Figure 7. Phosphatase activity of PP2A is decreased upon IV H1N1(M) infection.

A549 (a,c) or Calu-3 (d) cells were infected with IV H1N1(M) (MOI 5) for 0.5 h and super-infected with S. aureus 6850 (MOI 50) (a,c,d), in the presence of 1 μM (b,c) or 250 nM (d) OA and the solvent DMSO. Extracellular bacteria were removed by gentamicin treatment 3 h after bacterial infection (a,c,d), and then incubated with the inhibitor (c,d). A549 cells were incubated in the presence of 1 μM OA or solvent DMSO for 7.5 h (b). Cell lysates were subjected to PP2A activity assays according to the manufacturer’s instructions (a,b). IL-6 mRNA levels were measured in duplicates at 8 h p.i. (c,d). Means ± SD of three independent experiments are shown. Mock-infected samples (a), DMSO treated (b) or DMSO treated super-infected (c,d) cells were arbitrarily set as 100%. After normalisation, one-way ANOVA followed by Dunnett’s multiple comparison tests were performed for comparison between mock-treated and IV H1N1(M)-infected or IV H1N1(M)/S. aureus 6850 super-infected samples, control- and OA-treated samples (*p < 0.05, **p < 0.01, ***p < 0.001).