Abstract: The morbidity and moratily of chronic kidney disease (CKD) are increasing worldwide. Renal fibrosis is the result of almost all progressive renal diseases and is regulated by multiple signaling pathways. So far, there are few therapies targeting signaling pathways to slow down fibrosis. As a member of the basic helix／ring／helix per Arnt-sim (bHLH-PAS) superfamily, aromatic hydrocarbon receptor (AHR) is a ligand-dependent transcription factor widely expressed in many cell types and involved in many biological processes. The function of AHR is not fully understood, but it has been shown to play an important role in the progression of tissue fibrosis through its crosstalk with a variety of signaling pathways. Tryptophan metabolite, as a ligand of AHR, can promote the formation of renal fibrosis. Studies have confirmed that drugs targeting tryptophan metabolism can regulate fibrosis through AHR and signaling pathways, opening up a new way for the treatment of renal fibrosis.

Key words: aryl hydrocarbon receptor, signaling pathways, renal fibrosis, tryptophan metabolites