title: Transforming growth factor beta 1 gene expression in human airways.
abstract: BACKGROUND
  Asthmatic airways have a characteristic deposition of connective tissue under the epithelial basement membrane, but the mediators involved in this alteration are unknown. Several authors have postulated that transforming growth factor beta 1 (TGF-beta 1) could be overexpressed in asthmatic airways.
  
  
  METHODS
  Lung samples from 16 asthmatic patients, six patients with chronic obstructive pulmonary disease (COPD), and six non-obstructed smokers were analysed. RNA was extracted from these tissues to measure expression of TGF-beta 1 by Northern blot analysis using a cDNA probe for TGF-beta 1. The level of expression was quantitated by densitometry using glyceraldehyde 3-phosphate dehydrogenase mRNA as a control. TGF-beta 1 was localised to specific cell types in these lungs by immunohistochemical analysis using polyclonal antibodies specific for intracellular and extracellular TGF-beta 1.
  
  
  RESULTS
  The 2.5 kb TGF-beta 1 mRNA was seen in all 18 samples analysed by Northern blotting and densitometric analysis showed no difference between the asthmatic group (mean (SD) 108% (43%)), the group with COPD (122% (33%)), and the non-obstructed group (100% (49%)). The TGF-beta 1 precursor was immunolocalised throughout the airway wall including the epithelium and in alveolar macrophages. The mature TGF-beta 1 was localised primarily within the connective tissue of the airway wall. These patterns of expression of both forms of TGF-beta 1 were similar in lungs from asthmatic patients, those with COPD, and controls.
  
  
  CONCLUSIONS
  While TGF-beta 1 mRNA and protein are abundantly expressed in human lungs, there is no clear difference in expression between the airways of asthmatic subjects and those of smokers with and without COPD.
authors.affiliation: UBC Pulmonary Research Laboratory, St Paul's Hospital, Vancouver, British Columbia, Canada.
authors.forename: J D
authors.initials: JD
authors.lastname: Aubert
authors.forename: B I
authors.initials: BI
authors.lastname: Dalal
authors.forename: T R
authors.initials: TR
authors.lastname: Bai
authors.forename: C R
authors.initials: CR
authors.lastname: Roberts
authors.forename: S
authors.initials: S
authors.lastname: Hayashi
authors.forename: J C
authors.initials: JC
authors.lastname: Hogg
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001249:Asthma / Q000235:genetics*; D015152:Blotting, Northern; D002648:Child; D002675:Child, Preschool; D015342:DNA Probes; D005260:Female; D015870:Gene Expression; D006801:Humans; D007150:Immunohistochemistry; D008168:Lung / Q000737:chemistry*; D008173:Lung Diseases, Obstructive / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D012333:RNA, Messenger / Q000378:metabolism; D012907:Smoking; D016212:Transforming Growth Factor beta / Q000235:genetics* / Q000378:metabolism
chemical_list: D015342:DNA Probes; D012333:RNA, Messenger; D016212:Transforming Growth Factor beta