TGFB1 and idiopathic pulmonary fibrosis: However, in human IPF lungs, bulk RNA-seq data of tissue-resident and monocyte-derived alveolar macrophages showed no obvious upregulation of all isoforms of TGFβ38, while the expression of SPP1 (a gene of osteopontin) was increased, and that could enhance the “TGF-β1-induced” fibroblast-to-myofibroblast differentiation50,51.