Down-regulation of E-cadherin in human bronchial epithelial cells leads to epidermal growth factor receptor-dependent Th2 cell-promoting activity

J Immunol. 2007 Jun 15;178(12):7678-85. doi: 10.4049/jimmunol.178.12.7678.

Abstract

Airway epithelial cells are well-known producers of thymus- and activation-regulated chemokine (TARC), a Th2 cell-attracting chemokine that may play an important role in the development of allergic airway inflammation. However, the mechanism responsible for up-regulation of TARC in allergy is still unknown. In the asthmatic airways, loss of expression of the cell-cell contact molecule E-cadherin and reduced epithelial barrier function has been observed, which may be the result of an inadequate repair response. Because E-cadherin also suppressed multiple signaling pathways, we studied whether disruption of E-cadherin-mediated cell contact may contribute to increased proallergic activity of epithelial cells, e.g., production of the chemokine TARC. We down-regulated E-cadherin in bronchial epithelial cells by small interference RNA and studied effects on electrical resistance, signaling pathways, and TARC expression (by electric cell-substrate impedance sensing, immunodetection, immunofluorescent staining, and real-time PCR). Small interference RNA silencing of E-cadherin resulted in loss of E-cadherin-mediated junctions, enhanced phosphorylation of epidermal growth factor receptor (EGFR), and the downstream targets MEK/ERK-1/2 and p38 MAPK, finally resulting in up-regulation of TARC as well as thymic stromal lymphopoietin expression. The use of specific inhibitors revealed that the effect on TARC is mediated by EGFR-dependent activation of the MAPK pathways. In contrast to TARC, expression of the Th1/Treg cell-attracting chemokine RANTES was unaffected by E-cadherin down-regulation. In summary, we show that loss of E-cadherin-mediated epithelial cell-cell contact by damaging stimuli, e.g., allergens, may result in reduced suppression of EGFR-dependent signaling pathways and subsequent induction of Th2 cell-attracting molecule TARC. Thus, disruption of intercellular epithelial contacts may specifically promote Th2 cell recruitment in allergic asthma.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Asthma / immunology*
  • Bronchi / immunology*
  • Bronchi / metabolism
  • Cadherins / antagonists & inhibitors
  • Cadherins / genetics
  • Cadherins / physiology*
  • Cells, Cultured
  • Chemokine CCL17
  • Chemokines, CC / analysis
  • Chemokines, CC / genetics
  • Chemokines, CC / metabolism
  • Cytokines / metabolism
  • Down-Regulation
  • ErbB Receptors / metabolism
  • Humans
  • Mitogen-Activated Protein Kinase Kinases / immunology
  • Phosphorylation
  • RNA, Small Interfering / pharmacology
  • Respiratory Mucosa / immunology*
  • Th2 Cells / immunology*
  • Thymic Stromal Lymphopoietin

Substances

  • CCL17 protein, human
  • Cadherins
  • Chemokine CCL17
  • Chemokines, CC
  • Cytokines
  • RNA, Small Interfering
  • ErbB Receptors
  • Mitogen-Activated Protein Kinase Kinases
  • Thymic Stromal Lymphopoietin