TGFB1 and pulmonary arterial hypertension: Pn-expressing cell-targeted inhibition of TGF-β signaling (Pn-Cre/Tgfbr1fl/fl mice) effectively attenuated the development of PAH under hypoxic condition, suggesting that Pn-positive cells are crucial for TGF-β-mediated vascular remodeling in PAH.