Expression and function of fibroblast growth factor (FGF) 7 during liver regeneration

Previous studies have shown that fibroblast growth factors (FGFs) are involved in the process of liver injury repair. Liver regeneration after partial hepatectomy (PH) is impaired in transgenic mice expressing dominant-negative FGFR2b in hepatocytes. Although FGF7, a ligand specifically bound to FGFR2b, is expressed by activated hepatic stellate cells (HSCs) in fibrotic livers, the expressions and functions of FGF7 and FGFR2b after PH remain unexplored. Therefore, this study sought to examine the potential role of FGF7 signaling during liver regeneration.

We examined the expression of FGF7 and FGFR2b in normal and regenerating livers. Effects of FGF7 on hepatocytes were examined in vitro using primary hepatocyte culture with FGF7 recombinant protein and in vivo by hydrodynamic-based gene transfer method.

We found that FGF7 expression was increased according to the activation status of HSCs after PH. The receptor, FGFR2b, was also increased in hepatocytes during liver regeneration. In vitro treatment with FGF7 protein activated ERK1/2 and promoted proliferation of hepatocytes isolated from regenerating livers. In vivo overexpression of exogenous FGF7 could notably promote hepatic proliferation and activate MAPKs after PH.

This study suggests a role for activated HSC-expressed FGF7 in stimulating FGF signaling pathways in hepatocytes and regulating liver regeneration.