(A) HUVECs were treated with IL-33 (10−12 to 10−8 mol/L) for 30 min. IL-33-induced phosphorylation of JNK as evaluated by Western immunoblot analysis. Bars represent results from densitometric analyses of each phosphorylation signal after normalization to total protein and relative to conditioned medium (CM). Blots are representative of three independent experiments. *P <0.05 vs. CM. (B) HUVECs were pretreated with SP600125 (JNK inhibitor, 30 μmol/L) for 2 hrs, and then incubated with IL-33 (10−9 mol/L) for 30 min. Bars represent results from densitometric analyses of each phosphorylation signal after normalization to total protein and relative to untreated control. Blots are representative of three independent experiments. *P <0.05 vs. untreated control. †P <0.05 vs. IL-33. (C and D) HUVECs were pre-incubated with SP600125 (30 μmol/L) for 2 hrs, followed by additional incubation with IL-33 (10−9 mol/L) for 4 hrs (C, IL-8 mRNA), and IL-33 (10-9mol/L) and IL-1β (10-11mol/L) for 24 hrs (D, IL-8 secretion). IL-8 mRNA and protein secretion were evaluated by real time RT-PCR (C, n = 3) and ELISA (D, n = 3), respectively. *P <0.05 vs. untreated control. †P <0.05 vs. IL-33. ‡P <0.05 vs. IL-1β.