MiR‐132‐3p regulates ADAMTS‐5 expression and promotes chondrogenic differentiation of rat mesenchymal stem cells

: Previous study showed that miRNA aberrant expression is involved in chondrogenic differentiation. In this study, we aimed to investigate the effects of miR-132-3p on chondrogenic differentiation and the underlying mechanisms. First, quantitative PCR were performed to determine the level of MiR-132-3p. Then, we used luciferase assay to examine the target of miR-132-3p. Proteoglycan was tested by Alcian blue staining assay. Moreover, the sex determining region Y-box 9 (SOX9), Collagen type II alpha 1 chain (COL2A1) and Aggrecan (ACAN) levels were analyzed by quantitative PCR, immunofluorescence and Western blotting. Our results showed that MiR-132-3p level was reduced in rat MSCs (rMSCs) during chondrogenic differentiation. Ectopic expression of miR-132-3p induced proteoglycan accumulation and the increase of ACAN, SOX9 and COL2A1 expression, which were involved in inducing chondrogenic differentiation of rMSCs. More importantly, ADAMTS-5 was identified as the target of MiR-132-3p. Knockdown of ADAMTS-5 increased proteoglycan level, but reduced the SOX9, ACAN, and COL2A1 levels during chondrogenic differentiation of rMSCs. Taken together, our results revels that MiR-132-3p promotes rMSCs chondrogenic differentiation, possibly mediated by targeting ADAMTS-5, which provided new perspective on the chondrogenic differentiation and pathology of osteoarthritis.