Similarly, hypoxia increased mRNA levels of ECM proteins (collagens, fibronectin, and matrix metalloproteases) in isolated primary murine AEC2s (Figure 1g and Supplementary Figure S1), consistent with the observation of epithelial plasticity in lungs of IPF patients.27 In summary, our findings indicate that epithelial hypoxia is a profibrotic insult capable of altering the lung matrix as seen in IPF. This evidence concerns the gene FN1 and idiopathic pulmonary fibrosis.