昆虫肠道防御及微生物稳态维持机制

在长期的进化过程中,昆虫形成了独特的肠道防御系统,主要由物理屏障和免疫系统共同作用来抵御外来微生物的入侵。如大部分后生动物一样,昆虫肠道上皮细胞无时无刻不与微生物接触,其种类从有益的共生菌、随食物进入的微生物到影响宿主生命的病原菌。在这样一种复杂的环境中,为了实现防御肠道病原微生物的同时又能维持共生微生物稳定的目的,宿主肠道上皮细胞必须在免疫应激和免疫耐受之间保持一种稳态平衡。Duox-ROS免疫系统和免疫缺陷(immune deficiency,Imd)信号通路作为肠道免疫反应的基本途径,必然参与调节此过程。本文从昆虫肠道防御组成、肠道免疫信号通路作用分子机制以及肠道免疫系统在肠道微生物群落稳态维持中的作用的最新研究进展进行综述。

Intestinal defense system and mechanism of maintenance of microbiota homeostasis in insects

In the long-term evolution process, insects have formed a unique intestinal defense system. The combination of physical barrier and the immune system resists invasive microbes. Alike most metazoans, the guts of insects are in permanent contact with the microbial realm that includes beneficial symbionts, food-borne microbes and life-threatening pathogens. Thus, gut epithelium can tolerate a certain amount of commensal microbes proliferation for the beneficial gut-microbe interactions, accompanied by the proficient elimination of detrimental microbes. Based on the function of Duox-ROS system and immune deficiency pathway in the intestinal immune response, these immune systems are involved in the regulation of gut microbiota homeostasis. In this article, we reviewed recent advances in insect intestinal defense mechanisms, combined with the intestinal immune signaling pathways and the regulation mechanism of intestinal immune system on the gut microbiota homeostasis.