miR-142-5p as a CXCR4-Targeted MicroRNA Attenuates SDF-1-Induced Chondrocyte Apoptosis and Cartilage Degradation via Inactivating MAPK Signaling Pathway

Figure 2

CXCR4 is a direct target of miR-142-5p and is negatively regulated by miR-142-5p. (a) A design scheme showing the binding of miR-142-5p to the predicted 3′UTR site of CXCR4. The binding site of miR-142-5p, AGUGC, was mutated to UGAGC in the reporter vector bearing the mutant 3′UTR. The luciferase activity of the reporter vectors was detected in 293T cells at 48 hours after cotransfection of wild-type (WT) or mutant (Mut) CXCR4 3′UTR with miR-142-5p mimics or negative control mimic. N = 3 for each group. (b-e) Primary human OA chondrocytes were transfected with a negative control (NC) mimic, miR-142-5p mimic, NC inhibitor, and miR-142-5p inhibitor and further incubated with SDF-1 (100 ng/ml) for 24 h. The expression levels of miR-142-5p (b) and CXCR4 (c) were then measured by qRT-PCR. The protein levels of CXCR4 were determined by Western blot. The representative bands images are shown (d), and relative bands intensity was summarized (e). N = 3 for each group. Data are presented as the mean ± SEM (n = 3). ; versus NC mimic; and versus NC inhibitor. miRNAs, microRNAs; SDF-1, stromal cell-derived factor 1; NC, negative control; Gapdh, glyceraldehyde‐3‐phosphate dehydrogenase.

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