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

Figure 4

miR-142-5p counteracted inflammation and matrix degradation in SDF-1-induced chondrocytes. (a–k) Primary human OA chondrocytes were transfected with the indicated miRNA mimics and plasmids. At 48 h after transfection, cells were then treated with SDF-1(100 ng/ml) for another 24 h. The release of (a) IL-1β, (b) IL-10, and (c) TNF-α in culture supernatant was measured by ELISA kits. (d) The mRNA level of MMP-13 expression was measured by qRT-PCR. (e, f) The protein level of MMP-13 expression was measured by Western blot assays. The representative bands images are shown (e), and relative bands intensity was summarized (f). (g-h) Immunofluorescence analysis of collagen II (g) and aggrecan (h) expression in primary human OA chondrocytes after indicated transfection. Scale bar, 50 μm. (i–k) The protein expressions of collagen II (j) and aggrecan (k) were determined with Western blot assays, and the representative bands images are shown (i). ; versus the miR-NC + vector group; and versus the miR-142-5p mimic + vector group. Data are represented as the mean ± SD (n = 3). miRNAs, microRNAs; SDF-1, stromal cell-derived factor 1; NC, negative control; IL-1β, interleukin-1β; IL-10, interleukin–10; TNF-α, tumor necrosis factor α; MMP-13, matrix metalloproteinase-13; ACAN, aggrecan; collagen II, type II collagen; Gapdh, glyceraldehyde‐3‐phosphate dehydrogenase; DAPI, 4′,6-diamidino-2-phenylindole.

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