Lycorine alleviates intrahepatic cholestasis by reducing the accumulation of bile acids via TKT/ATF3 pathway

Cholestatic liver disease (CLD) is characterized by the dysfunction of bile synthesis and excretion, leading to progressive liver injury or fibrosis, but lacks effective treatment drugs. Lycorine, an alkaloid isolated from Lycoris bulbs, possesses antiviral, anti-inflammatory, analgesic, cardioprotective activities. However, there has been no report concerning its effects on CLD so far. We evaluated the hepatoprotective effect of lycorine on intrahepatic cholestasis mouse models induced by a-naphthylisothiocyanate (ANIT) or after multidrug resistance protein 2 knockout (Mdr2-/-). RNA-Sequencing (RNA-Seq), cellular thermal shift assay (CETSA) and mass spectrometry analysis were used to investigate the regulated molecular mechanism of lycorine. Lycorine alleviated intrahepatic cholestasis by decreasing the expression of activating transcription factor 3 (ATF3), and inhibiting the nuclear accumulation of unphosphorylated ATF3, a transcription repression factor of the bile salt export pump (BSEP) responsible for bile acid (BA) secretion. Additionally, lycorine bound with transketolase (TKT) protein directly and promoted its ubiquitination degradation, disrupting the interaction between TKT and ATF3, resulting in the increased interaction between Rho-associated protein kinase 1(ROCK1) and ATF3 and subsequently BSEP transcription repression. Conclusively, our results shed light on the protective effects and mechanisms of lycorine against CLD, which pave way for the design of novel clinical therapeutic strategies. Overall design: To investigate how lycorine regulates intrahepatic cholestasis, we conducted RNA sequencing (RNA-seq) on the Mdr2 knockout mouse livers treated with vehicle or lycorine.