title: Citrullination-acetylation interplay guides E2F-1 activity during the inflammatory response.
abstract: Peptidyl arginine deiminase 4 (PAD4) is a nuclear enzyme that converts arginine residues to citrulline. Although increasingly implicated in inflammatory disease and cancer, the mechanism of action of PAD4 and its functionally relevant pathways remains unclear. E2F transcription factors are a family of master regulators that coordinate gene expression during cellular proliferation and diverse cell fates. We show that E2F-1 is citrullinated by PAD4 in inflammatory cells. Citrullination of E2F-1 assists its chromatin association, specifically to cytokine genes in granulocyte cells. Mechanistically, citrullination augments binding of the BET (bromodomain and extra-terminal domain) family bromodomain reader BRD4 (bromodomain-containing protein 4) to an acetylated domain in E2F-1, and PAD4 and BRD4 coexist with E2F-1 on cytokine gene promoters. Accordingly, the combined inhibition of PAD4 and BRD4 disrupts the chromatin-bound complex and suppresses cytokine gene expression. In the murine collagen-induced arthritis model, chromatin-bound E2F-1 in inflammatory cells and consequent cytokine expression are diminished upon small-molecule inhibition of PAD4 and BRD4, and the combined treatment is clinically efficacious in preventing disease progression. Our results shed light on a new transcription-based mechanism that mediates the inflammatory effect of PAD4 and establish the interplay between citrullination and acetylation in the control of E2F-1 as a regulatory interface for driving inflammatory gene expression.
authors.affiliation: Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Ghari
authors.affiliation: Kennedy Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Anne-Marie
authors.identifier: 0000-0003-2335-1631
authors.initials: AM
authors.lastname: Quirke
authors.affiliation: Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Shonagh
authors.initials: S
authors.lastname: Munro
authors.affiliation: Kennedy Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Joanna
authors.identifier: 0000-0003-2581-8397
authors.initials: J
authors.lastname: Kawalkowska
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Sarah
authors.initials: S
authors.lastname: Picaud
authors.affiliation: University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
authors.forename: Joanna
authors.initials: J
authors.lastname: McGouran
authors.affiliation: Ludwig Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Venkataraman
authors.initials: V
authors.lastname: Subramanian
authors.affiliation: Ludwig Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Aaron
authors.identifier: 0000-0002-6178-7682
authors.initials: A
authors.lastname: Muth
authors.affiliation: Kennedy Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Richard
authors.identifier: 0000-0001-5473-5270
authors.initials: R
authors.lastname: Williams
authors.affiliation: University of Massachusetts Medical School, 55 Lake Avenue North, Worcester, MA 01655, USA.
authors.forename: Benedikt
authors.initials: B
authors.lastname: Kessler
authors.affiliation: Ludwig Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Paul R
authors.initials: PR
authors.lastname: Thompson
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK.; Target Discovery Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Panagis
authors.initials: P
authors.lastname: Fillipakopoulos
authors.affiliation: Structural Genomics Consortium, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Stefan
authors.identifier: 0000-0002-0604-9185
authors.initials: S
authors.lastname: Knapp
authors.affiliation: Kennedy Institute, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Patrick J
authors.initials: PJ
authors.lastname: Venables
authors.affiliation: Department of Oncology, University of Oxford, Oxford OX3 7DQ, UK.
authors.forename: Nicholas B
authors.initials: NB
authors.lastname: La Thangue
mesh_terms: D000107:Acetylation; D000818:Animals; D001169:Arthritis, Experimental / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D018797:Cell Cycle Proteins; D002460:Cell Line; D002956:Citrulline / Q000378:metabolism*; D016207:Cytokines / Q000235:genetics; D050687:E2F1 Transcription Factor / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D005786:Gene Expression Regulation; D018922:HL-60 Cells; D006801:Humans; D006867:Hydrolases / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism; D007249:Inflammation / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D008297:Male; D051379:Mice; D008811:Mice, Inbred DBA; D009687:Nuclear Proteins / Q000378:metabolism; D011401:Promoter Regions, Genetic; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases; D034741:RNA, Small Interfering / Q000235:genetics; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000378:metabolism; D000092468:Bromodomain Containing Proteins
chemical_list: D018797:Cell Cycle Proteins; D002956:Citrulline; D016207:Cytokines; D050687:E2F1 Transcription Factor; D006867:Hydrolases; D009687:Nuclear Proteins; D000080002:Protein-Arginine Deiminase Type 4; D000076342:Protein-Arginine Deiminases; D034741:RNA, Small Interfering; D011994:Recombinant Proteins; D014157:Transcription Factors; C441289:BRD4 protein, human; D000092468:Bromodomain Containing Proteins; C493753:E2F1 protein, human; C000629235:PADI4 protein, human; C552151:peptidylarginine deiminase 4, mouse
keywords: BRD4; E2F-1; PAD4; cancer; citrullination; immune response; inflammation