Expression of miRNA-21 in colonic mucosa and peripheral blood CD4+ T cells of 49 patients with active inflammatory bowel disease

Abstract

Objective To investigate the role and significance of miRNA-21 in the pathogenesis and development of inflammatory bowel disease (IBD). Methods The expressions of microRNA-21 (miRNA-21) in colonic mucosa and peripheral blood CD4+ T cells were analyzed by fluorescence quantitative polymerase chain reaction (PCR) in 26 patients with active Crohn's disease (CD), 23 patients with active ulcerative colitis (UC) and 19 healthy controls. The relative expression amount of miRNA-21 in colonic mucosal and peripheral blood CD4+ T cells in 11 patients with CD was compared before and after infliximab (IFX) treatment, and its correlation with tumor necrosis factor(TNF)-α was analyzed. t-test was performed for comparison between groups. The correlation between miRNA-21 expression in peripheral blood CD4+ T cells and serum TNF-α was analyzed by Spearman correlation analysis. Results The expression of miRNA-21 in colonic mucosa of CD patients and UC patients was 4.720±0.397 and 4.993±0.415, respectively, which were both higher than that of healthy control group (1.101±0.284), and the differences were statistically significant (t=7.657 and 8.356, both P<0.01). The expression of miRNA-21 in peripheral blood CD4+ T cells of CD patients and UC patients was 3.254±0.323 and 3.450±0.311, which were both higher than that of healthy control group (0.891±0.220), and the differences were statistically significant (t=6.007 and 7.098, both P<0.01). After 12 weeks of IFX treatment, simple endoscopic score for Crohn's disease (SES-CD) of CD patients was 8.019±0.349, which was lower than that before treatment (21.502±1.185), and the difference was statistically significant (t=10.910, P<0.01). The serum TNF-α level was 61.570±6.252, which was lower than that before treatment (173.500±12.670), and the difference was statistically significant (t=7.926, P<0.01). The results of correlation analysis indicated that serum TNF-α level was positively correlated with miRNA-21 expression in peripheral blood CD4+ T cells (r=0.780 4, P<0.01). Conclusions The increasing of miRNA-21 expression in IBD was closely correlated with the serum TNF-α level and severity of inflammation. miRNA-21 might be a new target for IBD treatment. Key words: miRNA-21; Inflammatory bowel diseases; Crohn disease; Colitis, ulcerative