Figure 3

Signal tranducer and activator of transcription 3 (STAT3) mediates IL-17-induced Bcl-2 upregulation in synoviocytes in rheumatoid arthritis (RA). (A) IL-17 upregulated the expression of STAT3 in RA-fibroblast-like synoviocytes (FLSs). RA-FLSs (n = 3) were cultured with IL-17 (0, 1 and 10 ng/ml) for 12 hours. The expressions of STAT3 and phosphorylated STAT3 (pSTAT3 705 and pSTAT3 727) were measured by western blot. The representative figure is shown in the left panel. Data are expressed as mean ± SD of three independent experiments. *P < 0.05, **P < 0.01 compared with the untreated group. (B) RA-FLSs (n = 3) were cultured with IL-17 (0 and 10 ng/ml) in the presence or absence of STAT3 inhibitor (STA21 50 μM) for 12 hours. The expression of Bcl-2 mRNA and protein was evaluated by real-time PCR and western blot. (C) Co-localization of STAT3 and Bcl-2 in rheumatoid synovium. Tissue sections from the synovium of patients with RA (n = 3) or osteoarthritis (OA) (n = 3) were stained with anti-Bcl-2, anti- pSTAT3 727 and anti-pSTAT3 705 antibodies. Co-localization of STAT3 and Bcl-2 was observed in synovial lining cells of RA patients. The representative figure is shown.