Fig. 4.

Effect of retinoic acid-inducible gene-I (RIG-I) knockdown on the expression of interferon (IFN)-γ-inducible protein-10 (IP-10) in cultured fibroblast-like synoviocytes. The cells were transfected with siRNA against RIG-I, and after 24 h the cells were treated with 2 ng/ml IFN-γ. The cells were incubated for additional 48 h, and culture medium and cell lysates were collected. The expression of mRNAs for RIG-I, IP-10 and monokine induced by IFN-γ were examined by reverse transcription–polymerase chain reaction (upper panel). The result of Western blot analysis for RIG-I was shown in the middle panel. The concentration of IP-10 in the culture medium was examined by an enzyme-linked immunosorbent assay (lower panel). Means ± standard deviation (n = 3) are shown. *P < 0·01. GAPDH, glyceraldehyde-3-phosphate dehydrogenase, ELISA, enzyme-linked immunosorbent assay.