title: Chloride ion transport and overexpression of TMEM16A in a guinea-pig asthma model.
abstract: BACKGROUND
  TMEM16A, a Ca-activated Cl channel, regulates various physiological functions such as mucin secretion. However, the role of TMEM16A in hyper-secretion in asthma is not fully understood.
  
  
  OBJECTIVE
  The aim of this study is to evaluate Cl ion transport via TMEM16A and determine the localization of TMEM16A in a guinea-pig asthma model.
  
  
  METHODS
  Guinea-pigs were sensitized with ovalbumin (OVA) i.p. on Days 1 and 8. On Day 22, we assessed OVA challenge-induced Cl ion transport in the sensitized tracheas ex vivo in an Ussing chamber, compared with the non-sensitized tracheas. We then examined the effect of T16Ainh-A01, a TMEM16A inhibitor, on the increase in Cl ion transport. The tracheal epithelium was immunostained with an anti-TMEM16A antibody. Epithelial cells from guinea-pig tracheas were cultured at the air-liquid interface in the presence of IL-13 for in vitro study. We studied the effect of TMEM16A inhibitors on Ca-dependent agonist, uridine triphosphate (UTP)-induced increases in Cl ion transport in the cultured cells. The cells were immunostained with an anti-TMEM16A antibody, an anti-MUC5AC antibody and an anti-α-tubulin antibody.
  
  
  RESULTS
  OVA challenge induced an increase in short circuit current within 1 min in the OVA-sensitized tracheas but not in the non-sensitized tracheas, which was inhibited by pretreatment of T16Ainh-A01. Sensitized tracheas showed goblet cell metaplasia with more positive TMEM16A immunostaining, particularly in the apical portion compared with the non-sensitized tracheas. The in vitro UTP-induced increase in Cl ion transport was strongly inhibited by pretreatment with T16Ainh-A01, benzbromarone, and niflumic acid. TMEM16A was positively immunostained at the apical portion and in the MUC5AC-positive area in IL-13-induced goblet cell metaplasia.
  
  
  CONCLUSIONS
  Antigen challenge and Ca-dependent agonist treatment increased Cl ion transport via the overexpression of TMEM16A in goblet cell metaplasia in a guinea-pig asthma model. TMEM16A inhibitors may be useful for the treatment of hyper-secretion in asthma.
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: M
authors.identifier: http://orcid.org/0000-0003-3673-5431
authors.initials: M
authors.lastname: Kondo
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Tsuji
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Hara
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Arimura
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: O
authors.initials: O
authors.lastname: Yagi
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Tagaya
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Takeyama
authors.affiliation: First Department of Medicine, Tokyo Women's Medical University School of Medicine, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Tamaoki
mesh_terms: D000818:Animals; D000075369:Anoctamin-1 / Q000276:immunology*; D001249:Asthma / Q000276:immunology / Q000378:metabolism*; D002478:Cells, Cultured; D020397:Goblet Cells / Q000276:immunology / Q000378:metabolism; D006168:Guinea Pigs; D017136:Ion Transport / Q000276:immunology*; D008297:Male
chemical_list: D000075369:Anoctamin-1
keywords: CaCC; Cl channel; IL-13; TMEM16A; animal models; asthma; epithelium; goblet cell; mucus