Discovery of a High Affinity, Selective and β-arrestin Biased 5-HT7R Agonist

项目摘要/摘要：5-羟色胺7受体(5-HT7R)是G蛋白的一员。 偶联5-羟色胺受体家族。大量研究表明，5-HT7R在多种疾病中发挥着重要作用。 行为和心理生理功能，如情绪稳定性、认知和运动功能、行为 抑制、上瘾行为、疼痛耐受性、睡眠模式、食欲、荷尔蒙变化和体温调节。 临床前研究结果证实5-HT7R在自闭症谱系障碍、脆性X综合征中的作用 (FXS)、癫痫、睡眠障碍、神经性疼痛和偏头痛。因此，5-HT7R正在成为一个潜在的目标 用于治疗各种精神疾病和其他相关疾病。同时，几种5-HT7R激动剂， 包括AS-19、E-55888、LP-12、LP-44、LP-211、AGH-192和化合物1G。 可能用于各种中枢神经系统疾病(疼痛、记忆和认知)、神经病理性疼痛、睡眠障碍、 酗酒和吸毒正在接受调查。然而，激活或封锁 在这些情况下，5-HT7R通常不是明确确定的，主要是由于缺乏选择性的5-HT7R。 HT7R试剂。更关键的是不存在有偏见的配体，这可能会澄清几个有争议的问题 与5-HT7R有关的观察结果。因此，我们的目标是设计、合成和药理学评估 对G蛋白或β-arrestin信号通路有偏见的新药物在 了解5-HT7R及其在各种中枢神经系统疾病治疗中的应用。 在本申请中提出了三个具体目标。具体目标1将专注于扩展我们的 先导化合物(44080、55933和57544)的脑等类药物性质研究 渗透率、药代动力学研究、代谢概况、生物利用度评估和心血管 毒性预测(HERG，5-HT2BR)。基于我们的先导化合物55933的代谢评价 初步研究、新化合物的合成和筛选是在具体目标2中提出的。这一具体目标 AIM还将专注于新制剂的优化和设计，以解决代谢稳定性问题，如 正如在初步研究中观察到的芳构化和葡萄糖醛酸化反应。因此，芳构化反应 敏感的四氢异喹啉(THI)部分将被不能接受的异吲哚取代 芳构化和CH2OH基团将被取代，如-F，-CONH2，以限制 葡萄糖醛酸化反应，同时保持良好的类药物特性。此外，生物等位体置换 将进行含二氢二萘酮(DNO)部分的吲哚。此外，探索电子 THI/异吲哚周围的捐赠/退出(σ值)和亲水/疏水(pi值)空间 具有氯、OME、CN、SOCH3和NMe2等取代基的环系统将在其 类似毒品的特征。同时，将利用同源模型进行对接研究，以确定 与诱导β-Arrestin构象相关的关键氨基酸残基的相互作用 招募到5-HT7R。具体目标3将包括铅5-HT7R配体的功能选择性研究 它们的激动剂/拮抗剂特性和G蛋白或β-arrestin信号偏向 活体条件下对睡眠结构和NREM/REM睡眠模式的影响。最后，精选测试 化合物将与SB269970(5-HT7R拮抗剂)和化合物1G(5-HT7R部分激动剂)进行比较 (作为阳性对照)对非快速眼动/快速眼动睡眠模式的影响以及β-arrestin偏向活动的相关性 使用的是小鼠模型。

Project Summary/Abstract: The 5-hydroxytryptamine 7 receptor (5-HT7R) is a member of the G protein- coupled 5-HT receptor family. Numerous studies have indicated that 5-HT7R plays a significant role in various behavioral and psychophysiological functions such as mood stability, cognitive and motor functions, behavioral inhibition, addictive behaviors, pain tolerance, sleep patterns, appetite, hormonal changes and thermoregulation. Pre-clinical findings have established the role of 5-HT7R in autism spectrum disorders, Fragile X syndrome (FXS), epilepsy, sleep disorders, neuropathic pain and migraine. Thus, 5-HT7R is emerging as a potential target for the treatment of various psychiatric and other associated disorders. Meanwhile, several 5-HT7R agonists, including AS-19, E-55888, LP-12, LP-44, LP-211, AGH-192 and compound 1g have been reported and their potential use in various CNS conditions (pain, memory and cognition), neuropathic pain, sleep disorders, alcohol and drug abuse are being investigated. However, the beneficial effects of activation or blockade of the 5-HT7R in each of these conditions is not often clearly established, primarily due to the lack of selective 5- HT7R agents. Even more critical is the absence of biased ligands that could clarify several controversial observations that relate to the 5-HT7R. Thus, our goal to design, synthesize and pharmacologically evaluate new agents with biased signaling towards G-Protein or β-arrestin signaling pathways hold great promise in understanding the 5-HT7R and its application to the treatment of various CNS disorders. There are three specific aims proposed in this application. Specific aim 1 will focus on extending our studies on the lead compounds (44080, 55933 and 57544) for their drug-like properties including brain penetration, pharmacokinetic studies, metabolic profiling, bioavailability assessments and cardiovascular toxicity predictions (HERG, 5-HT2BR). Based on the metabolic evaluations of lead compound 55933 from our preliminary studies, the synthesis and screening of new compounds is proposed in specific aim 2. This specific aim will also focus on the optimization and design of new agents to address the metabolic stability issues such as aromatization and glucuronidation observed in the preliminary studies. For this reason, aromatization susceptible tetrahydroisoquinoline (THI) moiety will be replaced with isoindoline which could not undergo aromatization and the CH2OH group will be replaced with substituents such as -F, -CONH2 to restrict glucuronidation while maintaining good drug-like characteristics. In addition, bioisosteric replacement of indanone with dihydronaphthalenone (DNO) moiety will be carried out. Furthermore, exploring the electron donating/withdrawing (σ values) and hydrophilic/hydrophobic (pi values) space around the THI/isoindoline ring systems with substituents such as Cl, OMe, CN, SOCH3 and NMe2, will reveal any improvements in their drug-like characteristics. Simultaneously, docking studies will be carried out using homology models to identify interactions with the key amino acid residues involved in inducing conformations associated with β-arrestin recruitment to the 5-HT7R. Specific Aim 3 will cover functional selectivity studies of lead 5-HT7R ligands for their agonist/antagonist properties and G-Protein or β-arrestin signaling bias followed by evaluation of their effect on sleep architecture and NREM/REM sleep pattern under in vivo conditions. Finally, selected test compounds will be compared with SB269970 (5-HT7R antagonist) and compound 1g, a 5-HT7R partial agonist (as a positive control) for their effect on NREM/REM sleep pattern and correlation of β-arrestin biased activity using a mice model.