As a major member of the RAS, the ACE2-Ang (1–7)-Mas axis has been pointed to have the effects against lung fibrosis [44], pulmonary hypertension [45], pyroptosis [46], and prevents apoptosis of pulmonary microvascular endothelial cells [47], which is considered that it occurs mainly through anti-inflammatory and antioxidant pathways [12]. The gene discussed is ACE2; the disease is pulmonary arterial hypertension.