Figure 3

Treatment of microglia with IL4 increased TGFβ2 expression and secretion. Primary microglia were treated with or without IL4 (10 ng/ml) for 24 hours. Total mRNA and proteins were isolated from the cells for RT-PCR and western blotting, respectively. Conditioned medium from IL4-treated microglia (MCM-IL4) as well as non-treated microglia (MCM) was collected and the mink lung epithelial cell (MLEC) assay and enzyme-linked immunosorbent assay (ELISA) were performed. Quantitative RT-PCR for TGFβ1 (A), TGFβ2 (B) and TGFβ3 (C) revealed increased TGFβ2 expression after IL4 treatment. Intracellular TGFβ2 protein levels were significantly increased (P < 0.05) in primary microglia after treatment with IL4 (D). MLEC assay (E) shows that primary microglia secreted a certain amount of inactive TGFβ, which was significantly increased by IL4 treatment (P < 0.01). Direct TGFβ2 ELISA (F) showed that TGFβ2 secretion was significantly increased after IL4 treatment (P < 0.05). All experiments were repeated at least three times. Data are presented as mean ± standard error: *P < 0.05, **P < 0.01, ***P < 0.001(Student’s t-test).