Hyperplastic type II AECs from IPF patients’ lungs highly express this NOX isoform (Amara et al., 2010) and Nox4-dependent ROS generation induces epithelial-to-mesenchymal transition (EMT) in alveolar epithelial cells (Hecker et al., 2009; Cameli et al., 2020). Here, NOX4 is linked to idiopathic interstitial pneumonia.