BackgroundNitrative stress is a characteristic feature of the pathology of human pulmonary arterial hypertension. However, the role of nitrative stress in the pathogenesis of obliterative vascular remodelling and severe pulmonary arterial hypertension remains largely unclear.MethodOur recently identified novel mouse model (Egln1^Tie2Cre, Egln1encoding prolyl hydroxylase 2 (PHD2)) has obliterative vascular remodelling and right heart failure, making it an excellent model to use in this study to examine the role of nitrative stress in obliterative vascular remodelling.ResultsNitrative stress was markedly elevated whereas endothelial caveolin-1 (Cav1) expression was suppressed in the lungs ofEgln1^Tie2Cremice. Treatment with a superoxide dismutase mimetic, manganese (III) tetrakis (1-methyl-4-pyridyl) porphyrin pentachloride or endothelialNos3knockdown using endothelial cell-targeted nanoparticle delivery of CRISPR–Cas9/guide RNA plasmid DNA inhibited obliterative pulmonary vascular remodelling and attenuated severe pulmonary hypertension inEgln1^Tie2Cremice. Genetic restoration of Cav1 expression inEgln1^Tie2Cremice normalised nitrative stress, reduced pulmonary hypertension and improved right heart function.ConclusionThese data suggest that suppression of Cav1 expression secondary to PHD2 deficiency augments nitrative stress through endothelial nitric oxide synthase activation, which contributes to obliterative vascular remodelling and severe pulmonary hypertension. Thus, a reactive oxygen/nitrogen species scavenger might have therapeutic potential for the inhibition of obliterative vascular remodelling and severe pulmonary arterial hypertension.