title: Gelsolin secretion in interleukin-4-treated bronchial epithelia and in asthmatic airways.
abstract: BACKGROUND
  The airway surface liquid, the thin layer of liquid covering the airways, is essential for mucociliary clearance and as a barrier against microbial and other noxious agents. Proteins secreted into the airway surface liquid by epithelial and nonepithelial cells may be important in innate immunity and to improve the fluidity of mucous secretions.
  
  
  OBJECTIVE
  We aimed to identify proteins specifically secreted into the airway surface liquid by human bronchial epithelial cells, in resting conditions and after treatment with interleukin 4 (IL-4), a cytokine released in asthma.
  
  
  RESULTS
  By using a proteomics approach, we found that one of the most abundant proteins was gelsolin, which breaks down actin filaments. Gelsolin mRNA and protein secretion were increased threefold in the airway surface liquid of epithelia treated with IL-4. These results were confirmed at the functional level by measuring actin depolymerization using a fluorescence assay. Gelsolin protein was also upregulated in the airways of subjects with asthma.
  
  
  CONCLUSIONS
  Our findings indicate that gelsolin is released by epithelial cells into the airways and that its secretion is increased by IL-4 in vitro. In addition, we found that the concentration of both IL-4 and gelsolin were raised in the bronchoalveolar lavage of patients with asthma. These results suggest that gelsolin might improve the fluidity of airway surface liquid in asthma by breaking down filamentous actin that may be released in large amounts by dying cells during inflammation.
authors.affiliation: Laboratory of Uremic Physiopathology, Istituto G. Gaslini, Genoa-16148, Italy.
authors.forename: Giovanni
authors.initials: G
authors.lastname: Candiano
authors.forename: Maurizio
authors.initials: M
authors.lastname: Bruschi
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Pedemonte
authors.forename: Emanuela
authors.initials: E
authors.lastname: Caci
authors.forename: Sabrina
authors.initials: S
authors.lastname: Liberatori
authors.forename: Luca
authors.initials: L
authors.lastname: Bini
authors.forename: Carlo
authors.initials: C
authors.lastname: Pellegrini
authors.forename: Mario
authors.initials: M
authors.lastname: Viganò
authors.forename: Brian J
authors.initials: BJ
authors.lastname: O'Connor
authors.forename: Tak H
authors.initials: TH
authors.lastname: Lee
authors.forename: Luis J V
authors.initials: LJ
authors.lastname: Galietta
authors.forename: Olga
authors.initials: O
authors.lastname: Zegarra-Moran
mesh_terms: D001249:Asthma / Q000276:immunology* / Q000378:metabolism; D001980:Bronchi / Q000378:metabolism* / Q000473:pathology; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D016022:Case-Control Studies; D018929:Cell Culture Techniques; D015180:Electrophoresis, Gel, Two-Dimensional; D004847:Epithelial Cells / Q000378:metabolism*; D018260:Gelsolin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D018928:Immunity, Mucosal; D015847:Interleukin-4 / Q000502:physiology*; D012333:RNA, Messenger / Q000032:analysis
chemical_list: D018260:Gelsolin; D012333:RNA, Messenger; D015847:Interleukin-4