Glutamine protects against oxidative stress injury through inhibiting the activation of PI3K/Akt signaling pathway in parkinsonian cell model

Abstract

Background: Parkinson's disease is a neurodegenerative disorder, and recent studies suggested that oxidative stress contributes to the degeneration of dopamine cell in Parkinson's disease. Glutamine also has a positive role in reducing oxidative stress damage. In this study, we hypothesized that glutamine offers protection against oxidative stress injury in 1-methyl-4-phenylpyridinium (MPP + )-induced Parkinson's disease cell model. Methods: MPP + was used to induce PD models in PC12 cells and classified into control, M0 (MPP + ), G0 (glutamine), and M0+G0 groups. CCK-8 and AO/EB staining assays were used to examine cell proliferation and apoptosis, respectively. Western blotting was applied to examine the protein expression of PI3K, P-Akt, Akt, P-mTOR, and mTOR. Results: We showed that glutamine suppressed cytotoxicity induced by MPP + in PC12 cells. MPP + decreased the superoxide dismutase and glutathione peroxidase activity and increased the malondialdehyde content, which were restored by glutamine. Moreover, MPP + increased the expression of PI3K, P-Akt, Akt, P-mTOR, and mTOR, which were inhibited by glutamine. And the antioxidant capacity of glutamine on PC12 cells could be improved by LY294002 and inhibited by IGF-1. Conclusion: These results suggest that glutamine strengthens the antioxidant capacity in PC12 cells induced by MPP + through inhibiting the activation of the PI3K/Akt signaling pathway. The effects of glutamine should be investigated and the protective mechanism of glutamine in PD must be explored in future studies.