| Summary: | 碩士 === 臺灣大學 === 動物學研究所 === 98 === Autophagy is involved in the degradation of organelles and long-lived proteins, but also plays an important role in cell development, differentiation and survival. Autophagy is mainly induced under stress and causes autophagosome formation. The formation of autophagosome requires the recruitment of LC3; therefore, LC3 could be a marker of autophagosomes. It has been shown that both dopamine and zinc cause dopaminergic neuron death which may be responsible for Parkinson’s disease (PD). The neuropathologic hallmark of PD is the presence of α-synuclein accumulation in the Lewy bodies. However, it is not clear whether autophagy is involved in these processes. To determine the roles of autophagy plays in cells treated with dopamine and zinc, PC12 cells were transfected with GFP-fused LC3 and the aggregations of the fluorescence were used to represent the presence of autophagosomes. Our results showed that the number of autophagosomes in cells pretreated with dopamine (250 μM) or zinc (200 μM) was higher than that of control cells. This increase was inhibited by the pretreatment of LY294002 (5 μM) and wortmannin (5 μM), the inhibitors of phosphatidylinositol 3-kinase. In addition, the occurrence of apoptosis in cells pretreated with dopamine was increased and further, enhanced by LY294002 treatment. When PC12 cells coexpressing Dsred-fused LC3 and CFP-fused α-synuclein, LC3, but not α-synuclein, was aggregated by doapmien and Zn2+ treatment. These results suggested that the formation of autophagosome in PC12 cells treated with dopamine and zinc is mediated by PI3K pathway, and autophagy may play a protective role in PC12 cells.
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