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疾病 人民。从代偿性肥厚到心力衰竭的转变 通常伴随着心肌细胞的凋亡性死亡，但 这一现象的发生机制和生理相关性尚不清楚。 拟议研究的目的是阐明信号转导 负责心肌细胞凋亡的途径并检测其 与心力衰竭有关。具体地说，我们将检验这个假设 应激激活的MAP激酶(SAP激酶)的成员级联， CJun氨基末端激酶(JNK)和p38激酶，介导心脏 α基因表达增加引起的心肌肥大和细胞凋亡 异源三聚体G蛋白Gq亚基的体外和体内实验。 ICE/半胱氨酸天冬氨酸蛋白酶家族可能参与 还将评估细胞的凋亡反应，以测试其 心力衰竭的潜在治疗效果。第一 特定目的利用培养的新生大鼠心肌细胞作为 模型系统。表达野生型腺病毒载体的心肌细胞 类型或结构性激活的Galphaq清单特征 肥大(ANF表达增加，细胞增大，肌丝 组织)进展为细胞凋亡性死亡(染色体 碎裂和核凝结)。拟议的研究将 分析肥大与细胞凋亡的时序性发展及其意义 与Galphaq信号强度的关系，参与 SAP下游蛋白激酶及其与caspase的关系 激活。第二个具体目的是利用转基因动物 同时表达Galphaq和显性负性突变体SAP 确定SAPK在Galphaq诱导的肥厚中的具体作用。 在第三个特定目标中，将对同一组小鼠进行实验 通过横向腹主动脉环扎术、注射激动剂或 以确定SAPKs在诱导妊娠中的作用 在Galphaq转基因小鼠中观察到的凋亡性心力衰竭 这些实验性的操作。在最终的具体目标中， JNK和p38的结构性活性上游激活剂，显示为 诱导培养的心肌细胞肥大和凋亡 在转基因小鼠的心脏中有条件表达。心脏的变化 激活基因表达所导致的功能和形态 将分析SAPK的上游激活剂。如果发生了细胞凋亡， 将给予半胱氨酸天冬氨酸酶抑制剂在体内测试它们的 细胞凋亡的参与及其与心脏的关系 总体而言，这些研究应该有助于我们理解 肥厚转变为心力衰竭的机制和 最终到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.