Downregulation of ATP13A2 in midbrain dopaminergic neurons is related to defective autophagy in a mouse model of Parkinson's disease

Parkinson's disease (PD) is one of the most common diseases of the nervous system characterized by movement disorders arising from loss of midbrain dopaminergic neurons. The relationship between PD and autophagy has received considerable attention. This study aimed to investigate the involvement of the ATP13A2 gene in damage of dopaminergic neurons induced by abnormal autophagy in a MPTP-induced PD mouse model. MPTP was intraperitoneally injected into C57BL mice at 40 mg/kg for 7 days in experimental group. Saline was injected into mice in the control group. After the injection, the mice were tested at different time points for abnormal limb movement by a swimming test. The brain tissue was collected on day 1, 5, and 7 to measure concentration of intracellular calcium. The expression of ATP13A2 was evaluated by real-time PCR. The expression of alpha-synclein, LC3, LAMP-2, and CaMKK protein was detected by western blot. We found significant motor dysfunction on day 7 in the experimental group, and the expression of alpha-synclein in the substantia nigra of the midbrain was significantly increased while the expression of ATP13A2 gene was reduced significantly compared with the control group. The concentration of intracellular calcium in the experimental group was significantly higher than in the control group. Autophagy associated proteins LC3-II and LAMP-2 were downregulated and CaMKK protein was upregulated in midbrain tissues of the experimental group compared to control group. In conclusion, our findings suggest that decreased expression of ATP13A2 may lead to defective autophagy and damage to midbrain dopaminergic neurons.