Endothelin-1 enhances neutrophil adhesion to human coronary artery endothelial cells: role of ET(A) receptors and platelet-activating factor.
1. The potent coronary vasoconstrictor, endothelin-1 (ET-1) may also regulate neutrophil traffic into tissues. The aim of the present study was to characterize the endothelin receptors responsible and to investigate the underlying mechanisms. 2. ET-1 (1 nM - 1 microM) markedly enhanced attachment of human neutrophils to lipopolysaccharide-, and to a lesser extent, to ET-1-activated human coronary artery endothelial cells (HCAEC). This can partially be blocked by monoclonal antibodies against E-selectin, L-selectin or CD18, whereas combination of the three antibodies inhibited adhesion by approximately 83%. Increases in neutrophil adhesion evoked by ET-1 were also blocked by the platelet-activating factor (PAF) antagonists, BN 52021 (50 microM) and WEB 2086 (10 microM). 3. ET-1 downregulated the expression of L-selectin and upregulated expression of CD11b/CD18 and CD45 on the neutrophil surface and induced gelatinase release with EC50 values of approximately 2 nM. These actions of ET-1 were almost completely prevented by the ET(A) receptor antagonist FR 139317 (1 microM) and the ET(A)/ET(B) receptor antagonist bosentan (10 microM), whereas the ET(B) receptor antagonist BQ 788 (1 microM) had no effect. ET-1 slightly increased the expression of E-selectin and ICAM-1 on HCAEC, that was prevented by BQ 788, but not by FR 139317. 4. Receptor binding studies indicated the presence of ET(B) receptors (KD: 40 pM) on phosphoramidon-treated HCAEC and the predominant expression of ET(A) receptors (KD: 38 pM) on neutrophils. 5. These results indicate that promotion by ET-1 of neutrophil adhesion to HCAEC is predominantly mediated through activation of ET(A) receptors on neutrophils and subsequent generation of PAF.
Zouki
C
C
Research Center, Maisonneuve-Rosemont Hospital, Department of Medicine, University of Montréal, Québec, Canada.
Baron
C
C
Fournier
A
A
Filep
J G
JG
D000328:Adult; D018821:CD18 Antigens / Q000096:biosynthesis; D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000187:drug effects*; D019040:E-Selectin / Q000096:biosynthesis; D019332:Endothelin-1 / Q000378:metabolism / Q000494:pharmacology*; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects*; D005260:Female; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000096:biosynthesis; D019041:L-Selectin / Q000096:biosynthesis; D008297:Male; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D010972:Platelet Activating Factor / Q000502:physiology*; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin / Q000502:physiology*
D018821:CD18 Antigens; D019040:E-Selectin; D019332:Endothelin-1; D010972:Platelet Activating Factor; D044022:Receptor, Endothelin A; D017466:Receptors, Endothelin; D018799:Intercellular Adhesion Molecule-1; D019041:L-Selectin