ATF6 and pulmonary fibrosis: To further clarify the relationship between the PI3K/AKT/mTOR pathway and ER stress in lung fibrosis, the protein level of each molecule at some earlier time point were checked and the results showed that the expression of phosphorylated AKT was increased at 30 minutes after bleomycin was added, followed by increased expression of ER stress associated proteins including PERK, ATF6 and IRE1 at 90 minutes after bleomycin treatment (Supplementary Figure S3A).