MicroRNA-21 increases the expression level of occludin through regulating ROCK1 in prevention of intestinal barrier dysfunction

Objective: The aim of this study is to investigate the role of molecular mechanism of microRNA (miR)-21 on tight junction (TJ)-proteins and its protective effects on the intestinal barrier. Methods: TJ proteins and target genes expression were analyzed in miR-21 inhibition and overexpression NCM460 cell lines. To further verify the role of miR-21, the mmu-miR-21 intestinal epithelial conditional knockout (IKO) mice model was established. MiR-21 expression was detected in clinical specimens of acute stercoral obstruction patients. Results: Rho-associated protein kinase 1 (ROCK1) were identified as target genes of miR-21. There is a negative correlation between miR-21 expression level and TJ proteins levels. TJ protein and ROCK1 were significantly decreased in miR-21 IKO mice, which presented intestinal inflammation response and intestinal barrier dysfunction (both P < 0.05). Determination of clinical samples showed consistent results with NCM460 cell line and miR-21 IKO mice. Conclusions: MiR-21 could be a protective factor of intestinal barrier dysfunction, which promoting the expression of TJ protein by targeting ROCK1 in vivo and in vitro.