For the evaluation of this system as a model to study lung fibrosis, it is of note that the TGF-β1 treatment also led to upregulation of periostin (POSTN) and versican (VCAN), which together with fibronectin and Tenascin C have been shown to be upregulated in fibroblastic foci, which are considered to constitute remodelling hotspots in IPF35,36. This evidence concerns the gene FN1 and pulmonary fibrosis.