Selective modulation of bacterial chaperonins by targeting novel small molecule binding sites

通过靶向新的小分子结合位点选择性调节细菌伴侣蛋白

• 批准号: 9892222
• 负责人: Steven Michael Johnson
• 金额: $ 12.5万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 2017
• 资助国家: 美国
• 起止时间: 2017-05-01 至 2022-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9892222
• 关键词: Acinetobacter baumannii; Antibiotic Resistance; Antibiotics; Bacteria; Bacterial Antibiotic Resistance; Bacterial Infections; Binding; Binding Sites; Cells; Centers for Disease Control and Prevention (U.S.); Communicable Diseases; Data; Development; Enterobacter; Enterococcus faecium; Goals; Human; In Vitro; Incidence; Infection; Klebsiella pneumonia bacterium; Laboratories; Lead; Literature; Medical Care Costs; Mitochondria; Molecular Machines; Morbidity - disease rate; Multiple Bacterial Drug Resistance; Proteins; Pseudomonas aeruginosa; Research; Risk; Site; Staphylococcus aureus; Structure; Superbug; System; Tissues; Toxic effect; United States; chaperonin; combat; drug resistant pathogen; functional loss; inhibitor/antagonist; innovation; mortality; novel; novel therapeutics; outcome forecast; pathogen; proteostasis; side effect; small molecule; small molecule inhibitor; societal costs

PROJECT SUMMARY: The growing incidences of antibiotic resistance is epitomized by the emergence of six multi-drug resistant bacteria referred to as the “ESKAPE” pathogens: Enterococcus faecium, Staphylococcus aureus, Klebsiella pneumoniae, Acinetobacter baumannii, Pseudomonas aeruginosa, and Enterobacter species. Without research to develop new antibiotics that are effective against these drug resistant pathogens, we risk regressing to a pre-antibiotic era where infections were a leading cause of morbidity and mortality. To counter this threat, the long-term goal of this research is to develop new antibiotics that function by targeting bacterial GroEL chaperonin systems. GroEL is a centralized molecular machine that maintains the proper structure and function of hundreds of other proteins. Thus, targeting this one molecular machine will have the cascading effect of inhibiting hundreds of proteins at once, the functional losses of which bacteria will not be able to recover from. A caveat to this strategy is that human cells have a mitochondrial counterpart, called HSP60, and there remains the possibility of inhibitor cross-talk that could lead to toxic effects on host tissues. The central hypothesis is that the structural and functional divergence between bacterial and mammalian chaperonins, as well as other mammalian proteins, will allow the selective targeting of small molecule inhibitors for GroEL and bacteria without toxic side effects to human cells. This hypothesis has been formulated on the basis of well-established findings on chaperonin structure and function presented in the literature, and preliminary data for chaperonin inhibitors produced in the applicants' laboratories. In particular, human HSP60 functions as a single-ring oligomer, which removes many of the allosteric transitions that regulate the function of double-ring bacterial GroEL. In addition, preliminary data suggest there are multiple distinct binding sites on bacterial GroEL that compounds can interact with to block chaperonin function. Thus, the possibility of small molecules targeting these unique binding sites to selectively inhibit bacterial GroEL over HSP60 and other human proteins is high. The overall objective of this proposal is to identify these unique allosteric binding sites, elucidate the structural/functional mechanisms of action for molecules binding to these sites, and define the selectivity profiles for site-specific inhibitors in vitro and in cells. The rationale for the proposed studies is that delineating the precise structural/functional mechanisms of action of chaperonin inhibitors will permit the rational development GroEL-targeting antibiotic candidates. The approach is innovative because it proposes a unique and unexplored strategy of exploiting proteostasis machinery – specifically GroEL chaperonins – for killing infectious bacteria. Without a fundamental shift in strategy for treating infectious diseases, antibiotic resistance will continue to rise and the prognosis for surviving infection by these superbugs will continue to worsen. Therefore, the proposed studies will have significant impact because the research findings will open novel therapeutic strategies for a broad range of intractable infectious diseases.

项目概述：抗生素耐药性的发生率不断增加，这体现在六种抗生素耐药性的出现。 多重耐药菌称为“ESKAPE”病原体：屎肠球菌、葡萄球菌 金黄色葡萄球菌、肺炎克雷伯菌、鲍曼不动杆菌、铜绿假单胞菌和肠杆菌 物种如果没有研究开发出有效对抗这些耐药病原体的新抗生素， 我们有可能倒退到前抗生素时代，在这个时代，感染是发病率和死亡率的主要原因。到 为了应对这一威胁，这项研究的长期目标是开发新的抗生素， 细菌GroEL伴侣蛋白系统。GroEL是一个集中的分子机器， 其他数百种蛋白质的结构和功能。因此，以这一分子机器为目标， 一次抑制数百种蛋白质的级联效应，其中细菌的功能损失不会被破坏。 能够从中恢复。这种策略的一个警告是，人类细胞有一个线粒体对应物，称为 HSP 60，并且仍然存在抑制剂串扰的可能性，其可能导致对宿主组织的毒性作用。 核心假设是细菌和哺乳动物之间的结构和功能差异 伴侣蛋白以及其他哺乳动物蛋白质将允许小分子抑制剂的选择性靶向 对GroEL和细菌没有对人体细胞的毒副作用。这一假设是根据 基于文献中提出的关于伴侣蛋白结构和功能的明确发现，以及 在申请人的实验室中产生的伴侣蛋白抑制剂的初步数据。特别地，人HSP 60 作为单环寡聚体发挥作用，这消除了许多调节功能的变构转换 双环细菌GroEL。此外，初步的数据表明，有多个不同的结合位点， 这些化合物可以与细菌GroEL相互作用以阻断伴侣蛋白功能。因此， 靶向这些独特的结合位点的分子，以选择性地抑制细菌GroEL超过HSP 60和其他 人体蛋白质含量高。该提议的总体目标是鉴定这些独特的变构结合位点， 阐明与这些位点结合的分子的结构/功能作用机制，并定义 体外和细胞中位点特异性抑制剂的选择性概况。拟议研究的理由是， 描述伴侣蛋白抑制剂作用的精确结构/功能机制将允许 合理开发GroEL靶向抗生素候选物。该方法是创新的，因为它提出了一个 利用蛋白质稳定机制-特别是GroEL伴侣蛋白-进行杀伤的独特且未探索的策略 传染性细菌如果不从根本上改变治疗传染病的策略，抗生素耐药性 将继续上升，这些超级细菌感染存活的预后将继续恶化。 因此，拟议的研究将产生重大影响，因为研究结果将打开新的 广泛的难治性感染性疾病的治疗策略。