Effect of inhibitors and mimics of miRNA-146a and miRNA-146b upon IL-1β–induced IL-8 and RANTES release. A549 cells were exposed to transfection reagent alone (blank), control inhibitor or mimic, miR-146a inhibitor or mimic and miR-146b inhibitor or mimic for 4 h and then exposed to either 1 ng/ml IL-1β (a,c) or the indicated IL-1β concentration (b,d) and the concentration of IL-8 and RANTES in the supernatant was determined at 6 h and 24 h, respectively. The results are expressed as the mean ± SEM of 3 individual samples and are representative of at least 3 independent experiments. * p < 0.05 versus time-matched (a,c) or concentration-matched (b,d) transfected controls.