Transforming growth factor beta regulates hepatic progenitor cells migration via PI3K/AKT/mTOR/p70S6K pathway

Abstract

Objective: To investigate the effect and mechanism of transforming growth factor β (TGFβ) on the migration ability of hepatic progenitor cells in vitro. Methods: Primary hepatic progenitor cells of male wild-type C57BL/6J mice were isolated by two-step perfusion method and stimulated with different concentrations of TGFβ .The morphological changes were observed under phase -contrast microscopy. The effects of TGFβ on migration ability of hepatic progenitor cells were evaluated by scratch test and transwell method. Expression profiling and signaling phospho antibody array detected the signaling pathways involved in the regulation of TGFβ on hepatic progenitor cells. Protein level of PI3K/AKT/mTOR/p70S6K signaling pathway and the localization of each signaling molecules in hepatic progenitor cells were detected. Data comparison between the two groups was performed by independent sample t-test. One-way ANOVA was used for data comparison between multiple groups. Results: TGFβ made the liver progenitor cells from oval to long spindle type. Scratch test showed that the scratch healing rates of 24 h control group, and 2 ng/ml and 10 ng/ml TGF-beta groups were 36.48% ± 4.37%, 57.35% ± 4.60%, and 73.14% ± 5.02% (F = 65.87, P < 0.01), respectively. Transwell test showed that the number of migrating cells in 24 h control group, 2 ng/ml and 10 ng/ml TGF-beta groups were 127 ± 16, 230 ± 18, and 385 ±36 (F = 94.99, P < 0.01), respectively. The results of expression profiling showed that TGFβ regulates gene expression in hepatic progenitor cells, and differentially expressed genes participate in the PI3K-AKT signaling pathway. Signaling phospho antibody array and western blot showed that TGFβ regulated PI3K/AKT/mTOR/p70S6K signaling pathway in hepatic progenitor cells. Concurrently, immunofluorescence assay showed phosphorylation (p) 70s6k, p AKT1 and PI3K and F-actin co-localizations. Conclusion: TGFβ can promote hepatic progenitor cell migration through PI3K/AKT/mTOR/p70S6K pathway, and p70S6K, pAKT1 and PI3K signaling molecules are involved in the regulation of morphology and migration of liver progenitor cells.