Regulation of lysophosphatidic acid-induced epidermal growth factor receptor transactivation and interleukin-8 secretion in human bronchial epithelial cells by protein kinase Cdelta, Lyn kinase, and matrix metalloproteinases

J Biol Chem. 2006 Jul 14;281(28):19501-11. doi: 10.1074/jbc.M511224200. Epub 2006 May 10.

Abstract

We have demonstrated earlier that lysophosphatidic acid (LPA)-induced interleukin-8 (IL-8) secretion is regulated by protein kinase Cdelta (PKCdelta)-dependent NF-kappaB activation in human bronchial epithelial cells (HBEpCs). Here we provide evidence for signaling pathways that regulate LPA-mediated transactivation of epidermal growth factor receptor (EGFR) and the role of cross-talk between G-protein-coupled receptors and receptor-tyrosine kinases in IL-8 secretion in HBEpCs. Treatment of HBEpCs with LPA stimulated tyrosine phosphorylation of EGFR, which was attenuated by matrix metalloproteinase (MMP) inhibitor (GM6001), heparin binding (HB)-EGF inhibitor (CRM 197), and HB-EGF neutralizing antibody. Overexpression of dominant negative PKCdelta or pretreatment with a PKCdelta inhibitor (rottlerin) or Src kinase family inhibitor (PP2) partially blocked LPA-induced MMP activation, proHB-EGF shedding, and EGFR tyrosine phosphorylation. Down-regulation of Lyn kinase, but not Src kinase, by specific small interfering RNA mitigated LPA-induced MMP activation, proHB-EGF shedding, and EGFR phosphorylation. In addition, overexpression of dominant negative PKCdelta blocked LPA-induced phosphorylation and translocation of Lyn kinase to the plasma membrane. Furthermore, down-regulation of EGFR by EGFR small interfering RNA or pretreatment of cells with EGFR inhibitors AG1478 and PD158780 almost completely blocked LPA-dependent EGFR phosphorylation and partially attenuated IL-8 secretion, respectively. These results demonstrate that LPA-induced IL-8 secretion is partly dependent on EGFR transactivation regulated by PKCdelta-dependent activation of Lyn kinase and MMPs and proHB-EGF shedding, suggesting a novel mechanism of cross-talk and interaction between G-protein-coupled receptors and receptor-tyrosine kinases in HBEpCs.

Publication types

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

MeSH terms

  • Bronchi / cytology*
  • Enzyme Inhibitors / pharmacology
  • Epidermal Growth Factor / metabolism*
  • Epithelial Cells / cytology*
  • ErbB Receptors / metabolism*
  • Gene Expression Regulation*
  • Heparin-binding EGF-like Growth Factor
  • Humans
  • Intercellular Signaling Peptides and Proteins
  • Interleukin-8 / metabolism*
  • Lysophospholipids / pharmacology*
  • Matrix Metalloproteinases / metabolism*
  • Protein Kinase C-delta / metabolism*
  • Transcriptional Activation*
  • src-Family Kinases / metabolism*

Substances

  • Enzyme Inhibitors
  • HBEGF protein, human
  • Heparin-binding EGF-like Growth Factor
  • Intercellular Signaling Peptides and Proteins
  • Interleukin-8
  • Lysophospholipids
  • Epidermal Growth Factor
  • ErbB Receptors
  • lyn protein-tyrosine kinase
  • src-Family Kinases
  • Protein Kinase C-delta
  • Matrix Metalloproteinases
  • lysophosphatidic acid