Mechanisms Underlying Sympathetic Activation-dependent Endothelial Cell Activation by Chronic Intermittent Hypoxia

项目概要-项目3 患有睡眠呼吸暂停（SA）的患者和暴露于间歇性缺氧（IH）的啮齿动物（SA的一个标志）， 内皮细胞（EC）活化是心血管疾病发展的早期病理事件， 疾病当被激活时，EC表达水平增加的促炎细胞因子和细胞粘附 导致白细胞粘附到EC的分子。项目3的总体目标是确定 由SA/IH引起的潜在EC活化。我们从IH暴露小鼠和主动脉内皮细胞的初步数据表明， SA/IH诱导的EC激活不是由IH直接引起的，而是由IH诱导的交感神经激活引起的。 激活衍生的肾上腺素（不是去甲肾上腺素）。此外，我们发现， 肾上腺素激活缺氧诱导因子（HIF）-1，并增加糖酵解，这两个都是我们最近发现的。 发现在异常血流下EC激活所需。根据初步数据，项目3将 检验SA/IH通过交感神经激活衍生的肾上腺素间接引起EC激活的假设， 通过β 2-肾上腺素能受体激活HIF-1 α，导致糖酵解上调，这是必需的 激活EC。我们将在两个SA/IH模型中的三个具体目标中测试我们的假设：（1）实验性 暴露于IH和（2）具有自发SA的小鼠。在目标1中，我们将确定交感神经激活- 衍生的肾上腺素介导IH诱导的EC活化和巨噬细胞粘附。在目标2中，我们将确定 β 2-肾上腺素能受体是否是IH诱导的EC激活所必需的。在目标3中，我们将确定 IH诱导的肾上腺素通过HIF-1依赖的方式引起EC激活，并进一步评估 HIF-1被IH诱导的肾上腺素激活的机制。在目标4中，我们将确定 HIF-1增加的糖酵解是IH诱导的EC活化所必需的。项目3的主题联系紧密， 项目1、2和4，并利用核心B设施：a）将小鼠暴露于IH，B）维持和基因分型 基因工程小鼠; c）定量实时PCR分析。调查小组的成员已经 在拟议方法方面的长期经验和专门知识以及出色的工作业绩记录 联合出版物证明，多年来一直在一起。拟议的研究将提供一个框架， 了解CIH诱导的交感神经激活在引起EC炎症中的具体作用。结果 将使我们能够确定肾上腺素/β 2-肾上腺素能受体信号传导是否可以 有针对性地减轻SA/IH诱导的EC激活和由此产生的心血管疾病。

Project Summary- Project 3 Patients with sleep apnea (SA) and rodents exposed to intermittent hypoxia (IH), a hallmark of SA, exhibit endothelial cell (EC) activation, which is an early pathologic event in the development of cardiovascular disease. When activated, ECs express increased levels of pro-inflammatory cytokines and cell adhesion molecules leading to leukocyte adhesion to EC. The overall goal of Project 3 is to determine the mechanisms underlying EC activation caused by SA/IH. Our preliminary data from IH-exposed mice and aortic ECs suggest that SA/IH-induced EC activation is not caused directly by IH but secondarily by IH-induced sympathetic activation-derived epinephrine (not by norepinephrine). Furthermore, we found that treating ECs with epinephrine activates hypoxia-inducible factor (HIF)-1, and increases glycolysis, both of which we recently found to be required for EC activation under abnormal blood flow. Based on the preliminary data, Project 3 will test the hypothesis that SA/IH causes EC activation indirectly via sympathetic activation-derived epinephrine, which through β2-adrenergic receptors activates HIF-1α leading to upregulation of glycolysis, which is required for EC activation. We will test our hypothesis in three specific aims in two models of SA/IH: (1) experimental exposure of IH and (2) mice with spontaneous SA. In Aim 1, we will determine whether sympathetic activation- derived epinephrine mediates IH-induced EC activation and macrophage adhesion. In Aim 2, we will determine whether β2-adrenergic receptors are required for IH-induced EC activation. In Aim 3, we will determine whether IH-induced epinephrine causes EC activation through HIF-1-dependent manner and further assess the mechanism(s) by which HIF-1 is activated by IH-induced epinephrine. In Aim 4, we will determine whether increased glycolysis by HIF-1 is required for IH-induced EC activation. Project 3 has tight thematic linkages to Projects 1, 2, and 4 and utilizes Core B facilities for: a) exposing mice to IH, b) maintenance and genotyping of genetically engineered mice; c) quantitative real-time-PCR analysis. Members of the investigative team have long-standing experience and expertise with the proposed approaches and excellent track record of working together for number of years as evidenced by joint publications. The proposed studies will provide a framework for understanding the specific role of CIH-induced sympathetic activation in causing EC inflammation. Findings from the proposed studies will allow us to determine whether epinephrine/β2-adrenergic receptor signaling can be targeted to alleviate SA/IH-induced EC activation and the resulting cardiovascular disease.