Role of MiR-215 in Hirschsprung's Disease Pathogenesis by Targeting SIGLEC-8.

BACKGROUND/AIMS Hirschsprung's disease (HSCR), known as aganglionosis, is an infrequent congenital gut motility disorder characterized by absence of enteric neurons. In this study, we focus on the role of the intronic miR-215 and its host gene isoleucyl-tRNA synthetase 2 (IARS2) in the pathogenesis of HSCR. METHODS Quantitative real time PCR and Western blot were used to detect the miRNA, mRNAs, and proteins levels. The dual-luciferase reporter gene assay confirmed the direct regulation of the specific mRNA and miRNAs in cell lines. Transwell assays, CCK8 assay, and flow cytometry were used to measure cell function of the human 293T and SH-SY5Y cells. RESULTS Expression levels of miR-215 in HSCR patient colon tissues were outstandingly lower than controls, which was positively correlated with expression of the host gene IARS2 and negatively correlated with predicted target gene: sialic acid binding Ig-like lectin 8 (SIGLEC-8). The loss of miR-215 inhibited cell migration and proliferation, which was consistent with the reduction of IARS2. The dual-luciferase reporter gene assay confirmed that miR-215 resulted in the inhibition of SIGLEC-8 by directly binding to the 3'-UTR of SIGLEC-8. Moreover, knocking-down SIGLEC-8 rescued the extent of suppressed cell migration and proliferation that resulted from the diminishment of miR-215. CONCLUSIONS Our findings indicate that miR-215 acts in concert with the host gene IARS2 to affect neuron migration and proliferation through the target gene SIGLEC-8. We infer that the IARS2-miR-215-SIGLEC-8 pathway may play a crucial role in the pathogenesis of HSCR.