Redox Regulation of Arteriole Function

描述(来自申请的逐字)：在培养细胞中，机械 应变诱导肌动蛋白细胞骨架的改变，部分是由 小G蛋白，RAC。RAC通过NADPH刺激肌动蛋白聚合 依赖于氧化酶的活性氧自由基(ROS)增加，从而刺激 肌动蛋白细丝的脱帽。Rac在收缩平滑肌中的作用 细胞(SM)未知。我们证明了一条信号通路(S)，涉及 RAC、NADPH氧化酶、ROS和肌动蛋白聚合在 肌源性反应，由心肌梗死引起的小动脉SM收缩 跨壁压力。在小鼠小动脉中，肌源性反应是：i) 被抗氧化剂或抑制NADPH氧化酶选择性地取消，II) 表达显性-负性RAC突变体的转基因小鼠的抑郁 (RAC-dN)在表达A基因的转基因小鼠中增加 SM和IV)中的构成活性RAC突变体(RAC-CA)与 RAC-DN小动脉中ROS的生成增加。抑制 细胞松弛素D诱导的肌动蛋白聚合选择性抑制肌源性 回应。在这些实验的基础上，基于目前的平滑肌模型 收缩，我们认为肌源性反应涉及两个不同的 信号通路。一种涉及常规途径，即钙。 内流、钙-钙调蛋白依赖的肌球蛋白轻链激酶激活 肌球蛋白轻链的磷酸化。另一条途径包括 RACI、NADPH氧化酶的激活、ROS生成的增加和刺激 肌动蛋白聚合。后一种途径使VSM能够承受 压力升高，并允许肌球蛋白系统收缩动脉。 此外，由于这种反应在RAC-CA小鼠中的扩增是 与高血压相关，我们认为这一途径的失调可能 在这一疾病过程中导致血管功能改变。三个具体的 目的是分析生理和病理生理学。 ROS在小动脉中的调节和作用。实验将评估刺激物 负责ROS的产生，ROS诱导变化的潜在机制 血管收缩功能及该信号通路的调节 高血压。

DESCRIPTION (Verbatim from the application): In cultured cells, mechanical strain induces a change in the actin cytoskeleton, mediated in part by the small Gprotein, rac. Rac stimulates actin polymerization, via NADPH oxidase-dependent increase in reactive oxygen species (ROS), which stimulate uncapping of actin filaments. The role of rac in contractile smooth muscle cells (SM) is unknown. We demonstrate that a signaling pathway(s), involving rac, NADPH oxidase, ROS and actin polymerization, plays a key role in the myogenic response, the arteriolar SM constriction caused by elevation in transmural pressure. In mouse arterioles, the myogenic response was: i) selectively abolished by antioxidants or inhibition of NADPH oxidase, ii) depressed in transgenic mice expressing a dominant-negative mutant of rac (RAC-DN) in SM, iii) increased in transgenic mice expressing a constitutively-active rac mutant (RAC-CA) in SM, and iv) associated with increased production of ROS that was absent in RAC-DN arterioles. Inhibition of actin polymerization by cytochalasin D selectively inhibited the myogenic response. Based on these experiments, and on current models of smooth muscle contraction, we propose that the myogenic response involves two distinct signaling pathways. One involves the conventional pathway, namely calcium influx, calcium-calmodulin dependent activation of myosin light chain kinase and phosphorylation of myosin light chain. The other pathway involves activation of raci, NADPH oxidase, elevation of ROS production and stimulation of actin polymerization. This latter pathway enables the VSM to withstand elevated pressure and allows the myosin-based system to constrict the artery. Furthermore, since amplification of this response in the RAC-CA mouse was associated with hypertension, we propose that dysregulation of this pathway may contribute to altered vascular function in this disease process. Three specific aims are proposed to analyze the physiological and pathophysiological regulation and role of ROS in arterioles. Experiments will assess the stimuli responsible for ROS production, the mechanisms underlying ROS-induced changes in vasoconstriction and the regulation of this signaling pathway in hypertension.