摘要Objective:To investigate the nutritional immunoregulatory mechanism of metabolites derived from CRISPR-dCas9-targeted activation of tryptophan(Trp)metabolic pathways in gut microbiota on the aryl hydrocarbon receptor(AhR)/interleukin-22(IL-22)pathway in dendritic cells(DCs),providing a theoretical basis for nutritional intervention in inflammatory bowel disease(IBD).Methods:The CRISPR-dCas9-VP64 system was used to activate tnaA and kynU,key genes in Trp metabolism,to construct engineered Escherichia coli K12 strains.These strains were co-cultured in vitro with mouse bone marrow-derived DCs,with an exogenous Trp intervention group included.Expression of pathway-related genes and proteins was assessed via qPCR,Western blot,and ELISA,while levels of the Trp metabolite indole-3-acetic acid(IAA)were measured using LC-MS.Results:The engineered bacteria effectively activated the Trp metabolic pathway,significantly upregulating tnaA and kynU gene expression and increasing IAA production.The combination of engineered bacteria and Trp significantly activated the AhR/IL-22 pathway in DCs,enhanced IL-22-mediated immune responses,and showed a strong positive correlation between IAA levels and the degree of pathway activation.Furthermore,the synergistic effect of engineered bacteria and Trp enhanced DC regulation of genes associated with the intestinal mucosal barrier.Conclusion:CRISPR-dCas9-mediated activation of gut microbiota Trp metabolism elevates IAA levels and specifically activates the AhR/IL-22 pathway in DCs,revealing a novel nutritional regulatory mechanism within the gut microbiota-immune axis and providing experimental support for targeted nutritional interventions in IBD.