PHARMACOLOGICAL TARGETING OF GALPHA SUBUNITS IN DISEASE

项目总结/摘要 这个多PI基础科学项目旨在改变对生理学中G蛋白功能的理解 和疾病，并为开发治疗目前无法治疗的疾病的治疗方法提供了广泛适用的途径。 由突变的组成性活性G蛋白α亚基引起的疾病。它通过发展知识来做到这一点 需要以临床前和最终临床研究所需的规模设计和合成一系列 生物可利用的抑制剂，每一种都选择性地靶向密切相关的异源三聚体G蛋白。 这种方法的转化/临床潜力是基于最近的研究表明， 靶向Gq/11类G蛋白α亚基的抑制剂在小鼠模型中是治疗有效的， 葡萄膜黑色素瘤，一种由突变型组成型活性Gq/11驱动的无法治愈的疾病。类似 这些方法可能会产生广泛的影响，因为许多其他无法治愈的疾病是由各种类型的疾病驱动的。 突变的组成性活性G蛋白α亚基，包括分泌垂体瘤，粘膜 黑色素瘤、脉络膜血管瘤、肝脏小血管肿瘤，约占所有癌症的10-15%，Sturge-Weber 综合征、常染色体显性遗传性甲状旁腺功能减退症和某些形式的高钙血症和低钙血症。此外，委员会认为， 这种方法可用于调节疾病中的G蛋白活性， 由于受体冗余或G蛋白导致的剂量限制性副作用， 呼吸抑制或药物耐受性。 直接靶向G蛋白特定亚类的生物可利用的抑制剂将是极其有价值的 for basic基础science科学.它们将提供简单、快速、廉价和可靠的化学探针， G蛋白在正常生理学和疾病动物模型中的新功能，与传统的 击倒或击倒战略，这是缓慢和昂贵的，并可能遭受补偿或关闭- 目标效应。 该项目的基础是一对几乎相同的，生物可利用的，天然环状缩酚酸肽 有效和选择性抑制G蛋白α亚基的Gq/11亚家族的产物。的具体目标 该项目将解决四个关键挑战：1）这些抑制剂的有限可用性; 2）缺乏抑制剂 可以靶向疾病组织进行慢性治疗的衍生物; 3）对药物的有限理解， 抑制机制，其已经排除了靶向G蛋白的其他亚型的抑制剂的设计;以及4） 缺乏选择性靶向Gq/11以外的G蛋白亚型的抑制剂。这些目标将得到实现。 通过使用创新的合成有机化学，基于计算的对接和抑制剂设计， 分子FRET、NMR以及G蛋白功能的生物化学和基于细胞的测定。

Project Summary/Abstract This multi-PI basic science project aims to transform understanding of G-protein function in physiology and disease, and provide broadly applicable routes for developing therapeutics to treat currently untreatable diseases caused by mutant constitutively active G protein α-subunits. It does so by developing knowledge required to design and synthesize, at scales required for preclinical and eventual clinical studies, a family of bioavailable inhibitors, each of which selectively targets closely related groups of heterotrimeric G proteins. The translational/clinical potential of this approach is based on recent studies indicating that a bioavailable inhibitor that targets G protein α-subunits of the Gq/11 class is therapeutically effective in mouse models of uveal melanoma, an untreatable disease that is driven by mutant constitutively active Gq/11. Similar approaches could have broad impact, because many other untreatable diseases are driven by various types of mutant constitutively active G protein α-subunits, including hormone-secreting pituitary tumors, mucosal melanoma, choroidal hemangiomas, hepatic small-vessel neoplasms, ~10-15% of all cancers, Sturge-Weber syndrome, autosomal dominant hypoparathyroidism, and certain forms of hyper- and hypocalcemia. Moreover, this approach could be used to modulate G-protein activity in diseases where GPCR-targeted drugs are ineffective due to receptor redundancy or to G proteins that cause dose-limiting side effects such as respiratory suppression or drug tolerance. Bioavailable inhibitors that directly target specific subclasses of G proteins would be extremely valuable for basic science. They would provide simple, fast, cheap and reliable chemical probes with which to identify novel functions of G proteins in normal physiology and in animal models of disease, in contrast to conventional knockout or knockdown strategies, which are slow and expensive, and can suffer from compensatory or off- target effects. The foundation of this project is a pair of nearly identical, bioavailable, cyclic depsipeptide natural products that potently and selectively inhibit the Gq/11 subfamily of G protein α-subunits. The Specific Aims of this project will address four crucial challenges: 1) limited availability of these inhibitors; 2) lack of inhibitor derivatives that could be targeted to disease tissues for chronic therapy; 3) limited understanding of the inhibitory mechanism, which has precluded design of inhibitors that target other subtypes of G proteins; and 4) absence of inhibitors that selectively target G protein subtypes other than Gq/11. These Aims will be pursued by using innovative synthetic organic chemistry, computational-based docking and inhibitor design, single- molecule FRET, NMR, and biochemical and cell-based assays of G protein function.