BET bromodomain inhibitors attenuate transcription of a subset of IL-1-induced NF-κB target genes that promote inflammation in β-cells

Cytokine-stimulated transcription of NF-κB target genes is linked to the development of multiple inflammatory and autoimmune diseases. Inhibitors of bromodomain and extraterminal domain (BET) epigenetic reader proteins attenuate inflammatory gene transcription and delay the onset of several inflammatory diseases, including autoimmune diabetes. Our previous studies showed that BET bromodomain inhibitors disrupt the interaction between BET family member BRD4 and NF-κB transcription factor p65 in β-cells, thus attenuating cytokine-stimulated NF-κB-dependent gene and functional changes. However, the role of NF-κB in developing inflammatory disease is controversial, as NF-κB inhibition can promote disease progression in some contexts. NF-κB target genes play both physiological and pathophysiological roles in regulating the cellular response to cytokines. Here, using cytokine-stimulated pancreatic β-cells as an inflammatory disease model, we show that NF-κB-dependent gene products that participate in inflammation are sensitive to BET bromodomain inhibition. In contrast, gene products that maintain cellular homeostasis or protect β-cells from stressors are largely insensitive to BET bromodomain inhibition. These studies define a novel and selective role for BET bromodomain-containing proteins in regulating inflammatory gene activation. INS 832/13 rat insulinoma cells treated with BET bromodomain inhibitor (+)-JQ1 (dissolved in DMSO). DMSO was used as a control.