Fig. 4.

Effect of enzyme inhibition or siRNA on cytokine-induced iNOS protein production. p38α+/+ mouse embryonic fibroblasts (MEFs) (A[b]) or p38−/− MEFs (B[b]) were incubated for 4 h in the presence or absence of cytomix and the indicated enzyme inhibitors, after which whole-cell extracts were harvested and immunoblotted for iNOS, tubulin, and p38. C[b], INS-1 β cells were treated with siRNAs indicated for 72 h, and then exposed to cytomix for 4 h, after which extracts were subjected to immunoblot analysis for p38 and actin. D[b], INS-1 extracts subjected to RT-PCR for Nos2 mRNA. E, INS-1 extracts subjected to immunoblot for iNOS and actin. In panels C and E, the top panels show two representative immunoblots and the bottom panels show quantitation of the immunoblots from three experiments. *, P < 0.05 for the indicated value(s) in comparison with si-Control by Student's t test.