Pro-inflammatory cytokines play a crucial role in the destruction of pancreatic beta-cells, thereby triggering the development of autoimmune diabetes mellitus. We recently developed a cell-permeable fusion protein, PEP-1-heme oxygenase-1 (PEP-1-HO-1) and investigated the anti-inflammatory effects in macrophage cells. In this study, we transduced PEP-1-HO-1 into INS-1 insulinoma cells and examined its protective effect against cytokine-induced cell death. PEP-1-HO-1 was successfully delivered into INS-1 cells in time- and dose-dependent manner and was maintained within the cells for at least 48 h. Pretreatment with PEP-1-HO-1 increased the survival of INS-1 cells exposed to cytokine mixture (IL-1 beta, IFN-gamma, and TNF-alpha) in a dose-dependent manner. PEP-1-HO-1 markedly decreased cytokine-induced production of reactive oxygen species (ROS), nitric oxide (NO), and malondialdehyde (MDA). These protective effects of PEP-1-HO-1 against cytokines were correlated with the changes in the levels of signaling mediators of inflammation (iNOS and COX-2) and cell apoptosis/survival (Bcl-2, Bax, caspase-3, PARP, JNK, and Akt). These results showed that the transduced PEP-1-HO-1 efficiently prevented cytokine-induced cell death of INS-1 cells by alleviating oxidative/nitrosative stresses and inflammation. Further, these results suggested that PEP-1-mediated HO-1 transduction may be a potential therapeutic strategy to prevent beta-cell destruction in patients with autoimmune diabetes mellitus. (C) 2015 Elsevier Inc. All rights reserved.