Figure 6.

PADI4 inactivation induces FLS apoptosis. (A) RA-FLS transfected with sh-PADI4 and N-FLS transfected with Ad-PADI4 were cultured under hypoxia (1% O₂) for 3 days. Cell viability was measured by MTT. (B) FLS were stained with Annexin V-FITC (20 mg/ml) and PI (20 mg/l) under hypoxia for 5 days. Apoptosis was analyzed using flow cytometry. Data represent 3 independent experiments with presented as mean ± standard deviation. *P<0.01. Ad, adenovirus; FITC, fluorescein isothiocyanate; FLS, fibroblast-like synoviocytes; PADI4, peptidyl arginine deiminase type IV; PI, propidium iodide; RA, rheumatoid arthritis; sh, short hairpin RNA.