title: The danger signal, extracellular ATP, is a sensor for an airborne allergen and triggers IL-33 release and innate Th2-type responses.
abstract: The molecular mechanisms underlying the initiation of innate and adaptive proallergic Th2-type responses in the airways are not well understood. IL-33 is a new member of the IL-1 family of molecules that is implicated in Th2-type responses. Airway exposure of naive mice to a common environmental aeroallergen, the fungus Alternaria alternata, induces rapid release of IL-33 into the airway lumen, followed by innate Th2-type responses. Biologically active IL-33 is constitutively stored in the nuclei of human airway epithelial cells. Exposing these epithelial cells to A. alternata releases IL-33 extracellularly in vitro. Allergen exposure also induces acute extracellular accumulation of a danger signal, ATP; autocrine ATP sustains increases in intracellular Ca(2+) concentration and releases IL-33 through activation of P2 purinergic receptors. Pharmacological inhibitors of purinergic receptors or deficiency in the P2Y2 gene abrogate IL-33 release and Th2-type responses in the Alternaria-induced airway inflammation model in naive mice, emphasizing the essential roles for ATP and the P2Y(2) receptor. Thus, ATP and purinergic signaling in the respiratory epithelium are critical sensors for airway exposure to airborne allergens, and they may provide novel opportunities to dampen the hypersensitivity response in Th2-type airway diseases such as asthma.
authors.affiliation: Division of Allergic Diseases, Department of Internal Medicine, Mayo Clinic, Rochester, MN 55905, USA.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Kouzaki
authors.forename: Koji
authors.initials: K
authors.lastname: Iijima
authors.forename: Takao
authors.initials: T
authors.lastname: Kobayashi
authors.forename: Scott M
authors.initials: SM
authors.lastname: O'Grady
authors.forename: Hirohito
authors.initials: H
authors.lastname: Kita
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism* / Q000502:physiology; D000393:Air Pollutants / Q000276:immunology*; D000485:Allergens / Q000008:administration & dosage / Q000502:physiology*; D000528:Alternaria / Q000276:immunology; D000818:Animals; D000946:Antigens, Fungal / Q000008:administration & dosage / Q000276:immunology; D002460:Cell Line; D018920:Coculture Techniques; D005110:Extracellular Space / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D005260:Female; D006706:Homeostasis / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate; D000067596:Interleukin-33; D007378:Interleukins / Q000378:metabolism* / Q000502:physiology; D051379:Mice; D057507:Mice, 129 Strain; D008807:Mice, Inbred BALB C; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D020545:Respiratory Mucosa / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology; D018418:Th2 Cells / Q000276:immunology* / Q000378:metabolism / Q000382:microbiology
chemical_list: D000393:Air Pollutants; D000485:Allergens; D000946:Antigens, Fungal; C506535:Il33 protein, mouse; D000067596:Interleukin-33; D007378:Interleukins; D000255:Adenosine Triphosphate