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Summary Glucocorticoids (GCs) are effective anti-inflammatory drugs; yet, their mechanisms of action are poorly understood. GCs bind to the glucocorticoid receptor (GR), a ligand-gated transcription factor controlling gene expression in numerous cell types. Here, we characterize GR’s protein interactome and find the SETD1A (SET domain containing 1A)/COMPASS (complex of proteins associated with Set1) histone H3 lysine 4 (H3K4) methyltransferase complex highly enriched in activated mouse macrophages. We show that SETD1A/COMPASS is recruited by GR to specific cis-regulatory elements, coinciding with H3K4 methylation dynamics at subsets of sites, upon treatment with lipopolysaccharide (LPS) and GCs. By chromatin immunoprecipitation sequencing (ChIP-seq) and RNA-seq, we identify subsets of GR target loci that display SETD1A occupancy, H3K4 mono-, di-, or tri-methylation patterns, and transcriptional changes. However, our data on methylation status and COMPASS recruitment suggest that SETD1A has additional transcriptional functions. Setd1a loss-of-function studies reveal that SETD1A/COMPASS is required for GR-controlled transcription of subsets of macrophage target genes. We demonstrate that the SETD1A/COMPASS complex cooperates with GR to mediate anti-inflammatory effects.
Graphical Abstract
Highlights • GR’s transcriptional complex in macrophages includes COMPASS proteins • GR ligand changes SETD1A chromatin occupancy in activated macrophages • Subsets of GR target sites show COMPASS binding and H3K4 methylation dynamics • SETD1A is required for some of GR’s anti-inflammatory actions
Glucocorticoids such as dexamethasone are widely used immunomodulators. Combining proteomics, ChIP-seq, RNA-seq, and genetic loss-of-function studies in murine macrophages, Greulich et al. show that recruitment of the SETD1A/COMPASS complex to cis-regulatory elements by the glucocorticoid receptor mediates some of their anti-inflammatory actions.