For this reason, we previously developed an array of selective inhibitors and utilized ZL0591, a selective allosteric inhibitor that targets BRD4 BD1 with ∼100 nM affinity, while demonstrating low affinity for BRD4 BD2, BRD2 and BRD3, to enable elucidation of the role of BRD4 BD1 in pulmonary fibrosis (Liu et al., 2020; Liu et al., 2022). Here, BRD2 is linked to pulmonary fibrosis.