Small Molecule Inhibitors of P. aeruginosa Quinolone (Pqs) Quorum Sensing

项目总结 铜绿假单胞菌喹诺酮(PQS)群体感应的小分子抑制剂 提交RFA-AI-11-009：选择革兰氏阴性病原体的靶向耐药性(R21/R33) 铜绿假单胞菌是一种机会性的革兰氏阴性病原菌，对公众健康构成重大威胁 医院感染方面的威胁，特别是对烧伤等免疫功能低下的患者 受害者、癌症患者和患有囊性纤维化或艾滋病的个人。铜绿假单胞菌对抗生素也很敏感。 抗性，既有内在机制，也有后天机制。因此，有很大的发展需要 针对未开发的靶点的新型抗假单胞菌药物，这是本次RFA的一个具体重点。 为了解决这个问题，我们在这里建议开发新的小分子抗菌药，靶向 铜绿假单胞菌喹诺酮(PQS)群体感应系统。这是一个经过药理学验证的靶点 小鼠感染模型，有别于酰基高丝氨酸内酯(LAS，RHL)群体感应系统。 喹诺酮类是由细菌生物合成的小分子，用于细胞间的信号传递。他们 控制多种细菌毒力因子基因的表达，这些基因与致病性有关，但 细菌存活或生长不需要的。因此，针对这种毒力因子的新型抗菌药是 与传统的杀菌和抑菌抗生素相比，被认为不太可能引起耐药性。 在三个参与实验室(Tan、Rahme、Pesci)之前广泛工作的基础上，我们将 利用基于机理和结构的合理药物设计开发PqsA、And的小分子抑制剂 催化铜绿假单胞菌喹诺酮生物合成关键步骤的邻氨基甲酰辅酶A合成酶。PqsA 已经在使用简单底物类似物的小鼠模型中被验证为有效的抗菌靶，但 为了充分发挥这一靶点的治疗潜力，需要更有效和更特异的抑制剂。在 R21阶段，我们将使用已经应用的合理设计策略合成第一代抑制剂 成功地与TAN实验室中的相关靶点结合，然后在生化和细胞分析中评估它们的活性 用于PqsA活性和喹诺酮生产，此前在Pesci和Rahme实验室建立。在R33公路上 阶段，我们将优化抑制剂的生化、细胞和药理特性来开发 随后将在已建立的铜绿假单胞菌小鼠模型中进行体内评估的先导化合物 拉姆实验室的感染。这种多学科协作包含以下方面的必要综合专业知识 合成有机化学、药物化学、生物化学、药理学和微生物学。我们的长- 学期目标是为进一步的临床前和临床评估开发一个或多个高级候选者，如 用于对抗铜绿假单胞菌和其他可能致病的革兰氏阴性细菌的新型抗生素。

PROJECT SUMMARY Small Molecule Inhibitors of Pseudomonas aeruginosa Quinolone (Pqs) Quorum Sensing Submitted for RFA-AI-11-009: Targeting Resistance in Select Gram-Negative Pathogens (R21/R33) Pseudomonas aeruginosa is an opportunistic Gram-negative pathogen that poses a significant public health threat in the context of nosocomial infections, particularly for immunocompromised patients such as burn victims, cancer patients, and individuals having cystic fibrosis or AIDS. P. aeruginosa is also prone to antibiotic resistance, through both intrinsic and acquired mechanisms. Thus, there is a great need for the development of novel anti-Pseudomonas drugs that address unexploited targets, and this is a specific focus of this RFA. To address this problem, we propose herein to develop novel small molecule antibacterials that target the P. aeruginosa quinolone (Pqs) quorum sensing system. This is a pharmacologically validated target in a mouse model of infection and is distinct from acyl homoserine lactone (Las, Rhl) quorum sensing systems. Quinolones are small molecules that are biosynthesized by the bacteria and used in cell-cell signaling. They control expression of a variety of bacterial virulence factor genes that are associated with pathogenicity but are not required for bacterial viability or growth. As such, novel antibacterials that target such virulence factors are thought less likely to elicit drug resistance compared to traditional bacteriotoxic and bacteriostatic antibiotics. Building upon extensive previous work from the three participating laboratories (Tan, Rahme, Pesci), we will use mechanism- and structure-based rational drug design to develop small molecule inhibitors of PqsA, an anthraniloyl-CoA synthetase that catalyzes an essential step in P. aeruginosa quinolone biosynthesis. PqsA has been validated as an effective antibacterial target in a mouse model using simple substrate analogues, but more potent and specific inhibitors are required to exploit fully the therapeutic potential of this target. In the R21 phase, we will synthesize first-generation inhibitors using a rational design strategy that has been applied successfully to related targets in the Tan lab, then evaluate their activities in biochemical and cellular assays for PqsA activity and quinolone production established previously in the Pesci and Rahme labs. In the R33 phase, we will optimize the biochemical, cellular, and pharmacological properties of the inhibitors to develop lead compounds that will then be advanced to in vivo evaluation in established mouse models of P. aeruginosa infection in the Rahme lab. This multidisciplinary collaboration comprises the necessary combined expertise in synthetic organic chemistry, medicinal chemistry, biochemistry, pharmacology, and microbiology. Our long- term goals are to develop one or more advanced candidates for further preclinical and clinical evaluation as novel antibiotics to combat P. aeruginosa and potentially other pathogenic Gram-negative bacteria.