Figure 5. PKA type II and PGE₂ inhibit p40phox activation in AMs by targeting PI3K/Akt.

AMs were pretreated with 1 μM PGE₂ or 160 μM PKA-RII agonist 6-MBC-cAMP (PKA-RII-a) (A–D) for 10 min and then were challenged with 50:1 IgG-K. pneumoniae for 15 min. Cells were lysed, and proteins were subjected to immunoblot analysis for total PKCδ and p-PKCδ (A), total p40phox and p-PAK (B), total ERK and p-ERK (C), and total Akt and p-Akt (D). Blots were analyzed by densitometry, and data are expressed as the percentage of kinase phosphorylation in cells stimulated with IgG-K. pneumoniae alone (black in A, C, and D). Data represent the mean ± se from at least 3 independent experiments (A, C, and D), and (B) is a blot from 1 experiment with relative densitometric ratios noted below the p-PAK band. ^#P < 0.05 versus untreated cells; *P < 0.05 versus IgG-K. pneumoniae alone. p, phospho; a, agonist.