FIGURE 5.

Pyk2 regulates LPS-induced IL-8 expression through the p38 MAPK pathway. A, HUVEC was pretreated with vehicle or Tyrphostin A9 (5 μM) for 1 h at 37°C. The cells were then stimulated with LPS for various periods of time in EBM with 0.5% FBS. The cells were lysed and analyzed by Western blotting with anti-phospho-ERK1/2 (p-ERK1/2) Abs (upper left blots) or anti-phospho-p38 (p-38) Abs (lower left blots). The same blots were probed with anti-ERK1/2 or anti-p38 Abs, respectively. Data show one representative experiment of three independent experiments. For quantitative analysis of protein phosphorylation, the ratio of phosphorylation vs total protein in each lane was obtained by densitometry. The phosphorylation index of ERK and p38 was determined by calculating the value of this ratio in each lane and presenting the ratio as the fold increase over the control value (unstimulated sample; 0), which was designated as 1 (right). B, HUVEC pretreated with vehicle, the p38 MAPK inhibitor (SB203580, SB) (left) or the ERK kinase inhibitor (PD98059, PD) (right) for 1 h were stimulated with 100 ng/ml LPS and then the concentration of IL-8 in the supernatants was measured 24 h after stimulation. *, p < 0.05 compared with the vehicle control. Data represent mean ± SD of three independent experiments.