SDC1 and idiopathic pulmonary fibrosis: Detailed ligand-receptor analysis revealed that SCPEP1+ basal cells actively engaged in several IPF-relevant signaling axes, including pro-inflammatory MIF–CD74, pro-fibrotic and growth factor pathways MDK–NCL/SDC1, and adhesion/remodeling pathways such as THBS1–CD47/ITGB1 and ICAM1–ITGAL (Supplementary Figure S3A, B).