FIGURE 5.

Estrogen exerts its inhibitory effects via ERβ but not ERα. The effects of estrogen receptor agonists on macrophage arginase activity were analyzed. Cells were precultured with E2 (nonspecific ER agonist), PPT (ERα-specific agonist) and DPN (ERβ-specific agonist) at the indicated concentration for 48 h and stimulated with IL-4 for another 24 h (A) or cocultured with Hepa1-6 (B). Values were expressed as means ± S.E. (error bars) (n = 6 from three separate experiments; *, p < 0.05 versus IL-4 treated group). C, Western blot analysis of total extracts from macrophages that were exposed to E2 (10 nm), ERα-specific agonist PPT (10 nm), and ERβ-specific agonist DPN (100 nm) for 24 h. Socs1 level was analyzed by immunoblotting after treatment with E2, DPN, and PPT. D, extracellular surface receptor CD206 of ANA-1 macrophage was detected by flow cytometry. Macrophages were pretreated with Estrogen receptor antagonist (ICI182,780) or siRNA to knock down ERβ (siESR2). The treatment in each group was independent from the others. siESR2 could abolish the inhibitory effects of estrogen.