FIG. 3.

Inhibition of p38 reduces TNF-α and LPS induction of Stx2 cytotoxicity. (B) HUVEC were treated with SB202190 (a p38 MAPK inhibitor) before or after induction and then challenged with Stx2. Details are as follows (A). For preinduction, one of the following was added to the cells for 40 min: 20 μM SB202190 or control medium. For induction one of the following was added to the cells for 24 h: SB202190, TNF-α, LPS, TNF-α plus SB202190, LPS plus SB202190, or control medium. For postinduction one of the following was added to the cells for 40 min: SB202190 or control medium. For challenge one of the following was added to the cells for 24 h: SB202190, 1 nM Stx2, SB202190 plus Stx2, or control medium. For the cytotoxicity assay after 24 h of incubation with Stx2, CCK-8 cell viability assays were performed, and the results were expressed as percentages of the viability of an identical treatment without Stx2; the error bars indicate standard deviations (n = 4). An asterisk indicates that the value is statistically significantly (P < 0.01) different from the value for samples not treated with SB202190. The data are representative of three independent experiments. The data obtained with a separate p38 MAPK inhibitor, SB203580, were similar.