Regulation of epithelial cell tight junctions by protease-activated receptor 2.
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Although the application of a PAR2-activating peptide, PAR2-AP, from the apical side of MDCK cells failed to modify the transepithelial resistance (TER), its application from the basal side markedly suppressed the TER.A p38 MAP kinase inhibitor, SB202190, inhibited PAR2-AP-induced changes in TER.Our results suggest that the activation of PAR2 leads to the disruption of tight junctions and increases the barrier permeability through the activation of p38 MAPK, which may cause the initiation and exacerbation of inflammation.
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Affiliation: Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan.
ABSTRACT
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A layer of epithelial cells prevents the invasion of bacteria and the entry of foreign substances into the underlying tissue. The disruption of epithelial tight junctions initiates and exacerbates inflammation. However, the precise mechanism underlying the disruption of the epithelial tight junction remains unclear. The activation of protease-activated receptor 2 (PAR2) by serine proteases produced by some bacteria and mast cells contributes to inflammation in many tissues. In the present study, we tested the hypothesis that PAR2 activation affects the structure and function of tight junctions in Madin-Darby canine kidney (MDCK) cells. Although the application of a PAR2-activating peptide, PAR2-AP, from the apical side of MDCK cells failed to modify the transepithelial resistance (TER), its application from the basal side markedly suppressed the TER. In 3-dimensional cultures of MDCK cells expressing the mCherry-tagged PAR2, a lateral localization of PAR2 was observed. The application of PAR2-AP from the basal side changed the localization of the tight junctional protein, zonula occludin-1. Furthermore, PAR2-AP induced the phosphorylation of p38 MAP kinase. A p38 MAP kinase inhibitor, SB202190, inhibited PAR2-AP-induced changes in TER. Our results suggest that the activation of PAR2 leads to the disruption of tight junctions and increases the barrier permeability through the activation of p38 MAPK, which may cause the initiation and exacerbation of inflammation. Related in: MedlinePlus |
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fig_002: PAR2 localizes to the basolateral side of MDCK cystic cells.The mCherry-PAR2 MDCKcells were cultured in Matrigel to form cysts. Phase contrast image of cysts (A) andconfocal fluorescence microscopy images of E-cadherin (left panel), mCherry-PAR2(middle panel), and merged image of E-cadherin (green), mCherry-PAR2 (red) and actin(blue) (right panel) (B). Representative images from 3 independent experiments areshown. Scale bars; 800 µm (A) and 50 µm (B). Mentions: Next, we examined the localization of PAR2 in 3-dimensional cultures of the polyclonalmCherry-PAR2 MDCK cells. After 3 days of culture in Matrigel matrix, these cells formed aspherical cyst (Fig. 2AFig. 2. |
View Article: PubMed Central - PubMed
Affiliation: Laboratory of Veterinary Pharmacology, Joint Faculty of Veterinary Medicine, Yamaguchi University, 1677-1 Yoshida, Yamaguchi 753-8515, Japan.