Long noncoding RNA TUG1 regulates degradation of chondrocyte extracellular matrix via miR-320c/MMP-13 axis in osteoarthritis

Osteoarthritis (OA) is a common chronic joint disease. This study aimed to explore the function of long noncoding RNA taurine-upregulated gene 1 (TUG1) in the progression and initiation of OA. Levels of TUG1, microRNA-320c (miR-320c) and fucosyltransferase 4 (FUT4) were examined via quantitative reverse transcriptase polymerase chain reaction (qRT-PCR). 3-(4,5-Dimethyl-2-thiazolyl)-2,5-diphenyl-2-H-tetrazolium bromide and flow cytometry assays were used to detect cell viability and apoptosis, respectively. The expression of relative proteins was measured using Western blot. The interaction between miR-320c and TUG1 or FUT4 was confirmed utilizing dual-luciferase reporter and RNA immunoprecipitation assays. In this study, levels of TUG1 and FUT4 were distinctly upregulated, but miR-320c level significantly decreased in OA tissues and chondrocytes derived from OA tissues as well as in IL-1β-stimulated C28/I2 cells. Mechanically, TUG1 sponged miR-320c and miR-320c targeted FUT4. In addition, TUG1 knockdown accelerated cell proliferation and repressed apoptosis and extracellular matrix (ECM) degradation in IL-1β-induced C28/I2 cells, whereas these effects of TUG1 deletion were rescued by either miR-320c inhibitor or FUT4 upregulation. Meanwhile, TUG1 sponged miR-320c to regulate FUT4 expression in IL-1β-induced C28/I2 cells. Collectively, TUG1 modulated cell proliferation, apoptosis and ECM degradation in IL-1β-induced C28/I2 cells via the miR-320c/FUT4 axis, providing a new insight into the OA treatment.