BIOCHEMICAL MECHANISM OF REPERFUSION LUNG INJURY

目的：本提案的目标是确定生物化学 肺再灌注损伤的机制。 假设：1.黄嘌呤氧化酶（XO）在 引发肺再灌注损伤及其基因表达的变化， mRNA的加工和翻译，以及最终蛋白质的稳定性 产物是再灌注敏感性的重要决定因素 损伤2. 肺再灌注损伤的传播是由 缺血时细胞内能量代谢紊乱 并持续到再灌注的初始阶段。3. 硝酸 氧化物（NO.）在改善肺再灌注损伤中起重要作用。 研究：该项目将研究分子，生物化学， 肺再灌注损伤的生理基础。 第一个目标是 评估黄嘌呤受体的分子和细胞调节 氧化还原酶系统（XDH/XO），并建立 酶表达和再灌注敏感性的改变 损伤 从体外到原位再到体内的一系列方法 将采用体内试验来确定细胞因子和O2的重要性 张力作为转录调节、蛋白质修饰 XDH/XO酶活性与再灌注损伤易感性的关系。 第二个目标是表征细胞内能量的变化 在缺血和再灌注期间代谢。 全面评估 将描述腺嘌呤核苷酸及其催化剂的变化 在缺血和再灌注期间。 第三个目标将决定 NO在肺再灌注损伤中的作用。 我们的初步实验 表明L-精氨酸增强NO产生，但不 N-硝基-L-精氨酸是一种竞争性阻断NO的拮抗剂。 生产，防止肺再灌注损伤。 研究将检查 这种保护作用的机制特别关注 激活鸟苷酸环化酶，抑制Fe-S酶， 防止羟自由基（HO.）由血红素结合铁催化形成 占据催化铁配位位置。 研究还将 确定细胞因子和O2张力作为 NO合成酶的转录调控和酶活性。 意义：拟议的研究将提供更好的理解 肺再灌注损伤的方法， 可以设计过程。

OBJECTIVE: The goal of this proposal is to determine the biochemical mechanisms responsible for lung reperfusion injury. HYPOTHESES: 1. Xanthine oxidase (XO) is critically important in initiating lung reperfusion injury and changes in its gene expression, processing and translation of mRNA, and stability of the final protein product are important determinants of susceptibility to reperfusion injury. 2. Propagation of lung reperfusion injury is fostered by disturbances in intracellular energy metabolism created during ischemia and persisting through the initial stages of reperfusion. 3. Nitric oxide (NO.) plays a central role in ameliorating lung reperfusion injury. RESEARCH PLAN: The project will investigate the molecular, biochemical and physiologic basis for lung reperfusion injury. The first aim will be to assess the molecular and cellular regulation of the xanthine: acceptor oxidoreductase system (XDH/XO) and to establish the relationship between alterations in enzyme expression and susceptibility to reperfusion injury. A hierarchy of methods ranging from in vitro to in situ to in vivo will be employed to determine the importance of cytokines and 02 tension as modulators of transcriptional regulation, protein modification and enzyme activity of XDH/XO, and susceptibility to reperfusion injury. The second aim will be to characterize changes in intracellular energy metabolism during ischemia and reperfusion. A comprehensive assessment will characterize changes in adenine nucleotides and their catabolites during ischemia and reperfusion. The third aim will determine the role played by NO. in lung reperfusion injury. Our preliminary experiments indicate that L-arginine which enhances NO. production, but not Nw-nitro-L-arginine, a competitive antagonist which blocks NO. production, prevents lung reperfusion injury. Studies will examine the mechanism of this protective effect focusing in particular on the ability of NO. to activate guanylate cyclase, to inhibit Fe-S enzymes and to prevent hydroxyl radical (HO.) formation catalyzed by heme bound iron by occupying the catalytic iron coordination site. Studies will also determine the importance of cytokines and 02 tension as modulators of transcriptional regulation and enzyme activity of NO synthase. SIGNIFICANCE: The proposed research will provide a better understanding of lung reperfusion injury so that methods of preventing or interrupting the process can be designed.