Regulation of Microvascular Function by ROS

低血管紧张素II(Ang II)输注增加ROS，上调关键肾脏 NADPH氧化酶组分(p22Phox，NOx-1)并下调EC-SOD。抗氧化剂药物牵连 ROS在高血压发病中的作用，但肾脏和全身ROS在高血压发病中的特殊作用 血管收缩、盐滞留和NADPH氧化酶或减少的SOD依赖性的调节 在肾脏中的防御，在很大程度上是未知的。我们将研究BP动态平衡(遥测BP)、盐处理 和小鼠的敏感性和微血管机制(离体肾、灌流肾传入和肠系膜 阻力血管和活体显微镜)，以探索内皮来源的作用 微血管收缩因子(EDCF)和增强的VSMC收缩能力。我们将把这些联系起来 单个微解剖血管和肾小球内ROS、NO和钙活性的功能研究 血管平滑肌细胞。我们的主要策略是使用击倒模型和小干扰 针对靶基因肾内传递的RNA(SiRNAs)，以评估特异性的肾脏机制 高血压。这将通过肾交叉移植和cre-lox策略相结合来扩展 VSMC中特异的敲除基因首次确立了肾脏及其传入的作用 小动脉在ROS调节高血压中的作用。目标1将使用稳定、持续的微血管氧化应激的EC-SOD-/-小鼠模型来检验氧化应激的假设 应激释放内皮素，作用于A型或B型受体，参与环氧合酶衍生的EDCF 激活邻近的VSMCs，在这些细胞中，钙离子敏化途径介导的收缩作用增强 Rho/Rho激酶。AIM 2将使用EC-SOD-/-小鼠注射siRNA到IC-SOD选择性地传递到 来验证IC-SOD是肾脏的主要抗氧化防御的假设，以及它的肾脏 缺乏促进肾血管收缩、盐滞留和高血压。AIM 3将使用正常小鼠 将siRNA转p22Phox传递到肾脏或系统地测试肾脏NADPH的假设 血管紧张素转换酶介导血管紧张素Ⅱ的传入小动脉收缩、RVR、盐滞留和高血压的增加。 这些项目是一种综合的方法来剖析ROS在肾脏微血管反应性和 盐处理构成高血压的肾脏机制。

Low rates of Angiotensin II (Ang II) infusion increase reactive oxygen species (ROS), upregulate key renal components of NADPH oxidase (p22phox, NOX-1) and downregulate EC-SOD. Antioxidant drugs implicate ROS in the development of hypertension, yet the specific roles of renal and systemic ROS in vasoconstriction, salt retention and the mediation by NADPH oxidase, or by reduced SOD-dependent defense in the kidney, are largely undefined. We will study BP homeostasis (telemetric BP), salt handling and sensitivity and microvascular mechanisms in mice (isolated, perfused renal afferent and mesenteric resistance vessels and in vivo intravital microscopy) to explore the roles of an endothelium-derived contracting factor (EDCF) and enhanced VSMC contractility in the microvessels. We will relate these functional studies to ROS, NO, and calcium activity in individual microdissected vessels and pre-glomerular vascular smooth muscle cells. Our primary strategy is the use of knockout models and small interference RNAs (siRNAs) directed at target genes delivered intrarenally to assess specifically renal mechanisms of hypertension. This will be extended with kidney cross-transplantation combined with a cre-lox strategy to knockout genes specifically in VSMC to establish, for the first time, the roles of the kidney and its afferent arterioles in mediating hypertension with ROS. Aim 1 will use the EC-SOD -/- mouse model of stable, sustained microvascular oxidative stress to test the hypothesis that oxidative stress releases endothelin, which acts on type A or B receptors to engage a cyclooxygenase-derived EDCF that activates adjacent VSMCs where contractility is enhanced by a Ca++ sensitizing pathway mediated by rho/rho kinase. Aim 2 will use EC-SOD -/- mice administered siRNA to IC-SOD delivered selectively to the kidney to test the hypothesis that IC-SOD is the major antioxidant defense in the kidney and that its renal deficiency promotes renal vasoconstriction, salt retention, and hypertension. Aim 3 will use normal mice with siRNA to p22phox delivered to the kidney or systemically to test the hypothesis that renal NADPH oxidase mediates increased afferent arteriolar contractility, RVR, salt retention and hypertension with Ang II. These projects are an integrated approach to dissect the roles of ROS in renal microvascular reactivity and salt handling that constitute renal mechanisms of hypertension.