The nuclear receptor REV-ERBα regulates coumarin hepatotoxicity via DBP-dependent repression of CYP2A5 in mice

Coumarin exhibit various biological activities, including anti-inflammatory, antioxidant and anxiolytic effects. However, its clinical application is restricted due to significant hepatotoxicity observed in multiple animal models. CYP2A5 is the primary enzyme responsible for metabolizing coumarin in the mouse liver, homologous to human CYP2A6.

Acute toxicity and pharmacokinetic investigations were conducted on Rev-erbα^-/- and wild-type mice following coumarin administration. The regulatory effects of REV-ERBα on CYP2A5 expression were assessed both in vivo and in vitro. Western blotting and qPCR were used to measure the protein and mRNA levels, respectively.

Firstly, coumarin-induced hepatotoxicity was mitigated in Rev-erbα^-/- mice. Secondly, the systemic exposure of coumarin was lowered in Rev-erbα^-/- mice compared with wild-type mice. Thirdly, deletion of Rev-erbα resulted in significant upregulation of CYP2A5 mRNA and protein expression in mice. REV-ERBα negatively regulated CYP2A5/2A6 expression in Hepa-1c1c7 and HepG2 cells. Furthermore, luciferase reporter and chromatin immunoprecipitation (ChIP) assays indicated that REV-ERBα modulated Cyp2a5 transcription and expression through the repression of DBP.

The knockout of Rev-erbα significantly reduces the hepatotoxicity of coumarin by modulating CYP2A5. This research underscores the potential of targeting the REV-ERBα/CYP2A5 axis as a novel strategy for reducing coumarin-induced hepatotoxicity.