Redox Activity of the Pulmonary Endothelial Surface

描述（由申请人提供）：肺内皮影响血源性氧化还原活性内源性、药理学、毒理学和膳食化合物的氧化还原状态。它的作用是作为一个大的化学反应器表面，由细胞表面和位于静脉和动脉循环之间的细胞内氧化还原酶组成。内皮对这些化合物氧化还原状态的影响影响其生物活性，包括促或抗氧化作用、组织渗透性和化学反应性。醌类化合物是一类重要的氧化还原活性化合物，具有一系列的生理、药理和毒理学活性。这一提议的假设是，肺内皮细胞对醌的氧化还原代谢决定了醌还原产物及其在肺和内皮细胞、血浆、下游血管和器官系统中的生物活性。拟议研究的目标是确定和量化因素，关于细胞和醌的性质，决定了与肺内皮接触的给定醌的命运。具体目标是：1。鉴定和量化肺内皮醌还原酶和对苯二酚氧化酶介导的反应，这些反应有助于一系列具有不同物理和化学性质的醌的命运：2 .确定醌还原酶的活性对肺内皮氧化还原状态的影响：确定肺内皮对高氧的适应对醌命运的氧化还原过程的影响。为了实现这些目标，一般的方法包括：测量细胞内和细胞表面醌还原动力学，对苯二酚氧化和与细胞成分的关联，使用培养的完整的常氧肺动脉内皮细胞和适应高氧的细胞，作为氧化应激的模型。一组抑制剂和动力学模型将为所涉及的醌还原酶和对苯二酚氧化酶的功能和定量鉴定提供手段。细胞氧化还原状态将通过实验来确定其在与内皮细胞接触的醌的命运中的作用。最后，对照和高氧适应细胞中的醌还原酶将被分离和鉴定，以进一步表征它们对两种细胞类型对醌命运的净效应的贡献。由于醌还原酶和对苯二酚氧化酶在多种其他氧化还原活性化合物的代谢中起重要作用，因此该结果也将对物质的内皮加工产生影响。研究结果将揭示肺内皮处理血源性氧化还原活性物质的机制，以及它们对氧化应激的适应，以及它们在全身的药理学、生理和毒理学活性的影响。

DESCRIPTION (provided by applicant): The pulmonary endothelium influences the redox status of blood borne redox active endogenous, pharmacological, toxicological and dietary compounds. It does so by acting as a large chemical reactor surface comprised of cell surface and intracellular redox enzymes situated between the venous and arterial circulations. The impact of the endothelium on the redox status of these compounds affects their bioactivity, including pro-or anti-oxidant effects, tissue permeation, and chemical reactivity. Quinones represent 1 important class of redox-active compounds with a range of physiological, pharmacological, and toxicological activities. The hypothesis underlying this proposal is that redox metabolism of quinones by pulmonary endothelial cells determines the quinone reduction products, and their bioactivity, within the lung and endothelial cells, the plasma, and downstream vessels and organ systems. The goal of the proposed research is to identify and quantify the factors, with regard to properties of both the cells and quinones, that determine the fate of a given quinone that comes in contact with the pulmonary endothelium. The specific aims are to: 1. Identify and quantify the pulmonary endothelial quinone reductase and hydroquinone oxidase mediated reactions contributing to the fate of a series of quinones with varying physical and chemical properties: 2. Determine the dependence of the activities of quinone reductases contributing to the fate of a given quinone on the pulmonary endothelial redox status: 3. Determine the influence of adaptation of the pulmonary endothelium to hyperoxia on the redox processes contributing to quinone fate. To achieve these aims, the general approaches include: measuring the kinetics of intracellular and cell surface quinone reduction, hydroquinone oxidation and associations with cellular constituents using intact normoxic pulmonary arterial endothelial cells in culture and cells adapted to hyperoxia, as a model of oxidant stress. A panel of inhibitors and kinetic modeling will provide the means for functional and quantitative identification of the contributions of the quinone reductases and hydroquinone oxidases involved. Cell redox status will be manipulated experimentally to determine its role in the fate of the quinones that come in contact with the endothelial cells. Finally, the quinone reductases in the control and hyperoxia-adapted cells will be isolated and identified to further characterize their contributions to the net effect of both cell types to quinone fate. Since quinone reductases and hydroquinone oxidases are important in metabolism of a wide range of other redox active compounds, the results will have implications for endothelial processing of substances as well. The results will reveal pulmonary endothelial mechanisms involved in processing blood borne redox active substances, and their adaptation to oxidative stress, with implications for their pharmacological, physiological and toxicological activities throughout the body.