Because a null mutation of INHBA has been reported to be lethal in mice, we generated EC-specific conditional INHBA knockout (INHBA-ECKO) mice by mating INHBA-flox and VEcad-Cre-Tg mice, to further analyze the role of INHBA/ActA-mediated angiocrine in PAH. This evidence concerns the gene ACTA1 and pulmonary arterial hypertension.