Additionally, ER stress in AECII cells inhibited PINK1-mediated mitophagy, leading to extracellular release of mtDNA, which activated toll-like receptor 9 (TLR9) and triggered transforming growth factor-β (TGF-β) secretion, further increasing susceptibility to pulmonary fibrosis (Bueno et al., 2019). This evidence concerns the gene TGFB1 and pulmonary fibrosis.