Characterization and Development of Gs-biased ligands of Beta2-Adrenergic Receptor

项目摘要/摘要 哮喘是一种常见的慢性疾病，以呼吸道炎症和呼吸道通畅为特征。 肌肉(ASM)收缩导致呼吸道收缩。β2肾上腺素能受体(β2AR)是G 蛋白偶联受体(GPCR)在激活时促进呼吸道收缩的逆转， 是哮喘治疗的关键药物靶点。β激动剂一直是 哮喘但长期使用这些药物会导致治疗反应脱敏。这可以 会导致严重的不良反应，并增加哮喘发作期间猝死的风险。 通常，β2AR信号是通过与Gs蛋白的初始相互作用和随后的受体来介导的 磷酸化和arrestin募集。有证据表明，通过Gs途径发出的信号 促进肌浆网松弛，而arrestin结合促进β-2AR内化、脱敏 受体对β激动剂的反应，以及促炎信号。平衡激动剂，如目前的β- 激动剂药物激活这两条通路，导致治疗和有害的同时发生。 效果。我们实验室和其他实验室的研究表明，有偏见的激动剂可以不同地激活这些 通向离散生理反应的途径。这是我们的假设，分子选择性地 通过Gs途径促进信号传递，而拮抗arrestin募集将减弱 与目前用于哮喘的β激动剂相关的不良反应。GS偏向激动剂 而β2AR的变构调节剂的特征是通过Gs途径产生cAMP 和arrestin募集到受体，以及受体磷酸化的下游过程 并对内部化进行评估。Gs偏向的β2AR信号转导系统对 β激动剂的负面作用，cAMP产生/气道收缩功能减敏和 炎症反应，将在体外和生理模型中进行彻底评估。这个 拟议的工作旨在利用最近对GPCR生物学的见解，目标是 开发具有更好治疗性能的Gs偏置β2AR配体。

Project Summary/Abstract Asthma is a common, chronic disorder characterized by airway inflammation and airway smooth muscle (ASM) contraction leading to airway constriction. The β2-adrenergic receptor (β2AR) is a G protein coupled receptor (GPCR) that promotes the reversal of airway constriction when activated, and is a critical drug target for asthma therapeutics. β-agonists have been cornerstone therapies for asthma but long-term use of these drugs leads to desensitization of therapeutic response. This can cause severe adverse effects and an increased risk of sudden death during an asthma attack. Canonically, β2AR signaling is mediated by initial interaction with the Gs protein followed by receptor phosphorylation and arrestin recruitment. Evidence shows that signaling through the Gs pathway promotes the relaxation of ASM, while arrestin binding promotes β2AR internalization, desensitization of receptor response to β-agonists, and pro-inflammatory signaling. Balanced agonists, like current β- agonist drugs, activate both of these pathways, resulting in concurrent therapeutic and harmful effects. Studies from our lab and others indicate that biased agonists can differentially activate these pathways toward discrete physiological responses. It is our hypothesis that molecules that selectively promote signaling through the Gs pathway, while antagonizing arrestin recruitment would attenuate the adverse effects associated with β-agonists currently prescribed for asthma. Gs-biased agonists and allosteric modulators of β2AR will be characterized by cAMP production through the Gs pathway and arrestin recruitment to the receptor, and the downstream processes of receptor phosphorylation and internalization will be evaluated. The effects of Gs-biased β2AR signaling on key contributors to the negative effects of β-agonism, desensitization of cAMP production / airway contractility and inflammatory response, will be thoroughly assessed in vitro and in physiological models. The proposed work is designed to take advantage of recent insights into GPCR biology with the goal of developing Gs-biased β2AR ligands with improved therapeutic properties.