Abstract: Objective: To investigate the effect of the miR-21 and its target mRNA in renal tubular epithelial mesenchymal transformation (EMT) model induced by transformation growth factor-β1(TGF-β1) in human renal tubular epithelial (HK-2) cells.Methods: HK-2 cells were divided into 6 groups:normal control group, TGF-β1 group, miR-21 mimic negative group, miR-21 mimic group, miR-21 inhibitor negative group and miR-21 inhibitor group. EMT model was established in HK-2 cells induced by 4 ng/ml TGF-β1. The level of miR-21, the mRNA and protein expression of EMT related factors were detected. MiR-21 mimic plasmid and miR-21 inhibitor plasmid were transfected into HK-2 cells that treated with TGF-β1 respectively using liposome transfection technique. Observe the impact of overexpression or inhibition expression of miR-21 on the mRNA and protein expression of EMT related factors and PTEN.Results: ①Compared with the normal group, the level of miR-21 was significantly increased in model group (P<0.05), the mRNA and protein expression levels of epithelial cells marker E-cadherin was significantly decreased (P<0.01), while the mRNA and protein levels of mesenchymal cells marker α-SMA was significantly increased (P<0.05,P<0.01). ②Compared with the miR-21 mimic negative group, the level of miR-21 in miR-21 mimic group increased significantly (P<0.01), the mRNA and protein expression levels of PTEN and E-cadherin decreased significantly (P<0.05,P<0.01), the mRNA and protein levels of α-SMA increased significantly (P<0.05,P<0.01). Compared with the miR-21 inhibitor negative control group, the level of miR-21 in miR-21 inhibitor group decreased significantly (P<0.01), the mRNA and protein expression levels of PTEN and E-cadherin increased significantly (P<0.05,P<0.01), the mRNA and protein levels of α-SMA decreased significantly (P<0.05,P<0.01).Conclusion: MiR-21 may play an important role in EMT induced by TGF-β1 in HK-2 cells and regulate the expression of EMT related factors its target gene PTEN.

Key words: microRNA-21, HK-2 cells, transformation growth factor-β1, epithelial mesenchymal transformation