Prenatal microRNA miR-200b Therapy Improves Nitrofen-induced Pulmonary Hypoplasia Associated With Congenital Diaphragmatic Hernia.

We aimed to evaluate the use of miR-200b as a prenatal transplacental therapy in the nitrofen rat model of abnormal lung development and congenital diaphragmatic hernia (CDH). Pulmonary hypoplasia (PH) and pulmonary hypertension determine mortality and morbidity in CDH babies. There is no safe medical prenatal treatment available. We previously discovered that higher miR-200b is associated with better survival in CDH babies. Here, we investigate the role of miR-200b in the nitrofen rat model of PH and CDH and evaluate its use as an in vivo prenatal therapy. We profiled miR-200b expression during nitrofen-induced PH using RT-qPCR and in situ hybridization in the nitrofen rat model of PH and CDH. The effects of nitrofen on downstream miR-200b targets were studied in bronchial lung epithelial cells using a SMAD luciferase assay, Western blotting and Immunohistochemistry. We evaluated miR-200b as a lung growth promoting therapy ex vivo and in vivo using lung explant culture and transplacental prenatal therapy in the nitrofen rat model. We show that late lung hypoplasia in CDH is associated with (compensatory) upregulation of miR-200b in less hypoplastic lungs. Increasing miR-200b abundance with mimics early after nitrofen treatment decreases SMAD-driven TGF-β signaling and rescues lung hypoplasia both in vitro and in vivo. Also, prenatal miR-200b therapy decreases the observed incidence of CDH. Our data indicate that miR-200b improves PH and decreases the incidence of CDH. Future studies will further exploit this newly discovered prenatal therapy for lung hypoplasia and CDH.