The A2AR-D2R heteromer as a potential target against Parkinson's disease

描述（由申请人提供）：G蛋白偶联受体（GPCR）是临床实践中使用的许多药物的靶点，因为G蛋白介导过多的生理功能。最近，异聚GPCR复合物已成为药物开发中有吸引力的目标，因为它们表现出独特的药理学和细胞特异性定位于其各自的原聚体。然而，异聚化对许多GPCR的药理学和信号传导的影响仍然未知。我们已经承担了任务，以检查异聚化对通过腺苷2A受体（A2 AR）的Gs信号传导和通过多巴胺受体2型（D2 R）的Gi信号传导的影响。通过A2 AR-D2 R异聚体复合物的信号传导是非常令人感兴趣的，因为该异聚体是与功能失调的多巴胺能信号传导相关的病理学（例如帕金森病）的潜在药理学靶标。A2 AR拮抗剂已经被探索作为帕金森病的治疗剂，因为A2 AR变构地抑制通过D2 R的信号传导。因此，我们假设将D2 R完全激动剂与A2 AR拮抗剂组合将使通过异聚体的多巴胺能Gi信号传导最大化，并且将比目前仅靶向D2 R的治疗剂更有效地治疗帕金森病。为了验证这一假设，我们已经开发了特定的目标来表征各种D2 R和A2 AR配体对异聚信号传导的效力和功效。为了分析A2 AR-D2 R异源复合物交叉信号传导，我们使用异源表达通道作为GPCR信号传导的报告基因的电生理学测定。一旦我们在我们的异源表达系统中通过A2 AR-D2 R异聚体表征了Gs和Gi信号传导，我们将在天然细胞中验证结果以确保生理相关性。为了证实我们的发现，我们将使用体外[35 S]GTP？大鼠原代神经元S结合及体内微透析研究。通过A2 AR-D2 R异聚体的信号传导途径的表征将提供对什么配体通过D2 R优化多巴胺能信号传导的深入了解，从而导致帕金森病的新疗法的开发。

DESCRIPTION (provided by applicant): G protein-coupled receptors (GPCRs) are the targets of many drugs used in clinical practice because G proteins mediate a plethora of physiological functions. Recently, heteromeric GPCR complexes have become attractive targets in drug development since they exhibit distinct pharmacology and cell-specific localization from their respective protomers. Yet, the effect of heteromerization on the pharmacology and signaling of many GPCRs remains unknown. We have undertaken the task to examine the effect of heteromerization on the Gs signaling through the adenosine 2A receptor (A2AR) and Gi signaling through the dopamine receptor type 2 (D2R). Signaling through the A2AR-D2R heteromeric complex is of great interest as this heteromer is a potential pharmacological target for pathologies associated with dysfunctional dopaminergic signaling, such as Parkinson's disease. A2AR antagonists have been explored as therapeutics for Parkinson's disease because the A2AR allosterically inhibits signaling through the D2R. Therefore, we hypothesize that combining D2R full agonists with A2AR antagonists will maximize dopaminergic Gi signaling through the heteromer and will be more efficacious in treating Parkinson's disease than current therapeutics targeting just the D2R. To test this hypothesis, we have developed specific aims to characterize the potency and efficacy of various D2R and A2AR ligands on heteromeric signaling. In order to analyze A2AR-D2R heterocomplex cross signaling, we are using electrophysiological assays with heterologously expressed channels serving as reporters for GPCR signaling. Once we have characterized Gs and Gi signaling through the A2AR-D2R heteromer in our heterologous expression system, we will validate the results in native cells to ensure physiological relevance. To corroborate our findings, we will use in vitro [35S]GTP?S binding in primary neurons and in vivo microdialysis studies in rats. Characterization of the signaling pathway through the A2AR-D2R heteromer will provide insight into what ligands optimize dopaminergic signaling through the D2R leading to the development of novel therapeutics for Parkinson's disease.