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.

Gang Cao;Hua Miao;Yan-ni Wang;Dan-qian Chen;Xia-qing Wu;Lin Chen;Yan Guo;Liang Zou;Nosratola D.Vaziri;Ping Li;Ying-yong Zhao

School of Pharmacy,Zhejiang Chinese Medical University,No.548 Binwen Road,Hangzhou 310053,China;Faculty of Life Science&Medicine,Northwest University,No.229 Taibai North Road,Xi'an 710069,China;Beijing Key Lab for Immune-Mediated Inflammatory Diseases,Institute of Clinical Medical Science,Department of Nephrology,China-Japan Friendship Hospital,No.2 Yinghua East Road,Beijing 100029,China;Department of Internal Medicine,University of New Mexico,1700 Lomas Blvd NE,Albuquerque,NM 87131,USA;School of Food and Bioengineering,Chengdu University,No.2025 Chengluo Avenue,Chengdu 610106,China;Division of Nephrology and Hypertension,School of Medicine,University of California Irvine,1001 Health Sciences Rd,Irvine,CA 92897,USA

中国药理学报（英文版）

[1]Gang Cao;Hua Miao;Yan-ni Wang;Dan-qian Chen;Xia-qing Wu;Lin Chen;Yan Guo;Liang Zou;Nosratola D.Vaziri;Ping Li;Ying-yong Zhao-.Intrarenal 1-methoxypyrene,an aryl hydrocarbon receptor agonist,mediates progressive tubulointerstitial fibrosis in mice)[J].中国药理学报（英文版）,2022(11):2929-2945

Intrarenal,methoxypyrene,plantaginis,antagonising

aryl,hydrocarbon,receptor,mediates,tubulointerstitial,fibrosis,mice,Recent,studies,have,shown,that,endogenous,metabolites,via,AhR,signalling,pathway,TIF,pathogenesis,However,mechanisms,underlying,mediated,activation,poorly,characterised,this,study,conducted,untargeted,metabolomics,analysis,identify,significantly,altered,intrarenal,mouse,model,unilateral,ureteral,obstruction,UUO,found,levels,MP,expression,its,CYP1A1,CYP1A2,CYP1B1,COX,were,progressively,increased,obstructed,Weeks,Furthermore,these,changes,positively,correlated,NRK,52E,RAW,49F,cells,dose,dependently,upregulated,four,protein,nuclear,accompanied,by,collagen,SMA,fibronectin,well,downregulated,cadherin,Consistently,oral,administration,enhanced,activity,profibrotic,kidneys,effects,partially,inhibited,knockdown,treated,lines,addition,screened,identified,erythro,guaiacylglycerol,ferulic,acid,ether,GFA,which,was,isolated,from,Semen,new,antagonist,attenuated,Our,results,suggest,activates,thus,mediating,through,epithelial,mesenchymal,transition,macrophage,myofibroblast,crucial,contributes

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