Hypoxia was also found to induce pulmonary EndMT, as an upregulation of hypoxia-inducible transcription factor (HIF)-1α and HIF-2α was demonstrated in lung tissues and isolated pulmonary arterial endothelial cells from patients with idiopathic PAH and three different rodent models of PAH [35]. Here, HIF1A is linked to pulmonary arterial hypertension.