摘要Recent studies have shown that endogenous metabolites act via aryl hydrocarbon receptor(AhR)signalling pathway in tubulointerstitial fibrosis(TIF)pathogenesis.However,the mechanisms underlying endogenous metabolite-mediated AhR activation are poorly characterised.In this study,we conducted untargeted metabolomics analysis to identify the significantly altered intrarenal metabolites in a mouse model of unilateral ureteral obstruction(UUO).We found that the levels of the metabolite 1-methoxypyrene(MP)and the mRNA expression of AhR and its target genes CYP1A1,CYP1A2,CYP1B1 and COX-2 were progressively increased in the obstructed kidney at Weeks 1,2 and 3.Furthermore,these changes were positively correlated with progressive TIF in UUO mice.In NRK-52E,RAW 264.7 and NRK-49F cells,MP dose-dependently upregulated the mRNA expression of AhR and its four target genes and the protein expression of nuclear AhR,accompanied by the upregulated protein expression of collagen I,a-SMA and fibronectin,as well as downregulated E-cadherin expression.Consistently,oral administration of MP in mice progressively enhanced AhR activity and upregulated profibrotic protein expression in the kidneys;these effects were partially inhibited by AhR knockdown in MP-treated mice and cell lines.In addition,we screened and identified erythro-guaiacylglycerol-β-ferulic acid ether(GFA),which was isolated from Semen plantaginis,as a new AhR antagonist.GFA significantly attenuated TIF in MP-treated NRK-52E cells and mice by partially antagonising AhR activity.Our results suggest that MP activates AhR signalling,thus mediating TIF through epithelial-mesenchymal transition and macrophage-myofibroblast transition.MP is a crucial metabolite that contributes to TIF via AhR signalling pathway.