TGFB1 and pulmonary fibrosis: Given that alveolar epithelial cells play a critical role in the pathogenesis of pulmonary fibrosis, we challenged primary mouse alveolar epithelial type II cells (pMATII) and A549 cells (human lung alveolar epithelial type II cells) with TGF-β in serum-free medium to induce EMT and primary cilium formation (Fig. 2A).