title: The effect of pharmacological PI3Kγ inhibitor on eotaxin-induced human eosinophil functions.
abstract: BACKGROUND
  Asthma is characterized by chronic inflammation caused by activation of immune cells including Th2 lymphocytes and eosinophils. Phosphoinositide 3-kinase (PI3K) γ deficient asthmatic mice did not develop lung eosinophilia, although the detailed mechanisms are not well known. A CC chemokine eotaxin (CCL11) plays a prominent role in developing eosinophilic inflammation through CCR3. In this study, we tested the roles of PI3Kγ in eotaxin-induced eosinophil functions using a pharmacological inhibitor.
  
  
  METHODS
  Human peripheral blood eosinophils were isolated by CD16-negative selection method. The effect of AS605240, synthetic PI3Kγ inhibitor on eotaxin-induced adhesion, chemotaxis, and degranulation were studied using intracellular adhesion molecule-1 (ICAM-1)-coated plates, Boyden chamber system, ELISA for eosinophil-derived neurotoxin (EDN) levels in the culture supernatant, respectively. CCR3 expression levels and extracellular signal-regulated kinase 1/2 (ERK1/2) phosphorylation were assessed by flowcytometry. Involvement of PI3Kγ in spontaneous apoptosis was studied using flowcytometry.
  
  
  RESULTS
  Although AS605240 did not affect the eosinophil spontaneous apoptosis, eotaxin-induced chemotaxis, adhesion to ICAM-1 coated plate, and EDN release were inhibited by AS605240. AS605240 also inhibited the eotaxin-induced ERK1/2 phosphorylation without down-regulation of surface CCR3 expression.
  
  
  CONCLUSIONS
  These results indicate that PI3Kγ inhibitor attenuates eotaxin-induced eosinophil functions by suppressing the downstream signaling of CCR3 without significant cytotoxicity. PI3Kγ plays an important role in the development of eosinophilic inflammation and blockade of PI3Kγ might be a therapeutic strategy for treatment of eosinophil-related diseases including asthma.
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Yukiko
authors: Y
authors: Saito
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan. Electronic address: takeda-56@hos.akita-u.ac.jp.
authors: Masahide
authors: M
authors: Takeda
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Junko
authors: J
authors: Nishikawa
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Yasunori
authors: Y
authors: Konno
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Mami
authors: M
authors: Tamaki
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Masamichi
authors: M
authors: Itoga
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Yoshiki
authors: Y
authors: Kobayashi
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Yuki
authors: Y
authors: Moritoki
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Wataru
authors: W
authors: Ito
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Junichi
authors: J
authors: Chihara
authors: Department of Infection, Allergy, Clinical Immunology and Laboratory Medicine, Akita University Graduate School of Medicine, Akita, Japan.
authors: Shigeharu
authors: S
authors: Ueki
mesh_terms: D054413:Chemokine CCL11 / Q000378:metabolism*; D002633:Chemotaxis / Q000187:drug effects; D058544:Class Ib Phosphatidylinositol 3-Kinase / Q000378:metabolism; D015536:Down-Regulation / Q000187:drug effects; D004797:Enzyme-Linked Immunosorbent Assay; D047208:Eosinophil-Derived Neurotoxin / Q000378:metabolism; D004804:Eosinophils / Q000187:drug effects* / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D000081082:Phosphoinositide-3 Kinase Inhibitors; D010766:Phosphorylation; D011810:Quinoxalines / Q000494:pharmacology*; D045162:Thiazolidinediones / Q000494:pharmacology*
chemical_list: C505144:5-quinoxalin-6-ylmethylenethiazolidine-2,4-dione; D054413:Chemokine CCL11; D000081082:Phosphoinositide-3 Kinase Inhibitors; D011810:Quinoxalines; D045162:Thiazolidinediones; D058544:Class Ib Phosphatidylinositol 3-Kinase; C546760:PIK3CG protein, human; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D047208:Eosinophil-Derived Neurotoxin
keywords: Asthma; Eosinophil; Eotaxin; PI3Kγ