Effect of the transforming growth factor-β1 signaling pathway in inducing the differentiation of hepatic progenitor cells

Abstract

Objective To investigate the effect of the transforming growth factor-β1( TGF-β1) signaling pathway on the differentiation of hepatic progenitor cells( HPCs). Methods HPC-E14. 5 cells were cultured in vitro and immunofluorescent staining was performed for identification. The cells were divided into control group( HPCs),HPCs + TGF-β1 group,and HPCs + SB431542 group. The cells in the HPCs + TGF-β1 group were treated with exogenous TGF-β1,and those in the HPCs + SB431542 group were treated with the TGF-β1 receptor inhibitor SB431542; after 72 hours of treatment,qRT-PCR and Western blot were used to measure the mRNA and protein expression of the stem cell marker alpha-fetoprotein( AFP),the hepatocyte marker albumin( Alb),and the cholangiocyte marker cytokeratin 19( CK19),and periodic acid-Schiff staining was used to evaluate function after differentiation. A one-way analysis of variance was used for comparison of continuous data between multiple groups,and the Dunnett's t-test was used for further comparison between two groups. Results The results of qRT-PCR showed that the control group had significantly higher mRNA expression of AFP than the other two groups( F = 128. 937,P < 0. 01),the HPCs + TGF-β1 group had significantly higher mRNA expression of CK19 than the other two groups( F =414. 467,P < 0. 01),and the HPCs + SB431542 group had the highest mRNA expression of Alb( F = 794. 929,P < 0. 01). The results of Western blot showed that the control group had significantly higher protein expression of AFP than the other two groups( F = 269. 000,P <0. 01),the HPCs + TGF-β1 group had significantly higher protein expression of CK19 than the other two groups( F = 93. 010,P < 0. 01),and the HPCs + SB431542 group had significantly higher protein expression of Alb than the other two groups( F = 1086. 000,P < 0. 01).Periodic acid-Schiff staining showed that the control group had a significantly smaller positive staining area than the other two groups( F =79. 251,P < 0. 05). Conclusion The TGF-β1 signaling pathway induces HPC differentiation into functional cholangiocytes; however,HPCs tend to differentiate into mature hepatocytes after the TGF-β1 signaling pathway is blocked. Such cholangiocytes and hepatocytes have the normal function of glycogen storage and synthesis and may participate in metabolic activities.