Structural elucidation and development of agonists for the human orexin receptors

项目摘要/摘要 这项建议的目标是获得对人类增食欲素受体激动剂的生物物理了解。 结合和激活，并利用这一知识开发小分子增食欲素受体激动剂 治疗发作性睡病/猝倒和其他疾病的神经药理工具和潜在疗法。 嗜睡症是一种终生衰弱的疾病，影响着大约20万美国人，这是 以无法保持清醒、睡眠发作、肌肉功能突然丧失和睡眠为特征的 瘫痪。目前治疗发作性睡病的药物(如精神刺激剂)不能治疗潜在的 神经化学缺陷，并表现出不良副作用。人类的动物模型和临床研究 患者表明发作性睡病是由于缺乏食欲素(下丘脑)神经肽引起的。 而外源性替代食欲素的活性可能会治愈这种疾病。 然而，食欲素不能用作治疗剂，因为它们是多肽，不能穿透 血脑屏障，口服后由于代谢分解而表现出较差的活性。 我们建议利用GPCR结构生物学的新技术进展来确定 食欲素受体处于食欲素结合和小分子激动剂结合的状态，揭示了食欲素受体与食欲素和小分子激动剂结合的详细的非 稳定这些复合体的共价相互作用以及受体构象的变化 是激动剂结合的结果。在第二个目标中，我们将开发特定构象的纳米体 即结合和稳定增食欲素受体的活性状态，并解决纳米体共晶结构的理解 通过连接细胞外神经肽结合部位的膜传播的结构变化 和胞内G蛋白偶联部位。在第三个目标中，我们将把结构性见解与 计算机对接/模拟和药物化学，以提高小分子药物的亲和力和效力 以前在高通量筛选中发现的分子增食欲素受体激动剂。我们的组合 在结构生物学、合成和药物化学以及计算化学方面的优势 使我们处于独特的位置来设计小分子食欲素模拟物，具有药物样的特性，可以 进一步发展成为治疗发作性睡病和其他神经疾病的治疗学。

Project Summary/Abstract The goal of this proposal is to gain a biophysical understanding of human orexin receptor agonist binding and activation, and to use this knowledge to develop small-molecule orexin receptor agonists as neuropharmacological tools and potential therapeutics for narcolepsy/cataplexy and other diseases. Narcolepsy is a life-long debilitating disorder affecting approximately 200,000 Americans, which is characterized by an inability to maintain wakefulness, sleep attacks, sudden loss of muscle function, and sleep paralysis. Current treatments for narcolepsy (such as psychostimulant drugs) do not treat the underlying neurochemical deficits and exhibit undesirable side-effects. Animal models and clinical investigations of human patients show that narcolepsy is caused by deficiency of the orexin (hypocretin) neuropeptides produced by neurons of the lateral hypothalamus, and that exogenous replacement of orexin activity may cure the disease. However, orexins cannot be used as therapeutic agents because they are peptides, which do not penetrate the blood-brain barrier and show poor activity after oral administration due to metabolic decomposition. We propose to use new technical advances in GPCR structural biology to determine X-ray structures of the orexin receptors in orexin-bound and small-molecule agonist-bound states, revealing the detailed non- covalent interactions that stabilize these complexes as well as changes in conformation of the receptors that are a consequence of agonist binding. In the second Aim, we will develop conformation-specific nanobodies that bind and stabilize the orexin receptor active state, and solve nanobody co-crystal structures to understand the propagated structural changes across the membrane that link the extracellular neuropeptide binding site and the intracellular G protein coupling site. In the third Aim, we will integrate structural insights with computational docking/simulation and medicinal chemistry to improve the affinity and potency of small- molecule orexin receptor agonists that were previously identified in a high-throughput screen. Our combination of strengths in GPCR structural biology, synthetic and medicinal chemistry, and computational chemistry places us in a unique position to design small-molecule orexin mimics with drug-like properties that can be further developed into therapeutics for the treatment of narcolepsy and other neurological disorders.