FN1 and pulmonary fibrosis: In the pathological process of pulmonary fibrosis, TGF-β1 activates Smad and non-Smad transcription factors via the serine-threonine kinase transduction pathway and then promotes the transcription of genes involved in ECM formation, stimulates fibroblast migration and proliferation, induces the deposition of collagen and fibronectin, and promotes alveolar epithelial cell injury (Fernandez and Eickelberg, 2012).