title: Adenosine triphosphate induces P2Y2 activation and interleukin-8 release in human esophageal epithelial cells.
abstract: OBJECTIVE
  Immune-mediated mucosal inflammation characterized by the release of interleukin (IL)-8 is associated with gastroesophageal reflux disease. ATP released by human esophageal epithelial cells (HEECs) mediates the release of cytokines through P2 nucleotide receptors that are present on various cells, including HEECs. This study characterized and identified human esophageal epithelial P2 receptors that are responsible for ATP-mediated release of IL-8 by using a human esophageal stratified squamous epithelial model.
  
  
  METHODS
  Primary HEECs were cultured with the use of an air-liquid interface (ALI) system. The ATP analogue adenosine 5'-O-3-thiotriphosphate (ATP-γ-S) was added to the basolateral compartment, and IL-8 release was measured. Involvement of the P2Y2 receptor was assessed with the use of selective and non-selective receptor antagonists and a P2Y2 receptor agonist. Expression of the P2Y2 receptor was assessed using western blotting and immunohistochemistry.
  
  
  RESULTS
  Adenosine triphosphate-γ-S induced IL-8 release through the P2Y2 receptor. A P2Y2 receptor antagonist but not a P2X3 receptor antagonist or a P2Y1 receptor antagonist blocked ATP-γ-S-mediated IL-8 release. Conversely, a P2Y2 receptor agonist induced IL-8 release. Western blotting and immunohistochemistry of the P2Y2 receptor showed strong expression of the P2Y2 receptor on ALI-cultured HEECs and in human esophagus. Inhibition of extracellular signal-regulated kinase but not of protein kinase C blocked the ATP-mediated release of IL-8. ATP-γ-S induced phosphorylation of extracellular signal-regulated kinase, and a P2Y2 receptor antagonist blocked this phosphorylation.
  
  
  CONCLUSIONS
  Interleukin-8 release after purinergic stimulation in ALI-cultured HEECs is mediated through P2Y2 receptor activation. ATP-induced IL-8 release maybe involved in the pathogenesis of refractory gastroesophageal reflux disease.
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.|Department of Gastroenterology, The Third People's Hospital of Chengdu, Chengdu, China.
authors.forename: Liping
authors.initials: L
authors.lastname: Wu
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.
authors.forename: Tadayuki
authors.initials: T
authors.lastname: Oshima
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.
authors.forename: Hirokazu
authors.initials: H
authors.lastname: Fukui
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.
authors.forename: Jiro
authors.initials: J
authors.lastname: Watari
authors.affiliation: Division of Gastroenterology, Department of Internal Medicine, Hyogo College of Medicine, Nishinomiya, Japan.
authors.forename: Hiroto
authors.initials: H
authors.lastname: Miwa
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology* / Q000502:physiology*; D002478:Cells, Cultured; D004847:Epithelial Cells / Q000378:metabolism*; D004947:Esophagus / Q000166:cytology*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism*; D058473:Receptors, Purinergic P2Y2 / Q000378:metabolism* / Q000502:physiology*
chemical_list: C508606:CXCL8 protein, human; D016209:Interleukin-8; D058473:Receptors, Purinergic P2Y2; D000255:Adenosine Triphosphate
keywords: P2Y2 receptor; adenosine triphosphate; air-liquid interface; interleukin-8; stratified epithelium