Novel Molecular Mechanisms Promote GPCR-Induced Bronchodilation in Asthma

项目概要 我们对这种跨学科 PPG 的更新仍然集中在新颖的分子机制的主题上 抑制人气道平滑肌（HASM）收缩并促进支气管扩张 气道炎症和哮喘。主要假设指出 G 蛋白偶联受体 (GPCR) 脱敏和无偏信号传导限制了传统支气管扩张剂的功效，因此靶向 脱敏机制、促进偏向激动、规避 ASM 机制 过度收缩/气道高反应性（AHR），或采用新型支气管松弛机制 HASM 将为哮喘提供卓越的治疗方法。每个项目通过以下任一方式解决这一假设：1）优化亲 3 种不同 GPCR 之一的松弛信号传导能力，采用基于尖端生物物理或技术的策略 药理学方法；或 2) 建立介导炎症驱动的 AHR 的新细胞内靶标，以及 GPCR 促收缩信号传导增强。 项目 1 将建立 TGF-β1 调节兴奋-收缩 (EC) 耦合的机制 HASM 从而确定与 AHR 和增加的 GPCR 介导相关的新治疗靶点 收缩。项目 2 将推进最近发现的苦味受体 (TAS2R) 的新颖性 支气管扩张剂阐明TAS2R亚型在HASM中的作用、其调节模式和改善手段 它们的功效是通过有偏见的激动来实现的。项目 3 将描述 β2AR 偏向信号传导的分子基础 开发通过抑制 β-arrestin 与 Gs 偏向信号传导的化合物 激动剂占据的 β2AR（抑制素偏向负变构调节剂 (NAM)）或通过增强 β2AR 至 Gs（偏向正构激动剂）。项目 4 将类似地描述偏见背后的机制 OGR1 信号传导，开发新的偏向 OGR1 苯二氮卓衍生物，具有卓越的支气管扩张能力，以及 确定外周苯二氮卓受体激活的相对贡献和机制 候选药物。 这四个项目将得到核心 A 的支持，该核心 A 将使用小分子的高通量筛选 文库、全基因组、shRNA 混合文库和虚拟筛选方法来识别目标和 支气管扩张的效应器。 Core B将提供所有去识别的人体细胞和组织模型来研究新的 HASM 中 EC 耦合的调节机制。 Core C 将为该计划提供行政支持。 该计划的优势在于共同关注单一主题以及各部门之间富有成效的工作关系 研究人员能够将尖端的 GPCR 生物学应用于哮喘生物学和药理学的关键问题。

Project Summary Our renewal of this interdisciplinary PPG remains focused on the theme of novel molecular mechanisms to inhibit human airway smooth muscle (HASM) contraction and promote bronchodilation within the context of airway inflammation and asthma. The principal hypothesis states that G protein coupled receptor (GPCR) desensitization and unbiased signaling limits the efficacy of conventional bronchodilators, such that targeting desensitization mechanisms, promoting biased agonism, circumventing mechanisms of ASM hypercontractility/airway hyperresponsiveness (AHR), or engaging novel bronchorelaxant mechanisms in HASM will provide superior therapy for asthma. Each Project addresses this hypothesis by either: 1) optimizing pro- relaxant signaling abilities of one of 3 different GPCRs using strategies rooted in cutting edge biophysical or pharmacological approaches; or 2) establishing novel intracellular targets mediating inflammation-driven AHR and increased GPCR pro-contractile signaling. Project 1 will establish the mechanisms by which TGF-β1 modulates excitation-contraction (EC) coupling of HASM and thereby identify novel therapeutic targets linked to both AHR and increased GPCR-mediated contraction. Project 2 will advance the recent discovery of bitter taste receptors (TAS2R) as novel bronchodilators clarifying the role of TAS2R subtypes in HASM, their mode of regulation and means to improve their efficacy through biased agonism. Project 3 will characterize the molecular basis of β2AR biased signaling to develop compounds that mediate Gs-biased signaling through either inhibition of β-arrestin interaction with the agonist-occupied β2AR (arrestin-biased negative allosteric modulators (NAMs)) or by enhancing coupling of the β2AR to Gs (biased orthosteric agonists). Project 4 will similarly characterize the mechanisms underlying biased signaling of OGR1, develop new biased OGR1 benzodiazepine derivatives with superior ability to bronchodilate, and determine the relative contribution of and mechanisms underlying peripheral benzodiazepine receptor activation by candidate drugs. The four projects will be supported by Core A that will use high through-put screening of small molecule libraries, whole genome, pooled shRNA libraries and virtual screening approaches to identify targets and effectors of bronchodilation. Core B will provide all de-identified human cell and tissue models to study novel mechanisms regulating EC coupling in HASM. Core C will provide administrative support for the program. The strengths of this Program are the common focus on a single theme and the productive working relationship among investigators with the ability to apply cutting edge GPCR biology to key questions in asthma biology and pharmacology.