TGFB1 and idiopathic pulmonary fibrosis: Snail2 (SNAI2) depletion (Fig. 5a) in ATII cells eliminated the effects of CM from ATG5-depleted ATII cells on activation of fibroblasts in the presence of TGF-β (Fig. 5c), highlighting the importance of Snail2 (SNAI2) as a key regulator of paracrine signalling between alveolar cells and fibroblasts in IPF under conditions where autophagy is defective.