IL-33 stimulates ERK activation and cytokine release from mouse acinar cells.

<p>A) ERK is activated in mouse acinar cells following IL-33 stimulation, and this activation is inhibited by DN.ERK expression. Cells were infected with 5 MOI of Ad.EV or Ad.DN.ERK2 for 48 hrs and then stimulated with IL-33 (100 ng/ml) for 5 or 20 min. β-Actin expression was used as a protein loading control, while increased ERK expression verified overexpression of DN.ERK. Densitometric ratios of pERK to β-actin expression were normalized to unstimulated controls. B) IL-33 stimulation leads to increased CXCL2/MIP-2α release from mouse acinar cells which is inhibited by DN.ERK expression. Cells were infected with 5 MOI of Ad.GFP or Ad.DN.ERK2 for 48 hrs and then stimulated with IL-33 (100 ng/ml) for 6 hrs before collecting medium for ELISA analysis. CXCL2/MIP-2α levels in the medium were normalized to total protein in cells. Data are mean ± SEM; n = 3 wells/group; ANOVA, asterisk (*) indicates significance compared to unstimulated control, pound sign (#) indicates significance versus stimulated control and unstimulated control, p<0.05. (C & D) IL-33 stimulation of mouse acinar cells leads to increased: C) IL-6 release and D) CCL2/MCP-1 release. Cells were stimulated with IL-33 (25 ng/ml) for 6 hrs before collecting medium for ELISA analysis. Pretreatment with luteolin (10 µM) for 15 min inhibited both IL-6 and CCL2/MCP-1 release compared to untreated cells following stimulation. Data are mean ± SEM; n = 3 wells/group; ANOVA; asterisk (*) indicates significance compared to unstimulated control, p<0.05.