Background: Increasing evidence has suggested the important role of miRNAs in the progression of osteoarthritis (OA). In the current study, we explored the role of miR-181-5p in the peripheral blood and bone tissues of OA patients for the first time.
Methods: The level of miR-181-5p was evaluated in the peripheral blood and cartilage of OA patients using real time PCR analysis. ROC analysis was performed to explore whether peripheral blood and cartilage miR-181-5p could screen OA patients from normal controls. Western blot assay and dual luciferase reporter assay were carried out to validate the possible target gene of miR-181-5p in SW1353 cells.
Results: For the first time, we confirmed that the expression of miR-181-5p was significantly reduced in the peripheral blood and cartilage of OA patients, suggesting that miR-181-5p may be involved in the process of cartilage injury in OA degradation. Furthermore, ROC analysis showed that both peripheral blood and cartilage miR181-5p could screen OA patients from healthy controls. Moreover, we found that overexpression of miR-181-5p significantly suppressed the expression of TNFα, while inhibition of miR-181-5p enhanced the level of TNFα. Bioinformatic predictions identified a conserved binding site in the 3'UTR of TNFα by miR-181-5p. In addition, dual luciferase reporter assay indicated that miR-181-5p markedly suppressed the relative luciferase activity of TNFα. These data indicated that TNFα was a target gene of miR-181-5p.
Conclusions: In summary, reduced miR-181-5p expression in the peripheral blood and cartilage tissues may serve as a potential biomarker to screen OA patients from healthy controls mainly by targeting TNFα.