FIG. 7.

Involvement of p38 and p42/44 MAPK in the induction of NRAMP1 by LPS, TNF-α, and IL-1β. Adherent alveolar macrophages were pretreated for 30 min with PD98059 (1, 10, 50, or 100 μM) or SD203580 (0.5, 5, 20, or 50 μM) before being stimulated with 0.1 μg of LPS per ml for another 16 h. For inhibition of TNF-α- and IL-1β-induced NRAMP1 expression, 50 μM PD98059 or 20 μM SD203580 was used to pretreat cells for 30 min before stimulation for 16 h with the two cytokines, each at 10 ng/ml. An equal volume (1:1,000) of dimethyl sulfoxide, the solvent of MAPK inhibitors, was added to each well during incubation. Total RNA then was isolated, and 5 μg/sample was subjected to Northern analysis. After detection with NRAMP1, blots were stripped of the probe and then hybridized with the GAPDH cDNA probe. Results are expressed as a percentage of NRAMP1 expression according to the formula described in the legend of Fig. 6. Data are representative of two independent experiments with similar results.