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

TLDR: Glutamine strengthens the antioxidant capacity in PC12 cells induced by MPP+ through inhibiting the activation of the PI3K/Akt signaling pathway, suggesting that glutamine offers protection against oxidative stress injury in 1-methyl-4-phenylpyridinium-induced Parkinson’s disease cell model.

Abstract: 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. 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. 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. 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.