title: Epithelial N-cadherin and nuclear β-catenin are up-regulated during early development of human lung.
abstract: BACKGROUND
  The aim of this study was to analyze the cell-specific expression of E- and N-cadherin and β-catenin in developing human lung tissues from 12 to 40 weeks of gestation.
  
  
  METHODS
  Forty-seven cases of developing human lung including pseudoglandular, canalicular, saccular and alveolar periods were analyzed by immunohistochemistry for E- and N-cadherin and β-catenin and twenty-one cases were also investigated by RT-PCR for E- and N-cadherin and β-catenin. For identifying the lung cells, the sections were also stained with antibodies against thyroid transcription factor-1 (TTF-1) and caveolin-1. Normal adult lung tissue was used as a control. E-cadherin was strongly expressed in epithelium of bronchi and large bronchioles from week 12 onwards and it was also positive in alveoli in pretype II cells and type II cells. N-cadherin was present in most of the epithelial cells of bronchi and the largest bronchioles during the pseudo-glandular and canalicular periods. N-cadherin was not detected in epithelium of developing alveoli. β-catenin was strongly membrane-bound and positively expressed in bronchial epithelium from week 12 to week 40; it showed nuclear positivity in both developing airway epithelium and in the cells underneath the epithelium during pseudo-glandular period and to a lesser degree also in the canalicular period. β-catenin was positive in pretype II cells as well as in type I and type II pneumocytes within alveoli. RT-PCR analyses revealed detectable amounts of RNAs of E- and N-cadherin and β-catenin in all cases studied. The amounts of RNAs were higher in early stages of gestation.
  
  
  CONCLUSIONS
  E-cadherin is widely expressed in bronchial and alveolar epithelial cells. N-cadherin exhibit extensive epithelial positivity in bronchial epithelial cells during early lung development. The presence of β-catenin was observed in several cell types with a distinct location in tissue and cells in various gestational stages, indicating that it possesses several roles during lung development. The expressions of protein and mRNAs of E- and N-cadherin and β-catenin were higher in early gestation compared to of the end. Moreover, the expressions of these factors were higher during the lung development than in the adult human lung.
authors.affiliation: Institute of Clinical Medicine, Department of Internal Medicine/Respiratory Research Unit, Centre of Excellence in Research, University of Oulu and Oulu University Hospital, Oulu, Finland. riitta.kaarteenaho@oulu.fi
authors.forename: Riitta
authors.initials: R
authors.lastname: Kaarteenaho
authors.forename: Elisa
authors.initials: E
authors.lastname: Lappi-Blanco
authors.forename: Siri
authors.initials: S
authors.lastname: Lehtonen
mesh_terms: D000328:Adult; D015703:Antigens, CD / Q000235:genetics / Q000378:metabolism*; D015820:Cadherins / Q000235:genetics / Q000378:metabolism*; D051242:Caveolin 1 / Q000235:genetics / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004847:Epithelial Cells / Q000166:cytology / Q000502:physiology*; D005260:Female; D005333:Fetus / Q000033:anatomy & histology / Q000502:physiology; D005865:Gestational Age; D006801:Humans; D007223:Infant; D008168:Lung / Q000033:anatomy & histology / Q000196:embryology* / Q000378:metabolism; D011247:Pregnancy; D020545:Respiratory Mucosa / Q000166:cytology; D012189:Retrospective Studies; D014157:Transcription Factors; D015854:Up-Regulation; D051176:beta Catenin / Q000235:genetics / Q000378:metabolism*
chemical_list: D015703:Antigens, CD; C050361:CDH2 protein, human; D015820:Cadherins; D051242:Caveolin 1; D004268:DNA-Binding Proteins; C504003:TTF1 protein, human; D014157:Transcription Factors; D051176:beta Catenin