Calpains as Mediators of Cardiac Ischemic Injury

钙蛋白酶作为心脏缺血性损伤的调节剂

• 批准号: 7147457
• 负责人: Gerald W. Dorn
• 金额: $ 38.38万
• 依托单位: UNIVERSITY OF CINCINNATI
• 依托单位国家: 美国
• 财政年份: 2006
• 资助国家: 美国
• 起止时间: 2006-08-01 至 2011-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7147457
• 关键词: BCL2 gene /protein; apoptosis; biological signal transduction; calcium; calpain; cardiac myocytes; cysteine endopeptidases; enzyme activity; genetically modified animals; heart function; immunocytochemistry; laboratory mouse; mature animal; myocardial infarction; myocardial ischemia /hypoxia; necrosis; newborn animals; protein kinase C; terminal nick end labeling; tissue /cell culture

DESCRIPTION (provided by applicant): Myocardial ischemia negatively impacts cardiac function through: 1) Immediate post-ischemic contractile dysfunction of non-infarcted, reperfused myocardium (stunning); 2) Myocardial infarction and infarct extension; and 3) Delayed left ventricular remodeling. Since cardiac ischemia and infarction are associated with increased free cytosolic calcium, activation of calpains (calcium-activated cystein proteases) is thought to contribute to ischemic cardiac injury. Limb-Girdle Muscular Dystrophy 2A (or "calpainopathy") in patients with loss of function mutations in the calpain-3 gene result reveals an essential function for calpains in skeletal muscle health. We have created a myocardial calpain loss-of-function mouse (transgenic overexpression of calpain-inhibitory calpastatin) which develops a cardiomyopathy with many of the histologic features of skeletal calpainopathy. Based on these observations, our GENERAL HYPOTHESIS is that calpains 1 and 2 have unique functions in normal cardiac health, and due to differential activation by calcium and differential mRNA regulation after infarction, play distinct roles in mediating post-ischemic injury. To test this hypothesis we created cardiac-specific calpain 1 and 2 knockout and conditional overexpression mice, and will pursue these SPECIFIC AIMS: SA #1 -Define the normal functions of myocardial calpain 1 and calpain 2 in studies of cardiac structure, function, and cell signaling. SA#2-Delineate the pathophysiological consequences and relevant cellular mechanisms of calpain 1 and calpain 2 activation after myocardial infarction and ischemia-reperfusion injury by defining the relative roles of apoptotic and necrotic cardiomyocyte death. SA#3-Determine the biochemical mechanisms for calpain-mediated caspase activation and stimulation of apoptosis in studies of calpain 1 and 2-modulated cultured neonatal and adult cardiac myocytes. Collectively, these studies will apply state-of-the-art techniques for in vivo genetic manipulation, microphysiologic analysis, and biochemical assessment to achieve insight into the roles of myocardial calpains in health and disease.

描述（由申请人提供）：心肌缺血通过以下方式对心脏功能产生负面影响：1）无敏感的，重复的心肌（令人惊叹）的立即缺血后收缩功能障碍； 2）心肌梗塞和梗塞延伸； 3）延迟左心室重塑。由于心脏缺血和梗塞与自由胞质钙的增加有关，因此人们认为CALPAIN（钙激活的Cystein蛋白酶）的激活被认为会导致缺血性心脏损伤。 Calpain-3基因中功能突变损失的患者的肢体束肌营养不良2A（或“ Calpainopathy”）结果表明，骨骼肌健康中钙蛋白酶的重要功能。我们创建了一种心肌钙蛋白酶功能丧失的小鼠（Calpain抑制性钙蛋白酶的转基因过表达），该小鼠具有骨骼钙质病的许多组织学特征。基于这些观察结果，我们的一般假设是Calpains 1和2在正常心脏健康中具有独特的功能，并且由于梗塞后钙和差异mRNA调节的差异激活，因此在介导缺血后损伤中起着不同的作用。为了检验这一假设，我们创建了心脏特异性的钙蛋白酶1和2敲除和有条件的过表达小鼠，并将追求这些特定目标：SA＃1-定义心肌钙蛋白酶1和Calpain 2在心脏结构，功能和功能和功能研究中的正常功能细胞信号传导。 SA＃2终止于心肌梗死和缺血 - 再灌注损伤后，钙蛋白酶1和钙蛋白酶2激活的病理生理后果和相关的细胞机制，通过确定凋亡和坏死性心脏肌细胞死亡的相对作用。 SA＃3确定性的生化机制在钙蛋白酶1和2型培养的新生儿和成人心肌细胞的研究中，用于钙蛋白酶介导的caspase激活和刺激凋亡的生化机制。总的来说，这些研究将采用最新技术来用于体内遗传操作，微生物生理分析和生化评估，以深入了解心肌钙质在健康和疾病中的作用。