title: Effect of cigarette smoke extract on insulin transport in alveolar epithelial cell line A549.
abstract: BACKGROUND
  The main purpose of this study was to evaluate the effect of cigarette smoke extract (CSE) on insulin transport in alveolar epithelial cells.
  
  
  METHODS
  We first examined the effect of CSE pretreatment on cell viability, mRNA expression, and lamellar body structures in A549 cells. Then the effect of CSE pretreatment on FITC-insulin transport was examined.
  
  
  RESULTS
  When A549 cells were treated with 30 μg/ml of CSE for 48 h, the expression of some mRNAs abundantly expressed in type II alveolar epithelial cells such as surfactant protein B was significantly increased. Lamellar bodylike structures became more evident with CSE treatment. FITC-insulin uptake from the apical side and subsequent efflux to the basal side was enhanced by CSE treatment in A549 cells. The enhancing effect of CSE on FITC-insulin uptake was concentration-dependent and reversible. A concentration-dependent enhancing effect of CSE on FITC-insulin uptake was also observed in normal, primary cultured alveolar type II epithelial cells isolated from rats.
  
  
  CONCLUSIONS
  Treatment of A549 cells by CSE may direct the cells to a more type II-like phenotype. In accordance with this observation, FITC-insulin uptake was enhanced by CSE treatment. These results may partly explain the higher insulin absorption from the lung in smokers than in nonsmokers.
authors.affiliation: Department of Pharmaceutics and Therapeutics, Graduate School of Biomedical Sciences, Hiroshima University, 1-2-3 Kasumi, Minami-ku, Hiroshima, 734-8553, Japan. takanom@hiroshima-u.ac.jp
authors.forename: Mikihisa
authors.initials: M
authors.lastname: Takano
authors.forename: Taishi
authors.initials: T
authors.lastname: Horiuchi
authors.forename: Junya
authors.initials: J
authors.lastname: Nagai
authors.forename: Ryoko
authors.initials: R
authors.lastname: Yumoto
mesh_terms: D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002460:Cell Line; D002470:Cell Survival; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000378:metabolism; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D018613:Microscopy, Confocal; D011650:Pulmonary Alveoli / Q000378:metabolism* / Q000648:ultrastructure; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012906:Smoke / Q000032:analysis; D014026:Nicotiana / Q000737:chemistry*
chemical_list: D007328:Insulin; D012333:RNA, Messenger; D012906:Smoke