title: Inhibition of MicroRNA-21 by an antagomir ameliorates allergic inflammation in a mouse model of asthma.
abstract: MicroRNA-21 (miR-21) is up-regulated during allergic airway inflammation, reflecting a Th2 immune response. We investigated the effects of an miR-21 antagomir and its mechanism of action in a mouse model of acute bronchial asthma.
  
  
  
  BALB/c mice were sensitized and challenged with ovalbumin (OVA). The anti-miR-21 antagomir was administered by intranasal inhalation from the day of sensitization. Changes in cell counts, Th2 cytokine levels in bronchoalveolar (BAL) fluid, and airway hyper-responsiveness (AHR) were examined. Histopathological changes and expression levels of miR-21 in lung tissues were analyzed. The mechanism of action of the antagomir was investigated by counting CD4+/CD8-T cells in splenocytes and by measuring the expression levels of transcription factors associated with T cell polarization.
  
  
  
  MiR-21 expression was selectively down-regulated in the lung tissues of mice treated with anti-miR-21. The antagomir suppressed AHR compared with that of the OVA-challenged and scrambled RNA-treated groups. It also reduced the total cell and eosinophil counts in BAL fluid and the levels of Th2 cytokines, including IL-4, IL-5, and IL-13. The direct target of miR-21, IL-12p35, was induced in the antagomir-treated group, decreasing the CD4+/CD8-T cell proportions in splenocytes. The levels of transcription factors involved in the Th2-signaling pathway were reduced in lung tissues on treatment with the antagomir.
  
  
  
  The miR-21 antagomir suppresses the development of allergic airway inflammation in a mouse model of acute bronchial asthma, inhibiting Th2 activation. These results suggest that this antagomir might be useful for treating bronchial asthma.
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: Hwa Young
authors.initials: HY
authors.lastname: Lee
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: Hea Yon
authors.initials: HY
authors.lastname: Lee
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: Joon Young
authors.initials: JY
authors.lastname: Choi
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: Jung
authors.initials: J
authors.lastname: Hur
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: In Kyoung
authors.initials: IK
authors.lastname: Kim
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: Young Kyoon
authors.initials: YK
authors.lastname: Kim
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: Ji Young
authors.initials: JY
authors.lastname: Kang
authors.affiliation: a Division of Pulmonary, Allergy and Critical Care Medicine, Department of Internal Medicine , The Catholic University of Korea , Seoul , South Korea.
authors.forename: Sook Young
authors.initials: SY
authors.lastname: Lee
mesh_terms: D000818:Animals; D000070416:Antagomirs / Q000494:pharmacology*; D001249:Asthma / Q000188:drug therapy; D007249:Inflammation / Q000188:drug therapy*; D008213:Lymphocyte Activation / Q000187:drug effects; D051379:Mice; D008807:Mice, Inbred BALB C; D035683:MicroRNAs / Q000037:antagonists & inhibitors*; D012130:Respiratory Hypersensitivity / Q000473:pathology*; D018418:Th2 Cells / Q000276:immunology; D015854:Up-Regulation
chemical_list: D000070416:Antagomirs; D035683:MicroRNAs; C531950:MIRN21 microRNA, mouse
keywords: MicroRNA-21; allergy; asthma