Structure-Function of Opioid Receptors

说明(申请人提供)：涉及阿片系统的物质是广泛使用的药物；用于治疗慢性疼痛的激动剂(麻醉性止痛剂)；一般用于治疗成瘾障碍的拮抗剂，包括药物滥用(阿片剂、酒精、安非他明)和非物质，即行为成瘾。鉴于阿片类激动剂治疗的困难、过量致死的高风险(2008年报告的受害者比过量海洛因和可卡因的总和还要多)以及耐受性和成瘾的形成，需要更安全的麻醉性镇痛剂。拟议的研究计划使用结构、计算、生物物理、生化和药理学方法：(1)发展对阿片受体、|j，6，K和伤害素受体作用的新水平的理解，定义分子识别和激活的结构基础；(2)设计新的结合配体。目的是(1)利用X射线结晶学和核磁共振技术了解阿片受体的分子识别和功能选择性；(2)通过计算方法了解四种阿片受体功能和药理选择性的分子机制；(3)了解配体引导的信号(G蛋白、Arrestin和JNK依赖)及其在介导阿片受体作用中的相关性。四个核心小组通过项目间协作支持的三个项目将以今年以前想象不到的规模解决重要但困难的问题。项目1将对配体结合络合物进行结构测定。项目2将进行计算研究，以确定阿片受体的结合口袋，并进行计算机辅助SBDD，以设计一系列新的优化化合物，包括变构、功能选择性和双位配体。项目3将进行体外和体内研究，以表征配体的药理性质，并产生新的受体偏向突变体，以测试与功能选择性和阿片受体作用有关的假说。核心小组支持所有3个项目的目标，并将负责(1)纯化阿片受体的大规模生产；(2)阿片配体的合成，包括用于结构和功能研究的新设计的工具化合物；(3)新小分子的分子图谱和筛选；以及(4)整个计划的管理和行政。设施资源将由NIGMS GPCR网络的大规模蛋白质生产和结构解决方案的结构确定管道和NIMH精神活性药物筛选计划资源提供，用于选择性分析新的小分子。

DESCRIPTION (provided by applicant): Substances addressing the opioid system are widely used pharmaceuticals; agonists (narcotic analgesics) for the treatment of chronic pain; antagonists generally for the treatment of addictive disorders, including substance abuse (opiate, alcohol, amphetamine) and non-substance, i.e. behavioral addictions. Given the difficulties associated with opioid agonist therapy, high risk of death due to overdose (more victims were reported in 2008, than overdose of heroin and cocaine combined) and the development of tolerance and addiction, there is a need for safer narcotic analgesics. The proposed research program uses structural, computational, biophysical, biochemical, and pharmacological approaches: (1) to develop a new level of understanding of the action the opioid receptors, | j , 6, K, and the nociceptin receptor, defining the structural basis for molecuar recognition and activation, and (2) to design new binding ligands. Aims are to (1) understand opioid receptor molecular recognition and functional selectivity using X-ray crystallography and NMR; (2) understand the molecular mechanisms for functional and pharmacological selectivity for the four receptors using computational approaches; and (3) understand ligand-directed signaling (G-protein-, arrestin-, JNK-dependent) and its relevance in mediating opioid receptor action. Three projects supported by four core groups via inter-project collaborations will address important but difficult questions at a scale not imagined prior to this year. Project 1 will carry ut structural determination on ligand bound complexes. Project 2 will carry out computational studies to define the binding pockets of opioid receptors and perform computer-assisted SBDD to design a new series of optimized compounds including allosteric, functionally selective and bitopic ligands. Project 3, will carry out in vitro and in vivo studies to characterize pharmacological properties of ligands and generate new receptor biased mutants to test hypotheses related to functional selectivity and opioid receptor actions. Core groups support the aims of all 3 projects and will be responsible for (1) large-scale production of purified opioid receptors; (2) synthesis of opiate ligands including newly designed tool compounds for structural and functional studies; (3) molecular profiling and screening of new small molecules, and (4) management and administration of the overall program. Facility resources will be provided by the NIGMS GPCR Networks' Structural Determination Pipeline for large-scale protein production and structure solution and the NIMH Psychoactive Drug Screening Program resources for selectivity profiling of novel small molecules.