PERP-p53-MDM2反馈环路在肠炎沙门氏菌致鸭颗粒细胞凋亡的作用机制

鸭肠炎沙门菌伴随产蛋周期持续定植于卵泡颗粒细胞，引起卵泡退化，不仅影响鸭产蛋量，还会造成鸭蛋和水体污染。本课题前期发现肠炎沙门菌的效应蛋白SipC与鸭卵泡颗粒细胞（dGC）表面跨膜蛋白PERP相结合，感染肠炎沙门菌的dGCs差异表达基因高度富集在PERP-p53-MDM2信号通路，并发生凋亡，但具体调控机制不清楚。本项目将利用肠炎沙门菌的SipC缺失株感染dGCs，验证PERP对dGCs凋亡及PERP-p53-MDM2信号通路基因表达的影响；采用COIP-WB和ChIP技术检测PERP-p53-MDM2信号通路关键节点的互作方式，解析其基因表达的变化对dGCs凋亡的影响；深入探究PERP负反馈对p53-MDM2模块形成的机制。研究将有助于全面阐明PERP-p53-MDM2反馈环路在肠炎沙门菌感染dGCs致凋亡的调控机制，同时也可为降低鸭肠炎沙门菌感染，提高禽蛋的安全性提供一定的参考依据。

Salmonella enteritidis (SE) can be colonized persistently in the follicular granulosa cells and accompanied follicular degradation, which not only affect egg production, but also cause eggs and water pollution. Recently, we found SE effector protein SipC was combined with the surface transmembrane protein PERP of granulosa cells, differentially expressed genes between normal and SE-infected duck follicular granulosa cells were highly enriched in the PERP-p53-MDM2 signaling pathway and the apoptosis of granulosa cells. However, the specific regulatory mechanism was not clear. This project will focus on the effect of PERP on the apoptosis of dGCs and the downstream gene expression of PERP-p53-MDM2 signaling pathway will be confirmed by using the SipC deletion strain of SE. Firstly, the combination mode of key nodes of PERP-p53-MDM2 signal pathway will be detected by chromatin immunoprecipitation. And then gene overexpression and knockdown of key nodes of PERP-p53-MDM2 signal pathway will be used to regulate the genes transcription to investigate the change of upstream and downstream genes expression and the apoptosis of granulosa cells. Finally, co-immunoprecipitation and western blot will be used to explore the effect of PERP negative feedback regulation on the formation of p53-MDM2 module in order to elucidate the mechanism of PERP-p53-MDM2 feedback loop in the apoptosis of dGCs challenged by SE-infected. The results will provide a reference for reducing the infection of SE and improving the hygiene of eggs.