TGFB1 and pulmonary arterial hypertension: The experimental Schistosomiasis-associated PAH potentially depends on upregulation of IL-13, which can activate TGF-β1 via phospho-STAT6 signaling, or via increased matrix metalloproteinase-inducing muscular hypertrophy and periadventitial fibrosis in pulmonary arteries (Graham et al., 2010).