Fig. 7

Aberrant LAMP-2 expression results in impaired autophagic flux. a Confocal microscopic fluorescence images of lysosomal characters by LysoTracker Red DND-99 staining. PC12 cells were treated with 15 μg/mL ZnO NPs for 12 h, and 32 cells were analyzed to select the representative images. Scale bar, 10 μm. Flow cytometry analysis of lysosomes (b) and lysosomal pH (c) in ZnO NPs-treated PC12 cells. The cells were treated as above, then stained by LysoTracker Red DND-99 and LysoSensor Green DND 189, respectively. d Effects of ZnO NPs on the lysosomal-related protein expression of LAMP-1, LAMP-2 and Rab7. Cell lysates were analyzed by Western blotting. e Flow cytometry analysis of autophagosomes by MDC staining in ZnO NPs-induced PC12 cells for 6 h with or without 10 μM SP600125 pre-treatment for 1 h. Data from at least three independent experiments were expressed as the means ± SD. ***p < 0.001 compared with the untreated control. f Effect of the JNK inhibitor SP600125 on the level of p62. Cells were treated with 15 μg/mL ZnO NPs for 6 h in the presence or absence of SP600125 pre-treatment for 1 h. Western blotting was performed to determine the level of p62 expression. The densitometry of the above bolts from at least three independent experiments was shown in Figure S9A and B