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

项目摘要-项目3 睡眠呼吸暂停(SA)患者和暴露于间歇性低氧(IH)的啮齿动物，这是SA的一个特征，表现为 血管内皮细胞(EC)激活是心血管疾病发展的早期病理事件 疾病。当被激活时，内皮细胞表达更多的促炎细胞因子和细胞黏附。 导致白细胞与EC黏附的分子。项目3的总体目标是确定机制 SA/IH引起的潜在EC激活。我们来自暴露于IH的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诱导的交感神经引起的 激活衍生的肾上腺素(不是通过去甲肾上腺素)。此外，我们还发现，用 肾上腺素激活低氧诱导因子(HIF)-1，增加糖酵解，这两点我们最近 在血流异常的情况下被发现是EC激活所必需的。根据初步数据，项目3将 验证SA/IH通过交感神经激活衍生肾上腺素间接引起EC激活的假设， 它通过β2-肾上腺素能受体激活HIF-1α，导致糖酵解上调，这是必需的 用于EC激活。在SA/IH的两个模型中，我们将在三个特定目标上检验我们的假设：(1)实验 暴露于IH和(2)自发SA小鼠。在目标1中，我们将确定交感神经是否激活- 衍生肾上腺素介导IH诱导的EC激活和巨噬细胞黏附。在目标2中，我们将确定 IH诱导的EC激活是否需要β2肾上腺素能受体。在目标3中，我们将确定是否 缺氧诱导的肾上腺素通过HIF-1依赖的方式诱导内皮细胞激活，并进一步评估 IH诱导的肾上腺素激活HIF-1的机制(S)。在目标4中，我们将确定是否 HIF-1促进糖酵解是IH诱导的EC激活所必需的。项目3与以下主题密切相关 项目1、2和4，并利用核心B设施：a)将小鼠暴露于IH，b)维护和基因分型 转基因小鼠；c)实时定量聚合酶链式反应分析。调查组成员已经 在建议的方法方面有长期的经验和专业知识，并有良好的工作记录 正如联合出版物所证明的那样，在一起工作了几年。拟议的研究将提供一个框架 以了解CIH诱导的交感神经激活在引起EC炎症中的具体作用。发现 将使我们能够确定肾上腺素/β2-肾上腺素能受体信号转导是否可以 以减轻SA/IH诱导的EC激活和由此导致的心血管疾病为目标。

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.