AntimiR-30b Inhibits TNF-α Mediated Apoptosis and Attenuated Cartilage Degradation through Enhancing Autophagy
Objective: 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. Methods: 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. Results: 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 3ʹ-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. Conclusions: 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.