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，称为晚期预适应(PC)，对缺血/再灌注损伤具有强大而持久的保护作用。我们和其他人以前的工作表明，晚期PC是通过一系列应激反应蛋白的上调而介导的，即iNOS、HO-1和EcSOD，它们通过联合调节心肌中NO和CO的水平来减轻组织损伤。我们的初步数据表明，这些蛋白质是分级组织的，并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，并探索用遗传或药物方法上调该模块以实现慢性预防性心脏保护的可行性。该方案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)是否会导致长期保护的表型，并将阐明这三个应激反应基因如何相互作用调节NO和CO水平。这个项目将测试一个新的想法，即基因治疗可以用来达到一种永久的预适应状态。项目2(Prabhu)将确定相同的三个基因(iNOS、HO-1和EcSOD)是否可以减轻慢性梗死后心肌重构和由此导致的心力衰竭，并将探讨这些有益影响的机制。在项目1中测试的在急性缺血/再灌注损伤环境中测试的相同基因治疗策略将在项目2中在梗死后左室重构环境中测试。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这一新想法。项目3(Xuan)将研究NO和CO诱导延迟保护的信号和分子机制，重点是这些分子抑制细胞凋亡的显著能力。该项目的中心假设是，NO-CO轴在心脏对应激的适应中发挥着关键作用，因为它能够以促进细胞存活的方式对心脏进行基因重组。项目4(Bhatnagar)将测试这一假设，即在预适应的心脏中，iNOS和HO-1抑制线粒体呼吸，从而减少自由基的产生，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，这些核心将在小鼠手术、心脏基因转移、转基因和基因敲除小鼠的产生、病毒载体的生产和病理学方面提供服务。本计划项目是我们先前关于晚期PC的工作的自然演变--确定NO和CO是这种适应的关键介质后，我们将研究NO-CO轴的保护机制和治疗效用。由于NO和CO的作用无处不在，这一结果将对许多生物学过程具有广泛的病理生理意义，其中NO和CO是已知的服务和重要的调节功能。此外，这一结果可能为将心脏保护疗法转化为临床领域提供一个框架。

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.