hIAPP is formed in islet β cells, misfolded hIAPP results in the deposition inside the β-cells and shows a damage to the β-cells. The mechanism of hIAPP deposition after islet transplantation is mainly focused on non-immune factors and there is no report whether calcineurin inhibitors will increase hIAPP deposition after islet transplantation.Method
The stably expressing hIAPP INS-1(hIAPP-INS1) cells was established. The hIAPP-INS1 cells and its control were cultured with different concentrations of tacrolimus and cyclosporine A, respectively. The hIAPP mRNA expression was detected by quantitative RT-PCR (qRT-PCR). The deposition of hIAPP was stained by thioflavin S using fluorescent microscope and chemiluminescence detector. The proliferation activity was test by MTS. The GSIS (glucose stimulated insulin secretion) was measured by ELISA. The expression of JAK2, Foxa2 and hIAPP was detected when the cells were treated with tacrolimus. The change of hIAPP and the GSIS was investigated when the cells were then cultured with resveratrol.Results
The expression of hIAPP was obviously upregulated in hIAPP-INS1 cells. Compared with control, hIAPP-INS1 cells had a significant decrease in GSIS. There was a significant difference on proliferation activity, hIAPP expression and GSIS with the increase concentrations of tacrolimus in hIAPP-INS1 cells (P <0.05). However, there was no obvious difference on proliferation activity, hIAPP expression and GSIS with the increase concentrations of cyclosporine A in hIAPP-INS1 cells. In addition, tacrolimus stimulated Foxa2 expression to promote hIAPP deposition and resveratrol could degrade the deposition of hIAPP to protect hIAPP-INS1 cells.Conclusion
hIAPP impaired GSIS in hIAPP-INS1 cells. Compared with cyclosporine A, tacrolimus significantly induced hIAPP deposition, inhibited hIAPP-INS1 cell proliferation activity and impaired GSIS in hIAPP-INS1 cells. Tacrolimus increased the deposition of hIAPP through the JAK2/Foxa2/hIAPP signaling pathway and resveratrol protects against tacrolimus induced hIAPP deposition in hIAPP-INS1 cells.