Negative allosteric modulators of the D3 dopamine receptor as therapeutic leads for substance use disorders

标题：作为治疗先导的D3多巴胺受体的负变构调节剂 治疗物质使用障碍 摘要：多巴胺受体(DR)在细胞信号转导过程中起着关键作用。 神经系统内信息传递的调节。DRS由五个不同的 亚型分为D1型(D1R和D5R)和D2型(D2R，D3R， 和D4R)，它们会产生非常不同的生理效应。尤其是D3R 拮抗剂已被研究为治疗药物使用的一种治疗方法 精神障碍(SODS)，在扰乱寻求毒品的动机和防止复发方面都是如此。 在过去的十年里，吸毒过量死亡人数增加了一倍多，主要是由于 阿片类药物滥用，强调迫切需要确定新的SUD疗法， 对阿片类苏德有效。最近的证据表明，D3R对抗可能是一种 对阿片类SUD的治疗尤为有效。然而，高度的序列同源性 由D3R和其他GPCR在其正构体结合位点内共享，使得 高选择性化合物的发现困难，导致潜在的偏离目标的一面 由于这类药物同时调节受体而产生的效应。现在，它被认为是 除了高度保守的正构体位点，许多G蛋白偶联受体， 包括DRS在内，具有明显的、非保守的变构位点。因此，化合物 通过与变构位点的相互作用来调节受体有可能是 精挑细选。在这里，我们试图开发结构新颖的D3R负变构 具有特殊D3R选择性的调制器，作为新的化学探针和 治疗线索，首要目标是支持D3R拮抗剂的开发 苏德疗法。为了寻找D3R的高度选择性变构拮抗剂， 我们采用了NIH小分子文库的高通量筛选。图书馆是 用D3R介导的β-arrestin募集试验进行初步筛选。对抗性命中 使用正构体配体进行放射性配基置换的反筛选 从而鉴定出三个具有变构性质的HIT化合物。在这 研究后，我们将制定灵活、稳健的合成路线，以方便每个支架 药物化学。将对三种支架的类似物进行效力评估，D3R 用于鉴定MOST的选择性和初步体外药代动力学性质 有望在迭代药物化学优化中取得进展。最多的 前景看好的系列将进一步优化，重点是以下必备特性 一种体内的探针化合物。将对该探头进行密集的D3R选择性表征 在几个功能输出中，包括β-arrestin募集和G-蛋白激活。 斯柴尔德类型的功能分析将被用来确认这种化合物在非 在D3R上的竞争态度。最后，体内药代动力学实验将提供 关于复方剂量的指南。该探针化合物将用于研究 D3R变构部位的药理作用、D3R拮抗剂的治疗潜力和 为肥皂水提供新的治疗线索。

Title: Negative allosteric modulators of the D3 dopamine receptor as therapeutic leads for substance use disorders Summary: Dopamine receptors (DRs) play a critical role in cell signaling processes and modulation of information transfer within the nervous system. DRs comprise five distinct subtypes subdivided into two families, D1-like (D1R and D5R) and D2-like (D2R, D3R, and D4R), that produce profoundly diverse physiological effects. In particular, D3R antagonists have been investigated as a therapeutic approach to treating substance use disorders (SUDs), both in disrupting drug seeking motivation and preventing relapse. Drug overdose deaths have more than doubled in the past decade driven largely by rising opioid abuse, underscoring the urgent need to identify new SUD therapies that are effective for opioid SUD. Recent evidence suggests that D3R antagonism may be an especially effective treatment for opioid SUD. However, the high sequence homology shared by the D3R and other GPCRs within their orthosteric binding sites has made the discovery of highly selective compounds difficult, leading to the potential for off-target side effects due to simultaneous receptor modulation by such agents. It is now appreciated that, in addition to highly conserved orthosteric sites, many G protein-coupled receptors, including DRs, possess distinct and non-conserved allosteric sites. Thus, compounds that modulate receptors through the interaction with an allosteric site have the potential to be profoundly selective. Here we seek to develop structurally novel D3R negative allosteric modulators that possess exceptional D3R selectivity as new chemical probes and therapeutic leads, in an overarching goal to support development of a D3R antagonist SUD therapy. In an effort to discover highly selective allosteric antagonists for the D3R, we employed a high-throughput screen of the NIH small molecule library. The library was initially screened using a D3R-mediated β-arrestin recruitment assay. Antagonist hits were counter-screened for radioligand displacement using an orthosteric ligand, which led to the identification of three promising hit compounds with allosteric properties. In this study, we will develop flexible, robust synthetic routes to each scaffold to facilitate medicinal chemistry. Analogs of the three scaffolds will be evaluated for potency, D3R selectivity and preliminary in vitro pharmacokinetic properties to identify the most promising series to advance for iterative medicinal chemistry optimization. The most promising series will be further optimized with an emphasis on the requisite properties for an in vivo probe compound. The probe will be intensively characterized for D3R selectivity in several functional outputs including β-arrestin recruitment and G-protein activation. Schild-type functional assays will be used to confirm that this compound acts in a non- competitive manner at the D3R. Finally, in vivo pharmacokinetic experiments will provide a guide for compound dosing. The probe compound will be used to study the pharmacology of D3R allosteric sites, the therapeutic potential of D3R antagonists and provide new therapeutic leads for SUDs.