Figure 4.

Monosodium urate (MSU) and H₂O₂ elicit IL-1β without inducing ASC speck formation. Cells were transfected and stimulated for NLRP3 activation as described in the Methods: Inflammasome Activation. (A) IL-1β processing and speck formation exhibits positive correlation in nigericin-stimulated cells. (B) Unlike speck formation, IL-1β processing is dependent on NLRP3 in F novicida U112-infected cells. (C) IL-1β and speck formation shows no correlation in H₂O₂-treated cells. H₂O₂-treated cells do not induce speck formation. (D) IL-1β and speck formation shows no correlation in MSU-treated cells. MSU-treated cells do not induce speck formation. (E) Time-course analysis of H₂O₂-treated IL-1β processing in inflammasome-reconstituted HEK293T cells. (F) Cells were treated with 5 µm nigericin (red) or 100 µM H₂O₂ (blue) for 1 h and analyzed for ASC speck+ cells by TOFIE. (G) Cells were treated with either 5 µm nigericin (red) or 150 µg/ml MSU (cyan) for 1 h and analyzed for ASC speck+ cells by TOFIE. Data represented as mean ± SEM for a minimum of three independent experiments (A–E). Data represented as mean ± SEM for two independent experiments (F, G). *p < 0.05, **p < 0.01, ***p < 0.001, ****p < 0.0001 for comparison with respective untreated; two-way ANOVA followed by Sidak’s multiple comparison tests.