PTEN and pulmonary fibrosis: For example, extracellular vesicles containing microRNA-23b-3p and microRNA-495-3p derived from lung fibroblasts increase reactive oxygen species levels in mitochondria and cause mitochondria-related damage in lung epithelial cells, resulting in DNA damage and subsequently, epithelial cell senescence (Kadota et al., 2020); another recent study reported that the PTEN/NF-κB pathway in senescent AECs facilitated the accumulation of collagen in fibroblasts, leading to lung fibrosis (Tian et al., 2019).