The vital roles of Brd4 and its inhibitor JQ1 have been proven in the epigenetic regulation of p300 in various profibrotic genes, such as NOX4, snail family transcriptional repressor 1 (SNAI1), and CTGF in IPF and myocardial infarction (MI) induced cardiac fibrosis [54, 56–59]. The gene discussed is SNAI1; the disease is idiopathic pulmonary fibrosis.