Figure 1 revealed that in PAH model ECs layer dissociated, vWF and αSMA co-expressed in some of EC cells, with part of ECs migrate toward to inner layer, which indicate that endothelial mesenchymal transition occurs in MCT and hypoxia PAH models, in addition, Figure 1B and 1C shown Gal-3 co-expressed with αSMA and vWF and accompanied with their upregulation suggesting that Gal-3 may regulate endothelial cells transition in vascular pathologies. The gene discussed is LGALS3; the disease is pulmonary arterial hypertension.