Novel Molecular Mechanisms Promote GPCR-Induced Bronchodilation in Asthma

项目摘要 我们对这一跨学科PPG的更新仍然专注于新的分子机制的主题 抑制人呼吸道平滑肌(HASM)收缩，促进支气管扩张 呼吸道炎症和哮喘。主要的假说是G蛋白偶联受体(GPCR) 脱敏和无偏向信号传递限制了传统的支气管扩张剂的疗效，如靶向 ASM的脱敏机制、促进偏向激动症、规避机制 过度收缩/气道高反应性(AHR)，或采用新的支气管松弛机制 HASM将为哮喘提供更好的治疗方法。每个项目都通过以下方式解决这一假设：1)优化PRO- 3种不同GPCR中的一种使用植根于尖端生物物理或 药理学方法；或2)建立新的细胞内靶点，介导炎症驱动的AHR和 增加GPCR亲收缩信号。 项目1将建立转化生长因子-β1调节心肌细胞兴奋-收缩(EC)偶联的机制。 HASM，从而确定与AHR和增加的GPCR介导的增加相关联的新的治疗靶点 收缩。项目2将推进最近发现的苦味受体(TAS2R)作为新的 支气管扩张剂阐明TAS2R亚型在HASM中的作用、调节模式和改进方法 它们通过有偏见的激励性而产生的效果。项目3将描述β2AR偏向信号的分子基础 开发通过抑制β-arrestin与 激动剂占据的β2AR(芳香素偏置的负变构调节剂)或通过增强 β2AR至Gs(偏向的正构体激动剂)。项目4将以类似的方式描述偏见背后的机制 OGR1的信号转导，开发具有更好的支气管扩张能力的新的偏向OGR1苯二氮卓类衍生物，以及 确定外周苯二氮卓类受体激活的相对贡献和机制 候选药物。 这四个项目将得到Core A的支持，该项目将使用高通量的小分子筛选 文库、全基因组、汇集的shRNA文库和虚拟筛选方法以识别靶点和 支气管扩张效应器。核心B将提供所有未识别的人类细胞和组织模型来研究新的 HASM中EC偶联的调控机制。核心C将为该计划提供行政支持。 这一计划的优点是共同关注单一主题，以及 研究人员有能力将尖端的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.