RÉSUMÉ
Hepatotoxicity induced by bioactive constituents in traditional Chinese medicines or herbs,such as bavachin(BV)in Fructus Psoraleae,has a prolonged latency to overt drug-induced liver injury in the clinic.Several studies have described BV-induced liver damage and underlying toxicity mechanisms,but little attention has been paid to the deciphering of organisms or cellular responses to BV at no-observed-adverse-effect level,and the underlying molecular mechanisms and specific indicators are also lacking during the asymptomatic phase,making it much harder for early recognition of hepatotoxicity.Here,we treated mice with BV for 7 days and did not detect any abnormalities in biochemical tests,but found subtle steatosis in BV-treated hepatocytes.We then profiled the gene expression of hepatocytes and non-parenchymal cells at single-cell resolution and discovered three types of hepatocyte subsets in the BV-treated liver.Among these,the hepa3 subtype suffered from a vast alteration in lipid metabolism,which was characterized by enhanced expression of apolipoproteins,carboxylesterases,and stearoyl-CoA desaturase 1(Scd1).In particular,increased Scd1 promoted monounsaturated fatty acids(MUFAs)syn-thesis and was considered to be related to BV-induced steatosis and polyunsaturated fatty acids(PUFAs)generation,which participates in the initiation of ferroptosis.Additionally,we demonstrated that mul-tiple intrinsic transcription factors,including Srebf1 and Hnf4a,and extrinsic signals from niche cells may regulate the above-mentioned molecular events in BV-treated hepatocytes.Collectively,our study deciphered the features of hepatocytes in response to BV insult,decoded the underlying molecular mechanisms,and suggested that Scd1 could be a hub molecule for the prediction of hepatotoxicity at an early stage.