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

The aim of this research is to explore the effect of miR‐200b‐3p targeting DNMT 3A on the proliferation and apoptosis of osteoarthritis ( OA ) cartilage cells. Quantitative RT ‐ PCR was performed to analyse the expression of miR‐200b‐3p, DNMT 3A , MMP 1 , MMP 3 , MMP 9 , MMP 13 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 DNMT 3A . We also constructed eukaryotic expression vector to overexpress miR‐200b‐3p and DNMT 3A . We detected the expression level of MMP s 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 DNMT 3A 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 DNMT 3A and MMP s was up‐regulated in OA cartilage tissues. The expressions of DNMT 3A , MMP s 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 DNMT 3A . In overexpressed miR‐200b‐3p cartilage cells, DNMT 3A and MMP s were significantly down‐regulated, COL II was significantly up‐regulated, cell viability was enhanced and apoptosis rate was decreased ( P < 0.05). In overexpressed DNM 3T cartilage cells, MMP s 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 MMP s , promoted the synthesis of COL II and enhanced the growth and proliferation of OA cartilage cells through inhibiting the expression of DNMT 3A .