Cytokine-induced beta cell pathophysiology is characterised by the induction of iNOS expression. Inhibition of iNOS expression protects beta cells from cytokine-mediated destruction. The development of vector-based shRNA strategies capable of stably suppressing iNOS expression may provide a novel platform to protect beta cells from cytokine toxicity. In this report the utility of lentiviral shRNA vectors to silence iNOS expression was evaluated with respect to insulinoma cell viability, the induction of iNOS expression and the accumulation of nitrite in a cytokine-induced beta cell toxicity model. Here, we report for the first time on the use of lentiviral vector-based shRNA delivery to efficiently suppress the IL-1 beta-mediated induction of iNOS expression, the accumulation of nitrite and provide significant protection against the cytotoxic effects of IL-1 beta exposure. Moreover, non-specific knockdown of endogenous beta cell nNOS did not occur. (c) 2007 Elsevier Inc All rights reserved.