Figure 4

Effect of metastatic tumor antigen 1 (MTA1) knockdown on monosodium urate (MSU) crystal-induced cytokine production in RAW264.7 cells. (A) Time course of the MSU crystal (1 mg/ml) induced increase in MTA1 and TG2 mRNA expression in RAW264.7 detected by RT-PCR. Quantification of RT-PCR analysis of MTA1 and TG2 mRNA expressions is also shown. (B) RT-PCR analysis of RAW264.7 cells transfected with MTA1 specific small interfering RNAs (siRNAs) for 48 h and stimulated then with or without MSU crystals (1 mg/ml) for 4 h. Quantification of RT-PCR analysis of MTA1, TG2, TGF-β1, IL-1β and TNF-α mRNA expressions. (C) Cells were stimulated with or without MSU crystals (1 mg/ml) for 36 h. The levels of TGF-β1, IL-1β and TNF-α in supernatants were collected and evaluated by ELISA. (D) In addition, MTA1 knockdown macrophages were also treated by MSU crystals (1 mg/ml) in the presence of recombinant TG2 (10 ng/ml) or IgG (10 ng/ml) for 36 h. The levels of TGF-β1, IL-1β and TNF-α in supernatants were collected and evaluated by ELISA. The results are expressed as the means ± SEM from three independent experiments (n ≧ 3, * = P < 0.05, ** = P < 0.01 compared with control (100%)).