ABSTRACT
AIM:To investigate the role of microRNA-21(miR-21)in regulation of tight junction(TJ)-asso-ciated protein occludin in human normal colon mucosal epithelial cell line NCM 460, and to analyze related target genes. METHODS:Using miR-21 over-expression lentivirus, the NCM460 cells with miR-21 overexpression were established. The expression level of miR-21 was detected by qPCR.The expression of occludin was determined by Western blot.The target genes of miR-21 were predict by bioinformatic method.According to the scores and the appropriate literature search, a target gene was selected for further study.The miR-21 mimic and inhibitor were transfected into NCM 460 cells,and the expression levels of miR-21 and ROCK1 were measured.Dual-luciferase reporter assay was also performed to verify ROCK1 as the target gene of miR-21.RESULTS:In miR-21-overexpressing NCM460 cells,the protein expression level of occlu-din was upregulated.Bioinformatics and literature analysis predicted that the target gene of miR-21 was ROCK1.The mR-NA and protein levels of ROCK1 were down-regulated in the NCM460 cells transfected with miR-21 mimic.Accordingly, the mRNA and protein levels of ROCK1 were up-regulated in the NCM460 cells transfected with miR-21 inhibitor.Lucifer-ase assay confirmed that miR-21-binding sequence was on the 3'UTR of ROCK1,indicating that ROCK1 is the target gene of miR-21.CONCLUSION: In NCM460 cells, miR-21 up-regulates the expression of occludin, which functions in the maintenance of intestinal epithelial mechanical barrier.ROCK1 is a target gene of miR-21,and is involved in the miR-21 regulation of occludin.