ECSIT介导的线粒体ROS途径在拟穴青蟹血淋巴菌群稳态调控中的作用及分子机制

Unlike that in vertebrates, there exists a microbiota in hemolymph in invertebrates. It keeps not fully understood that what is the function and how does the host keep the hemostasis of the hemolymph microbiota in invertebrates. During our study, we found by chance that the diversity and composition of hemolymph microbiota was significantly changed when Ecsit in the innate immunity was knockdown in mud crab Scylla paramamosain. Meantime, Reactive Oxygen Species (ROS) in the mitochondria in mud crab was declined accordingly. The data suggested that ECSIT could maintain the hemostasis of the hemolymph microbiota by regulating the mitochondrial ROS. .Based on above mentioned research data, we plan to perform the further investigations of the changes of the diversity and composition of the hemolymph microbiota in Ecsit silenced crabs, the clearance of various pathogens and specificity of pathogenic clearing in Escit-involved pathway. In addition, the positive/negative regulators in ECSIT-TRAF6 complex of the mitochondria would be isolated. Furthermore, the diversity and composition of the hemolymph microbiota was also investigated after the knockdown of some negative regulator in our study. The project would be useful for the clarification of the novel effector for maintaining the hemostasis of the hemolymph microbiota in mud crab and enrichment of the theory of innate immunity in invertebrates. The project would also be helpful, in practice, for the prevention of diseases by managing the indigenous microbiota of the crab in crab aquaculture.

脊椎动物血液通常为无菌，而无脊椎动物却存在血淋巴菌群，目前关于血淋巴菌群的多样性及调控机制还知之甚少。我们发现，先天免疫系统中的Toll途径进化保守介导因子(Ecsit)被干扰后，青蟹血淋巴菌群数量显著上升及结构显著改变。进一步研究发现，Ecsit干扰组血细胞线粒体ROS显著下降。表明在青蟹中，ECSIT通过线粒体ROS的生成调控血淋巴菌群稳态平衡。项目在此基础上，拟进一步从Ecsit干扰后（ROS降低）血淋巴菌群的结构功能及青蟹病原清除能力变化，ECSIT-TRAF6复合体的调控蛋白筛选，负调控蛋白干扰后（ROS升高）的血淋巴菌群结构功能及病原清除能力变化等方面，深入揭示青蟹ECSIT介导的线粒体ROS途径在调控血淋巴菌群稳态平衡中的分子机制。研究结果理论上有助于阐明青蟹血淋巴菌群稳态平衡的调控机制，扩展无脊椎动物先天免疫的基础知识；实践上可为利用体内菌群平衡进行青蟹健康养殖提供参考。

脊椎动物血液通常为无菌，而无脊椎动物却存在血淋巴菌群，目前关于血淋巴菌群的多样性及调控机制还知之甚少。我们在建立虾蟹甲壳动物血淋巴菌群精确计数的基础上发现，青蟹血淋巴菌群的稳态平衡（即数量和结构）受到了ECSIT-TRAF6复合体通过ROS等途径的免疫调控。在国家基金的支持下，项目组聚焦与拟穴青蟹血淋巴菌群的调控机制，探讨血淋巴菌群与先天免疫的关系，获得了如下成果：1）阐明了能够抵抗副溶血弧菌感染并存活的青蟹（即存活组）的血淋巴菌群特征；2）阐明青蟹在不同ROS下的菌群结构，核心菌群，功能及代谢特性；3）已鉴定了ECSIT-TRAF6复合体的多个调控蛋白，并对其中的负调控蛋白HSP70进行了深入研究。4）阐明了由ROS介导的血淋巴菌群稳态平衡的分子机理，并在此基础上发现了外泌体通过miRNAs介导的线粒体ROS途径。研究结果有助于进一步阐明青蟹血淋巴菌群稳态平衡的调控机制，扩展了无脊椎动物先天免疫的基础知识；实践上可为利用体内菌群平衡进行青蟹健康养殖提供参考。