Fig. 4

GLS1 is upregulated in RA-FLS. a GLS1 protein levels in 4 OA-FLS and 4 RA-FLS were determined by immunoblotting. GAC is a splicing variant of GLS1. b Protein levels were calculated by phosphorimager analysis. Bars indicate mean ± SEM. *P < 0.05 by Mann-Whitney U test. c RA-FLS were stimulated with LPS (1 μg/ml), TNF-α (10 ng/ml), IL-1β (2 ng/ml), IL-17 (20 ng/ml), PDGF (10 ng/ml), and IL-6 (100 ng/ml) and sIL-6R (100 ng/ml), or PBS for 24 h, and the GLS1 mRNA levels were analyzed by real-time PCR (n = 8). Each experiment was performed in triplicate. Bars indicate mean ± SEM. *P < 0.05, **P < 0.01, versus PBS. GAC Glutaminase C, GAPDH glyceraldehyde-3-phosphate dehydrogenase, GLS glutaminase, IL interleukin, LPS lipopolysaccharide, OA-FLS fibroblast-like synoviocytes from osteoarthritis patients, PBS phosphate-buffered saline, PDGF platelet-derived growth factor, RA-FLS fibroblast-like synoviocytes from rheumatoid arthritis patients, sIL-6R soluble IL-6 receptor, TNF tumor necrosis factor