Small molecule inhibitors of bacterial iron acquisition systems

细菌铁获取系统的小分子抑制剂

基本信息

批准号：
8891411
负责人：
HARRY L. MOBLEY
金额：
$ 39.48万
依托单位：
UNIVERSITY OF MICHIGAN AT ANN ARBOR
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-07-15 至 2017-06-30
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8891411
关键词：
Antibiotic Resistance Antibiotics Assimilations Attention Bacteremia Bacteria Bacterial Infections Binding Biological Biological Assay Biological Factors Blood Circulation Chemicals Complement Data Development Disease Dose Enzymes Escherichia coli Ferritin Fimbrial Adhesins Funding Gastroenteritis Gene Cluster Goals Grouping Growth Health Heme Hemoglobin Human Incidence Infection Investigation Ions Iron Iron Chelation Knowledge Licensing Life Mediating Outcome Pathway interactions Prevention Production Proteins Proteomics Public Health Quinolones Recurrence Research Respiratory System Respiratory tract structure Sampling Scourge Series Services Siderophores Site Structure Structure-Activity Relationship System Testing Therapeutic Agents Toxin Trimethoprim-Sulfamethoxazole Urinary tract Urinary tract infection Uropathogenic E. coli Vaccination Vaccines Virulence Woman Work antimicrobial antimicrobial drug base burden of illness cofactor combat cost counterscreen disability experience fitness follow-up heme-binding protein high throughput screening improved inhibitor/antagonist men novel pathogen pathogenic Escherichia coli prevent receptor resistant strain response small molecule small molecule libraries transcriptomics uptake vaccine development

项目摘要

DESCRIPTION (provided by applicant): The urinary tract is among the most common sites of bacterial infection and Escherichia coli is by far the most common species infecting this site. Infections are routinely treated with antibiotics including trimethoprim- sulfamethoxazole or quinolones. While vaccine development is in the pipeline, there are no vaccines currently licensed for use in the U.S. In the face of steadily climbing rates of antibiotic resistance and dramatic reduction in development of new antibiotics, isolation of novel small molecule antimicrobials are desperately needed. Lack of such new treatments will result in urinary tract infections (UTI) with multiply antibiotic-resistant strains that are untreatable. Using a series of unbiased screens including transcriptomic, proteomic, immunoproteomic, and qPCR assays, we have identified iron acquisition systems (siderophore- and heme- mediated) as vulnerable targets for inhibition and potential therapy. Our long-term research goal is to prevent and therapeutically treat UTIs in women and men. The objective is to identify and characterize small molecule inhibitors of iron uptake in gram-negative bacterial pathogens. In a pilot high throughput culture-based screen of 6298 compounds, we had an initial hit rate of 2.3% (147 compounds) [overall Z' factor=0.81 (avg Z' per plate=0.9), S/B=6, CV=6%] with a cutoff set at 3 SD below the negative control and inhibitory activity higher than 30%. Five hits were validated by counterscreens, dose response curves, and inhibition with fresh chemical samples. For one compound, data are consistent with inihibition of the TonB system as its target. Our central hypothesis is that specific small molecule inhibitors that do not depend on iron chelation can specifically block iron acquisition in bacteria. This discovery will drive biological investigationof the diverse iron acquisition mechanisms and complement our vaccination efforts using iron receptor protein targets. We will achieve our objective by completing the following specific aims: 1) Develop and implement a high throughput screen to identify small molecule inhibitors of iron acquisition by extraintestinal pathogenic Escherichia coli (ExPEC); 2) Conduct counter screens, validate hits using fresh chemical samples, and analyze structure-activity relationships (SAR) for small molecule inhibitors of ExPEC iron acquisition; and 3) Determine common targets used by iron acquisition pathways that are inhibited by each validated small molecule inhibitor. The expected outcomes of these aims will be to identify compounds and develop derivatives that arrest bacterial growth by preventing bacterial iron assimilation. The positive impact of these studies will be substantial. We will identify novel small molecule inhibitors of bacterial iron uptake from among 150,000 chemical compounds and 27,278 natural product extracts, validate these hits with fresh samples, and improve upon these products by assessment of derivatives. This knowledge will provide us with alternate therapeutic agents beyond existing antibiotics and potential vaccines to prevent this public health scourge in women with recurrent UTI and those susceptible to their first UTI.

描述（由申请人提供）：尿路是最常见的细菌感染部位之一，而大肠杆菌是迄今为止感染该部位最常见的物种。感染通常用抗生素治疗，包括甲氧苄啶-磺胺甲恶唑或喹诺酮类药物。虽然疫苗开发正在进行中，但目前在美国还没有获得使用许可的疫苗。面对抗生素耐药性比率稳步上升和新抗生素开发急剧减少的情况，迫切需要分离新型小分子抗菌药物。缺乏此类新疗法将导致尿路感染 (UTI) 出现无法治愈的多重耐药菌株。使用一系列通过包括转录组学、蛋白质组学、免疫蛋白质组学和 qPCR 检测在内的公正筛选，我们已确定铁获取系统（铁载体和血红素介导）作为抑制和潜在治疗的脆弱靶点。我们的长期研究目标是预防和治疗女性和男性的尿路感染。目的是鉴定和表征革兰氏阴性细菌病原体中铁吸收的小分子抑制剂。在对 6298 种化合物进行基于高通量培养的试点筛选中，我们的初始命中率为 2.3%（147 种化合物）[总体 Z' 因子 = 0.81（每板平均 Z' = 0.9），S/B=6，CV =6%]，截止值设置为低于阴性对照 3 SD，抑制活性高于 30%。通过反筛选、剂量反应曲线和新鲜化学样品的抑制作用验证了五次命中。对于一种化合物，数据与作为其目标的 TonB 系统的抑制一致。我们的中心假设是，不依赖于铁螯合的特定小分子抑制剂可以特异性阻止细菌中铁的获取。这一发现将推动对不同铁获取机制的生物学研究，并补充我们使用铁受体蛋白靶点的疫苗接种工作。我们将通过完成以下具体目标来实现我们的目标：1）开发并实施高通量筛选，以识别肠外致病性大肠杆菌（ExPEC）获取铁的小分子抑制剂； 2) 进行计数器筛选，使用新鲜化学样品验证命中，并分析 ExPEC 铁获取的小分子抑制剂的构效关系 (SAR)； 3) 确定被每种经过验证的小分子抑制剂抑制的铁获取途径所使用的共同目标。这些目标的预期结果将是识别化合物并开发衍生物，通过阻止细菌铁同化来阻止细菌生长。这些研究的积极影响将是巨大的。我们将从 150,000 种化合物和 27,278 种天然产物提取物中鉴定出细菌铁吸收的新型小分子抑制剂，用新鲜样品验证这些抑制剂，并通过评估衍生物来改进这些产品。这些知识将为我们提供现有抗生素和潜在疫苗之外的替代治疗药物，以防止患有复发性尿路感染和首次感染尿路感染的女性遭受这种公共卫生祸害。