Fig. 1.

Western blot analysis of native and modified HDL-induced MAPK activation in the absence or presence of MAPK inhibitors in endothelial cells. (A and C) Cells were incubated with 100 μg/ml HDL or HOCl–HDL (oxidant:lipoprotein molar ratio 200:1) for the indicated times or (B and D) with indicated concentrations of HDL or HOCl–HDL for 5 min. (E) Cells were preincubated for 30 min with 25 μM PD98059 or 10 μM SB203580 prior to stimulation with 100 μg/ml HOCl–HDL for 5 min. (F) Cells were incubated with 100 μg/ml native HDL or HDL modified by reagent HOCl (HOCl–HDL) or by the MPO–H₂O₂-system in the absence (MPO–HDL) or presence of ascorbate (MPO–Asc–HDL) for 5 min. (A–F) Cells were lysed and equal amounts of proteins were subjected to Western blot analysis for pp42/44 and pp38 MAPK. After stripping membranes, β-actin was used as a loading control. In all Western blots, lane 1 represents non-stimulated controls, i.e. cells in the absence of lipoproteins. One representative experiment out of three is shown.