miR-141 Regulates colonic leukocytic trafficking by targeting CXCL12β during murine colitis and human Crohn's disease.

Emerging evidence suggests that microRNA (miRNA)-mediated gene regulation influences a variety of autoimmune disease processes, including Crohn's disease (CD), but the biological function of miRNAs in CD remains unclear. We examine miRNA level in colon tissues and study the potential functions of miRNAs that regulate pathological genes during the inflammation process. miRNA levels were assayed in the inflamed colon of 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced and IL-10 knockout (KO) chronic colitis mice and CD patients by microarray or qRT-PCR. The influence of differently expressed miR-141 on its putative target genes, CXCL12β, and leukocyte migration was investigated in colonic epithelia cells, colitis models and CD patients. The role of miR-141 was further studied in the experimental colitis mice by intracolonic administration of miR-141 precursors or inhibitors. An inverse correlation between miR-141 and CXCL12β/total-CXCL12 was observed predominantly in the epithelial cells of the inflamed colons from colitic mice and CD patients. Further study demonstrated that miR-141 directly regulated CXCL12β expression and CXCL12β-mediated leukocyte migration. Upregulation or downregulation of miR-141 in the TNBS-induced or IL-10 KO colitic colon regulated leukocyte infiltration and alleviated or aggravated experimental colitis, respectively. Additionally, colonic overexpression of CXCL12β abolished the therapeutic effect of miR-141 in TNBS-induced colitis. This study showed that the pathway of miR-141 targeting CXCL12β is a possible mechanism underlying inflammatory cell trafficking during colonic inflammation process. Inhibiting colonic CXCL12β expression and blocking colonic immune cell recruitment by using miRNA precursors represents a promising approach that may be valuable for CD treatment.