PDGFRB and pulmonary fibrosis: NPNT was initially identified as an extracellular matrix ligand for integrin α8β1.[22] Following TGF‐β treatment, pulmonary PDGFRβ+ stromal cells with ITGA8 deficiency exhibited increased Col1a1 mRNA expression; however, no functional differences were observed in vivo,[20] suggesting a redundant role of ITGA8 in pulmonary fibrosis.