ENDOTHELIN AND RECEPTOR GENE EXPRESSION IN HYPOXIA

描述(改编自申请人的摘要)：本报告的目标 研究阐明内皮素-1(ET-1)和ET受体在血管紧张性疾病中的作用 缺氧性肺动脉高压。过去4年的研究结果 多年来证实了ET-1基因表达和ET-1的假设 暴露在低氧环境中的大鼠的肺合成被选择性地增强。 此外，研究证实ET-1受体的基因表达， ET-A和ET-B在这些动物的肺中同时增强。 低氧诱导ET-1、ET-A、ET-B基因表达上调及ET-1 释放有所有平行的功能和组织病理学证据 发展为肺动脉高压。据认为，ET-1产生了 在低氧条件下，通过旁分泌机制作用于肺组织ET-A 受体，并通过其相互作用，发挥基本的病原学作用 在低氧诱导的肺血管收缩、血管重塑和 慢性肺动脉高压的维持。最近这些调查人员 已经证明选择性ET-A受体拮抗剂和联合 ET-A+ET-B受体拮抗剂既能预防又能逆转急慢性 缺氧性肺血管收缩和肺动脉高压。 这些数据定义了ET-1作为一种重要的调节因子的作用 缺氧性肺动脉高压。当前的具体目标 建议如下：1)检验ET-1与急性和慢性心力衰竭的关系 大鼠慢性血流动力学和结构对低氧的适应性 激活ET-A和ET-B受体。2)确定蜂窝位置 对照条件下ET-1和ET-A、ET-B受体基因表达的变化 以及对低氧的反应。3)定义顺式调控元件(S) 参与转录扩增的ET-1基因5‘侧翼区 ET-1基因在低氧环境中的表达。4)识别和 低氧反应转录因子蛋白(S)的特性 调节ET-1基因表达以应对低氧。Spraogue-Dawley大鼠 暴露于低氧(10%O2，1atm。)否则将对室内空气进行研究 特异性靶标1和2.携带人前内毒素-1的转基因小鼠 启动子/荧光素酶报告基因的研究将有针对性地进行2。 培养的人和大鼠血管内皮细胞和平滑肌细胞 将在#年研究肺微血管和全身血管床 具体目标3和4。

DESCRIPTION (Adapted from the applicant's abstract): The goal of this research is elucidate the role of endothelin-1 (ET-1) and ET receptors in hypoxia-induced pulmonary hypertension. Results of studies over the last 4 years have confirmed the hypothesis that ET-1 gene expression and ET-1 synthesis are selectively enhanced in lungs of rats exposed to hypoxia. Moreover, studies have confirmed that gene expression of the ET-1 receptors, ET-A and ET-B, is concomitantly enhanced in lungs of these animals. Hypoxia-induced upregulation of ET-1, ET-A and ET-B gene expression and ET-1 release have all paralleled functional and histopathologic evidence of the development of pulmonary hypertension. It is believed that ET-1, generated in conditions of hypoxia, acts via a paracrine mechanism on pulmonary ET-A receptors and, through its interaction, plays a fundamental etiologic role in hypoxia-induced pulmonary vasoconstriction, vascular remodelling, and maintenance of chronic pulmonary hypertension. Recently these investigators have demonstrated that selective ET-A receptor antagonists and a combined ET-A+ET-B receptor antagonist can both prevent and reverse acute and chronic hypoxia-induced pulmonary vasoconstriction and pulmonary hypertension. These data define a role for ET-1 as an important mediator of hypoxia-induced pulmonary hypertension. The specific aims of the current proposal are: 1) To test the hypothesis that ET-1 contributes to acute and chronic hemodynamic and structural adaptations to hypoxia in the rat by activating both ET-A and ET-B receptors. 2) To determine the cellular sites of ET-1 and ET-A and ET-B receptor gene expression under control conditions and in response to hypoxia. 3) To define the cis-regulatory element(s) in the 5' flanking region of the ET-1 gene involved in amplifying transcription of the ET-1 gene during exposure to hypoxia. 4) To identify and characterize the hypoxia-responsive transcription factor protein(s) that regulate ET-1 gene expression in response to hypoxia. Sprague-Dawley rats exposed to hypoxia (10 percent O2 at 1 atm.) or room air will be studies for Specific Aims 1 and 2. Transgenic mice harboring a human prepro-ET-1 promoter/luciferase reporter gene will be studied in Specific Aim 2. Cultured endothelial and smooth muscle cells derived from human and rat pulmonary microvessels and systemic vascular beds will be studied in Specific Aims 3 and 4.