Arthritic synovial fibroblasts have impaired adhesion and spreading on citrullinated fibronectin, but normal gelatin degradation. (A) Synovial fibroblasts derived from arthritic mice were plated on fibronectin (FN) or citrullinated fibronectin (FNC) and were imaged using time-lapse microscopy at 10× magnification. The percentage of cells attached in a 10× field was determined every 5 minutes. Graph depicts average and standard error at each time point (n = 3 experiments). (B) Synovial fibroblasts derived from the synovial fluid of patients with rheumatoid arthritis were plated on FN or FNC and imaged using time-lapse microscopy as in (A). Graph depicts average and standard error at each time point (n = 3 experiments). (C) Representative images of rheumatoid synovial fibroblasts plated on FN or FNC for 3 hours. Magnification is 20×. Bar = 100 μm. (D) Synovial fibroblasts from TNFα-overexpressing mice were plated on coverslips coated with fluorescent gelatin and either FN or FNC. After 4 hours, coverslips were fixed and stained for cortactin (a marker of invadopodia). Representative images of degrading cells are shown at 60× with the same field shown for both cortactin and gelatin. Bar = 20 μm. (E) Graph depicts the percentage of cells that showed areas of gelatin degradation. For each experiment, 100 cells were evaluated per sample (n = 3 experiments). *P < 0.05, **P < 0.01, ***P < 0.005.
Shelef et al. Arthritis Research & Therapy 2012 14:R240 doi:10.1186/ar4083