Oxidants & Caspases: Initiation of Reperfusion Injury

氧化剂

• 批准号: 7006058
• 负责人: KIMM J HAMANN
• 金额: $ 37.23万
• 依托单位: UNIVERSITY OF CHICAGO
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-01-15 至 2009-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7006058
• 关键词: Bax gene /protein; RNA interference; antioxidants; apoptosis; cardiac myocytes; cellular pathology; cysteine endopeptidases; cytochrome c; disease /disorder model; electron transport; enzyme activity; free radical oxygen; free radical scavengers; genetically modified animals; heart arrest; laboratory mouse; mitochondria; molecular pathology; myocardial ischemia /hypoxia; oxidizing agents; reperfusion; tissue /cell culture

DESCRIPTION (provided by applicant): Therapeutic manipulation of caspases or their regulators offers significant promise in controlling cellular injury in ischemia/reperfusion. Because blockade of specific caspases can result in apoptotic progression via alternative or compensatory pathways, however, it is critical to understand the roles of individual caspases and those molecules which directly control caspase activities or which provide "short-circuits" leading to so-called "caspase independent" downstream mechanisms of cell death. The central hypothesis of this proposal is that following ischemia/reperfusion (I/R) in cardiomyocytes, generation of reactive oxygen species (ROS) and caspase-2 activation lead to mitochondrial perturbations resulting in release of cytochrome c (cyt c) and disruption of the electron transport chain and apoptotic cell death. Using a combination of cellular and animal models, depletion of specific proteins via RNA interference and specific knockout mice, we propose to study the roles of specific caspases and their regulators, including Smac/DIABLO and inhibitor of apoptosis proteins (IAPs) in two major specific aims: 1) Determine the interactive roles of caspase-2, mitochondrial ROS, and Bax and Bid ininitiating ischemia/reperfusion-induced injury to cardiomyocytes. We hypothesize that IR results in generation of mitochondrial ROS and the activation of Bax and caspase-2. In these studies we will examine also the effects of specific ROS, such as superoxide and hydrogen peroxide, and antioxidant treatment on the activation of Bax and caspase-2. Further, we postulate that active caspase-2 acts directly on the mitochondria and/or via Bid cleavage to cause the release of cyt c and further ROS generation; 2) Determine the role of caspase-2 in the release of pro-apoptotic mitochiondrial protein Smac/DIABLO, its effects on IAP blockade of caspase activity and their relative roles in amplification of I/R-induced apoptosis. We hypothesize that in I/Rstimulated cardiomyocytes, caspases can cause differential release of apoptogenic mitochondrial proteins, such as cyt c and the IAP-inhibiting Smac/DIABLO, and that these affect caspase-mediated amplification of I/R-induced cell death. A better understanding of specific caspase activity and the physiological interplay between caspases, mitochondrial ROS, and the endogenous regulators which act on or are released from the mitochondria will be critical in assessing the therapeutic potential of these targets.

描述（由申请人提供）：胱天蛋白酶或其调节剂的治疗操作在控制缺血/再灌注中的细胞损伤方面有很大的希望。但是，由于特定胱天蛋白酶的阻塞会通过替代或补偿途径导致凋亡进展，因此了解单个胱天蛋白酶的作用和直接控制caspase活性或提供“短路”的分子的作用至关重要，从而导致所谓的“ caspase”独立的“独立的”独立的“独立”细胞死亡机制。该提议的中心假设是，心肌细胞中的缺血/再灌注（I/R），活性氧（ROS）的产生（ROS）和caspase-2激活导致线粒体扰动，导致线粒体扰动导致cytochrome C（Cytt c）释放，以及电子传输链和Apoptotic the Eleth the Electon Transport the Electon the Electon the Electon the Electon。利用细胞和动物模型的组合，通过RNA干扰和特定的敲除小鼠的特异性蛋白质消耗，我们建议研究特定caspase及其调节剂的作用，包括SMAC/DIABLO和凋亡蛋白的抑制剂和两个主要特定目的的凋亡蛋白（IAP）（IAP）：1）缺血/再灌注引起的心肌细胞损伤。我们假设IR会导致线粒体ROS的产生以及Bax和Caspase-2的激活。在这些研究中，我们还将研究特定ROS的影响，例如超氧化物和过氧化氢以及抗氧化剂治疗对BAX和CASPASE-2的激活。此外，我们假设活性caspase-2直接作用于线粒体和/或通过竞标裂解引起Cyt C和进一步的ROS产生。 2）确定caspase-2在促凋亡的线性蛋白SMAC/Diablo的释放中的作用，其对IAP阻断caspase活性的影响及其在I/R诱导的细胞凋亡的扩增中的相对作用。我们假设在I/r构的心肌细胞中，胱天蛋白酶可能导致凋亡性线粒体蛋白的差异释放，例如Cyt C和IAP抑制SMAC/DIABLO，并且这些会影响caspase介导的I/R诱导细胞死亡的扩增。更好地理解caspase，线粒体ROS和从线粒体上作用或释放的内源性调节剂之间的特定caspase活性和生理相互作用对于评估这些靶标的治疗潜力至关重要。