Reactive Oxygen Species and Vascular O2 Sensing

描述（由申请人提供）：该提案重点在于定义Nox氧化酶衍生的过氧化氢以及胞质NADPH和NADH氧化还原系统在控制信号传导机制的过程中的作用，该信号传导机制调节血管平滑肌对PO 2生理变化的反应。本申请中的研究调查了我们的新证据的重要性，即胞质NADPH和可能的NADH水平控制基线Nox氧化酶衍生的过氧化氢介导的牛肺动脉舒张，其被缺氧去除，导致收缩。另一方面，牛冠状动脉维持较低水平的NADPH和NADPH生成戊糖磷酸途径（PPP）酶葡萄糖-6-磷酸脱氢酶。我们假设，在冠状动脉PPP的功能差异导致缺氧引起的氧化胞质NADPH，激活松弛通过我们已经证明是由PPP控制的机制。目标1中的研究将调查PO 2如何调节涉及NOx衍生的过氧化氢的血管反应的表达。目的2的重点是了解如何PO 2调节胞质NADH和NADPH氧化还原相关的信号机制，有助于控制力的产生。目的3中的研究旨在确定Nox氧化酶活性和胞质NAD（P）H氧化还原控制差异的起源，这些差异有助于在肺动脉和冠状动脉中观察到的缺氧引起的收缩和舒张反应。分离内皮去除冠状动脉和肺管道和阻力动脉将研究与扰动，改变氮氧化物的活性和表达，和胞质NADH和NADPH氧化还原，以确定如何信号系统调节这些过程可能在PO 2引起的反应。胞质NAD（P）H氧化还原和氧化剂生产的PO 2的控制将检查与代谢测量，组织荧光和荧光技术，细胞荧光成像方法的组合，旨在表征ROS和氧化还原方面的信号转导机制所涉及的。还将检查大鼠动脉，以确定由Nox和胞质NAD（P）H氧化还原控制的PO 2引起的反应机制的相似性和差异。这些研究应有助于确定肺动脉和冠状动脉对氧张力变化的生理反应差异的起源。

DESCRIPTION (provided by applicant): This proposal focuses on defining the role of Nox oxidase-derived hydrogen peroxide, and cytosolic NADPH and NADH redox systems in processes that control signaling mechanisms regulating vascular smooth muscle force responses to physiological changes in PO2. Studies in this application investigate the importance of our new evidence that cytosolic NADPH and possibly NADH levels control a baseline Nox oxidase-derived hydrogen peroxide-mediated relaxation of bovine pulmonary arteries which is removed by hypoxia, resulting in contraction. On the other hand, bovine coronary arteries maintain a lower level of NADPH and the NADPH generating pentose phosphate pathway (PPP) enzyme glucose-6-phosphate dehydrogenase. We hypothesize that differences in the function of the PPP in coronary arteries results in a hypoxia-elicited oxidation of cytosolic NADPH, which activates relaxation through a mechanism we have shown to be controlled by the PPP. Studies in Aim 1 will investigate how PO2 regulates the expression of vascular responses involving Nox-derived hydrogen peroxide. Aim 2 focuses on understanding how PO2 regulates cytosolic NADH and NADPH redox-linked signaling mechanisms that contribute to the control of force generation. Studies in Aim 3 are to define the origins of differences in the control of Nox oxidase activity and cytosolic NAD(P)H redox that contribute to hypoxia-elicited contractile and relaxing responses observed in pulmonary and coronary arteries. Isolated endothelium-removed coronary and pulmonary conduit and resistance arteries will be studied with perturbations that alter Nox activity and expression, and cytosolic NADH and NADPH redox to define how signaling systems regulated by these processes may function in PO2-elicited responses. The control of cytosolic NAD(P)H redox and oxidant production by PO2 will be examined with a combination of metabolic measurements, tissue fluorescence and chemiluminescent techniques, and cellular fluorescence imaging approaches which are designed to characterize the ROS and redox aspects of the signaling mechanisms that are involved. Rat arteries will also be examined to identify similarities and differences in mechanisms of PO2-elicited responses controlled by Nox and cytosolic NAD(P)H redox. These studies should help define the origins of differences in physiological responses of pulmonary and coronary arteries to changes in O2 tension.