在手术、创伤等应激状态下，神经内分泌的改变会引起肠道内条件致病菌绿脓杆菌发生表型变化成为侵袭力强的绿脓杆菌，继而发生细菌移位，导致肠源性脓毒症。研究发现，绿脓杆菌多重毒力调节子（MvfR）可通过细菌密度感应系统识别外部信号分子，如阿片类物质，造成绿脓杆菌表型变化。本项目进一步提出，绿脓杆菌MvfR可通过与吗啡结合，促进PA-IL生成，引起肠粘膜屏障功能损伤，从而触发肠源性脓毒症。.本研究采用CRISPR/Cas9系统及基因互补技术构建绿脓杆菌mvfR基因缺失突变菌株及基因互补菌株，通过体内外实验，进行绿脓杆菌的mvfR基因功能研究；从分子和细胞水平探讨绿脓杆菌MvfR及吗啡对绿脓杆菌PA-IL生成的作用；通过建立吗啡慢性释放的动物模型，探讨绿脓杆菌MvfR在肠粘膜屏障功能损伤及肠源性脓毒症中的作用；揭示肠源性脓毒症发生发展新机制，发现防治绿脓杆菌引起的肠源性脓毒症可能作用的分子药物靶标。

Following changes of environmental signals present in the gut during stress, opportunistic bacteria within the gastrointestinal tract, such as the gram-negative bacterium Pseudomonas aeruginosa, may pose a phenotypic change to pathogenic state. Opportunistic Pseudomonas aeruginosa may play a role in the development of bacterial translocation and gut-derived sepsis during stress. Multiple virulence factor regulator (MvfR) modulates the expression of multiple quorum sensing (QS)-regulated virulent states. In this study, we further assume that P. aeruginosa is activated to induce PA-IL production in respond to the opioid peptide morphine through MvfR, disrupting the intestinal epithelial barrier and triggering gut-derived sepsis..We investigated the effects of morphine on intestinal epithelial barrier dysfunction by using P. aeruginosa strain PAO1 as well as corresponding mvfR mutant and complemented strain. P. aeruginosa mvfR mutant was constructed by using CRISPR/Cas9, and then the complemented strain was constructed. TSB with morphine and without morphine was used, and then the experiment of bacterial motility was taken. Virulence expression in P. aeruginosa was examined in vitro by assessing expression of the PA-IL, a barrier disrupting protein. Additionally, mice were implanted with a slow release morphine or placebo pellet with and without intestinal inoculation of P. aeruginosa created by direct cecal injection. Levels of plasma cytokines, bacterial translocation to distant organs were determined 36h later. The demonstration of such effect would suggest a new mechanism for the development of gut-derived sepsis. Our results are helpful for preventing and combating gut-derived sepsis.