The results presented in this manuscript using EP300inh in vitro (Fig. 8b–e, 8g, Supplementary Fig. 7), in vivo (Fig. 7a–e), and ex vivo (Fig. 8d, 8f, and Supplementary Fig. 8) strongly suggest that inhibition of the bromodomain is crucial for the role of EP300 during IPF. This evidence concerns the gene EP300 and idiopathic pulmonary fibrosis.