METTL14-mediated lncRNA-FAS-AS1 promotes osteoarthritis progression by up-regulating ADAM8

Osteoarthritis (OA) is a prevalent degenerative disease. We explored the role and regulatory mechanisms of lncRNA-FAS-AS1 in OA progression.

We exposed human immortalized chondrocytes to IL-1β for 24 h to induce an OA cell model. The target molecule levels were assessed using western blot and quantitative real-time PCR (RT-qPCR). Cell viability and apoptosis were measured using CCK-8 and flow cytometry. The m6A modification of FAS-AS1 was determined using MeRIP. We examined the binding relationships between FAS-AS1, Fragile X mental retardation 1 (FMR1), and A disintegrin and metalloproteinase 8 (ADAM8) using RIP and RNA pull-down. The OA animal model was established by separating the medial collateral ligament and medial meniscus. Safranin-O staining and Mankin's scale were employed to evaluate pathological changes within the cartilage.

FAS-AS1, METTL14, and ADAM8 were upregulated, and the JAK/STAT3 signaling pathway was activated in OA mice and IL-1β-induced chondrocytes. FAS-AS1 knockdown inhibited extracellular matrix degradation in IL-1β-induced chondrocytes; however, ADAM8 overexpression reversed this effect. FAS-AS1 maintained the stability of ADAM8 mRNA by recruiting FMR1. METTL14 knockdown repressed FAS-AS1 expression in an m6A-dependent manner. FAS-AS1 overexpression reversed the inhibitory effects of METTL14 knockdown on JAK/STAT3 signaling and cartilage damage in the OA model both in vitro and in vivo.

METTL14-mediated FAS-AS1 promotes OA progression through the FMR1/ADAM8/JAK/STAT3 axis.