Fig. 3.

Induction of IL-1Ra expression by poly(I:C)-mediated TLR3 activation is independent of IFN-β and proinflammatory cytokines. Human FLS were stimulated by poly(I:C) for 1, 3, 8, 24, 48, 72, or 96 h. The cells were harvested and the levels of IFN-β and IL-1Ra mRNA expression were measured by real-time PCR (a). Human FLS were stimulated with poly(I:C), IFN-β (10 ng/mL) and/or anti-IFN-β mAb (10 μg/mL) for 24 h (b). Human FLS were pre-treated with cycloheximide (10 μg/mL) for 1 h and stimulated by poly(I:C) for 24 h. The concentrations of IFN-β (c), IL-1Ra (b, d), and IL-6 (e) in the culture supernatants were determined with ELISA. The relative levels of IL-1Ra mRNA expression in different groups of cells were measured by real-time PCR (f). Upregulation of IL-1Ra expression is compared with the group without poly(I:C) and cycloheximide. Results are presented as mean ± SEM (n = 5 per group) from 3 separate experiments. * p < 0.05 vs. the group with poly(I:C) and vehicle. IL, interleukin; IL-1Ra, IL-1 receptor antagonist.