The effects of dehydrocostus lactone in promoting KLF2 expression is mediated by ERK5. A. HAECs were treated with ox-LDL (10 μg/ml) with or without dehydrocostus lactone (DHL) at concentrations of 15 and 30 μM for 2 h. Phosphorylated and total ERK5 was determined by western blot analysis. B, C. Cells were treated with ox-LDL (10 μg/ml) with or without dehydrocostus lactone (DHL) (30 μM) or the specific ERK5 inhibitor XMD8-92 (100 nM). mRNA levels and protein levels of KLF2 were measured (*, #, $, P < 0.01 vs previous group, n = 5-6).