title: Gene-specific control of inflammation by TLR-induced chromatin modifications.
abstract: Toll-like receptors (TLRs) induce a multi-component inflammatory response that must be tightly regulated to avoid tissue damage. Most known regulatory mechanisms target TLR signalling pathways and thus broadly inhibit multiple aspects of the inflammatory response. Given the functional diversity of TLR-induced genes, we proposed that additional, gene-specific regulatory mechanisms exist to allow individual aspects of the TLR-induced response to be differentially regulated. Using an in vitro system of lipopolysaccharide tolerance in murine macrophages, we show that TLR-induced genes fall into two categories on the basis of their functions and regulatory requirements. We demonstrate that representatives from the two classes acquire distinct patterns of TLR-induced chromatin modifications. These gene-specific chromatin modifications are associated with transient silencing of one class of genes, which includes pro-inflammatory mediators, and priming of the second class, which includes antimicrobial effectors. These findings illustrate an adaptive response in macrophages and reveal component-specific regulation of inflammation.
authors.affiliation: Howard Hughes Medical Institute and Department of Immunobiology, Yale University School of Medicine, New Haven, Connecticut 06405, USA.
authors.forename: Simmie L
authors.initials: SL
authors.lastname: Foster
authors.forename: Diana C
authors.initials: DC
authors.lastname: Hargreaves
authors.forename: Ruslan
authors.initials: R
authors.lastname: Medzhitov
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D002843:Chromatin / Q000187:drug effects / Q000235:genetics* / Q000378:metabolism*; D042002:Chromatin Assembly and Disassembly / Q000187:drug effects; D005786:Gene Expression Regulation / Q000187:drug effects / Q000235:genetics*; D006657:Histones / Q000378:metabolism; D007249:Inflammation / Q000139:chemically induced / Q000235:genetics*; D008070:Lipopolysaccharides / Q000494:pharmacology; D008264:Macrophages / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D008957:Models, Genetic; D011401:Promoter Regions, Genetic / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000378:metabolism*; D014158:Transcription, Genetic / Q000187:drug effects / Q000235:genetics
chemical_list: D002843:Chromatin; D006657:Histones; D008070:Lipopolysaccharides; D051197:Toll-Like Receptor 4