Aging, Reperfusion, and Apoptosis:A Proteasome Approach

描述：（由申请人提供）减少 心脏供血不足是导致死亡和衰弱的主要原因 国际吧根据缺血事件的持续时间和严重程度， 细胞内稳态不可修复的改变导致坏死性细胞死亡。 然而，存活心脏组织的再灌注可通过以下方式导致细胞死亡： 与坏死无关的过程。部分原因是， 增加氧自由基的产生和诱导编程 细胞死亡，称为凋亡。蛋白酶体是一种主要的细胞内蛋白水解酶 系统，似乎发挥了关键作用，在预防细胞凋亡， 降解某些促凋亡因子。然而，蛋白酶体本身 被自由基过程修饰，并表现出活性急剧下降， 由于冠状动脉闭塞/再灌注。此外，蛋白酶 表达和比活性作为年龄的函数而降低。目标 研究的目的是建立年龄与 自由基诱导的蛋白酶体功能丧失和刺激 冠状动脉闭塞/再灌注期间的细胞凋亡过程。利用 冠状动脉闭塞的生理学相关的体内大鼠模型， 本研究旨在：1）确定蛋白酶体的改变 活性; 2）定义导致蛋白酶体损失的自由基过程 活性; 3）表征细胞凋亡的进展;和4）建立 蛋白酶体失活增强细胞凋亡的机制。在每个目标中， 闭塞和再灌注的持续时间以及动物的年龄的影响将 进行评估。因此，这些研究将建立生化机制， 蛋白酶体功能改变，并且当在冠状动脉闭塞的顺序中， 和再灌注时，发生关键的氧化事件。此外， 蛋白酶体失活在细胞凋亡诱导中的作用。 最后，蛋白酶体活性的年龄依赖性下降， 冠状动脉闭塞/再灌注诱导细胞凋亡的进展和程度 将被阐明。因此，拟议研究的结果将确定 可能影响心脏病长期进展的分子事件 疾病，并指出有效的策略，有利地影响 结果。

DESCRIPTION: (provided by applicant) Complications arising from reduction of blood supply to the heart are a leading cause of death and debilitation worldwide. Depending on the duration and severity of the ischemic event, irreparable alterations in cellular homeostasis lead to necrotic cell death. However, reperfusion of viable cardiac tissue can result in cell death by processes unrelated to necrosis. This has been attributed, in part, to increases in the production of oxygen radicals and the induction of programmed cell death, termed apoptosis. The proteasome, a major intracellular proteolytic system, appears to play a critical role in the prevention of apoptosis by degrading certain pro-apoptotic factors. Nevertheless, the proteasome is itself modified by free radical processes and exhibits dramatic declines in activity as a result of coronary occlusion/reperfusion. Furthermore, proteasome expression and specific activity decrease as a function of age. The objectives of the proposed research are to establish a mechanistic link between age and free radical induced loss in proteasome function and stimulation of the apoptotic process during coronary occlusion/reperfusion. Utilizing a physiologically relevant in vivo rat model of coronary occlusion and reperfusion this study seeks to: 1) Identify alterations in proteasome activity; 2) Defme free radical processes which result in loss in proteasome activity; 3) Characterize the progression of apoptosis; and 4) Establish mechanisms by which proteasome inactivation enhances apoptosis. In each aim, the effects of duration of occlusion and reperfusion and age of the animal will be assessed. Thus, these studies will establish biochemical mechanisms by which proteasome function is altered and when, in the sequence of coronary occlusion and reperfusion, critical oxidative events occur. Furthermore, the role of proteasome inactivation in the induction of apoptosis will be established. Finally, the contribution of age-dependent declines in proteasome activity to the progression and extent of coronary occlusion/reperfusion induced apoptosis will be elucidated. Results of the proposed study will therefore define molecular events which are likely to impact the long term progression of heart disease and indicate efficient strategies for favorably influencing the outcome.