Fig. 1

IL-17 and TNF-α stimulation promotes migration and invasion in RA FLS but not OA FLS. a Human FLS from donors with RA were incubated with or without IL-17 (10 ng/ml) and TNF-α (10 ng/ml) for 1 h. Cell migration was measured using a transwell chamber after 23 h and visualized with crystal violet staining. b Following solubilization, the crystal violet dye was quantitated. Data represent the fold change of the optical density of crystal violet-stained cells stimulated with IL-17 and TNF-α compared to unstimulated control cells. c To analyze the intrinsic surface expressions of IL-17 or TNF receptors, FLS were stained using APC-conjugated anti-human CD217 (IL-17Ra), BV421 anti-human CD120b (TNF receptor type II), and mouse anti-human CD120a (TNF receptor type I) with FITC-conjugated anti-mouse IgG secondary antibody. The isotype control is represented by the dotted line. OA FLS were indicated by the black line and RA FLS were represented by the red line. These were analyzed by flow cytometry. d After RA or OA FLS were stimulated with or without IL-17 (10 ng/ml) and TNF-α (10 ng/ml) for 1 h, cell migration was analyzed using a transwell chamber after 23 h. e The migrated cells were solubilized and quantitated. f Following scratch assay, the migrated cells were photographed. g Cell invasion was evaluated using Matrigel-coated transwell chambers after 3 days. Each symbol represents an individual donor, and the bar represents the mean. Data represent one experiment, which was performed in triplicate with similar results. *p < 0.05. Scale bar, 100 μm. Magnification is × 100