TY - JOUR
T1 - Apical and basolateral EGF receptors regulate gastric mucosal paracellular permeability
AU - Chen, Monica C.
AU - Goliger, Jeffrey
AU - Bunnett, Nigel
AU - Soll, Andrew H.
N1 - Copyright:
Copyright 2020 Elsevier B.V., All rights reserved.
PY - 2001/2
Y1 - 2001/2
N2 - Previous studies found that monolayers formed from canine oxyntic epithelial cells in primary culture displayed remarkable resistance to apical acidification and both mitogenic and migratory responses to epidermal growth factor (EGF) treatment. In our present studies, we found that EGF increased transepithelial resistance (TER) but not short-circuit current in these monolayers. Parallel effects of EGF on decreasing mannitol flux and increasing TER implicate direct regulation of paracellular permeability. EGF acting at either apical and basolateral receptors rapidly increased TER, but the apical response was sustained whereas the basolateral response was transient. 125I-labeled EGF binding revealed specific apical binding, but receptor numbers were 25-fold lower than on the basolateral surface. Both apical and basolateral EGF activated tyrosine phosphorylation of EGF receptors (EGFR), β-catenin, and cellular substrate as evident on confocal microscopy. Although apical EGF activated a lesser degree of receptor autophosphorylation than basolateral EGF, phosphorylation of β-catenin was equally prominent with apical and basolateral receptor activation. Together, these findings indicate that functional apical and basolateral EGFR exist on primary canine gastric epithelial cells and that these receptors regulate paracellular permeability. The sustained effect of apical EGFR activation and prominent phosphorylation of β-catenin suggest that apical EGFR may play a key role in this regulation.
AB - Previous studies found that monolayers formed from canine oxyntic epithelial cells in primary culture displayed remarkable resistance to apical acidification and both mitogenic and migratory responses to epidermal growth factor (EGF) treatment. In our present studies, we found that EGF increased transepithelial resistance (TER) but not short-circuit current in these monolayers. Parallel effects of EGF on decreasing mannitol flux and increasing TER implicate direct regulation of paracellular permeability. EGF acting at either apical and basolateral receptors rapidly increased TER, but the apical response was sustained whereas the basolateral response was transient. 125I-labeled EGF binding revealed specific apical binding, but receptor numbers were 25-fold lower than on the basolateral surface. Both apical and basolateral EGF activated tyrosine phosphorylation of EGF receptors (EGFR), β-catenin, and cellular substrate as evident on confocal microscopy. Although apical EGF activated a lesser degree of receptor autophosphorylation than basolateral EGF, phosphorylation of β-catenin was equally prominent with apical and basolateral receptor activation. Together, these findings indicate that functional apical and basolateral EGFR exist on primary canine gastric epithelial cells and that these receptors regulate paracellular permeability. The sustained effect of apical EGFR activation and prominent phosphorylation of β-catenin suggest that apical EGFR may play a key role in this regulation.
KW - Epidermal growth factor receptors
KW - Gastric mucosal defense
KW - Paracellular pathway
KW - Transforming growth factor receptors
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U2 - 10.1152/ajpgi.2001.280.2.g264
DO - 10.1152/ajpgi.2001.280.2.g264
M3 - Article
C2 - 11208549
AN - SCOPUS:0035018458
VL - 280
SP - G264-G272
JO - American Journal of Physiology - Gastrointestinal and Liver Physiology
JF - American Journal of Physiology - Gastrointestinal and Liver Physiology
SN - 0193-1857
IS - 2 43-2
ER -