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Signaling and Crosstalk by Airway Prostanoid Receptors

气道前列腺素受体的信号传导和串扰

基本信息

批准号：
7109297
负责人：
Dennis W McGraw
金额：
$ 33.73万
依托单位：
UNIVERSITY OF CINCINNATI
依托单位国家：
美国
项目类别：
财政年份：
2003
资助国家：
美国
起止时间：
2003-09-01 至 2007-08-31
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Prostanoids have been implicated in the pathogenesis of bronchoconstriction and airway hyperreactivity (AHR) because they potently contract airway smooth muscle (ASM), and their levels, are elevated in asthmatic lung. Thromboxane, PGD2 and PGF2alpha contract ASM via activation of thromboxane prostanoid (TP) receptors. Even PGE2, which is generally considered a bronchodilator, has the capacity to transduce a constrictor signal via one of the receptor subtypes (EP1) for which it is the cognate ligand. However, despite their potent effects on ASM, it has been difficult to unambiguously assign pathophysiological relevance to these receptors due to pleiotropic responses resulting from the simultaneous production of constrictor and relaxant prostanoids by the same general enzymatic pathway, receptor activation by multiple ligands, and the existence of multiple receptor isoforms with different signal transduction properties. We believe these limitations can be overcome by using transgenic and gene-targeted mice to selectively modulate signal transduction by specific prostanoid receptors. In this proposal, we will test the overall hypothesis that bronchoconstriction and AHR occur when the activation of bronchoconstrictor prostanoid receptors is favored over those that promote bronchodilation. In Specific Aim 1, we will use mice that overexpress the TP receptor in combination with TP receptor deficient gene-targeted mice to determine whether TP receptors promote bronchoconstriction and AHR. The signaling pathways, which mediate TP receptor-dependent contraction will be dissected in vitro using primary ASM cells, isolated from the genetically engineered mice, and their physiologic significance determined in tracheal rings and intact mice. In Specific Aim 2, we will determine whether the EPt receptor is a mediator of bronchoconstriction and AHR. The transgenic models developed for these experiments will enable us to discriminate between the effects of EP1 receptor activation and those of the other EP receptor subtypes. Since it widely recognized that the primary physiologic actions of one G-protein-coupled receptor are frequently modulated by another, experiments in Specific Aim 3 will test the hypothesis that receptor cross talk by TP and EP1 receptors is a mechanism of (-adrenergic receptor dysfunction in ASM. This hypothesis is supported by preliminary data that show TP and EP1 receptor agonists attenuate isoproterenol-mediated relaxation of tracheal rings. Each of these aims will merge biochemical, pharmacologic and physiologic studies from cells, tissues, and whole animals so that in vitro signaling events can be directly correlated to in vivo physiological function. Completion of these aims may identify novel signaling events that have therapeutic relevance to asthma and other obstructive lung diseases.

描述（由申请人提供）：前列腺素类与支气管收缩和气道高反应性（AHR）的发病机制有关，因为它们有效地收缩气道平滑肌（ASM），并且它们的水平在哮喘肺中升高。血栓素、PGD2 和 PGF2α 通过激活血栓素前列腺素 (TP) 受体来收缩 ASM。即使是通常被认为是支气管扩张剂的 PGE2，也具有通过其同源配体的受体亚型 (EP1) 之一转导收缩信号的能力。然而，尽管它们对 ASM 具有强大的作用，但由于通过相同的通用酶途径同时产生收缩剂和松弛剂前列腺素、多个配体激活受体以及存在具有不同信号转导特性的多种受体亚型而产生多效性反应，因此很难明确地确定这些受体的病理生理学相关性。我们相信，通过使用转基因和基因靶向小鼠选择性调节特定前列腺素受体的信号转导，可以克服这些限制。在本提案中，我们将检验以下总体假设：当支气管收缩前列腺素受体的激活优于促进支气管扩张的受体时，就会发生支气管收缩和 AHR。在具体目标 1 中，我们将使用过度表达 TP 受体的小鼠与 TP 受体缺陷基因靶向小鼠相结合，以确定 TP 受体是否促进支气管收缩和 AHR。介导 TP 受体依赖性收缩的信号通路将使用从基因工程小鼠中分离的原代 ASM 细胞在体外进行剖析，并在气管环和完整小鼠中确定其生理意义。在具体目标 2 中，我们将确定 EPt 受体是否是支气管收缩和 AHR 的介质。为这些实验开发的转基因模型将使我们能够区分 EP1 受体激活的影响和其他 EP 受体亚型的影响。由于人们广泛认识到一种 G 蛋白偶联受体的主要生理作用经常受到另一种 G 蛋白偶联受体的调节，因此特定目标 3 中的实验将检验以下假设：TP 和 EP1 受体的受体串扰是 ASM 中肾上腺素能受体功能障碍的一种机制。初步数据显示 TP 和 EP1 受体激动剂减弱异丙肾上腺素介导的功能，这一假设得到了支持。气管环松弛。这些目标中的每一个都将融合来自细胞、组织和整个动物的生化、药理学和生理学研究，以便体外信号事件可以与体内生理功能直接相关。完成这些目标可能会发现与哮喘和其他阻塞性肺病具有治疗相关性的新信号事件。