The expression of intronic miRNAs, miR-483 and miR-483*, and their host gene, Igf2, in murine osteoarthritis cartilage.

MicroRNAs (miRNAs) have been shown to be important regulators in the pathogenesis of osteoarthritis (OA). The objective of this study was to determine the expression levels of miR-483, miR-483*, their host gene (Igf2) and other cytokines in a murine model of OA. The expression of miR-483 was significantly up-regulated in old mouse and in all of the operation groups, particularly the group assessed 1 week after surgery. The expression of miR-483* was significantly increased in the old mouse group and the group assessed 5 weeks after surgery. The expression of miR-483 was negatively correlated with the expression of (mRNA) Bmp7 and TgfB and positively correlated with Mmp13 by Pearson correlation analysis, while miR-483* was positively correlated with Il1B. Surprisingly, there was no correlation between the expression of either miR-483 or miR-483* and Igf2. This study shows that the expression of miR-483 and miR-483* is up-regulated in murine OA. These data suggest that miR-483 and miR-483* may play critical roles in early and later pathogenesis of OA, respectively, without the involvement of their host gene Igf2.