Figure 3. Synthesis of NO is potentiated by overexpression of miR-21, and reduced by knockdown of miR-34a in the presence of cytokines. Cells (50 000 cells) were left untreated (A) or were exposed to IL-1β and IFN-γ for 24 h (B). Culture medium was retrieved and accumulated nitric oxide was determined using the Griess reaction. Results of 9 independent experiments are shown as means + SEM. Statistical significance was determined using a 2-way paired t test. ** P < 0.01 vs. miR-neg, *** P < 0.001 vs. miR-neg.