Arrestin Selectivity for GPCRs in Airway Smooth Muscle

描述（由申请人提供）：阻滞蛋白通过破坏GPCR-G蛋白相互作用和“阻滞”受体的信号传导能力来调节多种G蛋白偶联受体（gpcr）。尽管利用细胞过表达系统的研究已经证明了抑制的重要性，但我们对生理系统中内源性gpcr的抑制调节的理解是有限的。我们建议表征骤停药物调节气道平滑肌（ASM）中gpcr的能力和选择性，最终目标是将骤停药物作为提高吸入β激动剂治疗哮喘和COPD疗效的手段。根据本文提供的初步数据，我们假设β -arrestin-1和β -arrestin-2对Gq和Gs偶联受体的选择性差异可以用来增强β -激动剂放松其他gpcr收缩的ASM的能力。目的1和2将确定β -arrestin-1和β -arrestin-2对介导ASM收缩（包括毒瘤碱、半胱氨酸白三烯和组胺受体）或松弛（β -2-肾上腺素和前列腺素E2受体）的gpcr的选择性。Aim 1将利用分子和遗传方法在ASM细胞和来源于人类和小鼠的组织中靶向β -arrestin-1、β -arrestin-2或两者。我们将评估抑制基因抑制或基因消融对ASM信号传导和gpcr收缩特性的影响。目的2将进行补充生理测量，以确定抑制素基因消融对体内ASM收缩和舒张调节的影响。总的来说，这些研究将提供ASM中抑制素选择性的高度机制分析，并确定介导ASM收缩或舒张的差异调节受体的方法。

DESCRIPTION (provided by applicant): Arrestins regulate numerous G protein-coupled receptors (GPCRs) by disrupting GPCR-G protein interaction and "arresting" the ability of receptors to signal. Although considerable evidence of the importance of arrestins has come from studies employing cellular overexpression systems, our understanding of arrestin regulation of endogenous GPCRs in physiological systems is limited. We propose to characterize the capacity and selectivity of arrestins for regulating GPCRs in airway smooth muscle (ASM), with the ultimate goal of targeting arrestins as a means of improving the therapeutic efficacy of inhaled beta-agonists in the treatment of asthma and COPD. Based on preliminary data presented herein, we hypothesize that differences in beta-arrestin-1 and beta-arrestin-2 selectivity for Gq- and Gs- coupled receptors can be exploited to enhance the ability of beta-agonists to relax ASM contracted by other GPCRs. Aims 1 & 2 will establish the selectivity of beta-arrestin-1 and beta-arrestin-2 for those GPCRs that either mediate contraction (including muscarinic, cysteinyl leukotriene, and histamine receptors) or relaxation (beta-2-adreneric and prostaglandin E2 receptors) of ASM. Aim 1 will utilize molecular and genetic approaches to target beta-arrestin-1, beta-arrestin-2, or both in ASM cells and tissue derived from both humans and mice. Affects of arrestin inhibition or gene ablation on both ASM signaling and contractile properties by GPCRs will be assessed. Aim 2 will perform complementary physiological measurements to determine the effect of arrestin gene ablation on the regulation of ASM contraction and relaxation in vivo. Collectively, these studies will provide a highly mechanistic analysis of arrestin selectivity in ASM and identify approaches for differentially regulating receptors that mediate contraction or relaxation of ASM. PUBLIC HEALTH RELEVANCE: These studies seek to identify the usefulness (as an asthma therapy) of inhibiting a key regulatory molecule in airway smooth muscle. Understanding how beta-arrestin-1 or beta-arrestin-2 regulate receptors in smooth muscle may allow us to improve the ability of drugs to relax smooth muscle while at the same time inhibiting the stimuli that cause airway constriction and wheezing.