Autophagy protects the rotenone-induced cell death in α-synuclein overexpressing SH-SY5Y cells

Loss of dopaminergic cells induced by α-synuclein accumulation in substantia nigra causes the development of Parkinson's disease (PD). To date, although autophagy has been implicated in the pathology of PD, the molecular mechanism is still unclear. To study the role of autophagy in PD pathogenesis, we established stable SH-SY5Y cell lines overexpressing wild-type or mutant α-synuclein proteins (A30P or A53T). Overexpression of mutant α-synuclein induced some protein aggregates and cell death in the absence of drug. LC3-II protein, a critical marker for autophagy, was produced in an autophagy-dependent manner. The rotenone-induced cell death was interrupted by autophagy stimulation. Autophagy activation also restored the mitochondrial membrane potential (MMP) impaired by rotenone in mutant α-synuclein expressing cells. Additionally, autophagy activation significantly relieved rotenone-induced ROS accumulation and HIF-1α expression in neuronal cells expressing mutant α-synuclein proteins. These findings indicate that autophagy plays an important scavenger role against harmful influence of toxic protein aggregates produced in rotenone-treated cells.