SAP KINASES IN GQ INDUCED APOPTOTIC HEART FAILURE

心力衰竭是一种影响数百万美国人的流行病， 人 从代偿性肥大到心力衰竭的转变 常伴有心肌细胞凋亡， 这种现象的机制和生理相关性尚不清楚。 拟议研究的目的是阐明信号传导 负责心肌细胞凋亡的途径，并测试其 参与心力衰竭。 具体来说，我们将测试假设 应激激活MAP激酶（SAP激酶）级联反应的成员， cJun N-末端激酶（JNK）和p38激酶介导心脏 肥大和凋亡诱导的表达增加的α 亚基的异源三聚体G蛋白Gq在体外和体内。 ICE/caspase蛋白酶家族可能参与了 还将评估凋亡反应以测试它们的 心力衰竭的潜在治疗效果。 第一 specific aim利用培养的新生大鼠心室肌细胞作为 模型系统 用腺病毒载体感染的肌细胞表达野生型 型或组成性激活Galphaq表现出的特征 肥大（ANF表达增加、细胞增大、肌丝 组织），并进展为凋亡性细胞死亡（染色体 核分裂和核凝聚）。 拟议的研究将 分析细胞肥大和凋亡的时序性发展， 与Galphaq信号强度的关系， 下游SAP激酶以及这些反应与半胱天冬酶的关系 activation. 第二个具体目标是利用转基因动物 表达Galphaq和显性失活突变SAP激酶， 确定SAPK在Galphaq诱导的肥大中的具体作用。 在第三个具体目标中，将对同一组小鼠进行实验性研究。 通过横向主动脉结扎术、输注激动剂或 妊娠，以确定SAPKs在诱导 在Galphaq转基因小鼠中观察到的凋亡性心力衰竭， 这些实验操作。 在最后的具体目标中， JNK和p38的组成型活性上游激活剂，显示 诱导培养心肌细胞肥大和凋亡， 在转基因小鼠的心脏中有条件地表达。心脏变化 功能和形态所产生的表达的激活 将分析SAPK的上游活化剂。 如果发生细胞凋亡， 将施用半胱天冬酶抑制剂以在体内测试它们的 参与细胞凋亡及其与心脏的关系 失败 总的来说，这些研究应该有助于我们理解 肥大转变为心力衰竭的机制， 最终确定潜在有用的治疗方法， 防止或逆转失代偿过程。

Heart failure is a prevalent disease affecting millions of American people. The transition from compensated hypertrophy to cardiac failure is often accompanied by apoptotic death of cardiomyocytes but the mechanism and physiological relevance of this phenomenon is not clear. The objective of the proposed studies is to elucidate the signaling pathways responsible for apoptosis in cardiac myocytes and to test their involvement in heart failure. Specifically we will test the hypothesis that members of the stress activated MAP kinase (SAP kinase) cascade, cJun N-terminal kinase (JNK) and p38 kinase, mediate the cardiac hypertrophy and apoptosis induced by increased expression of the alpha subunit of the heterotrimeric G-protein Gq both in vitro and in vivo. The possible involvement of the ICE/caspase family of proteases in the apoptotic response will also be assessed in order to test their potential therapeutic effectiveness in heart failure. The first specific aim utilizes cultured neonatal rat ventricular myocytes as a model system. Myocytes infected with adenoviral vectors expressing wild type or constitutively activated Galphaq manifest features of hypertrophy (increased ANF expression, cell enlargement, myofilament organization) with a progression to apoptotic cell death (chromosomal fragmentation and nuclear condensation). The proposed studies will analyze the sequential development of hypertrophy and apoptosis and its relationship to the strength of Galphaq signaling, the involvement of downstream SAP kinase and the relationship of these responses to caspase activation. The second specific aim utilizes transgenic animals expressing both Galphaq and dominant negative mutant SAP kinase to determine specific roles of the SAPK in Galphaq induced hypertrophy. In the third specific aim, the same group of mice will be experimentally manipulated by transverse aortic banding, infusion of agonists or pregnancy in order to determine the role of SAPKs in the induction of apoptotic heart failure as observed in Galphaq transgenic mice under these experimental manipulations. In the final specific aim, constitutively active upstream activators of JNK and p38, shown to induce hypertrophy and apoptosis in cultured myocytes, will be conditionally expressed in hearts of transgenic mice. Changes in cardiac function and morphology resulting from the expression of the activated upstream activators of SAPK will be analyzed. If apoptosis occurs, caspase inhibitors will be administered to test in vivo their involvement in apoptosis and the relationship of apoptosis to heart failure Overall these studies should contribute to our understanding of the mechanisms by which hypertrophy transitions to heart failure and ultimately to the identification of potentially useful therapies to prevent or reverse the decompensation process.