title: Level of Fatty Acid Binding Protein 5 (FABP5) Is Increased in Sputum of Allergic Asthmatics and Links to Airway Remodeling and Inflammation.
abstract: BACKGROUND
  The inflammatory processes in the upper and lower airways in allergic rhinitis and asthma are similar. Induced sputum and nasal lavage fluid provide a non-invasive way to examine proteins involved in airway inflammation in these conditions.
  
  
  OBJECTIVE
  We conducted proteomic analyses of sputum and nasal lavage fluid samples to reveal differences in protein abundances and compositions between the asthma and rhinitis patients and to investigate potential underlying mechanisms.
  
  
  METHODS
  Induced sputum and nasal lavage fluid samples were collected from 172 subjects with 1) allergic rhinitis, 2) asthma combined with allergic rhinitis, 3) nonallergic rhinitis and 4) healthy controls. Proteome changes in 21 sputum samples were analysed with two-dimensional difference gel electrophoresis (2D-DIGE), and the found differentially regulated proteins identified with mass spectrometry. Immunological validation of identified proteins in the sputum and nasal lavage fluid samples was performed with Western blot and ELISA.
  
  
  RESULTS
  Altogether 31 different proteins were identified in the sputum proteome analysis, most of these were found also in the nasal lavage fluid. Fatty acid binding protein 5 (FABP5) was up-regulated in the sputum of asthmatics. Immunological validation in the whole study population confirmed the higher abundance levels of FABP5 in asthmatic subjects in both the sputum and nasal lavage fluid samples. In addition, the vascular endothelial growth factor (VEGF) level was increased in the nasal lavage fluid of asthmatics and there were positive correlations between FABP5 and VEGF levels (r=0.660, p<0.001) and concentrations of FABP5 and cysteinyl leukotriene (CysLT) (r=0.535, p<0.001) in the nasal lavage fluid.
  
  
  CONCLUSIONS
  FABP5 may contribute to the airway remodeling and inflammation in asthma by fine-tuning the levels of CysLTs, which induce VEGF production.
authors.affiliation: Occupational Medicine Team, Finnish Institute of Occupational Health, Helsinki, Finland.
authors.forename: Hille
authors.initials: H
authors.lastname: Suojalehto
authors.affiliation: Unit of Systems Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland.
authors.forename: Pia
authors.initials: P
authors.lastname: Kinaret
authors.affiliation: Department of Pulmonary Diseases and Allergology, University of Turku, Turku, Finland.
authors.forename: Maritta
authors.initials: M
authors.lastname: Kilpeläinen
authors.affiliation: Department of Otolaryngology- Head and Neck Surgery, Temple University, Philadelphia, United States of America.
authors.forename: Elina
authors.initials: E
authors.lastname: Toskala
authors.affiliation: Unit of Systems Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland.
authors.forename: Niina
authors.initials: N
authors.lastname: Ahonen
authors.affiliation: Unit of Systems Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland.
authors.forename: Henrik
authors.initials: H
authors.lastname: Wolff
authors.affiliation: Unit of Systems Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland.
authors.forename: Harri
authors.initials: H
authors.lastname: Alenius
authors.affiliation: Unit of Systems Toxicology, Finnish Institute of Occupational Health, Helsinki, Finland.
authors.forename: Anne
authors.initials: A
authors.lastname: Puustinen
mesh_terms: D000328:Adult; D056151:Airway Remodeling; D001249:Asthma / Q000378:metabolism*; D050556:Fatty Acid-Binding Proteins / Q000378:metabolism*; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007249:Inflammation / Q000378:metabolism; D008297:Male; D040901:Proteomics; D013183:Sputum / Q000378:metabolism*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis
chemical_list: C493412:FABP5 protein, human; D050556:Fatty Acid-Binding Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A