Objective    To investigate the effect of chenodeoxycholic acid (CDCA

the natural agonist of nuclear receptor

farnesoid X receptor

FXR ) on the expression of human protein C (PC) in HepG2 cells and the underlying related mechanism.      Methods    After HepG2 cells were treated with FXR agonist CDCA at the doses of 25

50 or 75 μmol/L for 24 h

RT-PCR was used to detect the mRNA expressions of small heterodimer partner (SHP) and PC

and real-time PCR was employed for PC mRNA expression. ELISA was used to detect the concentration of PC in the supernatants of HepG2 cells. Transient transfection Luciferase report assay was performed to analyze the change of PC promoter activity after cotansfecting the plasmid VP-FXR expressing activated FXR into human embryo hepatocyte L02 cells.     Results    CDCA remarkably elevated SHP and PC mRNA expressions

and PC concentration in the supernatants in a dose-dependent fashion.  CDCA at 75 μmol/L increased the amount of PC secretion by (4.22±0.97) fold in comparison to those treated by DMSO. Activated FXR enhanced the activity of PC promoter up to about 2.90 fold comparing with control group in L02 cells.      Conclusion    CDCA can activate FXR

and result in the up-regulation of PC in HepG2 cells. The underlying mechanism may be involved in the activation of PC promoter.