Novel Molecular Mechanisms Promote GPCR-Induced Bronchodilation in Asthma

项目摘要 我们对这个跨学科PPG的更新仍然集中在新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。主要假设是G蛋白偶联受体（GPCR） 脱敏和无偏信号传导限制了常规支气管扩张剂的功效， 脱敏机制，促进偏向激动，规避ASM机制 高收缩性/气道高反应性（AHR），或参与新的支气管舒张机制， HASM将为哮喘提供上级治疗。每个项目都通过以下方式解决这一假设：1）优化亲- 松弛信号传导能力的3种不同的GPCR之一，使用的战略植根于尖端的生物物理或 药理学方法;或2）建立介导炎症驱动的AHR的新的细胞内靶点， 增加GPCR促收缩信号传导。 项目1将建立TGF-β1调节兴奋-收缩（EC）偶联的机制， HASM，从而鉴定与AHR和GPCR介导的增加的GPCR相关的新的治疗靶点。 收缩。项目2将推进最近发现的苦味受体（TAS 2 R）作为新的 支气管扩张剂阐明TAS 2 R亚型在HASM中的作用，其调节模式和改善HASM的方法 通过偏向性激动来提高疗效。项目3将描述β 2 AR偏性信号传导的分子基础 为了开发通过抑制β-抑制蛋白相互作用与抑制蛋白相互作用来介导Gs偏置信号传导的化合物， 激动剂占据的β2AR（抑制蛋白偏向的负向变构调节剂（NAM））或通过增强β 2AR的偶联， β 2 AR至Gs（偏向性正构激动剂）。项目4将类似地描述偏见背后的机制 OGR 1的信号传导，开发具有上级支气管扩张能力的新的偏向OGR 1的苯二氮卓衍生物， 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，核心A将使用高通量筛选小分子 文库、全基因组、混合shRNA文库和虚拟筛选方法来鉴定靶点， 支气管扩张效应器。核心B将提供所有去识别的人类细胞和组织模型，以研究新型 调节HASM中EC偶联的机制。核心C将为该计划提供行政支持。 该计划的优势在于共同关注一个主题，并在以下方面建立富有成效的工作关系： 研究人员有能力将尖端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.