Secretion of IL-13 by airway epithelial cells enhances epithelial repair via HB-EGF

Am J Respir Cell Mol Biol. 2008 Feb;38(2):153-60. doi: 10.1165/rcmb.2007-0173OC. Epub 2007 Aug 23.

Abstract

Inappropriate repair after injury to the epithelium generates persistent activation, which may contribute to airway remodeling. In the present study we hypothesized that IL-13 is a normal mediator of airway epithelial repair. Mechanical injury of confluent airway epithelial cell (AEC) monolayers induced expression and release of IL-13 in a time-dependent manner coordinate with repair. Neutralizing of IL-13 secreted from injured epithelial cells by shIL-13Ralpha2.FC significantly reduced epithelial repair. Moreover, exogenous IL-13 enhanced epithelial repair and induced epidermal growth factor receptor (EGFR) phosphorylation. We examined secretion of two EGFR ligands, epidermal growth factor (EGF) and heparin-binding EGF (HB-EGF), after mechanical injury. Our data showed a sequential release of the EGF and HB-EGF by AEC after injury. Interestingly, we found that IL-13 induces HB-EGF, but not EGF, synthesis and release from AEC. IL-13-induced EGFR phosphorylation and the IL-13-reparative effect on AEC are mediated via HB-EGF. Finally, we demonstrated that inhibition of EGFR tyrosine kinase activity by tyrphostin AG1478 increases IL-13 release after injury, suggesting negative feedback between EGFR and IL-13 during repair. Our data, for the first time, showed that IL-13 plays an important role in epithelial repair, and that its effect is mediated through the autocrine release of HB-EGF and activation of EGFR. Dysregulation of EGFR phosphorylation may contribute to a persistent repair phenotype and chronically increased IL-13 release, and in turn result in airway remodeling.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Bronchi / cytology
  • Bronchi / metabolism*
  • Cell Line, Transformed
  • Culture Media, Serum-Free
  • DNA Primers
  • Enzyme-Linked Immunosorbent Assay
  • Epithelial Cells / cytology
  • Epithelial Cells / metabolism
  • ErbB Receptors / metabolism
  • Heparin-binding EGF-like Growth Factor
  • Humans
  • Intercellular Signaling Peptides and Proteins / metabolism*
  • Interleukin-13 / metabolism*
  • Ligands
  • Phosphorylation
  • Reverse Transcriptase Polymerase Chain Reaction

Substances

  • Culture Media, Serum-Free
  • DNA Primers
  • HBEGF protein, human
  • Heparin-binding EGF-like Growth Factor
  • Intercellular Signaling Peptides and Proteins
  • Interleukin-13
  • Ligands
  • ErbB Receptors