FIG 5.

PepO-induced upregulation of miR-155 was mediated by the TLR2 signaling pathway. (A) Wild-type (WT) or TLR2-deficient PEMs were stimulated with medium, LPS (100 ng/ml), or PepO (1 μg/ml) for 24 h and then incubated with Staphylococcus aureus at a multiplicity of infection of 100, and the phagocytic bacteria were enumerated. (B) WT or TLR2-deficient PEMs were stimulated with medium, LPS (100 ng/ml), peptidoglycan (PGN) (5 μg/ml), or PepO (1 μg/ml) for 6 h, after which miR-155 transcripts were determined by PCR analysis. (C and D) After treatment with PepO for indicated times, SHIP1 (C) and CR3 (D) expression in WT or TLR2-deficient cells was analyzed by Western blotting and immunofluorescence assays, respectively. (E) PEMs were pretreated with LY294002 (20 μM), BAY7085 (20 μM), SB203580 (20 μM), or U0126 (20 μM) for 1 h and then incubated with PepO for another 6 h. miR-155 transcripts were determined by quantitative PCR. (F) WT or TLR2-deficient cells were treated with PepO for indicated times. The activation of Akt was analyzed by Western blotting. The data are shown as the mean ± SD (n = 3). *, P < 0.05; **, P < 0.01; ***, P < 0.001; ns, not significant.