Project 2

项目摘要 多巴胺是一种神经递质，与多种神经和精神疾病有关。CNS。DA对靶神经元的各种作用是通过与各种效应系统偶联的原型7-跨膜G蛋白偶联受体（GPCR）介导的。治疗剂，包括所有临床有效的抗精神病药，与DA D2受体（D2 R）相互作用并引起有益和不想要的副作用。在以前的工作中，我们已经证明，纹状体D2 Rs中棘神经（MSN）介导-他们的一些行动，通过G蛋白依赖和独立的机制。这些G蛋白非依赖性作用通过与AKt/GSKS信号通路的组分形成B-抑制蛋白2依赖性信号复合物而发生。在我们之前的U-19 NCDD资助期间的工作已经确定了基于抗精神病药物阿立哌唑的支架的新型小分子，该支架可以作为Db2 R的真菌选择性配体。这些D2 R配体是G蛋白介导的cAMP产生抑制的激动剂以及D2 R/B-抑制蛋白2相互作用的拮抗剂，反之亦然。此外，使用高多巴胺能功能的药理学或遗传小鼠模型，作为选择性D2 R/B抑制蛋白2相互作用的化合物显示出有效的抗精神病活性特征，而没有相关的僵硬症副作用。相比之下，这些化合物在不存在b2 R/β-抑制蛋白2相互作用的β-抑制蛋白2敲除小鼠中引起显著的副作用。这些结果表明，D2 R1/B-arrestin 2信号传导可以防止这些不必要的影响。在项目2中，我们将使用细胞和脑区域的选择性失活或拯救的，D2 R信号通路的组件，以验证我们的初步结果，并确定负责抗精神病的新发现的功能选择性D2 R配体的概况（S）的细胞和分子事件。目标1：我们将通过使用小鼠来验证D2 R/抗精神病作用的新小鼠模型，其中在各种神经元群体中表达的D2 R中B-抑制蛋白2和GSK 3B已被选择性灭活;目的2：我们将在小鼠中分析新配体，其中内源性D2 R已被野生型B2 R或能够选择性偶联至G蛋白或p-抑制蛋白2信号传导的突变的D2 R病毒取代。目标3;我们将通过在各种动物模型中检查与这些药物的有益/副作用相关的生化、生理和细胞事件来确定新型抗精神病药物的细胞和分子谱。我们预计，这些努力将导致概念验证，靶向D2 R/B-arrestin 2信号转导将为临床研究开发更具选择性和有效的治疗药物提供新的配体。

PROJECT SUMMARY Dopamine is a, neurotransmitter that has been implicated in multiple neurological and psychiatric disorders in the. CNS. The various actions of DA on target neurons are mediated via prototypical 7-transmembrane G protein-Coupled receptors (GPCR) that couple to various effector systems, Therapeutic agents, including all clinically effective antipsychotics, interact with DA D2 receptors (D2R) and elicit both beneficial and unwanted side effects. In previous work, we have demonstrated that striatal D2Rs on medium spiny nervous (MSN) mediate- some of their actions through both G protein-dependent and independent mechanisms. These G protein-independent action occur through formation of B-arrestin2-dependent signaling complexes with components of the AKt/GSKS signaling pathway. Work during our previous U-19 NCDD grant period has identified novel small molecules based on, the scaffold of the anti-phychotic drug aripipraziole that can act as FUNGTIONALLY SELECTIVE ligands at theDb2R. These D2R are ligands are agonists at the G protein-mediated inhibition of cAMP production as well as antagonists at D2R/B-arrestin2 interactions or vice versa. Moreover, using pharmacologicai or genetic mouse rnodels of hyperdopaminergic function, compounds that are selective D2R/B arrestin2 interactions show potent antipsychotic activity profiles without associated cataleptic side effect. By comparison, these .these compounds elicit significant side effects in B-arrestin2 knockout mice where b2R/p-arrestih2 interactions are absent. These results suggest; that D2R;/B-arrestin2 signaling may protect against these unwanted effects. In Project 2, we will use cell and brain-region selective inactivation or rescue of components of the,D2R signaling pathways to validate our initial results and to determine the cellular and molecular events responsible for the antipsychotic profile(s) of the newly discovered functionally-selective D2R ligands. Aim 1: We will validate new mouse models of D2R/antipsychotic action through the use of mice in which B-arrestin2 and GSK3B have been selectively inactivated in D2R expressing in various neuronal populations; Aim 2: We will profile the new ligands in mice in which the endogenous D2R has been virally replaced by wild type B2R or a mutated D2R capable of selectively coupling to G protein or p-arrestin2 signaling. Aim 3; We will determine the cellular-and molecular profiles of the novel antipsychotic drugs by examining the biochemical, physiological and cellular events that correlate with the beneficial /side-effect actions of these agents in bur various animal model's. We anticipate that these efforts will lead to the proof-of-concept that targeting D2R/B-arrestin2 signaling will provide novel ligands for the development of more selective and effective therapeutic agents for clinical studies.