To confirm the role of long noncoding RNA differentiation antagonizing non-protein coding RNA (DANCR) in chondrocyte inflammatory injury in osteoarthritis (OA) in vitro, as well as its molecular mechanism.
Human primary chondrocytes were treated with lipopolysaccharide (LPS) to construct a chondrocyte inflammatory injury in human OA cell model. Gene expression was detected using real-time quantitative polymerase chain reaction. Cell inflammatory injury was evaluated by Cell Counting Kit-8 assay, flow cytometry, and enzyme-linked immunosorbent assay. The interplay between miRNA-19a-3p (miR-19a) and DANCR was validated by dual-luciferase reporter assay and RNA immunoprecipitation.
Expression of DANCR was upregulated, and miR-19a was downregulated in human OA cartilage and LPS-treated primary chondrocytes in vitro. Moreover, DANCR expression was inversely correlated with miR-19a in OA patients. LPS reduced cell viability and increased the apoptotic rate and secretion of interleukin (IL)-1β, IL-6, IL-8, as well as tumor necrosis factor (TNF)-α in primary chondrocyte cells in vitro, suggesting an inflammatory injury model of OA. Functionally, knockdown of DANCR could attenuate LPS-induced apoptosis and inflammatory response, as evidenced by improved cell viability, and reduced apoptotic rate and products of IL-1β, IL-6, IL-8, and TNF-α. Notably, DANCR negatively regulated miR-19a expression, presumably via sponging. Furthermore, miR-19a deletion eliminated the effect of DANCR knockdown on apoptosis and the inflammatory response of primary chondrocytes under LPS stress.
Differentiation antagonizing non-protein coding RNA silencing could protect human chondrocyte cells against LPS-induced inflammatory injury and apoptosis through targeting miR-19a, suggesting a vital role of the DANCR/miR-19a axis in OA.