Amikacin Inhibits miR-497 Maturation and Exerts Post-ischemic Neuroprotection

MicroRNAs (miRNAs) are a group of small non-coding RNAs that regulate numerous signaling pathways involved in cerebral ischemia reperfusion injury. Recent finding demonstrated that miR-497 promotes ischemic neuronal death by negatively regulating anti-apoptotic proteins and therefore serves as a promising therapeutic target for cerebral ischemic injury. In this study, we present a systematic computational approach that includes 3D modeling, docking-based virtual screening, and molecular dynamics simulation to identify small-molecule inhibitors of pre-miR-497 maturation. The top hit, aminoglycosidic antibiotic, amikacin, formed a stable complex with pre-miR-497. Later, the protective efficacy of amikacin was evaluated against oxygen-glucose deprivation (OGD) and reoxygenation-induced neuronal cell death in SH-SY5Y cells and mouse organotypic hippocampal slice cultures. To confirm the inhibitory potential of amikacin on miR-497 maturation, quantitative real-time PCR was performed to check the expression of bcl-2, one of the primary anti-apoptotic targets of miR-497. Additionally, the expression level of mature miR-497 was quantified using TaqManA (R) MiRNA Assay Kit. Amikacin treatment effectively reduced OGD-induced cell death compared to control groups both in vitro and organotypic hippocampal slice cultures. Further, amikacin effectively increased the expression of bcl-2 in SH-SY5Y cells subjected to OGD. Interestingly, SH-SY5Y cells treated with amikacin displayed decreased expression of miR-497, probably due to inhibition of pre-miRic form. Our study provides strong evidence that amikacin inhibits miR-497 maturation and promotes ischemic neuronal survival by upregulating anti-apoptotic protein, bcl-2. Future studies directed at evaluating the neuroprotective efficacy and mechanism of amikacin animal models may lead to new therapeutic opportunities for preventing neuronal death after stroke.