TGFB1 and chronic obstructive pulmonary disease: Finally, our team recently showed that WNT/β-catenin signaling pathway is activated in the large airways of COPD patients, therefore contributing to enhance EMT, as in vitro extrinsic activation of WNT resulted in increased vimentin expression, fibronectin release, and p-SMAD2/TGF-β signaling (Carlier et al., 2020).