AntimiR-30b Inhibits TNF-α Mediated Apoptosis and Attenuated Cartilage Degradation through Enhancing Autophagy

Cell death plays an important role in the pathology associated with inflammatory diseases such as osteoarthritis. It has been reported that autophagy can protect cells against tumour necrosis factor-α (TNF-α)-induced apoptosis. This study aimed to determine the potential role of microRNA-30b (miR-30b) in TNF-α-induced apoptosis, autophagy and differentiation in the chondrogenic ADTC5 cell line.

To analyse the effect of TNF-α on the viability of ADTC5 cells, cell counting kit-8 and Hoechst 33342 staining were employed and the expression levels of caspase-3 and -9 were assessed. Autophagy was examined by analysing the levels of LC3B-II and p62 and quantitating GFP-LC3B by fluorescence microscopy. A luciferase reporter assay investigated the putative binding sites of miR-30b. The effects of miR-30b and antimiR-30b on autophagy, apoptosis and osteogenic differentiation of TNF-α-treated cells were determined by autophagosome, apoptosis and alkaline phosphatase assays, respectively.

TNF-α exposure decreased cell viability, increased apoptosis and positively regulated autophagy in ADTC5 cells. A direct interaction was detected between miR-30b and the mRNA 3'-UTRs of autophagy genes BECN1 and ATG5. Overexpression of miR-30b downregulated autophagy genes and upregulated pro-apoptotic gene expression in TNF-α-treated cells, while treatment with antimiR-30b had the inverse effect. Overexpression of miR-30b also downregulated ECM degradation and anti-miR-30b reverse TNF-α-induced ECM degradation.

Anti-miR-30b enhanced autophagy and attenuated cartilage degradation and played a protective role in TNF-α-induced apoptosis of ATDC5 cells. Anti-miR-30b may therefore elevate cellular survival during inflammation and has therapeutic potential for inflammatory diseases such as osteoarthritis.