Figure 3. PTPN11 expression in rheumatoid arthritis fibroblast-like synoviocytes is glucocorticoid responsive.

(A) After serum starvation for 24 hours, RA FLS were treated with increasing concentrations of dexamethasone (DEX) for 24 hours. PTPN11 mRNA expression was analyzed by qPCR, and results were normalized to GAPDH mRNA expression. Box-and-whisker plots depict median (line within box), 25th percentile and 75th percentile (bottom and top borders), and range of minimum to maximum values (whiskers) from 5 independent experiments with different rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) lines. Data were analyzed using Dunnett’s multiple comparisons test. (B) Female C57BL/6 mice (6–8 weeks of age) were administered 1 μg DEX or vehicle (n = 4 per group) by i.p. injection. Ptpn11 mRNA expression in ankle homogenates was measured after 24 hours by qPCR performed in triplicate. Box-and-whisker plots depict Ptpn11 expression normalized to Gapdh expression. Data were analyzed using the 2-tailed unpaired t test. (C) RA FLS were transfected with control siRNA or siRNA against glucocorticoid receptor (GR) mRNA. After 24 hours, RA FLS were serum starved for 24 hours and then cultured in the absence (left) or presence (right) of 100 nM DEX for 24 hours. qPCR was performed to assess transcript levels of GR and PTPN11. Results were normalized to GAPDH expression. Box-and-whisker plots depict 4 independent experiments with different RA FLS lines. Data were analyzed using the 2-tailed paired t test. (D) After serum starvation for 24 hours, RA FLS were treated with 100 nM β-estradiol (E2), 100 nM Cl-4AS-1, or 100 nM DEX for 24 hours. PTPN11 mRNA expression was analyzed by qPCR. Results were normalized to GAPDH mRNA. Scatter plot shows the mean ± SEM of 3 independent experiments with different RA FLS lines. Data were analyzed using the 2-tailed paired t test.