DCN and idiopathic pulmonary fibrosis: Among the proteins upregulated in lung tissue of IPF patients and conditional Nedd4-2−/− mice, we found COL14A1, which was reported to be expressed by a certain fibroblast subtype that undergoes expansion in bleomycin-induced fibrosis46 and acts as a major ECM binding site for the proteoglycan decorin, which is known to regulate TGFβ activity47,48.