Autophagy has been reported to be widely involved in the pathogenesis of osteoarthritis (OA). Increasing evidence suggested the important role of microRNAs (miRs) in the progression of OA. However, the functional role of miR-17-5p in OA development has remained to be fully elucidated. First, a mouse model of OA was established and the relative level of miR-17-5p was determined using PCR. Safranin O-fast green staining was applied to determine cartilage degeneration. TargetScan software and a dual luciferase reporter assay were applied to determine potential target genes of miR-17-5P. Autophagy measurement was performed using green fluorescent protein-microtubule-associated protein 1 light chain 3 (LC3) dot analysis. The results demonstrated that the relative expression of miR-17-5p was significantly decreased in OA model mice. In addition, the level of miR-17-5p was decreased in SW1353 human chondrosarcoma cells treated with interleukin-1β. Furthermore, autophagy was found to be suppressed in the knee joints of experimental OA model mice. The dual luciferase reporter assay confirmed that p62/sequestosome 1 was a target gene of miR-17-5p. Of note, miR-17-5p inhibitor-induced reduction of LC3 dots was markedly reversed by knockdown of p62 in SW1353 cells. In conclusion, decreased miR-17-5p expression in chondrocytes induced autophagy mainly through suppressing the expression of p62, thereby contributing to OA progression.
Keywords: autophagy; miR-17-5p; osteoarthritis; p62/SQSTM1.