LPA2 receptor-containing complexes in regulating secretory diarrhea

描述（由申请人提供）：本提案的统一假设是2型溶血磷脂酸受体（LPA2受体）和Na+/H+交换调节因子-2 （NHERF2）的大分子复合物在分泌性腹泻的致病过程中起重要作用。我们的目的是在生理和病理生理条件下，从分子水平研究在霍乱引起的腹泻中起关键作用的大分子复合物的形成和调控。此外，本研究还将研究LPA2受体介导的信号事件在腹泻动物模型中调控cftr依赖性的细胞电解质分泌和体液分泌的机制。研究的目的有三个：目的1：验证LPA2受体主要在肠道管腔表面表达并在某些腹泻疾病中下调的假设，以及验证激活LPA2受体抑制质膜区隔化cAMP生成的假设。目标2:测试的假设LPA可以调节的形成LPA2-containing大分子复杂通过进一步聚类microdomain质膜上,这个过程是由NHERF2-dependent蛋白质交互目标3:测试假设破坏大分子复杂的沉默NHERF2改变区划营水平的质膜和体内NHERF2基因敲除小鼠阵营回应CTX产生改变。这一建议对于从分子水平上了解致死性分泌性腹泻疾病的发病过程，以及可能的治疗干预具有重要意义。拟议的研究在概念进步和技术/技术发展方面都具有高度创新性。

DESCRIPTION (provided by applicant): The unifying hypothesis of this proposal is that macromolecular complex of type 2 lysophosphatidic acid receptor (LPA2 receptor) and Na+/H+ exchange regulatory factor-2 (NHERF2) plays important roles in the pathogenic process of secretory diarrhea. We aim to study the formation and regulation of the macromolecular complex at the molecular level under physiological and pathophysiological conditions that play a critical role in cholera induced diarrhea. Moreover, the research will study the mechanism through which LPA2 receptor- mediated signaling events regulate CFTR-dependent electrolyte secretion in cells and fluid secretion in an animal model of diarrhea. Three aims will be studied: Aim 1: To test the hypothesis that LPA2 receptor is primarily expressed on the luminal surface of the gut and is down regulated in certain forms of diarrheal diseases, and to test the hypothesis that activation of LPA2 receptor inhibits compartmentalized cAMP generation at the plasma membrane. Aim 2: To test the hypothesis that LPA can regulate the formation of the LPA2-containing macromolecular complex by further clustering it to microdomain on the plasma membrane and that the process is mediated by NHERF2-dependent protein-protein interactions Aim 3: To test the hypothesis that disruption of the macromolecular complex by silencing NHERF2 alters compartmentalized cAMP levels at the plasma membrane and that in vivo NHERF2 knockout mice generate altered cAMP in response to CTX. The proposal is of great importance and significance for understanding the pathogenic process of the deadly secretory diarrheal diseases at the molecular level, and for possible therapeutic intervention of the disease. The proposed study is highly innovative in both conceptual advance and in technology/technique development.