title: Overexpression of ATP-activated P2X7 receptors in the intestinal mucosa is implicated in the pathogenesis of Crohn's disease.
abstract: BACKGROUND
  Extracellular nucleotides released in conditions of cell stress alert the immune system from tissue injury or inflammation. We hypothesized that the P2X7 receptor (P2X7-R) could regulate key elements in inflammatory bowel disease pathogenesis.
  
  
  METHODS
  Colonoscopy samples obtained from patients with Crohn's disease (CD), ulcerative colitis, and controls were used to analyze P2X7-R expression by RT and real-time PCR, immunohistochemistry, and confocal microscopy. Inflammatory response was determined by the levels of cytokines by enzyme-linked immunosorbent assay in cultures of intestinal explants. Apoptosis was determined by the TUNEL assay. P2X7-R C57BL/6 mice were treated with trinitrobenzene sulfonic acid or dextran sulfate sodium (DSS) for inducing colitis.
  
  
  RESULTS
  P2X7-R was expressed in higher levels in inflamed CD epithelium and lamina propria, where it colocalizes more with dendritic cells and macrophages. Basal levels of P2X7-R mRNA were higher in CD inflamed mucosa compared with noninflamed CD and controls and were upregulated after interferon-γ in controls. Apoptotic rates were higher in CD epithelium and lamina propria compared with ulcerative colitis and controls. Levels of tumor necrosis factor-α, interleukin (IL)-1β, and IL-17 were higher, whereas IL-10 was lower in CD compared with controls. Levels of tumor necrosis factor-α-α and interleukin-1β increased after adenosine-triphosphate and decreased after KN62 treatment in CD. P2X7-R animals did not develop trinitrobenzene sulfonic acid or DSS colitis.
  
  
  CONCLUSIONS
  The upregulation of P2X7-R in CD inflamed mucosa is consistent with the involvement of purinoceptors in inflammation and apoptosis. These observations may implicate purinergic signaling in the pathogenesis of intestinal inflammation, and the P2X7-R may represent a novel therapeutic target in CD.
authors.affiliation: *Departamento de Clínica Médica, Hospital Universitário Clementino Fraga Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; †Laboratório de Imunologia Celular, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; ‡Programa de Imunobiologia, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil; §Laboratório de Inovações em Terapias, Ensino e Bioprodutos-LITEB, Instituto Oswaldo Cruz, Fiocruz, Rio de Janeiro, Brazil; and ‖Departamento de Biologia Celular e Molecular, Instituto de Biologia, Universidade Federal Fluminense, Niterói, Brasil.
authors.forename: Adriane R
authors.initials: AR
authors.lastname: Neves
authors.forename: Morgana T L
authors.initials: MT
authors.lastname: Castelo-Branco
authors.forename: Vanessa R
authors.initials: VR
authors.lastname: Figliuolo
authors.forename: Claudio
authors.initials: C
authors.lastname: Bernardazzi
authors.forename: Fernanda
authors.initials: F
authors.lastname: Buongusto
authors.forename: Agnes
authors.initials: A
authors.lastname: Yoshimoto
authors.forename: Hayandra F
authors.initials: HF
authors.lastname: Nanini
authors.forename: Claudia M L M
authors.initials: CM
authors.lastname: Coutinho
authors.forename: Antonio José V
authors.initials: AJ
authors.lastname: Carneiro
authors.forename: Robson
authors.initials: R
authors.lastname: Coutinho-Silva
authors.forename: Heitor S P
authors.initials: HS
authors.lastname: de Souza
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000293:Adolescent; D000328:Adult; D000818:Animals; D017209:Apoptosis; D015153:Blotting, Western; D016022:Case-Control Studies; D003093:Colitis, Ulcerative / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D003113:Colonoscopy; D003424:Crohn Disease / Q000235:genetics / Q000378:metabolism / Q000473:pathology*; D004797:Enzyme-Linked Immunosorbent Assay; D005260:Female; D005455:Fluorescent Antibody Technique; D005500:Follow-Up Studies; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D016753:Interleukin-10 / Q000235:genetics / Q000378:metabolism; D053583:Interleukin-1beta / Q000235:genetics / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008875:Middle Aged; D011379:Prognosis; D012333:RNA, Messenger / Q000235:genetics; D060888:Real-Time Polymerase Chain Reaction; D058486:Receptors, Purinergic P2X7 / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000378:metabolism; D055815:Young Adult
chemical_list: D053583:Interleukin-1beta; D012333:RNA, Messenger; D058486:Receptors, Purinergic P2X7; D014409:Tumor Necrosis Factor-alpha; D016753:Interleukin-10; D007371:Interferon-gamma; D000255:Adenosine Triphosphate