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

描述（由申请人提供）： 铜绿假单胞菌是一种机会性革兰氏阴性病原体，其在医院感染的背景下构成重大的公共卫生威胁，特别是对于免疫功能低下的患者，如烧伤患者、癌症患者和患有囊性纤维化或AIDS的个体。铜绿假单胞菌也容易通过内在和获得性机制产生抗生素耐药性。因此，非常需要开发针对未开发目标的新型抗假单胞菌药物，这是RFA的一个具体重点。为了解决这个问题，我们在此提出开发靶向铜绿假单胞菌喹诺酮（Pqs）群体感应系统的新型小分子抗菌剂。这是在小鼠感染模型中的经验证的靶标，并且不同于酰基高丝氨酸内酯（Las，Rhl）群体感应系统。喹诺酮是由细菌生物合成的小分子，用于细胞-细胞信号传导。它们控制多种与致病性相关的细菌毒力因子基因的表达，但不影响致病性。 是细菌存活或生长所必需的。因此，与传统的细菌毒性和耐药性相比，靶向这些致病因子的新型抗菌药物被认为不太可能引起耐药性。 抑菌抗生素在三个参与实验室（Tan，Rahme，Pesci）的广泛先前工作的基础上，我们将使用基于机制和结构的合理药物设计来开发PqsA的小分子抑制剂，PqsA是一种邻氨基苯酰辅酶A合成酶，催化铜绿假单胞菌喹诺酮生物合成的重要步骤。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标，但是需要更有效和特异性的抑制剂来充分利用这种抑制剂的治疗潜力。 目标在R21阶段，我们将使用合理的设计策略合成第一代抑制剂，该策略已成功应用于Tan实验室的相关靶标，然后在Pesci和Rahme实验室先前建立的PqsA活性和喹诺酮生产的生化和细胞测定中评估其活性。在R33阶段，我们将优化抑制剂的生物化学，细胞和药理学特性，以开发先导化合物，然后在Rahme实验室建立的铜绿假单胞菌感染小鼠模型中进行体内评价。这种多学科合作包括合成有机化学，药物化学，生物化学，药理学和微生物学方面的必要综合专业知识。我们的长期目标是开发一种或多种先进的候选药物，用于进一步的临床前和临床评价，作为对抗铜绿假单胞菌和潜在的其他致病性革兰氏阴性菌的新型抗生素。 公共卫生相关性：铜绿假单胞菌是一种致病性细菌，对住院的免疫功能低下的患者如烧伤患者、癌症患者和患有囊性纤维化或AIDS的个体构成重大的公共卫生威胁。该项目的目标是开发新型抗菌药物，通过靶向称为群体感应的细菌过程来对抗铜绿假单胞菌感染，该过程与毒力和致病性相关，并且可能不太容易引发抗菌药物耐药性。

DESCRIPTION (provided by applicant): 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 virulenc 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. PUBLIC HEALTH RELEVANCE: Pseudomonas aeruginosa is a pathogenic bacteria that poses a significant public health threat to hospitalized, immunocompromised patients such as burn victims, cancer patients, and individuals having cystic fibrosis or AIDS. The goal of this project is to develop novel antibacterial drugs to combat P. aeruginosa infections by targeting a bacterial process called quorum sensing, which is associated with virulence and pathogenicity and may be less prone to eliciting antibacterial resistance.