Vascular Signaling by Free Radicals

最近，许多报道在许多不同的水平上定义了活性氧(ROS)或血管生物学的作用。这些报道中的许多证据表明，ROS介导了血管壁上的各种信号事件，包括离子通道活性、细胞内第二信使的激活/抑制、蛋白质磷酸化、黏附分子的激活、内皮细胞和血管肌肉细胞有丝分裂通路的激活/抑制。拟议的计划项目赠款(PPG)将从遗传、细胞、分子、离子和整个动物水平开始，研究ROS介导/修改调节血管功能、血管生成和细胞凋亡的血管信号事件的机制。项目1由David Harder博士指导，将测试ROS启动和/或修改调节脑血流(CBF)的信号事件的假设。他的实验室将研究ROS通过激活小动脉肌肉中的离子通道活动和第二信使对脑血管信号的作用，确定自由基在小动脉肌肉第二信使自动调节中的作用，确定自由基在CBF自动调节中的作用，以及功能性充血对神经活动的反应。最后，项目I将确定ROS在改变星形胶质细胞介导的脑内毛细血管生成中的作用。由David Gutterman博士指导的项目II将确定ROS在调节血流(剪切)诱导的人类冠状动脉扩张中的作用。古特曼博士已经证明，在人类冠状动脉小动脉中，EDHF在剪切诱导的扩张中发挥着重要作用，并提供了令人信服的数据，表明ROS参与了这一反应。威廉·奇利安博士领导的项目III将确定ROS在内皮离子通道上的作用，负责设定和维持膜电位。奇利安博士和他的同事们将探索O2-通过内皮CI通道移动的新假设，这可能在抗氧化防御机制中发挥作用。彼得·纽曼博士将指导项目IV，并将检验PECAM-1是自由基靶点的假设。纽曼的研究小组已经证明，过氧化氢可以诱导酪氨酸残基的磷酸化和非硝化，从而激活和抑制PECAM-1。PECAM-1是一种具有抑制受体特性的黏附分子--自由基对PECAM-1活性的调节是影响细胞间相互作用和多种细胞信号通路的重要过程。项目V由Balaraman Kalyanaraman博士领导，将探索ROS在内皮细胞和血管有丝分裂活动中发挥关键作用的假设。本课题将研究NO和ROS在氧化型低密度脂蛋白诱导的细胞凋亡中的作用。Kalyanaraman博士和他的同事将定义ROS效应的矛盾效应，即启动和抑制血管壁上的细胞增殖。这些项目将依靠一个自由基和一个分析化学核心来测量和操纵自由基，并测量细胞信号分子。该计划汇集了一种关键的测量细胞信号分子的方法。该计划汇集了大量公认的研究人员和最先进的技术，以确定活性氧和氮物种在血管生物学中的生物作用。

Recently, numerous reports have defined actions of reactive oxygen species (ROS) or vascular biology, at many different levels. Many of these reports provide evidence that ROS mediate a variety of signaling events in the vascular wall including; ion channel activity, activation/inhibition of intracellular 2nd messengers, protein phosphorylation, activation of adhesion molecules, activation/inhibition of mitogenic pathways in endothelial and vascular muscle cells. The proposed Program Project Grant (PPG) will begin at the genetic; cellular, molecular, ionic, and whole animal level the mechanisms through which ROS mediate/modify vascular signaling events regulating vascular function, angiogenesis and apoptosis. Project 1 is directed by Dr. David Harder and will test the hypothesis that ROS act to initiate and/or modify signaling events regulating cerebral blood flow (CBF). His laboratory will study the action of ROS on cerebral vascular signaling through ion channel activity and activation of 2nd messengers in arteriolar muscle, define the role of radicals in autoregulation of 2nd messengers in arteriolar muscle, define the role of radicals in autoregulation of CBF, and functional hyperemia in response to neural activity. Finally, Project I will determine the action of ROS in modifying astrocyte mediated capillary angiogenesis in the brain. Project II directed by Dr. David Gutterman, will define the role of ROS in mediating flow (shear) induced dilation of human coronary arteries. Dr. Gutterman has demonstrated that in human coronary arterioles EDHF plays an important role in shear-induced dilation, and presents convincing data that ROS participate in this response. Project III, lead by Dr. William Chilian will define the action of ROS on endothelial ion channels responsible for setting and maintaining membrane potential. Dr. Chilian and colleagues will explore the novel hypothesis that O2-moves through endothelial CI-channels which may play a role in anti-oxidant defense mechanisms. Dr. Peter New man will direct Project IV and will test the hypothesis that PECAM-1 is a target for free radicals. Newman's group has shown that H2O2 induces phosphorylation, and OONO-nitration of tyrosine residues that activates and inhibits PECAM-1. PECAM-1 is an adhesion molecule with properties of an inhibitor receptor-regulation of PECAM-1 activity by free radicals is an important process that can effect cell-cell interaction and a variety of cellular signaling pathways. Project V is lead by Dr. Balaraman Kalyanaraman and will explore that hypothesis that ROS plays a pivotal role in endothelial and vascular mitotic activity. This project will study the actions of NO and ROS on apoptosis induced by oxidized LDL. Dr. Kalyanaraman and colleagues will define the paradoxical effect of Ros effect of ROS to both initiate and inhibit cellular proliferation in the vascular wall. These Projects will rely on a Free Radical and an Analytical Chemistry Core to measure and manipulate free radicals and to measure cellular signaling molecules. This Program brings together a critical measure cellular signaling molecules. This Program brings together a critical mass of recognized investigators and state-of-art techniques to define the biologic role of reactive oxygen and nitrogen species in vascular biology.