型（并采用一系列生物化学/分子生物学方法 技术，荧光显微镜与钙敏感指标，和 PAR-1基因敲除小鼠）的建议将阐明机制， 凝血酶等蛋白酶激活心肌细胞， 相关的问题，如是否正在开发的药物，以调节信号 在正常情况下或在 缺血性损伤的背景。

DESCRIPTION (Verbatim from the Applicant's Abstract): Studies in this application are based upon the evidence that protease-activated receptors (PARs) exert profound effects on cardiac myocytes; responses to PARs include robust changes in calcium and the induction of a hypertrophic growth program. Our preliminary data indicate that cardiomyocytes express at least two PARs (PAR-1 and PAR-2) which possesses similar (but not identical) signaling properties and that PARs induces a form of hypertrophy that is morphologically (distinct from that elicited by the prototypical Gq-coupled alpha1-adrenergic receptors. The molecular underpinnings for distinct hypertrophic programs in response to PAR and alpha1-AR activation are not known, but differences in PAR- vs 1alpha-adrenergic receptor-G protein coupling and the activation of several important signaling molecules are identified in the preliminary data which could be contributory. Collectively, these results emphasize that pharmaceuticals targeted to PARs may have important cardiac consequences. This application will address general questions related to mechanisms for PAR action as well as specific questions regarding the expression and detailed coupling/functional properties of individual PARs in cardiomyocytes, an area of research that has largely been neglected. The specific aims are (I) to investigate PAR linkage to downstream signaling pathways and growth responses; these studies will identify and distinguish the mechanisms for hypertrophic signaling by PARs vs. alpha1-adrenergic receptors, (II) to use newer molecular techniques to delineate the G protein-dependence of individual signaling pathways and define their contribution to hypertrophic signaling by PAR-1, and (III) to use PAR-1 knockout mice to define the functional role of PAR-1 in the integrated response in the intact mouse heart. By spanning cell culture to intact animal models (and employing a range of biochemical/molecular techniques, fluorescence microscopy with calcium-sensitive indicators, and PAR-1 knockout mice) the proposal will elucidate the mechanisms whereby proteases such as thrombin activate cardiomyocytes and resolve clinically relevant issues as whether drugs that are being developed to modulate signaling through PARs are likely to influence the heart under normal conditions or in the context of ischemic injury.