Project 4 - OGR1- and TSPO- dependent mechanisms mediated by benzodiazepines affecting ASM contraction

项目摘要 在上一个周期中，我们的特点是某些苯二氮卓类药物的能力，在合作减少 细胞外pH值，通过激活质子调节气道平滑肌（ASM）信号传导和功能。 敏感G蛋白偶联受体（GPCR）OGR 1（卵巢癌G蛋白偶联受体1，又名GPR 68）。 重要的是，我们发现OGR 1下游激活的多种信号通路可能是 选择性激活（即，偏倚）对ASM收缩和增殖产生不同的影响。在这 第二个周期，我们建议：1）描绘OGR 1信号发生偏置的机制; 2） 详细描述了苯二氮卓类药物的一个额外的、神经依赖性的效应臂，该效应臂也抑制ASM收缩; 以及3）采用建模来开发针对这些机制的更有效的苯二氮卓类药物。 这些目标将通过三个具体目标来实现。在目标1中，我们将采用基于细胞的综合模型 的ASM收缩，以澄清不同的苯二氮卓类药物如何促进特定的OGR 1-和外周 苯二氮卓受体-信号转导调节ASM收缩。在目标2中，将建立 通过评估决定G蛋白偶联的OGR 1的结构-功能特性来偏置OGR 1信号传导，以及 抑制蛋白的偏置功能。在Aim 3中，与Core A合作，我们将采用分子建模， 设计新的变构调节剂，使OGR 1信号传导偏向Gs/cAMP/PKA通路活化， 相关的治疗益处，使用目的1和2中采用的信号传导和功能测定来指导 开发和鉴定最有效的药物。通过建立机制， 通过OGR 1的信号传导和开发新的药物，最佳地偏向OGR 1和促进支气管扩张，我们将 显著推进受体生物学和哮喘治疗学领域。

Project Summary In the previous cycle we characterized the ability of certain benzodiazepines, in cooperation with decreased extracellular pH, to regulate airway smooth muscle (ASM) signaling and function via activation of the proton- sensing G protein-coupled receptor (GPCR) OGR1 (Ovarian cancer G-protein coupled receptor 1 aka GPR68). Importantly, we discovered that the multiple signaling pathways activated downstream of OGR1 could be selectively activated (i.e., biased) to produce differential effects on ASM contraction and proliferation. In this second cycle we propose to: 1) delineate the mechanisms by which the biasing of OGR1 signaling occurs; 2) detail an additional, mitochondrial-dependent effector arm of benzodiazepines that also inhibits ASM contraction; and 3) employ modeling to develop more efficacious benzodiazepine-like drugs that target these mechanisms. These goals will be achieved through 3 Specific Aims. In Aim 1 we will employ cell-based and integrative models of ASM contraction to clarify the how different benzodiazepines promote specific OGR1- and peripheral benzodiazepine receptor- signaling to regulate ASM contraction. In Aim 2 will establish the mechanistic basis of biased OGR1 signaling by assessing structure-function properties of OGR1 that dictate G protein coupling, and the biasing function of arrestins. In Aim 3 in collaboration with Core A we will employ molecular modeling to design new allosteric modulators to bias OGR1 signaling towards Gs/cAMP/PKA pathway activation and the associated therapeutic benefits, using the signaling and functional assays employed in Aims 1 and 2 to guide development and identify the most efficacious drugs. By establishing mechanisms mediating qualitative signaling by OGR1 and developing new agents that optimally bias OGR1 and promote bronchodilation, we will significantly advance the fields of both receptor biology and asthma therapeutics.