Cholesterol Regulation of EGFR-dependent Vasoconstriction in Chronic Hypoxia-induced Pulmonary Hypertension

项目摘要 慢性缺氧（CH）诱导的肺动脉高压（PH）是发病率的重要来源， 慢性阻塞性肺疾病患者的死亡率。人们普遍认为血管收缩 是PH的关键介质，尽管所涉及的机制知之甚少。我们以前的研究 已经证明，CH后血管收缩敏感性的增强涉及血管收缩因子的必要降低。 肺动脉平滑肌细胞（PASMC）膜胆固醇含量。我们还证明 CH通过从主要依赖于钙离子的信号传导转换来增强血管收缩反应性， 涉及表皮生长因子受体（EGFR）的Ca2+敏化途径的机制， 活性氧（ROS）。然而，CH降低膜胆固醇的机制和 这是如何揭示EGFR依赖性血管收缩的还有待评估。 这些研究将探讨血管收缩刺激与血管收缩反应的偶联的中心假设。 CH后的EGFR信号通过ROS依赖性降低PASMC的收缩功能促进PASMC过度收缩。 膜胆固醇为了检验这一假设，方案将采用体内和体外方法， 从分子和单细胞成像研究到视频显微镜的各种实验准备， 使用CH诱导的PH的大鼠模型加压小肺动脉。 我们计划实现以下具体目标： 具体目的1：确定CH降低PASMC膜胆固醇的机制。 假设：CH过程中ROS的产生增加减少了膜胆固醇。 具体目标2：确定降低的PASMC膜胆固醇增加的机制 CH后血管收缩敏感性。 假设：对CH反应的PASMC膜胆固醇降低揭示了EGFR依赖性 通过调节NOX2和Rac 1引起肺血管收缩。 申请人将沉浸在UNM血管生理学组丰富的培训环境中 医学院通过一个独特的，多赞助商的指导团队，将促进他的研究培训， 定义ROS改变PASMC膜微环境以影响细胞增殖的新机制 建议的培训计划将为申请人提供密集的培训经验 在各种新的实验方法，完善他的口头和书面沟通技巧， 专业发展培训，这将有助于他实现他的目标，作为一个独立的，学术 肺研究领域的医生兼科学家

Project Summary Chronic Hypoxia (CH)-induced pulmonary hypertension (PH) is a significant source of morbidity and mortality in patients with chronic obstructive pulmonary diseases. It is widely recognized that vasoconstriction is a critical mediator of PH, although the mechanisms involved are poorly understood. Our previous studies have demonstrated that enhanced vasoconstrictor sensitivity following CH involves a requisite reduction in pulmonary arterial smooth muscle cell (PASMC) membrane cholesterol content. We have also demonstrated that CH augments vasoconstrictor reactivity by a switch in signaling from primarily calcium-dependent mechanisms to a Ca2+ sensitization pathway that involves the epidermal growth factor receptor (EGFR) and reactive oxygen species (ROS). However, the mechanisms by which CH decreases membrane cholesterol and how this unmasks EGFR-dependent vasoconstriction has yet to be assessed. The proposed studies will investigate the central hypothesis that coupling of vasoconstrictor stimuli to EGFR signaling following CH promotes PASMC hypercontractility through a ROS-dependent decrease in membrane cholesterol. To test this hypothesis, protocols will employ both in vivo and in vitro approaches using a variety of experimental preparations from molecular and single cell imaging studies to video-microscopy of pressurized small pulmonary arteries using a rat model of CH-induced PH. We plan to pursue the following specific aims: Specific Aim 1: Determine the mechanism by which CH decreases PASMC membrane cholesterol. Hypothesis: Elevated ROS production during CH diminishes membrane cholesterol. Specific Aim 2: Determine the mechanism by which decreased PASMC membrane cholesterol augments vasoconstrictor sensitivity following CH. Hypothesis: Decreased PASMC membrane cholesterol in response to CH unmasks EGFR-dependent pulmonary vasoconstriction through regulation of NOX2 and Rac1. The applicant will be immersed in a rich training environment in the Vascular Physiology Group at the UNM School of Medicine through a unique, multi-sponsor mentoring team that will facilitate his research training in defining novel mechanisms by which ROS alter the PASMC membrane microenvironment to affect cellular function in CH-induced PH. The proposed training plan will afford the applicant intensive training experiences in a variety of new experimental approaches, refinement of his oral and written communication skills, and professional development training that will aid him in achieving his goal as an independent, academic physician-scientist in pulmonary research.