TLR5 Antagonists for Infectious Disease Therapy

描述（由申请人提供）：在多种人类细胞类型上发现的保守toll样受体（TLR）家族在识别入侵病原体和启动有效的炎症免疫应答中发挥重要作用。这些受体中的每一种都与特定的微生物配体结合，并触发信号转导途径，导致编码促炎细胞因子、趋化因子和各种先天宿主防御分子的基因转录。TLR的激活对于动员先天免疫应答是至关重要的，先天免疫应答是许多细菌感染期间人类宿主的早期作用保护机制。然而，令人惊讶的是，相同的信号通路可能对宿主有害并加剧感染，通过引发过度和破坏性炎症引起广泛的组织破坏和细菌传播。这发生在某些急性和慢性感染中，包括囊性纤维化中的铜绿假单胞菌和洋葱伯克霍尔德菌感染以及铜绿假单胞菌和B。肺炎和败血症中的类鼻疽感染。一种这样的TLR配体是鞭毛蛋白，其是细菌鞭毛运动装置的组分，其被TLR 5识别。在初步研究中，这种鞭毛蛋白-TLR 5相互作用被证明是铜绿假单胞菌在小鼠肺炎模型中毒力、存活和传播的主要原因。本研究的总体目标是开发拮抗由TLR 5和鞭毛蛋白之间的相互作用引起的促炎信号通路的治疗剂。在第一阶段，一个敏感的全细胞测定将被应用于筛选鞭毛蛋白/TLR 5相互作用的拮抗剂的化合物库。在确认来自高通量筛选的命中后，将在二级测定中表征活性化合物以鉴定无毒且特异性干扰鞭毛蛋白-TLR 5信号传导途径的那些。将在铜绿假单胞菌感染模型中测试最有效的特异性抑制剂，其中肺定殖和向器官中的传播取决于该生物体的鞭毛蛋白表达。该I期项目的结果将提供体内验证的TLR 5拮抗剂，用于开发降低细菌性脓毒症和慢性感染的发病率和死亡率的治疗方法。

DESCRIPTION (provided by applicant): A family of conserved toll-like receptors (TLRs) found on a variety of human cell types plays an important role in recognition of invading pathogens and in mounting an effective inflammatory immune response. Each these receptors binds a specific microbial ligand and triggers a signal transduction pathway leading to transcription of genes encoding pro-inflammatory cytokines, chemokines and variety of innate host-defense molecules . Activation of TLRs is critical for mobilization of the innate immune response, an early acting protective mechanism for the human host during many bacterial infections. Surprisingly, however, the same signaling pathways can be detrimental to the host and exacerbate the infection, causing extensive tissue destruction and bacterial dissemination by provoking excessive and damaging inflammation. This occurs in certain acute and chronic infections, including Pseudomonas aeruginosa and Burkholderia cepacia infections in cystic fibrosis as well as P. aeruginosa and B. pseudomallei infections in pneumonia and septicemia. One such TLR ligand is flagellin, a component of the bacterial flagellar motility apparatus, which is recognized by TLR5. In preliminary studies, this flagellin-TLR5 interaction was shown to be the major cause of Pseudomonas aeruginosa virulence, survival, and dissemination in a mouse pneumonia model. The overall objective of this research is to develop therapeutic agents that antagonize the pro-inflammatory signaling pathways resulting from the interaction between TLR5 and flagellin. In Phase I, a sensitive whole-cell assay will be applied to screen libraries of compounds for antagonists of flagellin/TLR5 interaction. Following confirmation of the hits from the high throughput screen, the active compounds will be characterized in secondary assays to identify those which are non-toxic and which specifically interfere with the flagellin-TLR5 signaling pathway. The most potent, specific, inhibitors will be tested in a P. aeruginosa infection model, in which lung colonization and dissemination into organs depends on the expression of flagellin by this organism. The results of this Phase I project will provide in vivo validated TLR5 antagonists for the development of therapeutics to reduce morbidity and mortality in bacterial sepsis and chronic infections.