Increased miR-381a-3p Contributes to Osteoarthritis by Targeting IkBα.

Osteoarthritis (OA) affects over 100 million individuals around the world. In this study, we mainly explore the functional role of miR-381a-3p in the regulation of OA. The expression of miR-381a-3p was studied in human articular cartilage and synovium of OA. Furthermore, the level of miR-381a-3p was analyzed in the OA rat model. MiR-381a-3p was overexpressed or inhibited with specific miR mimics or inhibitors. RT-PCR was applied to determine the levels of inflammatory factors such as TNFα, COX-2, iNOS, IL-6, and IL8. Bioinformatic predictions were applied to determine the possible target genes. Dual luciferase reporter assay was used to explore whether IκBα was the target gene of miR-381a-3p. The level of miR-381a-3p was significantly increased in the human articular cartilage and synovium of OA compared with normal control. Meanwhile, miR-381a-3p was enhanced in the OA rat model. Overexpression of miR-381a-3p significantly enhanced the levels of TNFα, COX-2, iNOS, IL-6 and IL8. IκBα was predicted as the target gene of miR-381a-3p. Dual luciferase reporter assay showed that miR-381a-3p could significantly decrease the luciferase activity of pmirGL-IκBα-3'UTR. In summary, enhanced miR-381a-3p expression contributed to the injury of OA mainly by inhibiting the expression of IκBα.