ML364作为新型广谱细菌毒力因子抑制剂的药效学及机制研究

细菌毒力因子抑制剂削弱细菌致病力的同时可延缓耐药性产生，是目前抗菌药物研发热点。但目前所研发的毒力因子抑制剂抗菌谱窄、适应症有限，远不能满足临床需求。因此本研究目的为研发广谱抗毒力因子药物。我们在前期筛选中获得了可同时抑制铜绿假单胞菌及金葡菌毒力因子的全新结构化合物ML364，其可显著提升耐药菌感染小鼠生存率。转录组结果显示，ML364主要影响了细菌的群体感应（QS）系统。而QS中的AI-2信号系统，为目前发现仅有的可跨革兰阳性与阴性菌不同种属毒力因子的调控系统。因此我们推测ML364可能通过干扰AI-2系统而发挥作用。为此拟利用哈氏弧菌、热蛋白质组学等研究ML364对AI-2信号系统的影响。同时，将研究ML364对不同种属菌株毒力因子的影响，并对其类似物进行构效关系分析，从而对化合物进行结构优化。最后，将对化合物安全性及体内药效学进行评价。期望本研究可为多重耐药细菌感染带来新的治疗策略。

Antivirulence agents can pose little threat to the survival of bacteria, weaken the pathogenicity of bacteria, and delay the development of bacterial resistance. The strategy of antivirulence has become one of the hotspots in the antibacterial discovery area. However, the currently developed antivirulence agents have a narrow antibacterial spectrum and limited indications, which would hardly meet the clinical needs. Therefore, our main purpose is to develop broad-spectrum anti-virulence agents that could target both gram-positive and gram-negative pathogens. We have obtained ML364, the novel lead compound, which could inhibit both pyocyanin and staphyloxanthin in high-throughput phenotypic screening. And the in vivo study showed that it could significantly improve the survival rate of systemically infected mice. Moreover, the transcriptome sequencing and enrichment analysis showed that the quorum sensing (QS) system of pathogens is mainly interfered with by ML364 treatment. To date, autoinducer-2 (AI-2) of the QS system is the only non-species-specific signaling molecule identified that is produced by many bacteria including both Gram-negative and Gram-positive species. Therefore, we will continue to investigate the influence of ML364 on the AI-2 signaling system by thermal proteome profiling, chemical genomics screening and Vibrio Campbellii MM32. And then we will further study the effects of ML364 on the production of major virulence factors in different species of bacteria. Moreover, the pharmacodynamics of analogs of ML364 will be studied, and structure-activity relationships (SAR) of such compounds will be analyzed. Finally, we will comprehensively evaluate the in vivo pharmacodynamics of the lead compounds by the maximal tolerable dose (MTD), cell proliferation assay and in vivo imaging of systemic infection mice. We hope this study would bring new strategies and ideas for combating multidrug-resistant bacteria.