Effects of leptin on BSEP protein expression and signaling pathway in HepG2 cells / 中国病理生理杂志

ABSTRACT

AIM:To investigate the effects of leptin on the expression of bile salt export pump ( BSEP) and signaling pathway in human hepatocellular carcinoma cell line HepG2.METHODS: HepG2 cells were cultured in vitro. Leptin at concentrations of 10 -8 , 10 -7 and 10 -6 mol/L was used as a stimulating factor.The protein levels of adenosine monophosphate-activated protein kinase alpha subunit (AMPKa), phosphorylated AMPKa (p-AMPKa) and BSEP in the HepG2 cells at 24 h, 48 h and 72 h were detected by Western blotting.The optimal culture time and leptin concentration were selected, and compound C at concentration of 10 μmol/L was added to this group.The protein expression of BSEP was detected by Western blotting.RESULTS:Intervention of HepG2 cells with leptin for 72 h increased the protein ex-pression of AMPKa gradually in a concentration-dependent manner, and leptin at concentration of 10 -6 mol/L induced the strongest AMPKa expression ( P<0.01 ) .Intervention of HepG2 cells with leptin for 24 h increased the phosphorylation level of AMPKa gradually in a dose-dependent manner (P<0.01).The effect of leptin on the increase in the protein ex-pression of p-AMPKa was also in a time-dependent manner ( P<0.01) .After intervention with different concentrations of leptin for 24 h, the protein expression of BSEP in the HepG2 cells was gradually increased by the stimulation of leptin in a concentration-and time-dependent manner (P<0.01).Compared with NC group, the protein expression of BSEP in 10 -6 mol/L leptin group and 10 -6 mol/L leptin+10μmol/L compound C group was increased at 72 h (P<0.01), and that in 10-6 mol/L leptin+10 μmol/L compound C group was lower than that in 10 -6 mol/L leptin group at 72 h ( P<0.01 ) . CONCLUSION:Leptin promotes the protein expression of BSEP in HepG2 cells by leptin-AMPK-BSEP signaling path-way.Leptin promotes the increases in AMPKa protein and the level of phosphorylation of AMPKa in HepG2 cells.