PHARMACOLOGICAL TARGETING OF GALPHA SUBUNITS IN DISEASE

项目摘要/摘要 这个多PI的基础科学项目旨在改变生理学中对G蛋白功能的理解 和疾病，并为开发治疗目前无法治愈的疗法提供了广泛适用的途径 突变的G蛋白α亚基引起的疾病。它通过发展知识来做到这一点 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，每一种都选择性地针对密切相关的异源三聚体G蛋白基团。 这种方法的翻译/临床潜力是基于最近的研究表明，一种生物可利用度 靶向GQ/11类G蛋白α亚单位的抑制剂对小鼠模型有治疗作用 葡萄膜黑色素瘤，一种无法治疗的疾病，由突变的构成活性的GQ/11驱动。 方法可能会产生广泛的影响，因为许多其他无法治疗的疾病是由各种类型的 突变的成分活性G蛋白α亚基，包括分泌激素的垂体瘤，粘膜 黑色素瘤、脉络膜血管瘤、肝小血管肿瘤，约占所有癌症的10%-15% 综合征，常染色体显性遗传性甲状旁腺功能减退，以及某些形式的高钙和低钙血症。此外， 这种方法可以用来调节疾病中G蛋白的活性，其中GPCR靶向药物是 由于受体冗余或引起剂量限制副作用的G蛋白无效，如 呼吸抑制或药物耐受。 直接针对特定G蛋白亚类的生物可用抑制剂将是非常有价值的 为了基础科学。它们将提供简单、快速、廉价和可靠的化学探针来识别 G蛋白在正常生理和疾病动物模型中的新功能 击倒或击倒战略，这是缓慢和昂贵的，可能受到补偿或关闭- 目标效果。 这个项目的基础是一对几乎相同的、生物可用的、环状的天然脱脂肽 有效和选择性地抑制G蛋白α亚单位的GQ/11亚家族的产品。的具体目标 该项目将解决四个关键挑战：1)这些抑制剂的可获得性有限；2)缺乏抑制剂 可针对疾病组织进行慢性治疗的衍生物；3)对 抑制机制，这排除了针对其他G蛋白亚型的抑制剂的设计；以及4) 没有选择性地针对G蛋白亚型而不是GQ/11的抑制剂。将追求这些目标 通过使用创新的合成有机化学、基于计算的对接和缓蚀剂设计，单一的- 分子FRET、核磁共振、生化和基于细胞的G蛋白功能分析。

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.