Long noncoding RNA maternally expressed gene 3 knockdown alleviates lipopolysaccharide-induced inflammatory injury by up-regulation of miR-203 in ATDC5 cells.

BACKGROUND: Osteoarthritis (OA) is a common degenerative joint disease, which seriously impacts the health of elderly. However, there is no effective treatment for curing this disease until now. Numerous studies reported that long noncoding RNAs (lncRNAs) are closely related to the pathogenesis of OA. Therefore, the study aims to investigate the effect of maternally expressed gene 3 (MEG3) on lipopolysaccharide (LPS)-induced inflammatory injury of ATDC5 cells.

METHODS: Different concentrations (0, 1, 5, and 10 μg/ml) of LPS were used to induce ATDC5 cells injury. The specific expressing vectors were then transfected into ATDC5 cells to alter MEG3, Sirt1 and miR-203 expressions. Flow cytometry, luciferase reporter, qRT-PCR and western blot assays were used to detect cell viability, apoptosis, and the expressions of apoptosis-related proteins and pro-inflammatory factors (IL-1β, IL-6, IL-8 and TNF-α). Meanwhile, ELISA was used for analyzing the concentrations of inflammatory cytokines in culture supernatant. Besides, the key pathways of PI3K/AKT and NF-κB were examined by western blot.

RESULTS: LPS decreased cell viability, increased cell apoptosis, promoted the release of pro-inflammatory factors, and down-regulated MEG3 expression, Moreover, MEG3 knockdown alleviated LPS-induced inflammatory injury. MEG3 acted as a competing endogenous RNAs (ceRNA) for miR-203, and MEG3 knockdown reduced inflammatory injury by regulating miR-203. Furthermore, miR-203 positively regulated Sirt1 expression, and Sirt1 alleviated LPS-induced inflammatory injury via mediating PI3K/AKT and NF-κB pathways.

CONCLUSION: This study showed that MEG3 knockdown alleviated LPS-induced inflammatory injury in ATDC5 cells by regulating miR-203 expression. Hence, the findings may offer a potential treatment perspective of OA.