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Figure 3 | Arthritis Research & Therapy

Figure 3

From: The metastatic tumor antigen 1-transglutaminase-2 pathway is involved in self-limitation of monosodium urate crystal-induced inflammation by upregulating TGF-β1

Figure 3

Cross-linking activity of transglutaminase 2 (TG2) attenuates monosodium urate (MSU) crystal-induced production of IL-1β. (A) RT-PCR analysis of IL-1β and TGF-β1 mRNA expression in WT and TG2-KO MEF cells stimulated with or without MSU crystals (0.1-2.0 mg/ml) for 4 h. Quantification of RT-PCR analysis of IL-1β and TGF-β1 mRNA expression is also shown. (B) Cells were stimulated with or without MSU crystals (2 mg/ml). The levels of IL-1β and TGF-β1 in supernatants were evaluated by ELISA at the indicated time points. (C) RT-PCR analysis of TG2, TGF-β1 and IL-1β mRNA expression in WT MEF cells stimulated with 2 mg/ml MSU crystals for the indicated time points in the presence of 30 μg/ml ZDON, an active-site inhibitor of TG2. Quantification of RT-PCR analysis of TG2, TGF-β1 and IL-1β mRNA expressions is also shown. (D) Cells were stimulated with MSU crystals (2 mg/ml) for 36 h in the presence of increasing concentrations of ZDON. The levels of TGF-β1 and IL-1β in supernatants were evaluated by ELISA. Mean control value of TGF-β1 (278.3 ± 18.2 pg/ml) and IL-1β (39.4 ± 5.9 pg/ml). (E) Quantification of RT-PCR analysis for IL-1β expression in WT and TG2-KO MEF cells stimulated with or without MSU crystals (2 mg/ml) for 4 h in the presence of increasing amounts of neutralizing anti-TGF-β1 or its isotype control antibody. (F) MEF cells were stimulated with MSU crystals (2 mg/ml) for 36 h in the presence and absence of neutralizing TGF-β antibody. IL-1β in supernatants was 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%)).

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