MFN1 and pulmonary fibrosis: To assess AEC2 cell injury and proliferation in the bleomycin-induced lung fibrosis mouse model and to explore the biological processes affected in AEC2 cells after deletion of Mfn1 or Mfn2, we generated Mfn1loxP/loxPSftpcCreERT2+/−ROSA26tdTomato+/− (Mfn1iΔAEC2/tdTomato-AEC2) and Mfn2loxP/loxPSftpcCreERT2+/−ROSA26tdTomato+/− (Mfn2iΔAEC2/tdTomato-AEC2) mice (Supplementary Fig. 10a), and performed transcriptomic profiling in Mfn1- and Mfn2-deficient AEC2 cells.