Inhibition of p38 MAPK activity suppresses AICAR-induced efferocytosis.

<p><b>(A)</b> RAW 264.7 cells were cultured with AICAR at the indicated doses for 1 h and then incubated with apoptotic thymocytes for 90 min followed by flow cytometry. Each bar represents the mean ± SD (n = 4). <b>(B)</b> RAW 264.7 cells were cultured with AICAR (2 mM) for the indicated times. Cell lysates were subjected to Western blot analysis using specific antibodies. <b>(C)</b> Representative Western blots show the levels of p38α or actin in RAW 264.7 cells treated with control siRNA or siRNA specific to p38α. <b>(D)</b> RAW 264.7 cells treated with control siRNA or siRNA specific to p38α were incubated with AICAR (0 or 2 mM) for 1 h and then cultured with apoptotic thymocytes for an additional 90 min, followed by flow cytometry. *<i>P</i> < 0.05 compared with the control. ^†<i>P</i> < 0.05 compared with control cells treated with AICAR. Each bar represents the mean ± SD (n = 4). <b>(E)</b> Peritoneal macrophages cultured with AICAR (0.3 mM) for the indicated times and subjected to Western blot analysis. <b>(F, G)</b> Macrophages were cultured with LY294002, a PI3K inhibitor, at the indicated concentrations for 30 min before exposure to AICAR (0 or 0.3 mM) for 1 h, followed by <b>(F)</b> Western blot analysis or <b>(G)</b> culturing with apoptotic thymocytes for an additional 90 min. The phagocytic indexes were measured by flow cytometry. Values represent the mean ± SD from four independent experiments. *<i>P</i> < 0.05 compared with untreated cells.