Effect of the interaction between MiR‐200b‐3p and DNMT3A on cartilage cells of osteoarthritis patients

The aim of this research is to explore the effect of miR-200b-3p targeting DNMT3A on the proliferation and apoptosis of osteoarthritis (OA) cartilage cells. Quantitative RT-PCR was performed to analyse the expression of miR-200b-3p, DNMT3A, MMP1, MMP3, MMP9, MMP13 and COL II in normal and OA cartilage tissues. The dual-luciferase reporter assay and Western blot assay were conducted to confirm the targeting relationship between miR-200b-3p and DNMT3A. We also constructed eukaryotic expression vector to overexpress miR-200b-3p and DNMT3A. We detected the expression level of MMPs and COL II in stable transfected cartilage cells using RT-PCR and Western blot. Cell proliferation and apoptosis were evaluated using the MTS, pellet culture and Hoechst 33342 staining method. Finally, we explored the effect of miR-200b-3p targeting DNMT3A on the proliferation and apoptosis of OA cartilage cells. The results of RT-PCR indicated that both miR-200b-3p and COL II were down-regulated in OA cartilage tissues, while the expression of DNMT3A and MMPs was up-regulated in OA cartilage tissues. The expressions of DNMT3A, MMPs and COL II detected by Western blot showed the same trend of the results of RT-PCR. The dual-luciferase reporter assay and Western blot assay confirmed the targeting relationship between miR-200b-3p and DNMT3A. In overexpressed miR-200b-3p cartilage cells, DNMT3A and MMPs were significantly down-regulated, COL II was significantly up-regulated, cell viability was enhanced and apoptosis rate was decreased (P < 0.05). In overexpressed DNM3T cartilage cells, MMPs were significantly up-regulated, COL II was significantly down-regulated, cell viability was weakened and apoptosis rate was increased (P < 0.05). MiR-200b-3p inhibited the secretion of MMPs, promoted the synthesis of COL II and enhanced the growth and proliferation of OA cartilage cells through inhibiting the expression of DNMT3A.