Epithelial miR-215 negatively modulates Th17-dominant inflammation by inhibiting CXCL12 production in the small intestine.

MicroRNAs are a class of non-coding short-chained RNAs that control cellular functions by downregulating their target genes. Recent research indicates that microRNAs play a role in the maintenance of gut homeostasis. miR-215 was found to be highly expressed in epithelial cells of the small intestine; however, the involvement of miR-215 in gut immunity remains unknown. Here, we show that miR-215 negatively regulates inflammation in the small intestine by inhibiting CXCL12 production. Mice lacking miR-215 showed high susceptibility to inflammation induced by indomethacin, accompanied by an increased number of Th17 cells in the lamina propria of the small intestine. Our findings provide a rationale for targeting miR-215 as a therapeutic intervention for inflammatory conditions in the small intestine.