FN1 and pulmonary arterial hypertension: This activation results in increased expression of COL1 and α-SMA, ultimately contributing to fibrosis.276 Furthermore, in PASMCs exposed to high oxygen levels, β-catenin activation upregulates CTGF and FN1 expression, promoting ECM remodeling and cell proliferation.274 The Wnt/β-catenin pathway also contributes to right heart failure in PAH by facilitating ECM remodeling.