MicroRNA-195-5p inhibitor prevents the development of osteoarthritis by targeting REGγ

Osteoarthritis (OA) is a common inflammatory joint disease. MicroRNAs (miRNAs/miRs) have been reported to be involved in the pathogenesis of OA; however, the role of miRNAs in OA remains largely unexplained. The purpose of the present study was to investigate the expression and role of miR-195-5p in OA, and to further explore the mechanism. The expression level of miR-195-5p was measured using reverse transcription-quantitative polymerase chain reaction (RT-qPCR). TargetScan and a luciferase reporter assay were used to reveal the associations between miR-195-5p and REGγ (also known as PSME3). To investigate the role of miR-195-5p in OA, a cell model of OA was established by treating ATDC5 cells with lipopolysaccharide (LPS). Then an MTT assay was conducted to detect cell proliferation ability, and an Annexin V-fluorescein isothiocyanate/propidium iodide apoptosis detection kit was used to measure cell apoptosis. In addition, the levels of interleukin (IL)-1β, IL-6 and tumor necrosis factor (TNF)-α were determined using ELISA. Furthermore, gene and protein expression was measured via RT-qPCR and western blot assay, respectively. The results revealed that miR-195-5p was significantly upregulated in the articular cartilage tissues of patients with OA and in LPS stimulated ATDC5 cells. REGγ was a direct target of miR-195-5p. The repressed cell proliferation ability and enhanced cell apoptosis of ATDC5 cells induced by LPS were reversed by miR-195-5p downregulation. Furthermore, LPS stimulation significantly upregulated the levels of IL-1β, IL-6 and TNF-α, while miR-195-5p downregulation markedly reduced the expression of inflammatory factors induced by LPS. The results also revealed that a miR-195-5p inhibitor inhibited the LPS induced repression of the Wnt/β-catenin signaling pathway and activation of nuclear factor (NF)-κB signaling pathway in ATDC5 cells. Notably, the results of the present study also indicated that all of the effects of the miR-195-5p inhibitor on ATDC5 cells were reversed by REGγ silencing. In conclusion, the results indicated that the miR-195-5p inhibitor served a protective role in OA by inhibiting chondrocyte apoptosis and inflammatory responses by regulating the Wnt/β-catenin and NF-κB signaling pathways.