NF-κB-dependent GR cistrome redistribution recruits GR to inflammatory genes but correlates with lesser...

While ligand-activated glucocorticoid receptor (GR) binds DNA to activate transcription, glucocorticoids, including budesonide, reduce inflammatory gene expression, yet recruit GR to many such gene loci. In epithelial cells, the inflammatory cytokine, interleukin-1β (IL1B), activates nuclear factor (NF)-κB to induce gene expression, and co-treatment with budesonide produces nanoscale GR-RELA nuclear co-localization. Such co-stimulation orchestrated reciprocal genome-wide redistribution of GR- and RELA-binding regions (GBRs and RBRs, respectively) relative to each mono-treatment to produce widespread GBR-RBR overlap. This correlated with increased RNA polymerase-2 presence and required NF-κB for GR cistrome remodeling. Mapping transcription start sites to the nearest GBR or RBR each revealed associations with upregulated, but not repressed, genes. Importantly, RBR proximity to budesonide-upregulated genes and GBR proximity to IL1B-upregulated genes correlated with attenuated repression on co-treatment. As this occurred on a background of glucocorticoid-induced repression, GR presence at specific IL1B-induced gene loci may reduce/protect from an otherwise more prevalent glucocorticoid-induced repression.