title: A functional study on CysLT(1) receptors in human eosinophils.
abstract: BACKGROUND
  The cysteinyl leukotrienes (CysLTs) mediate their biological actions through two receptors: CysLT(1) receptor and CysLT(2) receptor.
  
  
  OBJECTIVE
  This study was undertaken to examine the direct effects of CysLTs on eosinophils, such as chemotaxis and degranulation, focusing on CysLT(1).
  
  
  METHODS
  Eosinophils were isolated from venous blood from normal volunteers who had no history of allergy (purity >99%). They were subjected to reverse transcription-PCR analysis and flow-cytometric analysis for CysLT(1). Binding assays were performed with [(3)H]LTD(4). Purified eosinophils loaded with Fura-2 acetoxymethyl ester were stimulated with CysLTs, and Ca(2+) influx was measured. Eosinophil migration in response to CysLTs was measured using a 96-well multiwell Boyden chamber. Eosinophils were treated with LTD(4) at 10(-6) M for 60 min followed by incubation for 4 h at 37 degrees C in the presence or absence of IL-5 and eosinophil-derived neurotoxin (EDN) release was evaluated.
  
  
  RESULTS
  The expression of the mRNA and protein of CysLT(1) on eosinophils and [(3)H]LTD(4)-specific binding to eosinophils were observed. Neither Th1 cytokine (IFN-gamma) nor Th2 cytokines (IL-4 or IL-5) affected CysLT(1) expression in eosinophils. CysLTs induced an increase in intracellular free Ca(2+) in eosinophils via CysLT(1), as suggested by the efficient inhibition by a CysLT(1) antagonist, pranlukast, in addition to the rank order of potency being LTD(4), LTC(4) and LTE(4). LTD(4) stimulated eosinophils to migrate at 10(-6) M via CysLT(1). LTE(4) also induced significant eosinophil migration at 10(-6) M. LTD(4) enhanced EDN release induced by IL-5 via CysLT(1).
  
  
  CONCLUSIONS
  CysLTs induce migration and enhance degranulation in eosinophils via CysLT(1). Accordingly, interaction of CysLTs and CysLT(1) on eosinophils has the potential to play a prominent role in the pathophysiology of asthma.
authors.affiliation: Department of Respiratory Medicine, University of Tokyo Graduate School of Medicine, Tokyo, Japan.
authors.forename: Nobuharu
authors.initials: N
authors.lastname: Ohshima
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Nagase
authors.forename: Takeshi
authors.initials: T
authors.lastname: Koshino
authors.forename: Misato
authors.initials: M
authors.lastname: Miyamasu
authors.forename: Masao
authors.initials: M
authors.lastname: Yamaguchi
authors.forename: Koichi
authors.initials: K
authors.lastname: Hirai
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Yamamoto
authors.forename: Takao
authors.initials: T
authors.lastname: Fujisawa
authors.forename: Naoki
authors.initials: N
authors.lastname: Nakagawa
authors.forename: Katsuya
authors.initials: K
authors.lastname: Kishikawa
authors.forename: Yutaka
authors.initials: Y
authors.lastname: Morita
mesh_terms: D002118:Calcium / Q000378:metabolism; D015550:Cell Degranulation; D002465:Cell Movement / Q000187:drug effects; D002633:Chemotaxis / Q000187:drug effects; D003545:Cysteine / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology; D004804:Eosinophils / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D017998:Leukotriene D4 / Q000378:metabolism; D015289:Leukotrienes / Q000494:pharmacology; D008565:Membrane Proteins; D012333:RNA, Messenger / Q000032:analysis; D018077:Receptors, Leukotriene / Q000235:genetics / Q000502:physiology*
chemical_list: D016207:Cytokines; D015289:Leukotrienes; D008565:Membrane Proteins; D012333:RNA, Messenger; D018077:Receptors, Leukotriene; C112381:cysteinyl-leukotriene; D017998:Leukotriene D4; C412375:cysteinyl leukotriene receptor 2; D003545:Cysteine; C083169:leukotriene D4 receptor; D002118:Calcium