Reactive Oxygen Species and Vascular O2 Sensing

这项建议侧重于确定NOx氧化酶衍生的过氧化氢和细胞质NADPH的作用 和NADH氧化还原系统在控制调节血管平滑的信号机制的过程中 肌力对PO2生理变化的反应在这一应用中研究 细胞内NADPH和可能的NADH水平控制基线NOx的新证据的重要性 氧化物源性过氧化氢介导的牛主动脉松弛作用 缺氧，导致收缩。另一方面，牛冠状动脉维持较低水平的 NADPH及其产磷酸戊糖途径(PPP)酶葡萄糖-6-磷酸 脱氢酶。我们假设，冠状动脉中PPP功能的不同会导致 低氧引起胞浆NADPH的氧化，这通过我们拥有的一种机制激活松弛 表明受PPP控制。目标1中的研究将调查PO2是如何调节 涉及NOx衍生的过氧化氢的血管反应。目标2侧重于了解PO2如何 调节细胞内NADH和NADPH氧化还原相关的信号机制，有助于控制 力量的产生。目标3中的研究旨在确定NOx氧化酶控制差异的根源 细胞内NAD(P)H氧化还原活性和细胞内NAD(P)H氧化还原参与缺氧引起的收缩和松弛反应 可在肺和冠状动脉内观察到。去内皮离体冠脉和肺 管道和阻力动脉将通过改变NOx活性和表达的扰动进行研究，以及 细胞内NADH和NADPH氧化还原，以定义由这些过程调节的信号系统如何 在PO2引起的反应中起作用。PO2对胞内NAD(P)H氧化还原和氧化剂产生的控制 将通过代谢测量、组织荧光和化学发光相结合的方法进行检查 技术，以及细胞荧光成像方法，旨在表征ROS和 所涉及的信号机制的氧化还原方面。还将检查大鼠的动脉以确定 NOx和胞质控制的PO2诱导反应机制的异同 NAD(P)H氧化还原。这些研究应该有助于确定不同的生理反应的起源 肺和冠状动脉对氧分压变化的影响。

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 pulmdnary 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.