Insulin Stimulates Goose Liver Cell Growth by Activating PI3K-AKT-mTOR Signal Pathway

Abstract

Background/Aims: Recent studies have suggested a crucial role for PI3K-Akt-mTOR pathway in regulating cell proliferation, so we hypothesize that insulin acts goose hepatocellular growth by PI3K-Akt-mTOR signal pathway. Because the physiological status of liver cells in vitro is different from that in vivo, a simplified cell model in vitro was established. Methods: Goose primary hepatocytes were isolated and incubated in either no addition as a control or insulin or PI3K-Akt-mTOR pathway inhibitors or co-treatment with glucose and PI3K-Akt-mTOR pathway inhibitors; Then, cell DNA synthesis and cell cycle analysis were detected by BrdU-incorporation Assay and Flow cytometric analysis; the mRNA expression and protein expression of factors involved in the cell cycle were determined by Real-Time RT-PCR, ELISA, and western blot. Results: Here we first showed that insulin evidently increased the cell DNA synthesis, the mRNA level and protein content of factors involved in the cell proliferation of goose primary hepatocytes. Meanwhile, insulin evidently increased the mRNA level and protein content of factors involved in PI3K-Akt-mTOR pathway. However, the up-regulation of insulin on cell proliferation was decreased significantly by the inhibitors of PBK-Akt-mTOR pathway, LY294002, rapamycin or NVP-BEZ235. Conclusion: These findings suggest that PI3K-Akt-mTOR pathway plays an essential role in insulin-regulated cell proliferation of goose hepatocyte.