APLN and pulmonary arterial hypertension: The profile of gene expression in the lungs of Egln1Tie2Cre mice indicates that many of the PAH-causing genes such as bone morphogenetic protein receptor type 2 (BMPR2), activin A-receptor-like type 1 (ACVRL1), endothelin-1 (EDN1), apelin (APLN), IL6, and caveolin 1 (CAV1) are altered, as seen in IPAH patients [12,29].