MicroRNA-218 aggravates H₂O₂-induced damage in PC12 cells via spred2-mediated autophagy

The current study aimed to investigate the effects and underlying mechanism of miR-218 in H₂O₂-induced neuronal injury. The impacts of miR-218 knockdown on cell viability, apoptosis and autophagy-associated proteins were detected by Cell Counting Kit-8 assay, flow cytometry and western blotting in H₂O₂-injured PC12 cells, respectively. Reverse transcription-quantitative PCR (RT-qPCR) and western blotting was executed to explore the expression level of miR-218 and sprouty-related EVH1 domainprotein2 (spred2) in H₂O₂-stimulated cells. Besides, the regulatory association between miR-218 and spred2 was explored through bioinformatics and luciferase reporter assay. Following knockdown of miR-218 and spred2, the functions of miR-218 and spred2 in H₂O₂-injured cells were further studied. High expression level of miR-218 was observed in H₂O₂-disposed PC12 cells, while spred2 expression level was downregulated. Knockdown of miR-218 expression alleviated H₂O₂-induced PC12 cell injury by increasing cell proliferation, and decreasing apoptosis and autophagy. Furthermore, spred2 was identified as a direct target of miR-218 and was negatively regulated by miR-218. Moreover, suppression of spred2 abrogated the protective effects of miR-218 inhibition on H₂O₂-injured PC12 cells. Depletion of miR-218 protected PC12 cells against H₂O₂-induced cell injury via the upregulation of spred2, which provided a promising therapeutic strategy for spinal cord injury.