Hepatic stem cell Numb gene is a potential target of Huang Qi Decoction against cholestatic liver fibrosis

Numb is a negative regulator of Notch signal pathway. Previous study has demonstrated that Notch signal pathway activation is required for hepatic progenitor cell (HPC) differentiating into cholangiocytes in cholestatic liver fibrosis (CLF), and Huang Qi Decoction (HQD) could prevent CLF through inhibition of the Notch signal pathway. However, the role of Numb in HQD against CLF is yet unclear. Thus, CLF rats transplanted into rat bone marrow-derived mesenchymal stem cells with knocked down Numb gene (BMSC(Numb-KD)) were treated with HQD. Simultaneously, Numb gene knockdown was also performed in WB-F344 cell line and then treated with refined HQD in vitro. In vivo study revealed that liver fibrosis was inhibited by HQD plus BMSC(Numb-KD) treatment, while Hyp content in liver tissue, the gene and protein expression of α-SMA, gene expression of Col I, TNF-α, and TGF-β1 were increased compared to that in HQD group. Furthermore, Notch signal pathway was inhibited by HQD plus BMSC(Numb-KD), while the protein expression of Numb was decreased and RBP-Jκ and Hes1 was increased compared to that in HQD group. In vitro, HQD reduced the differentiation of WB-F344 cells into cholangiocyte phenotype, while this effect was attenuated after Numb-knockdown. This study highlights that the absence of hepatic stem cell Numb gene decreases effect of HQD against CLF, which give rise the conclusion that Numb might be a potential target for HQD against CLF.