title: Effects of corticosteroids on osteopontin expression in a murine model of allergic asthma.
abstract: BACKGROUND
  Osteopontin (OPN) contributes to the development of T helper 1 (Th1)-mediated immunity and Th1-associated diseases. However, the role of OPN in bronchial asthma is unclear. Corticosteroids reduce airway inflammation, as reflected by the low eosinophil and T-cell counts, and the low level of cytokine expression. We investigated OPN production and the inhibitory effects of corticosteroids on OPN production in a murine model of allergic asthma.
  
  
  METHODS
  BALB/c mice were sensitized by intraperitoneal injections of ovalbumin (OVA) with alum. Some mice received daily injections of dexamethasone (DEX) or phosphate-buffered saline for 1 week. All OVA-challenged mice were exposed to aerosolized 1% OVA for 30 min an hour after these injections. After the OVA challenge, the mice were killed, and bronchoalveolar lavage (BAL) fluid and lung tissue were examined.
  
  
  RESULTS
  The levels of OPN protein in BAL fluid and OPN mRNA in lung tissue increased after OVA challenge. Most OPN-expressing cells were CD11c+ cells and some were T cells. DEX decreased the levels of OPN protein in the BAL fluid, and those of OPN mRNA and OPN protein in lung tissue.
  
  
  CONCLUSIONS
  OPN may play an important role in allergic bronchial asthma. Corticosteroids inhibit OPN production in mice with allergic asthma. The beneficial effect of corticosteroids in bronchial asthma is partly due to their inhibitory effects on OPN production.
authors.affiliation: Division of Respiratory Medicine and Allergology, Department of Internal Medicine, Showa University School of Medicine, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8666, Japan. cdl94140@par.odn.ne.jp
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Kurokawa
authors.forename: Satoshi
authors.initials: S
authors.lastname: Konno
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsukura
authors.forename: Mio
authors.initials: M
authors.lastname: Kawaguchi
authors.forename: Koushi
authors.initials: K
authors.lastname: Ieki
authors.forename: Shintarou
authors.initials: S
authors.lastname: Suzuki
authors.forename: Miho
authors.initials: M
authors.lastname: Odaka
authors.forename: Shin
authors.initials: S
authors.lastname: Watanabe
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Homma
authors.forename: Masayuki
authors.initials: M
authors.lastname: Sato
authors.forename: Hiroko
authors.initials: H
authors.lastname: Takeuchi
authors.forename: Takashi
authors.initials: T
authors.lastname: Hirose
authors.forename: Shau-Ku
authors.initials: SK
authors.lastname: Huang
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Adachi
mesh_terms: D000818:Animals; D001249:Asthma / Q000276:immunology*; D018845:CD11 Antigens / Q000378:metabolism; D015704:CD4 Antigens / Q000378:metabolism; D003907:Dexamethasone / Q000008:administration & dosage / Q000494:pharmacology*; D004195:Disease Models, Animal; D015536:Down-Regulation; D005938:Glucocorticoids / Q000008:administration & dosage / Q000494:pharmacology*; D007114:Immunization; D007150:Immunohistochemistry; D007274:Injections, Intraperitoneal; D008168:Lung / Q000276:immunology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D053495:Osteopontin / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000235:genetics; D010047:Ovalbumin / Q000276:immunology; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000032:analysis; D018418:Th2 Cells / Q000276:immunology
chemical_list: D018845:CD11 Antigens; D015704:CD4 Antigens; D005938:Glucocorticoids; D012333:RNA, Messenger; D053495:Osteopontin; D003907:Dexamethasone; D010047:Ovalbumin