MicroRNA-490-3p inhibits inflammation and apoptosis induced by spinal cord injury via targeting MK2.

Abstract

To investigate the regulatory role of microRNA-490-3p in the recovery process of spinal cord injury (SCI) and its underlying mechanism. Expression levels of microRNA-490-3p and MK2 in peripheral blood of SCI patients and healthy controls were detected by quantitative Real Time-Polymerase Chain Reaction (qRT-PCR). Glial cells C8-D1A and C8-B4 were induced by H2O2 for constructing in vitro SCI model, followed by detection of microRNA-490-3p and MK2 levels. After glial cells were transfected with microRNA-490-3p mimic or inhibitor, respectively, cell apoptosis and levels of interleukin-6 (IL-6) and tumor necrosis factor-α (TNF-α) were detected. Bioinformatics was used to predict the binding site between microRNA-490-3p and MK2, which was further verified by dual-luciferase reporter gene assay. After construction of MK2 overexpression plasmid, rescue experiments were carried out to confirm the regulatory effect of microRNA-490-3p on MK2 in mediating SCI recovery. MicroRNA-490-3p expression was remarkably lower, whereas MK2 expression was higher in peripheral blood of SCI patients than those of healthy controls. Downregulated microRNA-490-3p and upregulated MK2 were observed in glial cells after H2O2 induction in C8-D1A and C8-B4 cells. Overexpression of microRNA-490-3p remarkably decreased levels of TNF-α and IL-6, as well as alleviated apoptosis in glial cells. Both protein and mRNA levels of MK2 were negatively regulated by microRNA-490-3p. Dual-luciferase reporter gene assay confirmed that MK2 was the target gene of microRNA-490-3p. Finally, rescue experiments verified that the regulatory effects of microRNA-490-3p on alleviating inflammation and apoptosis after SCI were reversed by MK2 overexpression. MicroRNA-490-3p is lowly expressed in glial cells after SCI. Overexpression of microRNA-490-3p alleviates inflammation and apoptosis via targeting MK2, thereafter promoting SCI recovery.