新型细菌成孔毒素抑制剂的设计、合成与活性评价

项目名称： 新型细菌成孔毒素抑制剂的设计、合成与活性评价

项目编号： No.21472114

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 环境科学、安全科学

项目作者： 郭忠武

作者单位： 山东大学

项目金额： 90万元

中文摘要： 近年来，随着耐药菌株的不断涌现，细菌感染再次成为人类健康的严重威胁，针对细菌感染的新药研发成为国际热点之一。许多细菌致病是由其分泌的成孔毒素所引起，成孔毒素因此成为研发抗菌新药的重要靶点。研究表明，气单胞菌溶素和CAMP因子等成孔毒素通过与宿主细胞表面的糖基磷脂酰肌醇（GPI）结合助其聚集成孔状低聚物，并自发地插入细胞膜中形成孔穴，从而破坏细胞的渗透屏障，导致反向离子交换和其他致命反应，最终杀死宿主细胞。因此，一种潜在抗菌新策略是发展基于GPI结构的新型毒素抑制剂来阻断成孔毒素与宿主细胞表面GPI的结合。本申请项目拟设计合成一系列GPI衍生物，探究其对成孔毒素与GPI结合的影响，发现成孔毒素抑制剂；同时发展一种以GPI荧光探针为基础的高通量筛选方法，用以评价毒素抑制剂的活性；此外，通过GPI修饰的脂质体模型、体外溶细胞、动物体内保护等实验，评价所设计毒素抑制剂的抗毒活性，并阐明其构效关系。

中文关键词： 细菌成孔毒素；抑制剂；GPI衍生物；抗菌活性；构效关系

英文摘要： With the insurgence of drug-resistant super bugs, bacterial infection has become once again one of the most important health problems worldwide in recent years. Consequently, studies directed at the development of new therapeutic strategies against bacterial infections have been immerging as a renascent subject. Many infectious bacteria cause diseases through the secretion of so-called pore-forming toxins.As the major virulent factors of these bacteria, pore-forming toxins have become a very attracting target for the development of novel antibacterial strategies. It has been further demonstrated that some of these toxins, such as aerolysin, CAMP factor and many others, bind to glycosylphosphatidylinositol (GPI) anchors present on the host cell surface to assist their formation of porous oligomers and then spontaneous insertion of the porous oligomers into the cell membrane to breach the cell permeability barrier, trigger adverse material exchanges, and finally cause cell death. As a result, a potential strategy for the treatment of related diseases is to develop new GPI-based inhibitors to prohibit the interactions between the pore-forming toxins and GPIs or GPI-anchored proteins on the host cell surface. This research project aims at the design and synthesis of a series of structurally well-defined GPI analogs as potential pore-forming toxin inhibitors and evaluation of their activities to inhibit the interaction between GPI anchors and pore-forming toxins, so as to find toxin inhibitors useful for the treatment of related diseases. In the meantime, new analytical methods will be developed for high throughput assays of toxin inhibitors using fluorescence-tagged GPI anchors as probes.Further more, the activities of these synthetic GPI analogs to inhibit GPI-toxin binding, inhibit the pore formation of toxins in lipid membrane and inhibit toxin-induced cytotoxicity will be investigated by using a GPI-decorated cell-mimic liposome model,by titration of toxin-induced hemolysis,and by protection of mice against bacterial infections and bacterial toxins.This research will not only yield novel pore-forming toxin inhibitors or promising lead compounds worthy further investigations but also provide with the structure-activity relationships (SARs) of GPI analogs as toxin inhibitors to guide further optimization of the inhibitor design. The results will have a major impact on antibacterial research.

英文关键词： Pore-forming bacterial toxin;Inhibitors;GPI derivatives;Antibacterial activity;Structure-activity relationship