In MCT-PAH rats, upregulation of TGF-β and increased phosphorylation of Smad2 leads to elevated expression of Gal-3 and α-SMA, facilitating EndMT.92 Furthermore, the neuroblastoma suppressor of tumorigenicity 1, a secreted glycoprotein associated with congenital heart disease-related PH, exacerbates the phenotypic transformation of PASMCs. Here, SMAD2 is linked to pulmonary arterial hypertension.