Figure 4

Fisetin inhibits the maturation of IL-1β by suppressing the formation of the NLRP3 inflammasome. BV2 microglial cells were treated with the indicated concentrations of fisetin (0–5 µM) for 2 h prior to stimulation with 1 µg/mL LPS for 2 h and subsequent stimulation with 1 mM ATP (LPS/ATP). (A–C) Total RNA was extracted after 9 h of treatment and total proteins were extracted after 18 h, following which RT-PCR (top) and western blotting (bottom) were performed. Relative densities were calculated using ImageJ software. (D) In a parallel experiment, cell culture media were collected after 48 h and the extracellular levels of IL-1β were quantified using ELISA. The results indicate the mean ± standard error median (SEM), and is representative of the results obtained from three independent experiments. ^### p < 0.001 vs. untreated cells; *** p < 0.001, ** p < 0.01, and * p < 0.05 vs. LPS/ATP-treated cells.