Figure 4.

The AMPK signaling pathway positively regulates PM_2.5-mediated autophagy in A549 cells. Representative images are shown in the left panels, and quantification relative to β-actin expression (mean ± SD of at least 3 separate experiments) is shown in the right panels. A. PM_2.5 activates AMPK in A549 cells. Cells were treated with 100 μg/ml PM_2.5 for variable periods (0, 6, 12 and 24 h). AMPK and p-AMPK expression was assessed by western blot analysis. B. Blocking AMPK activation attenuates PM_2.5 mediated autophagy. Cells were treated with 100 μg/ml PM_2.5 for 24 h following 6 h pretreatment with the AMPK inhibitor (40 μm/L)dorsomorphin (DM). DMSO was tested as a control. AMPK, p-AMPK and LC3 expression was assessed by western blot analysis.