Annexin A5 Protects SH-SY5Y Cells against L-Glutamate-Induced Cytotoxicity.

Background: L- glutamate- induced neurotoxicity is linked to neuronal loss in neurodegenerative diseases and stroke. Annexin A5 (ANXA5) is a cytosolic protein that binds calcium in eukaryotic organisms. This study aimed to evaluate the protective effects of a recombinant ANXA5 against L-glutamate-induced cell death and mitochondrial dysfunction in SH-SY5Y cells. Methods: ANXA5 was expressed in E. coli and subsequently purified using affinity chromatography. The effect of L-glutamate (0-300 mM) alone or in combination with ANXA5 (0-5µg/mL) on the viability of the SH-SY5Y cells was assessed using the MTT assay. Mitochondrial membrane potential (MMP) dissipation was detected by rhodamine 123 staining and the flow cytometry method. The expressions of Bax, Bcl-2, and NF-E2-Related Factor 2 (Nrf-2) genes were determined by real-time polymerase chain reaction. GraphPad Prism 8.0 was used to analyze the data using either one-way ANOVA or the Kruskal-Wallis test. P<0.05 was considered statistically significant. Results: The findings revealed that L-glutamate reduced the cell viability of SH-SY5Y cells in a dose-dependent manner (P<0.001) (IC50=165 mM). Moreover, treating SH-SY5Y cells with 165 mM of L-glutamate increased MMP dissipation, enhanced Bax expression, and reduced the expression of Bcl-2 and Nrf-2, compared to the control group. ANXA5 alone had no significant effects. However, it reversed the effects of L-glutamate on cell death, MMP dissipation, and gene expression in the SH-SY5Y cells. Conclusion: The data suggest that ANXA5 can protect SH-SY5Y cells against glutamate-induced cell death and mitochondrial dysfunction, indicating its possible protective effect against glutamate-induced neurodegeneration.