Alveolospheres formed from single iAEC2 over 14 d were stimulated for 72 h with a fibrosis cocktail (FC) containing TGF-β, TNF-α, platelet-derived growth factor AB (PDGF-AB), and lysophosphatidic acid, previously shown to induce phenotypic changes of epithelial cells in an ex vivo model mimicking alterations seen in IPF (27, 28) (Fig 1A). The gene discussed is TGFB1; the disease is idiopathic pulmonary fibrosis.