Expression of chemerin and ChemR23 by rheumatoid arthritis fibroblast-like synoviocytes. (A) and (B) Chemerin expression stimulated by TNF-α (A) or IFN-γ (B) and evaluated by ELISA using supernatants of cultured fibroblast-like synoviocytes (FLSs) isolated from synovial tissue samples taken from rheumatoid arthritis (RA) patients (n = 4). FLSs (2 × 104 cells/well) were stimulated at 37°C for 48 hours with TNF-α (0.1, 1 or 10 ng/ml) (A) or IFN-γ (1, 10 or 100 ng/ml) (A). Data in (A) and (B) are presented as means (± SEM) of one of four independent experiments analyzed in triplicate. *P < 0.05 relative to control. (C) through (E) Immunocytochemistry showing double-staining of cultured RA FLSs with (C) vimentin (D) ChemR23 and (E) a merged image of (C) and (D). (F) Western blot of ChemR23 protein expression in RA FLSs following TNF-α (10 ng/ml), IFN-γ (100 ng/ml), transforming growth factor (TGF)-β1 (1 ng/ml), IL-1β (5 ng/ml) or IL-6 (20 ng/ml) stimulation at 37°C for 24 hours.