SMAD2 and polyostotic fibrous dysplasia: In summary, PFD not only alleviated pulmonary fibrosis of mice models caused by BLM, but also relieved TGF-β1-induced HLFs damage, which were mainly realized by regulating Wnt/GSK-3β/β-catenin and TGF-β1/Smad2/3 signaling pathways.