Figure 3. miR-146b negatively regulates the expression of A2M. (A) miR-146b aligned with the 3′UTR of A2M mRNA. (B) chondrocytes co-transfected with a reporter carrying the wild type (wt) A2M 3′UTR along with miR-146b mimics. The A2M mutant (mu) recombinant vector was used as positive control. Targeting effect was measured by luciferase assay. (C) Immunohistochemical analysis of A2M expression in smooth OA cartilage and damaged OA cartilage. Scale bar: 100μm. The protein (D) levels of A2M expression in chondrocytes transfected with miR-146b-mimic and miR-146b-inhibitor were evaluated by western blot. *P<0.05.