Decreased endothelial micro-RNA-30b-5p impairs angiogenesis in fetal lambs with persistent pulmonary hypertension.

BACKGROUND: Impaired angiogenesis contributes to increased pulmonary vascular resistance in persistent pulmonary hypertension of the newborn (PPHN). Notch signaling, critical to lung angiogenesis, is modulated by micro-RNAs (miR). RNA sequencing of pulmonary arterial endothelial cells (PAEC) from a PPHN lamb model revealed downregulated miR-30b-5p. METHODS: We investigated whether decreased levels of miR-30b-5p in PPHN affect angiogenesis by facilitating excess Dll4, a predicted target for miR-30b-5p. We obtained PAEC from a fetal lamb model of PPHN and transfected them with miR-30b-5p mimic and inhibitor. We assessed protein levels by immunoblotting and in vitro angiogenesis by tube formation in Matrigel. We performed In-situ RNA hybridization for in vivo miR-30b-5p levels in the lamb lungs. RESULTS: PPHN lamb lungs showed decreased miR-30b-5p levels in vivo. PPHN PAEC transfected with miR-30b-5p mimic showed improved capillary tube formation. Control PAEC showed inhibition of tube formation after transfection with miR-30b-5p inhibitor. Transfection with miR-30b-5p led to the downregulation of Dll4, in PPHN PAEC. CONCLUSION: We conclude that decreased miR-30b-5p in PPHN facilitates overexpression of Dll4, which contributes to impaired angiogenesis in PPHN. MiR-30b-5p improves angiogenesis in PPHN by improving Dll4/Jag1 balance (Jag1, a proangiogenic notch ligand), suggesting an epigenetic role in PPHN. IMPACT: The present study describes a novel mechanism of epigenetic control of impaired angiogenesis in PPHN via miR-30b-5p. The present study also provides new direction for future in vivo studies in animals and patients with PPHN to investigate the role of miR-30b-5p as a biomarker of angiogenesis in PPHN.