Novel Antimicrobials Targeting Bacterial Type IV Secretion Systems

描述（由申请人提供）：抗生素耐药性的日益流行正在损害我们治疗感染的能力。因此，这项应用的广泛而长期的目标是开发和建立一种新的治疗方法的原理证明，以病原体和宿主相互作用为目标。许多细菌病原体利用专门的分泌系统将毒力因子注入宿主细胞。这些系统对毒力是绝对必需的，因此提供了一个有希望的治疗靶点。该提案的目的是建立IV型分泌系统(T4SS) -此类注射器械的主要类别之一-作为抗菌治疗的靶点。为了鉴定T4SS的小分子抑制剂，我们最近使用模型病原体嗜肺军团菌完成了对23.5万个化合物文库的高通量筛选。在这里，我们建议对从这项筛选工作中获得的初步数据进行跟进，有三个具体目标。首先，研究人员提出了实验来表征先前鉴定的强筛选命中，以确认特异性，确定效力，并表征嗜肺乳杆菌，伯纳氏Coxiella burnetii和一系列更远的t4ss依赖性病原体的活性谱。其次，迭代结构-活性关系研究将用于识别具有增强药理潜力的类似物。在第三部分中，选择的小分子抑制剂的活性将在嗜肺乳杆菌、伯纳氏杆菌和巴尔通体感染的小鼠模型中进行体内表征。综上所述，这些实验应该为T4SS治疗及其作为一种新的人类治疗方法的潜在应用奠定理论基础。

DESCRIPTION (provided by applicant): The increasing prevalence of antibiotic resistance is compromising our ability to treat infection. Therefore, this application's broad, long-term objective is to develop and establish proof of principle for a new class of therapeutics targeting pathogen host interaction. Many bacterial pathogens use specialized secretion systems to inject virulence factors into host cells. These systems are absolutely required for virulence and therefore offer a promising therapeutic target. The aim of this proposal is to establish type IV secretion systems (T4SS) -- one of the major classes of such injection apparatuses - as a target for antimicrobial therapy. We recently completed a high throughput screen of a 235,000 compound library using the model pathogen, Legionella pneumophila, in order to identify small molecule inhibitors of T4SS. Here, we propose to follow up on preliminary data obtained from this screening effort with three specific aims. In the first, experiments are proposed to characterize previously identified, strong screening hits in order to confirm specificity, define potency, and characterize activity spectrum in L. pneumophila, Coxiella burnetii and a series of more distantly related T4SS-dependent pathogens. In the second, iterative structure-activity relationship studies will be used to identify analogues with the enhanced pharmacological potential. In the third, the activity of select small molecule inhibitors will be characterized in ivo in murine models of infection with L. pneumophila, C. burnetii, and Bartonella. Taken together these experiments should establish the theoretical basis for T4SS therapy and its potential use as a new human therapeutic.