Objective To observe the effect of methamphetamine (METH) on PTEN-induced kinase 1 (PINK1)/Parkin-mediated autophagy and the impact of the autophagic process on apoptosis in human neuroblastoma (SH-SY5Y) cells.
Methods SH-SY5Y cells were treated with METH at various dosages (0.0, 1.0, 1.5, 2.0 mmol/L) for 24 hours. Cell apoptosis was detected with cytometry; ultrastructure of mitochondria in the SH-SY5Y cells was observed using transmission electron microscope and the activity of lysosome phagocytosis was observed with laser confocal microscope. The expression of autophagy marker protein light chain 3 (LC3) and P62 and autophagy regulation protein PINK1 and Parkin were detected with Western bolt.
Results The number of apoptosis in SH-SY5Y cells was positively correlated with the dose of METH significantly 24 hours after the treatment (P < 0.05). The ultrastructure of mitochondria was seriously damaged and the number of mitochondria decreased, but that of lysosomes increased and the activity of phagocytosis increased (P < 0.05); autophagosomes were observed. The ratio of LC3-II/LC3-I proteins increased significantly (P < 0.05). The expression of P62 protein did not changed first but then decreased significantly 48 hours after the treatment (P < 0.05). The expression of Parkin protein increased but no significant variation was observed in the expression of PINK1.
Conclusion METH may induce mitochondrial autophagy mediated by PINK1/Parkin signaling pathway in SH-SY5Y cells, with unobstructed autophagy flux and delayed terminal feedback, which may result in the apoptosis of SH-SY5Y cells.
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