miR-590-5p affects chondrocyte proliferation, apoptosis, and inflammation by targeting FGF18 in osteoarthritis.

OBJECTIVE To investigate the potential miRNA targeting FGF18, and its role in regulating the proliferation, apoptosis and inflammation in human primary chondrocytes. METHODS The normal human chondrocytes were induced by IL-1β to mimic OA in vitro. qPCR and Western blotting were performed to evaluate the expression of FGF18. Target Scan analysis was performed to predict the miRNA targeting FGF18. Then, the expression of miR-590-5p was quantified by qPCR in IL-1β-induced chondrocytes. After transfection of miR-590-5p mimics or inhibitors, CCK-8 assay was conducted to determine the cell viability and apoptosis-related proteins, and cartilage degeneration related biomarkers were assayed by qPCR and Western blotting. The levels of tumor necrosis factor (TNF)-α, interleukin (IL)-6 and IL-8 were determined by ELISA. The targeting relationship between miR-590-5p and FGF18 was assayed by luciferase reporter assay in IL-1β-induced chondrocytes. RESULTS Target Scan analysis predicted that FGF18 is directly targeted by miR-590-5p. miR-590-5p was up-regulated, whereas FGF18 expression was inhibited in IL-1β-induced chondrocytes. miR-590-5p mimics reduced the expression of FGF18 protein, inhibited the cell viability of chondrocytes, and promoted secretion of inflammatory factors in chondrocytes, while miR-590-5p inhibitors increased FGF18 levels in IL-1β-treated chondrocytes. Furthermore, expression of inflammatory factors in chondrocytes was reduced by miR-590-5p inhibitors. The luciferase reporter assay showed that miR-590-5p could target FGF18. CONCLUSIONS miR-590-5p promotes OA progression by targeting FGF18, which serves as a potential therapeutic target for OA.