In addition, our lab demonstrated that RAS-activated ATII cells provide paracrine signals to augment fibroblast activation.76, 77, 78 While ZEB1 knock-out mice presented with less mesenchymal gene expressions,79 ZEB1 is recognized as a pivotal transcription factor that governs the expression of secreted factors from AECs undergoing EMT.76, 77, 78 In return, secreted protein acidic and rich in cysteine (SPARC) from IPF fibroblasts could disturb the integrity of the alveolar epithelium by disrupting junctional contacts.80 The gene discussed is SPARC; the disease is idiopathic pulmonary fibrosis.