Figure 3

Inhibition of the NF-κB pathway eliminates the proinflammatory effects of FSTL1. (A) FLSs cultured in a 6-well plate were pretreated with BAY 11–7082 for 1 hour before addition of FSTL1, and then incubated with FSTL1 or vehicle (PBS solution) for 48 hrs. The relative levels of TNF-α, IL-1β and IL-6 mRNA were analyzed by real-time PCR as in Figure 1. (B-D) Cell supernatants were collected, and TNF-α, IL-1β and IL-6 concentrations were evaluated by ELISA. All results are presented as mean ± (standard deviation) SD of three independent experiments (each FLS cell line from an individual patient was used for each experiment). ^* P <0.05, ^** P <0.01, ^*** P <0.001, relative to the control or between groups as indicated, Student t test. ELISA, enzyme-linked immunosorbent assay; FLS, fibroblast-like synoviocyte; FSTL1, follistatin-like protein 1; IL-1β, interleukin-1β; IL-6, interleukin-6; NF-κB, nuclear factor kappa B; PBS, phosphate-buffered saline; PCR, polymerase chain reaction; TNF-α, tumor necrosis factor alpha.