SMAD2 and pulmonary fibrosis: It was demonstrated that GA attenuated BLM-induced pulmonary fibrosis by regulating CF modifications of TGF-βRI, TGF-βRII, and WNT, important receptor proteins in the TGF-β/Smad2/3 and WNT/β-catenin signaling pathways, while having a little effect on the receptors themselves.