Downregulation of miRNA-134 protects neural cells against ischemic injury in N2A cells and mouse brain with ischemic stroke by targeting HSPA12B

• Downregulation of miR-134 reduces brain ischemic injuries.
• Downregulation of miR-134 increases HSPA12B protein levels.
• HSPA12B siRNAs block the neuroprotective events of miR-134 downregulation.
• MiR-134 plays an important role in brain ischemic injuries.

MicroRNAs (miRNAs) have emerged as a major regulator in neurological diseases, and understanding their molecular mechanism in modulating cerebral ischemic injury may provide potential therapeutic targets for ischemic stroke. However, as one of 19 differentially expressed miRNAs in mouse brain with middle cerebral artery occlusion (MCAO), the role of miR-134 in ischemic injury is not well understood. In this study, the miR-134 expression level was manipulated both in oxygen–glucose deprivation (OGD)-treated N2A neuroblastoma cells in vitro and mouse brain with MCAO-induced ischemic stroke in vivo, and its possible targets of heat shock protein A5 (HSPA5) and HSPA12B were determined by bioinformatics analysis and dual luciferase assay. The results showed that overexpression of miR-134 exacerbated cell death and apoptosis both in vitro and in vivo. Conversely, downregulating miR-134 levels reduced cell death and apoptosis. Furthermore, non-expression of miR-134 enhanced HSPA12B protein levels in OGD-treated N2A cells as well as in the ischemic region. It could attenuate brain infarction size and neural cell damage, and improve neurological outcomes in mice with ischemic stroke, whereas upregulation of miR-134 had the opposite effect. In addition, HSPA12B was validated to be a target of miR-134 and its short interfering RNAs (siRNAs) could block miR-134 inhibitor-induced neuroprotection in OGD-treated N2A cells. In conclusion, downregulation of miR-134 could induce neuroprotection against ischemic injury in vitro and in vivo by negatively upregulating HSPA12B protein expression.

Downregulation of miR-134 increased HSPA12B protein levels and induced neuroprotection against ischemic injury. HSPA12B was a target gene of miR-134 in mouse N2A Cells after oxygen-glucose deprivation (OGD) and in mouse brain with transient middle cerebral artery occlusion (MCAO). HSPA12B siRNAs blocked pre-miR-134 inhibitor-induced neuroprotection. MicroRNA-134 played an important effect on neural cell death and apoptosis in ischemic injury.Figure optionsDownload high-quality image (43 K)Download as PowerPoint slide