HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 294/2/G441    most recent 00303.2007v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via Google Scholar Google Scholar Articles by van der Merwe, J. Q. Articles by MacNaughton, W. K. Search for Related Content PubMed PubMed Citation Articles by van der Merwe, J. Q. Articles by MacNaughton, W. K.

MUCOSAL BIOLOGY

EGF receptor transactivation and MAP kinase mediate proteinase-activated receptor-2-induced chloride secretion in intestinal epithelial cells

Inflammation Research Network, Departments of ¹Physiology and Biophysics and ²Pharmacology and Therapeutics, University of Calgary, Calgary, Alberta, Canada

Submitted 5 July 2007 ; accepted in final form 15 November 2007

We examined the stimulus-secretion pathways whereby proteinase-activated receptor 2 (PAR-2) stimulates Cl^– secretion in intestinal epithelial cells. SCBN and T84 epithelial monolayers grown on Snapwell supports and mounted in modified Ussing chambers were activated by the PAR-2-activating peptides SLIGRL-NH₂ and 2-furoyl-LIGRLO-NH₂. Short-circuit current (I_sc) was used as a measure of net electrogenic ion transport. Basolateral, but not apical, application of SLIGRL-NH₂ or 2-furoyl-LIGRLO-NH₂ caused a concentration-dependent change in I_sc that was significantly reduced in Cl^–-free buffer and by the intracellular Ca²⁺ blockers thapsigargin and BAPTA-AM, but not by the Ca²⁺ channel blocker verapamil. Inhibitors of PKA (H-89) and CFTR (glibenclamide) also significantly reduced PAR-2-stimulated Cl^– transport. PAR-2 activation was associated with increases in cAMP and intracellular Ca²⁺. Immunoblot analysis revealed increases in phosphorylation of epidermal growth factor (EGF) receptor (EGFR) tyrosine kinase, Src, Pyk2, cRaf, and ERK1/2 in response to PAR-2 activation. Pretreatment with inhibitors of cyclooxygenases (indomethacin), tyrosine kinases (genistein), EGFR (PD-153035), MEK (PD-98059 or U-0126), and Src (PP1) inhibited SLIGRL-NH₂-induced increases in I_sc. Inhibition of Src, but not matrix metalloproteinases, reduced EGFR phosphorylation. Reduced EGFR phosphorylation paralleled the reduction in PAR-2-stimulated I_sc. We conclude that activation of basolateral, but not apical, PAR-2 induces epithelial Cl^– secretion via cAMP- and Ca²⁺-dependent mechanisms. The secretory effect involves EGFR transactivation by Src, leading to subsequent ERK1/2 activation and increased cyclooxygenase activity.

ion transport; proteinases; signal transduction; protein kinase; cyclooxygenase; mitogen-activated protein kinase; extracellular signal-regulated kinase 1/2