Unique tracheal fluid MicroRNA signature predicts response to FETO in patients with congenital diaphragmatic hernia

Objective and Background: Our objective was to determine the fetal in vivo microRNA signature in hypoplastic lungs of human fetuses with severe isolated congenital diaphragmatic hernia (CDH) and changes in tracheal and amniotic fluid of fetuses undergoing fetoscopic endoluminal tracheal occlusion (FETO) to reverse severe lung hypoplasia due to CDH. Methods: We profiled microRNA expression in prenatal human lungs by microarray analysis. We then validated this signature with real-time quantitative polymerase chain reaction in tracheal and amniotic fluid of CDH patients undergoing FETO. We further explored the role of miR-200β using semiquantitative in situ hybridization and immunohistochemistry for TGF-β2 in postnatal lung sections. We investigated miR-200β effects on TGF-β signaling using a SMAD-luciferase reporter assay and Western blotting for phospho-SMAD2/3 and ZEB-2 in cultures of human bronchial epithelial cells. Results: CDH lungs display an increased expression of 2 microRNAs: miR-200β and miR-10a as compared to control lungs. Fetuses undergoing FETO display increased miR-200 expression in their tracheal fluid at the time of balloon removal. Future survivors of FETO display significantly higher miR-200 expression than those with a limited response. miR-200β was expressed in bronchial epithelial cells and vascular endothelial cells. TGF-β2 expression was lower in CDH lungs. miR-200β inhibited TGF-β-induced SMAD signaling in cultures of human bronchial epithelial cells. Conclusions: Human fetal hypoplastic CDH lungs have a specific miR-200/miR-10a signature. Survival after FETO is associated with increased miR-200 family expression. miR-200β overexpression in CDH lungs results in decreased TGF-β/SMAD signaling.

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