Abstract:

Objective To explore the role and molecular mechanism of miR-4505 in Hirschsprung disease（HSCR）. Methods Stenotic and dilated colon segments of HSCR patients operated at Zhujiang Hospital of Southern Medical University were collected.qRT-PCR was performed to detected the expression of miR-4505 in colon tissuesspecimens.The miR-NC，miR-4505 mimics and miR-4505 inhibitors were transfected into human neuroblastoma cell line SH-SY5Y，followed by qRT-PCR to examine the expression of miR-4505 after transfection， CCK-8 assay and Transwell assay to detect the effect of miR-4505 on the proliferation and migration of SH-SY5Y cells.The downstream target genes of miR-4505 were predicted through bioinformatics and detected by dual luciferase reporter gene assay； the target genes were verified by Western blot and Immunohistochemistry. Results miR-4505 was highly expressed in the stenotic colon compared to the dilated segment （t = 11.25，P < 0.001）. Overexpression of miR-4505 inhibited cell proliferation and migration， and conversely，downregulation of miR-4505 enhanced cell proliferation and migration. Target gene prediction and dual-luciferase reporter gene assay suggested that the 3′-UTR of SOX-10 was a direct target of miR-4505. Moreover， Western blot confirmed that miR-4505 decreased SOX-10 protein levels in cells， while immunohistochemistry proved that SOX-10 was lowly expressed in HSCR disease colontissues. Conclusion Our study demonstrated that miR-4505 was differentially expressed between the diseased and dilated segments of HSCR.miR-4505 could inhibited cell proliferation and migration，and its role in HSCR may be achieved by suppressing the downstream SOX-10 gene expression.

Key words: hirschsprung disease, neural stem cell, miR-4505, SOX-10