miR-182-5p overexpression inhibits chondrogenesis by down-regulating PTHLH.

Human bone marrow mesenchymal stem cells (hBM-MSC) have the ability of differentiating into chondrocytes and osteoblasts. miR-182-5p promotes osteoclastogenesis and bone metastasis by up-regulating the expression of parathyroid hormone-like hormone (PTHLH). However, the function of miR-182-5p in chondrogenesis is still unknown. Mimic or inhibitor of miR-182-5p was used to upregulate or knock-down miR-182-5p expression, respectively. We analyzed chondrogenesis by Safranin O staining and Blyscan™ Sulfated Glycosaminoglycan Assay. Immunohistochemistry, real-time PCR, and Western bolts were used to detect related makers. miR-182-5p overexpression inhibited chondrogenesis. Dual-luciferase reporter assay indicated that PTHLH was one of the target genes of miR-182-5p. Further studies showed that miR-182-5p overexpression down-regulated the expression of SOX-9 and COL2A1, but up-regulated COL1A1 and COL10A1. Consistently, miR-182-5p knock-down had the opposite effects. This effect of miR-182-5p in BM-MSCs can be rescued by PTHLH overexpression. miR-182-5p may play a negative role in chondrogenesis by down-regulating PTHLH.