Figure 6

TGFβ1-mediated enhancement of IL4-induced Arg1 expression is dependent on the mitogen-activated protein (MAP) kinase pathway. BV2 cells and primary microglia were treated with IL4 (10 ng/ml), TGFβ1 (1 ng/ml) and IL4/TGFβ1 in the presence or absence of the MAP kinase inhibitor PD98059 (10 μM) for 24 hours. Total proteins were isolated and used for electrophoresis and western blotting. Arg1 protein levels were analysed by densitometric evaluation and normalised to GAPDH. The expression levels of Arg1 after co-treatment with IL4 and TGFβ1 were reduced in the presence of PD98059 in both BV2 (A) and primary microglia (B). Quantification of Arg1 expression levels in primary microglia after different treatments (C). Data are presented as means ± standard error from three independent experiments: **P < 0.01, ***P < 0.001 (two-way analysis of variance).