SMAD2 and chronic obstructive pulmonary disease: In conclusion, our results revealed that artesunate treatment significantly protected against CS-induced airway inflammation, as well as airway remodelling via PPAR-γ/TGF-β1/Smad2/3 signalling in vivo and in vitro, and provides a novel use for an ‘old’ drug to treat airway remodelling in COPD.