Protection of Ischemic Myocardium

描述（由申请人提供）： 心脏已经进化出一种对应激的适应性反应，称为晚期预处理（PC），其赋予对缺血/再灌注损伤的强有力和持续的保护。我们和其他人以前的工作表明，晚期PC是由一组应激反应蛋白，即iNOS，HO-1和ecSOD，通过联合调节NO和CO的心肌水平，减轻组织损伤的上调介导的。我们的初步数据表明，这些蛋白质是分层组织和相互作用，以实现细胞保护，从而形成一个功能模块。该项目的中心主题是阐明iNOS-HO-1-ecSOD模块强大的心脏保护作用的分子机制，并探索通过遗传或药理学方法上调该模块以实现慢性预防性心脏保护的可行性。该计划将包括四个项目和四个核心。项目1（Bolli）将确定增加心肌NO和CO水平的基因治疗策略（iNOS，HO-1或ecSOD基因治疗）是否会导致慢性保护表型，并将阐明这三种应激反应基因如何在调节NO和CO水平中相互作用。这个项目将测试新的想法，基因治疗可以用来实现一个永久的预处理样状态。项目2（Prabhu）将确定是否相同的三个基因（iNOS，HO-1和ecSOD）减轻慢性梗死后心肌重塑和由此产生的心力衰竭，并将研究这些有益作用的机制。在项目1中在急性缺血/再灌注损伤背景下测试的相同基因治疗策略将在项目2中在梗死后LV重构背景下测试。该项目将测试iNOS-HO-1-ecSOD模块是对抗心力衰竭的关键保护机制的新想法。项目3（Xuan）将研究NO和CO诱导延迟保护的信号和分子机制，重点关注这些分子抑制凋亡的显着能力。该项目的中心假设是，NO-CO轴凭借其以促进细胞存活的方式对心脏进行基因重编程的能力，在心脏适应应激中发挥关键作用。项目4（Bhatnagar）将测试在预处理心脏中iNOS和HO-1抑制线粒体呼吸的假设，这减少了自由基的产生，抑制线粒体通透性转换，并防止细胞死亡。这四个项目将得到四个核心的支持，这些核心将提供小鼠手术，心脏基因转移，转基因和敲除小鼠的产生，病毒载体生产和病理学服务。这个项目是我们以前对晚期PC的工作的自然演变-已经确定NO和CO作为这种适应的关键介质，我们将研究NO-CO轴的保护机制和治疗效用。由于NO和CO无处不在的作用，结果将有广泛的病理生理意义的许多生物过程中，NO和CO是已知的服务和重要的调节功能。此外，这些结果可能为将心脏保护疗法转化为临床竞技场提供一个框架。

DESCRIPTION (provided by applicant): The heart has evolved an adaptive response to stress, termed late preconditioning (PC), that confers powerful and sustained protection against ischemia/reperfusion injury. Previous work by us and others has shown that late PC is mediated by the upregulation of a cluster of stress-responsive proteins, namely, iNOS, HO-1, and ecSOD, which mitigate tissue injury via the combined regulation of the myocardial levels of NO and CO. Our preliminary data indicate that these proteins are organized hierarchically and interact with one another to effect cytoprotection, thereby forming a functional module. The central theme of this Program Project is to elucidate the molecular mechanisms responsible for the powerful cardioprotective effects of the iNOS-HO-1-ecSOD module, and to explore the feasibility of upregulating this module with genetic or pharmacologic approaches in order to achieve chronic prophylactic cardioprotection. The Program will consist of four Projects and four Cores. Project 1 (Bolli) will determine whether gene therapy strategies that increase myocardial NO and CO levels (iNOS, HO-1, or ecSOD gene therapy) result in a chronically-protected phenotype and will elucidate how these three-stress responsive genes interact in modulating NO and CO levels. This Project will test the novel idea that gene therapy can be used to achieve a permanent preconditioned-like state. Project 2 (Prabhu) will determine whether the same three genes (iNOS, HO-1, and ecSOD) mitigate chronic post-infarction myocardial remodeling and the resulting heart failure, and will investigate the mechanisms for these beneficial effects. The same gene therapy strategies tested in Project 1 in the setting of acute ischemia/reperfusion injury will be tested in Project 2 in the setting of post-infarction LV remodeling. This Project will test the novel idea that the iNOS-HO-1-ecSOD module is a critical protective mechanism against heart failure. Project 3 (Xuan) will investigate the signaling and molecular mechanisms Whereby NO and CO induce delayed protection, focusing on the remarkable ability of these molecules to suppress apoptosis. The central hypothesis of this Project is that the NO-CO axis plays a critical role in the cardiac adaptation to stress by virtue of its ability to genetically reprogram the heart in a manner that promotes cell survival. Project 4 (Bhatnagar) will test the hypothesis that in the preconditioned heart iNOS and HO-1 inhibit mitochondrial respiration, which decreases free radical generation, inhibits mitochondrial permeability transition, and prevents cell death. These four projects will be supported by four Cores that will provide services in mouse surgery, cardiac gene-transfer, transgenic and knockout mouse generation, viral vector production, and pathology. This Program Project is the natural evolution of our previous work on late PC - having identified NO and CO as key mediators of this adaptation, we will investigate the mechanism of protection and the therapeutic utility of the NO-CO axis. Because of the ubiquitous role of NO and CO, the results will have broad pathophysiological implications for numerous biological processes in which NO and CO are known to serve and important regulatory function. In addition, the results may provide a framework for translating cardioprotective therapies to the clinical arena.