FTY720 inhibits the activation of pancreatic stellate cells by promoting apoptosis and suppressing autophagy via the AMPK/mTOR pathway

Aims: Pancreatic stellate cells (PSCs) play a critical role in the development of pancreatic fibrosis. Any agents that can affect PSC activation could become potential candidates for treating pancreatic fibrosis. FTY720 can attenuate chronic pancreatic fibrosis by suppressing T-cell infiltration, but its effect on PSCs remains unknown. This study was conducted to investigate the effects of FTY720 on PSC activation in cultured rat PSCs.

Main methods: The viability of PSCs after FTY720 treatment was detected by MTT. Cell proliferation and migration analysis was performed using the iCELLigence System and a Transwell assay. Cell Apoptosis was assessed by flow cytometry, western blot and an activity assay. The mitochondrial membrane potential (MMP) was assessed by JC-1 staining. The expression of α-SMA, collagen I, fibronectin, Beclin-1, Atg5, p62 and LC3B were analysed by immunofluorescence, quantitative Real-Time PCR and western blot. Rapamycin and phenformin hydrochloride were used to determine whether FTY720 inhibits PSC Autophagy by the AMPK/mTOR pathway.

Key findings: FTY720 supressed PSC viability, proliferation and migration. FTY720 inhibited PSC activation, induced PSC Apoptosis and supressed PSC Autophagy. We also confirmed that FTY720 inhibited PSC Autophagy via the AMPK/mTOR pathway.

Significance: Our results indicated that FTY720 inhibited PSC activation by promoting cell Apoptosis and inhibiting PSC Autophagy by suppressing AMPK and activating the mTOR pathway. These findings may explain the therapeutic mechanisms of FTY720 in treating pancreatic fibrosis and further suggest that targeting Autophagy and the related signalling pathways may provide new strategies for the treatment of pancreatic fibrosis.