In mice, the lack of endothelial nitric oxide synthase (eNOS) and exposure to bleomycin led to decreased expression of phosphorylated VEGFR2 (KDR), suggesting that the disruption of the VEGF (vascular endothelial growth factor) signaling pathway contributes to PAH and impaired alveolar development. Here, VEGFA is linked to pulmonary arterial hypertension.