Fig. 4: SiNPs inhibit autophagic degradation.

a A549 cells were treated with different concentration of SiNPs as indicated for 24 h or with 50 μg/mL of SiNPs for different time as indicated. The cellular p62 expression was detected by western blot. The bottom panel shows the statistics for the relative p62 protein level. b A549 cells were treated with SiNPs at 50 μg/mL for 24 h. The expression of p62 was evaluated by indirect immunofluorescence assay. Quantification shown on the right represents the relative fluorescence intensity of p62. Scale bar: 5 μm, n = 50. c A549 cells were treated with SiNPs at 50 μg/mL in the absence or presence of CQ (20 μM) for 24 h, and the LC3 protein level was detected by western blot. The bottom panel shows the statistics for the relative LC3-II protein level. d A549 cells were treated with SiNPs at 50 μg/mL for 24 h or starvation medium, and then treated with 10 mM of 3-MA. The LC3 protein level was assessed by western blot at the indicated time. The bottom panel shows the statistics for the relative LC3-II protein level. e A549 cells transiently expressing GFP-LC3 were treated with 3-MA as in (d), and imaged by confocal microscopy. Scale bars: 10 μm. All quantitative data are presented as mean ± SEM, **P < 0.01