The p38 mitogen-activated protein kinase pathway plays a critical role in PAR2-induced endothelial IL-8 production and leukocyte adhesion.
A member of a new subfamily of G protein-coupled receptors, protease-activated receptor 2 (PAR2), is highly expressed on endothelial cells and plays an important role in inflammation. The purpose of this study was to determine the molecular mechanism used by PAR2 to induce IL-8 production and thereby mediate cell adhesion. We observed that PAR2-activating peptide (PAR2-AP) significantly increase peripheral blood mononuclear cells adhere to endothelial cells. Both PAR2-AP and the endogenous PAR2 activator trypsin caused concentration- and time-dependent increase in endothelial IL-8 production, and this effect was concentration dependently and selectively attenuated by the p38 mitogen-activated protein kinase (MAPK) inhibitor SB203580. Western blotting analysis showed that PAR2-AP induced phosphorylation of p38 MAPK and its upstream protein kinase MAPK kinase 3/6 (MKK3/6) in a time-dependent manner. Using reverse-transcriptase-polymerase chain reaction and enzyme-linked immunosorbent assay, PAR2-AP was found to cause an increase in IL-8 mRNA expression and its transcription factor activating transcription factor 2, respectively,. As expected, these signals were suppressed by SB203580 in a concentration-dependent manner. Furthermore, introduction of dominant-negative vectors targeting p38 MAPK, MKK3, and MKK6 abolished PAR2-AP-mediated IL-8 production and cell adhesion function. In conclusion, PAR2 via p38 MAPK signaling regulates IL-8 production and thereby mediates cell adhesion.
Pan
Shiow L
SL
Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan.
Tao
Kai Y
KY
Guh
Jih H
JH
Sun
Hui L
HL
Huang
Der Y
DY
Chang
Ya L
YL
Teng
Che M
CM
D051696:Activating Transcription Factors; D015153:Blotting, Western; D002448:Cell Adhesion / Q000187:drug effects*; D002478:Cells, Cultured; D018076:DNA, Complementary; D005419:Flavonoids / Q000494:pharmacology; D005434:Flow Cytometry; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D039041:Integrin alpha4beta1 / Q000378:metabolism; D018799:Intercellular Adhesion Molecule-1 / Q000378:metabolism; D016209:Interleukin-8 / Q000378:metabolism*; D007962:Leukocytes / Q000166:cytology* / Q000187:drug effects; D016169:Lymphocyte Function-Associated Antigen-1 / Q000378:metabolism; D016177:Macrophage-1 Antigen / Q000378:metabolism; D011725:Pyridines / Q000494:pharmacology; D044464:Receptor, PAR-2 / Q000819:agonists / Q000378:metabolism / Q000502:physiology*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D014357:Trypsin / Q000494:pharmacology; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*
D051696:Activating Transcription Factors; D018076:DNA, Complementary; D005419:Flavonoids; D007093:Imidazoles; D007211:Indoles; D039041:Integrin alpha4beta1; D016209:Interleukin-8; D016169:Lymphocyte Function-Associated Antigen-1; D016177:Macrophage-1 Antigen; D011725:Pyridines; D044464:Receptor, PAR-2; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1; D048051:p38 Mitogen-Activated Protein Kinases; D014357:Trypsin; C093642:SB 203580; C093973:2-(2-amino-3-methoxyphenyl)-4H-1-benzopyran-4-one; C064758:Ro 31-8220