FGD5-AS1 Inhibits Osteoarthritis Development by Modulating miR-302d-3p/TGFBR2 Axis

Osteoarthritis (OA) is a common joint disorder, accompanied by extracellular matrix (ECM) degradation. Reportedly, long noncoding RNAs (lncRNAs) are involved in OA pathogenesis. However, the role of lncRNA FYVE, RhoGEF, and PH domain containing 5 antisense RNA 1 (FGD5-AS1) in OA development is still not fully clarified. This study was aimed to clarify the role of FGD5-AS1 in OA.

FGD5-AS1 and miR-302d-3p expression levels were determined in cartilage tissues and chondrocytes by quantitative real-time polymerase chain reaction (qRT-PCR). Chondrocytes (C20/A4 cells) were stimulated with interleukin 1β (IL-1β) to mimic the inflammatory environment of OA. Cell viability was detected by cell counting kit-8 and 5-ethynyl-2'-deoxyuridine assays. Cell apoptosis was measured by the caspase-3 activity assay and flow cytometry. Transforming growth factor beta receptors II (TGFBR2), matrix metalloproteinase 13 (MMP-13), and ADAM metallopeptidase with thrombospondin type 1 motif 5 expression levels were examined by qRT-PCR or Western blot. The regulatory relationships among FGD5-AS1, miR-302d-3p, and TGFBR2 were predicted by the StarBase v2.0, miRanda, miRDB, and TargetScan databases, and confirmed by dual-luciferase reporter assay and RNA immunoprecipitation assay.

FGD5-AS1 and TGFBR2 expression levels were downregulated while miR-302d-3p expression was increased in cartilage tissues of OA patients. Knocking down FGD5-AS1 inhibited the viability of C20/A4 cells but induced apoptosis and ECM degradation, while FGD5-AS1 overexpression exerted opposite effects. MiR-302d-3p was identified as a target of FGD5-AS1, and TGFBR2 was identified as a target of miR-302d-3p. FGD5-AS1 positively regulated TGFBR2 expression by repressing miR-302d-3p expression, and miR-302d-3p inhibition or TGFBR2 restoration reversed the changes of cell viability, apoptosis, and ECM degradation induced by FGD5-AS1 knockdown.

FGD5-AS1 can probably inhibit OA progression by regulating miR-302d-3p/TGFBR2 axis.