MITOCHONDRIAL FUNCTION IN ISCHEMIC HEART DISEASE

由缺血和再灌注引起的心肌损伤涉及心脏的电生理、收缩和能量产生系统的损伤，并且线粒体在细胞存活和功能恢复中起关键作用。在缺血后心脏中已经注意到可逆或不可逆的线粒体功能障碍的几个部位，但对整体蛋白质谱如何改变以及这种变化是有害的还是自我保护的知之甚少。心肌预处理（PC）是保护心脏免受严重缺血后细胞死亡的最有力手段，清楚地说明了这一二分法。在缺血诱导的PC中，一系列短暂的亚致死性缺血事件触发了强大的细胞防御反应，最终限制了梗死面积。PC包含两个组件：一个早期窗口（经典），持续时间为几分钟到2-3小时，第二个窗口（晚期或延迟），在大约12小时和最后几天出现。这两个窗口在持续时间和保护的鲁棒性以及负责每个的潜在细胞机制方面不同。由于与缺血相关的保护和损伤都涉及线粒体水平的重大变化，因此本项目的重点将是表征缺血或其他 预处理刺激，影响线粒体蛋白质组。将这一目标提升到一个新的水平，我们将评估线粒体蛋白质谱的变化如何影响氧化磷酸化（OxPhos）的控制，使用计算方法和对缺血后心脏完整肌肉的实验。我们的基本假设是，PC改变线粒体亚蛋白质组的方式，引起严重和致命的侮辱的有害变化减轻相对于幼稚心肌和深入的时间分析将揭示潜在的机制。换句话说，比较幼稚和PC心肌中线粒体蛋白质组学的改变将揭示细胞生存斗争的核心蛋白质。通过对线粒体亚蛋白质组进行系统深入的蛋白质组学研究，包括对单个蛋白质和蛋白质复合物进行仔细的定量和表征， 这些变化的功能效应，我们将能够理解如何操纵OxPhos可以导致心脏保护，最终目标是在高危患者中诱导这些变化，以减少与急性MI相关的心肌损伤。

Cardiac muscle injury caused by ischemia and reperfusion involves impairment of the electrophysiological, contractile, and energy producing systems of the heart, and mitochondria play a key role in cell survival and recovery of function. Several sites of reversible or irreversible mitochondrial dysfunction have been noted in the post-ischemic heart, yet little is know about how the overall protein profile is altered and whether such changes are detrimental or self-protective. Myocardial preconditioning (PC), the most powerful means of protecting the heart against cell death after severe ischemia, clearly illustrates this dichotomy. With ischemia-induced PC, a series of short sublethal ischemic events trigger a powerful cellular defense response that ultimately limits infarct size. PC involves two components: an early window (classical) with duration of minutes to 2-3 hours and a second window (late or delayed) that develops at about 12 hours and last days. The two windows differ in duration and the robustness of protection and the underlying cellular mechanism(s) responsible for each. Since both the protection and injury associated with ischemia involve major changes at the level of the mitochondria, the focus of this project will be to characterize how ischemia, or other preconditioning stimuli, affect the mitochondrial proteome. Taking this objective to the next level, we will assess how the changes in the mitochondrial protein profile influence the control of oxidative phosphorylation (OxPhos), using both computational methods and experiments on intact muscles from post-ischemic hearts. Our underlying hypothesis is that PC alters the mitochondrial subproteome in such a manner that the detrimental changes elicited with a severe and lethal insult are mitigated with respect to naive myocardium and that in-depth temporal analysis will reveal the underlying mechanism. In other words, comparison of mitochondrial proteomic alterations in naive and PC myocardium will reveal the underlying proteins that are central to the cell's struggle for survival. By carrying out a systematic in-depth proteomic investigation of the mitochondrial subproteome, including careful quantification and characterization of individual proteins and protein complexes, coupled with a plan to assess the functional effects of such changes, we will be able to understand how manipulating OxPhos can result in cardioprotection, with the eventual goal of inducing these changes in high risk patients to reduce the myocardial damage associated with acute MI.