Regulation of Vascular Eicosanoid Receptors

血管类二十烷酸受体的调节

基本信息

批准号：
6749012
负责人：
EMER MARIA SMYTH
金额：
$ 27.74万
依托单位：
UNIVERSITY OF PENNSYLVANIA
依托单位国家：
美国
项目类别：
财政年份：
2002
资助国家：
美国
起止时间：
2002-07-01 至 2006-06-30
项目状态：
已结题

项目摘要

DESCRIPTION (provided by applicant): Prostacyclin (PG I2) and thromboxane (TxA2), two major cyclooxygenase products formed in the vasculature, exert opposing biological effects. PGI2 is a potent inhibitor of platelet aggregation, vasodilator, anti-thrombotic and anti-mitogen which may be protective in settings of vascular disease. In contrast, TxA2, which induces platelet aggregation, mitogenesis and vasoconstriction, appears to play a detrimental role in the pathogenesis of cardiovascular disorders. Both PGI2 and TxA2 transduce their effects by binding to their cell surface receptors, IP and TP (two splice variants alpha and beta), respectively. IP and TP are frequently co-expressed in cardiovascular cells and elevated PGI2 and TxA2 biosynthesis is coincident in vascular disorders. Cross-regulation of PGI2 and TxA2-responsive events is evident in smooth muscle cells, platelets and other cells types. However, despite our understanding of the regulation and signal transduction pathways utilized by these two systems, little is known about the impact of each signaling cascade on the other. This proposal aims to examine whether and how human (h) IP and hTP activation alone and in concert may modulate each other and seeks to understand the molecular mechanisms attendant to these interactions. We shall address following specific hypotheses.1. That co-activation of hIP and hTP modulates their regulation and G protein coupling. We shall examine heterologous regulation of hIP and hTPalpha/beta in vascular smooth muscle cells endogenously express both receptor types, or deficient in one or the other, and in cell lines expressing the receptors alone or in combination.2. That agonist-induced homo- and hetero- dimerization of IP and TPalpha/beta occurs and has functional and regulatory consequences. We shall examine dimer formation and receptor signaling in vascular smooth muscle cells from humans or cultured from IP or TP deficient mice and in hIP/hTP expressing cell lines.3. That hIP and hIP interact with novel cellular proteins. The role of the cGMP-phosphodiesterase-6 delta subunit, a novel hIP associated factor, in hIP signaling and regulation will be investigated. We shall use yeast-two hybrid technology to screen a vascular smooth muscle cell cDNA library and a proteomic approach to investigate other uncharacterized proteins that interact with hIP or hTP.These studies will define the interaction of two vasoactive eicosanoids at the level of receptor signaling and regulation and identify novel pathways through which G protein-coupled receptors in general, and IP and TP in particular, can heterologously modulate receptor function.

描述（由申请人提供）：前列环素（PG I2）和血栓素（TxA2）是脉管系统中形成的两种主要环氧合酶产物，发挥相反的生物效应。 PGI2 是一种有效的血小板聚集抑制剂、血管扩张剂、抗血栓剂和抗丝裂剂，对血管疾病可能具有保护作用。相比之下，诱导血小板聚集、有丝分裂和血管收缩的 TxA2 似乎在心血管疾病的发病机制中发挥着有害作用。 PGI2 和 TxA2 均通过分别结合其细胞表面受体 IP 和 TP（两种剪接变体 α 和 β）来转导其作用。 IP 和 TP 经常在心血管细胞中共表达，并且 PGI2 和 TxA2 生物合成升高在血管疾病中同时出现。 PGI2 和 TxA2 反应事件的交叉调节在平滑肌细胞、血小板和其他细胞类型中很明显。然而，尽管我们了解这两个系统所利用的调节和信号转导途径，但对每个信号级联对另一个系统的影响知之甚少。该提案旨在研究人类 (h) IP 和 hTP 单独激活和协同激活是否以及如何相互调节，并试图了解与这些相互作用相关的分子机制。我们将提出以下具体假设： 1． hIP 和 hTP 的共同激活调节它们的调节和 G 蛋白偶联。我们将检查hIP和hTPα/β在血管平滑肌细胞中内源性表达两种受体类型或缺乏其中一种受体，以及在单独或组合表达受体的细胞系中的异源调节。2．激动剂诱导的 IP 和 TPα/β 发生同源和异源二聚化，并产生功能和调节后果。我们将检查来自人类或从 IP 或 TP 缺陷小鼠培养的血管平滑肌细胞以及表达 hIP/hTP 的细胞系中的二聚体形成和受体信号传导。3． hIP 和 hIP 与新型细胞蛋白相互作用。我们将研究 cGMP-磷酸二酯酶-6 δ 亚基（一种新型 hIP 相关因子）在 hIP 信号传导和调节中的作用。我们将使用酵母-两种杂交技术来筛选血管平滑肌细胞 cDNA 文库，并使用蛋白质组学方法来研究与 hIP 或 hTP 相互作用的其他未表征的蛋白质。这些研究将在受体信号传导和水平上定义两种血管活性类二十烷酸的相互作用。调节并确定新的途径，通过这些途径，G 蛋白偶联受体，特别是 IP 和 TP，可以异源调节受体功能。