title: Sepsis induces specific changes in histone modification patterns in human monocytes.
abstract: BACKGROUND
  Sepsis is a global burden and the primary cause of death in intensive care units worldwide. The pathophysiological changes induced by the host's systemic inflammatory response to infection are not yet fully understood. During sepsis, the immune system is confronted with a variety of factors, which are integrated within the individual cells and result in changes of their basal state of responsiveness. Epigenetic mechanisms like histone modifications are known to participate in the control of immune reactions, but so far the situation during sepsis is unknown.
  
  
  RESULTS
  In a pilot approach, we performed combined chromatin immunoprecipitation followed by high-throughput sequencing to assess the genome-wide distribution of the chromatin modifications histone 3 lysine 4 and 27 trimethylation and lysine 9 acetylation in monocytes isolated from healthy donors (n = 4) and patients with sepsis (n = 2). Despite different underlying causes for sepsis, a comparison over promoter regions shows a high correlation between the patients for all chromatin marks. These findings hold true also when comparing patients to healthy controls. Despite the global similarity, differential analysis reveals a set of distinct promoters with significant enrichment or depletion of histone marks. Further analysis of overrepresented GO terms show an enrichment of genes involved in immune function. To the most prominent ones belong different members of the HLA family located within the MHC cluster together with the gene coding for the major regulator of this locus-CIITA.
  
  
  CONCLUSIONS
  We are able to show for the first time that sepsis in humans induces selective and precise changes of chromatin modifications in distinct promoter regions of immunologically relevant genes, shedding light on basal regulatory mechanisms that might be contributing to the functional changes occurring in monocytes.
authors: Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany; German Centre for Infection Research (DZIF), partner site Giessen-Marburg-Langen, Giessen, Germany.
authors: Sebastian
authors: S
authors: Weiterer
authors: Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany.
authors: Florian
authors: F
authors: Uhle
authors: Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany.
authors: Christoph
authors: C
authors: Lichtenstern
authors: Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany.
authors: Benedikt H
authors: BH
authors: Siegler
authors: Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors: Sabin
authors: S
authors: Bhuju
authors: Genome Analytics, Helmholtz Centre for Infection Research, Braunschweig, Germany.
authors: Michael
authors: M
authors: Jarek
authors: Institute for Genetics, Justus-Liebig-University, Giessen, Germany.
authors: Marek
authors: M
authors: Bartkuhn
authors: Department of Anaesthesiology, Heidelberg University Hospital, Heidelberg, Germany; German Centre for Infection Research (DZIF), partner site Giessen-Marburg-Langen, Giessen, Germany.
authors: Markus A
authors: MA
authors: Weigand
mesh_terms: D016022:Case-Control Studies; D002843:Chromatin; D047369:Chromatin Immunoprecipitation; D016000:Cluster Analysis; D000949:Histocompatibility Antigens Class II / Q000235:genetics / Q000378:metabolism; D006657:Histones / Q000378:metabolism*; D006801:Humans; D009000:Monocytes / Q000378:metabolism*; D011401:Promoter Regions, Genetic; D011499:Protein Processing, Post-Translational; D053574:Receptors, Interleukin-1 Type II / Q000235:genetics / Q000378:metabolism; D018805:Sepsis / Q000378:metabolism* / Q000473:pathology*
chemical_list: D002843:Chromatin; D000949:Histocompatibility Antigens Class II; D006657:Histones; C508592:IL1R2 protein, human; D053574:Receptors, Interleukin-1 Type II