FIGURE 4.

Caspase-1 is required for cytosolic flagellin-induced iNOS expression. PMs or BMDM from C57BL/6 or caspase-1^−/− mice were stimulated with 3 μg/ml purified free (FLA-BS) or cytosolic (FLA-BSDot) flagellin from B. subtilis (A, B, and E) or flagellin from S. typhimurium (FliC or FliCDot, respectively) (C and D) in the presence or absence of z-YVAD-fmk (2 μm). After 24 or 5 h, iNOS expression was evaluated in cell extracts by Western blot (B, C, and D) or at transcriptional levels by real-time RT-PCR (E), respectively. IL-1β secretion was determined in culture supernatants by ELISA (A). Numbers represent the mean ± S.D. of triplicate samples. ***, p < 0.001 when compared with control group. ###, p < 0.001 when compared with FLA-BSDot group from caspase-1^−/− BMDM. Data are representative of three independent experiments.