Transforming Growth Factor-beta signal responding in hepatic stem-like cells

Objective To investigate the effects of TGF-β on the expressions and distribution of phosphorated Smad2/3 and Smad7 in hepatic stem-like cells.Methods Using immunogold transmission electron microscopy,we observed the expressions and distribution of phosphorated Smad2/3,and Smad7 before and after TGF-β1(5 ng·mL-1)treatment for 4,8,and 24 hours in hepatic stem-like cells(WB cells).In addition,we also detected the apoptosis status after TGF-β1 stimulation by transmission electron microscopy.Results TGF-β1 stimulation can result in expression increasing of phosphorated Smad2/3 in WB cells,and reach the peak at 8 h,especially in the nuclear.After treatment with TGF-β1 for 24 h,the nuclear expression of phosphorated Smad2/3 gradually decreased.Additionally,we found that TGF-β1 treatment also contributed to increasing in protein level and alteration in cellular distribution of Smad7(translocation from the nucleus to the cytoplasm)in WB cells.Furthermore,we observed apoptotic body in WB cells after TGF-β1 treatment for 8 h.Conclusions These results indicate that TGF-β stimulation can alter the expression and cellular distribution of phosphorated Smad2/3 and Smad7 which are its downstream molecular,suggesting hepatic stem-like cells own intact responding to TGF-β.