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PAR‐2‐induced epithelial Cl‐ secretion involves EGFr transactivation
Author(s) -
Merwe Jacques,
MacNaughton Wallace
Publication year - 2006
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.20.5.a1116-a
Subject(s) - transactivation , proto oncogene tyrosine protein kinase src , phosphorylation , chemistry , western blot , secretion , kinase , receptor , microbiology and biotechnology , medicine , endocrinology , biology , biochemistry , gene expression , gene
Proteinase‐activated receptor (PAR)‐2 is activated by trypsin‐like serine proteinases. PAR‐2 activation stimulates intestinal epithelial Cl‐ secretion, but the underlying stimulation‐secretion coupling pathways are unclear. We have studied these pathways in the SCBN intestinal epithelial cell culture model. Methods 1. SCBN monolayers were grown on Snapwell supports and mounted in modified Ussing chambers. Short circuit current (Isc) was monitored as a measure of net electrogenic ion transport. The roles of PKC, MAP kinase (ERK1/2), Src, matrix metallo‐proteinases (MMPs) and the EGF receptor (EGFr) in the response to the PAR‐2 activating peptide SLIGRL‐NH 2 were determined using specific inhibitors (GFX, PD98059, PP1, GM6001, PD153035). 2. Western blot analysis was conducted for ERK1/2, Src and EGFr phosphorylation in response to PAR‐2 activation. Results 1. Pretreatment with GFX resulted in a reduction (p<0.05) in the response to PAR‐2 activation by SLIGRL‐NH 2 . PD98059 reduced responses to PAR‐2 activation as did pretreatment with PD153035 (p<0.05). Inhibition of Src, but not MMPs, resulted in a significant decrease in response to PAR‐2 activation by SLIGRL‐NH 2 . 2. As shown by Western blot, PAR‐2 activation resulted in EGFr, Src and ERK1/2 phosphorylation. Inhibition of Src, but not MMPs, resulted in significantly reduced EGFr phsophorylation following activation of PAR‐2 with SLIGRL‐NH 2 . Furthermore, inhibition of Src, EGFr or PKC prevented ERK1/2 phosphorylation. Conclusions PAR‐2 activation induces epithelial Cl − secretion that is mediated by Src‐dependent EGF receptor transactivation, subsequent ERK1/2 activation and PKC‐mediated signaling. Funding: Canadian Institutes of Health Research.