特殊官能团导向的西沙海绵共附生微生物的代谢产物研究

The sponge associated microorganisms, which have been proposed to be the true source of marine natural products, are important for marine drug development. The supply problem is a bottleneck for marine drug development. It will be valuable if a sponge-derived natural product can be obtained from the fermentation of its associated microorganisms. The applicants try to develop a new way to explore the sponge associated microorganisms by integrating the new technologies of microbiology, organic chemistry, biosynthesis, gene engineering and bioinformatics. On the basis of structure information of sponge-derived secondary metabolites isolated from Xisha island, the halogen and isocyanides are selected as specific functionalities to probe microorganisms bank. Genome screening (halogenase, isocyanides synthetase) and silent genome expression (OSMAC, epigenetics, or ribosome engineering) are employed to ensuring the discovery of the target microorganism and target secondary metabolites. The project will lead to the discovery of a series of new secondary metabolites with halogens or isocyanides. The results will be useful in clarifying the relationship between sponges and microorganisms and will build a new way to solve the bottleneck problem of marine drugs. We will also pan to explore the protein target and the biosynthetic pathway of some new skeletons. The research will provide new candidates for marine drugs.

海绵共附生菌是海洋新药研发的优质资源，利用共附生菌产生海绵代谢产物对解决药源瓶颈问题具有重要意义。本项目拟将微生物学、化学、生物合成、基因工程和生物信息分析等技术集成创新，建立海绵共附生菌研究的新模式。在前期对两种西沙海绵主成分研究基础上，选择海绵和微生物共有的“卤素和异硫腈”为目标官能团，以海绵宿主的共附生菌种库为研究对象，通过寻找含相同官能团化合物的途径寻找产生菌，并从功能基因筛选（卤化酶、异硫腈合成酶基因保守序列）和隐形生物合成基因激活（OSMAC策略、表观遗传学和核糖体工程等）两个技术层面保证获得目标菌株和活性代谢产物。研究将获得一系列含特殊官能团的海洋天然产物，探讨微生物与宿主之间的互作关系，为解决海洋药物的药源瓶颈问题探索一条新途径。对新颖的小分子将进行蛋白作用靶点和生物合成研究，并通过代谢调控进行结构改造和构效关系探讨，为海洋新药研发提供新型先导化合物。

本项目围绕含有特殊官能团的海洋天然产物开展海绵等无脊椎动物与共附生微生物的研究，主要取得了以下研究进展：利用西沙海绵等无脊椎动物的采样，建立共附生菌种库200株左右，筛选目标菌株60株，目前已经发现了56个化合物，结构类型包括formamido型二萜、溴代酪氨酸生物碱、聚酮和甾体、cembranoid型二萜二聚物和cambrane-capnosane二萜杂合二聚体，其中新化合物24个。活性评价中，6个化合物具有显著的细胞毒活性，2个化合物能显著诱导CD3+ T细胞分化，3个化合物能够显著诱导CD3+ T细胞增殖，4个化合物能够显著提高CD4+/CD8+的比例。研究结果已发表SCI论文10篇，申请专利2项。研究结果将为海洋无脊椎动物与共附生微生物之间的化学物质联系提供科学参考，为利用共附生微生物途径解决海洋药物药源问题提供新尝试，为新型海洋活性先导化合物的发现提供科学依据。