Figure 2

p38α is required for the IL-33-mediated inhibition of MCP-1 and ICAM-1 expression in human macrophages. Knockdown using adenovirus-encoding shRNA against p38α (p38) or scramble (Scr) sequence was carried out as Materials and Methods. THP-1 macrophages were then incubated for 12 h in the presence of vehicle (−) or 25 ng/ml IL-33 (+). The mRNA expression of p38α (A), MCP-1 (C) and ICAM-1 (D) was analyzed by RT-qPCR. Data represents mean ± SEM from six independent experiments. The expression of p38 protein levels was determined by Western blot analysis using β-actin as control (B). A representative image with signal from immunoreactive p38 or β-actin is shown (see Supplementary Fig. 4 for corresponding full-length image) with the histogram below it indicating p38 protein expression (mean ± SEM) normalized to β-actin from three independent experiments. The knockdown of p38α in vehicle- or IL-33 treated cells was determined in relation to the scramble control, which was arbitrarily assigned as 1 (A,B). The IL-33-mediated changes in MCP-1 and ICAM-1 expression in the scramble control was compared to that following knockdown of p38α (C,D) with values from cells infected with scramble shRNA or p38α shRNA and then treated with vehicle alone given an arbitrary value of 1. Statistical analysis was carried out using an unpaired Student’s t-test (A–C) or Man Whitney U test (D) (**p ≤ 0.01, ***p ≤ 0.001).