小肽转运载体1（PepT1）通过介导肠道细菌代谢产物胞壁酰二肽(MDP)的跨膜运输，对动物肠道细菌性炎症反应发挥着关键的调控作用。我们前期研究表明PepT1参与了MDP诱导的草鱼肠道炎症反应，但对其调控网络和作用机制尚不清楚。基于这一科学问题，本项目拟进一步通过干预草鱼肠道PepT1的功能，分析MDP刺激前后肠道形态、MPO活性和炎症因子水平的变化规律，在分子水平系统阐明PepT1对MDP诱导肠道炎症反应的调控作用；通过研究草鱼PepT1表达、肠道炎症水平、PepT1上游转录因子（NF-κB、STAT3等）及下游信号转导分子（NOD2、RICK等）之间的响应关系，解析草鱼PepT1在MDP诱导肠道炎症反应中的上游调控机制和下游信号转导途径。本研究不仅有助于理解PepT1在草鱼肠道细菌性炎症中的功能及MDP诱导肠道炎症反应的分子机制，同时还将为解析鱼类肠道炎症发生的机制提供理论基础。

The oligopeptide transporter 1 (PepT1) plays a crucial role in bacterial-induced intestinal inflammation through transport bacterial peptides muramyl dipeptide (MDP) into intestinal epithelial cells. We previously found that PepT1 was involved in MDP-induced intestinal inflammation of grass carp. However, their related regulation network and mechanism remain mysterious. Therefore, this project will further intervene the expression of PepT1 to clarify the regulation role of PepT1 in MDP-induced intestinal inflammation through the analysis of intestinal morphology, MPO activity and expression level of inflammatory cytokines at molecular levels. By analyzing response relation between the expression of PepT1, intestinal inflammation, upstream transcription factors (NF-κB and STAT3) and downstream signal transduction molecules (NOD2 and RICK), we will further reveal the upstream regulatory mechanism and downstream signaling pathways of PepT1 in MDP-induced intestinal inflammation. The approval and successful implementation of this project will not only contribute to understanding the function and molecular mechanisms of PepT1 in MDP-induced intestinal inflammation, but also provide a new insight into the mechanisms of intestinal inflammation in fish.