Protective functions of peroxiredoxin-1 against cytokine-induced MIN6 pancreatic beta-cell line death

Abstract

Pancreatic beta-cells play a crucial role in glucose homeostasis, and the failure of these cells to function results in the development of type 1 diabetes (T1D). The MIN6 cell line, which closely resembles pancreatic beta-cells, was used to unravel the relationship between pancreatic beta-cell function and the antioxidant enzyme PRX-1. PRX-1 was knocked down in MIN6 cells using a shPRX-1 lentiviral construct, and a mixture of inflammatory cytokines was administered to challenge the MIN6 cells. Nitric oxide (NO) production and inducible NO synthase (iNOS) expression were elevated in shPRX-1 compared with the control. Also, shPRX-1 transduced cells showed higher levels of NF-kappa B nuclear translocation, suggesting that PRX-1 has a regulatory role in NF-kappa B nuclear translocation and iNOS expression. In correlation with NO levels, decreased anti-apoptotic gene Bcl-xl level and elevated pro-apoptotic gene Bim levels were observed in shPRX-1 cells compared with scramble, and cell viability decreased accordingly. A rescue experiment was performed subsequently using an iNOS inhibitor to confirm NO as the cause of cell death. Overall, the results of this study suggest possible protective roles of the antioxidant enzyme PRX-1 in the insulinoma cell line MIN6 and possibly in pancreatic beta-cells under T1D conditions.