Exploring the physicochemical properties governing compound efflux in Gram-negative bacteria

项目摘要 多重耐药感染是对全球健康的主要威胁，已经观察到 每一种临床使用的抗生素，甚至那些被认为是最后治疗方法的抗生素。进一步复利 抗菌素耐药性危机是缺乏新的抗生素进入流水线，特别是对葛兰素史克。 具有不透性外膜的阴性病原体，限制小分子积累，以及 混杂的外排泵，可以识别和排出细胞中的大多数小分子。一门基础科学 了解促进化合物积累和减少所需的良好化学性质 需要外排倾向来开发对革兰氏阴性菌具有全细胞活性的抗菌药 病原体。Hergenrother实验室的初步努力已经确定了 化合物在大肠杆菌中的渗透，并成功地应用这些指南将几种革兰氏阳性 广谱药物只能用抗生素。虽然这一策略提高了革兰氏阴性菌的抗菌活性， 复合外排仍然不利于疗效，并阻止这些导向物发展为有效的抗生素。 了解支配化合物识别和外流的物理化学性质是非常必要的 提供一种新颖的设计平台来设计候选药物的外排敏感性。这样做的目的是 建议确定定义革兰氏阴性细菌复合外排的参数，并应用这些参数 发现消除了有希望的抗菌候选药物的外排倾向。 这里提出的工作将建立在对~200种化合物的外流倾向的初步研究的基础上 利用一种新的基于LC-MS/MS的蓄积分析(外流倾向评估(EXCL))，它可以 检测外排敏感性的微小变化，而不考虑抗菌活性和化学信息模型 它可以准确地将50%的化合物分类为外排底物和非底物。在具体目标1中， 用随机森林模型确定对复合外流具有重要意义的附加物理化学性质 将通过合成一个有针对性的并列比较文库来进行探索。这些化合物将是 添加到化合物合成、排泄试验和化学信息模型的数据集和迭代循环中 将执行验证。利用排泄试验和经鉴定与以下各项相关的初始性质 将探索一种激动型Fabi抑制剂的外排比，以确定有希望的抗菌药 减少特定目标的外排倾向2.将探索这些化合物的治疗潜力 通过毒性研究、药代动力学测定和对小鼠感染的疗效评估 模特们。具体目标1和2将同时进行，这些研究的完成将产生重大影响 抗菌研究和药物在抗菌临床流水线中的磨损点。

Project Summary Multi-drug resistant infections are a major threat to global health and resistance has been observed for every clinically-used antibiotic, even those considered to be the last lines of treatment. Further compounding the antimicrobial resistance crisis is the lack of new antibiotics entering the pipeline, particularly for Gram- negative pathogens which have an impermeable outer membrane, limiting small molecule accumulation, and promiscuous efflux pumps, which can recognize and expel most small molecules from the cell. A basic-science understanding of favorable chemical properties required to enhance compound accumulation and decrease efflux propensity is needed to develop antibacterial candidates with whole-cell activity against Gram-negative pathogens. Initial efforts in the Hergenrother lab have identified the physicochemical traits needed for compound permeation in E. coli and successfully applied these guidelines to convert several Gram-positive only antibiotics to broad-spectrum agents. While this strategy improves Gram-negative antibacterial activity, compound efflux is still detrimental to efficacy and prevents development of these leads into potent antibiotics. It is imperative to understand the physicochemical properties governing compound recognition and efflux to provide a novel design platform to engineer efflux susceptibility out of drug candidates. The objective of this proposal is to identify the parameters that define compound efflux in Gram-negative bacteria and apply these findings to remove efflux liability out of promising antibacterial candidates. Work proposed herein will build upon preliminary studies of the efflux propensity of ~200 compounds utilizing a novel LC-MS/MS-based accumulation (Efflux Propensity EvaLuation (EXPEL)) assay which can detect small changes in efflux susceptibilities irrespective of antibacterial activity and a chemoinformatic model which can accurately classify 50% of compounds as efflux substrates and non-substrates. In Specific Aim 1, additional physicochemical properties determined important for compound efflux by the random forest model will be probed through synthesis of a targeted library of side-by-side comparisons. These compounds will be added to the dataset and iterative cycles of compound synthesis, EXPEL assay, and chemoinformatic model validation will be performed. Utilizing the EXPEL assay and the initial properties identified as correlating to efflux ratios, derivatives of an exciting FabI inhibitor will be explored to identify promising antibacterials with decreased efflux liabilities in Specific Aim 2. The therapeutic potential of these compounds will be explored through toxicity studies, determination of pharmacokinetic profile, and evaluation of efficacy in mouse infection models. Specific Aims 1 and 2 will run concurrently and completion of these studies will significantly impact antibacterial research and remedy attrition points in the antibacterial clinical pipeline.