Contribution of the TLR3—TRIF axis in the IL-17A/polyI:C-provoked synergistic induction of gene expression.

<p>Transient transfection of BEAS-2B cells was performed using a TLR3 siRNA, a TICAM-1 siRNA or a random oligomer. At 24 hours after transfection, the transfection mix containing siRNAs was replaced with fresh LHC-9 medium. After 2 days from transfection, the cells were treated for 24 hours with IL-17A and/or polyI:C. mRNA levels of G-CSF, IL-8, TLR3, and TICAM-1were evaluated using quantitative real-time PCR. TLR3 siRNA (solid bars) attenuated its own mRNA level as compared with the random oligomer negative control (shadowed bars) (A). PolyI:C-induced G-CSF and IL-8 mRNA expression was suppressed by TLR3 siRNAs, and IL-17A/polyI:C-provoked synergistic induction was attenuated (B, C). TICAM-1 siRNA (solid bars) suppressed 80% of its own message compared with the negative control (shadowed bars) (D). PolyI:C-induced mRNA expression of G-CSF and IL-8 was suppressed by TICAM-1 siRNAs, and synergistic mRNA induction of G-CSF and IL-8 by co-treatment with IL-17A and polyI:C was significantly attenuated (E, F). All measurements were averaged from duplicate samples, and the experiment was repeated three times. * p < 0.001, siRNA vs. negative control. † p < 0.01, siRNA vs. negative control in polyI:C treatment. ‡ p < 0.01, siRNA vs. negative control in co-treatment with IL-17A and polyI:C. § p < 0.05, siRNA vs. negative control in polyI:C treatment.