Recombinant tumour necrosis factor-alpha and platelet-activating factor synergistically increase intercellular adhesion molecule-1 and E-selectin-dependent neutrophil adherence to endothelium in vitro.
Neutrophil adhesion to microvascular endothelium at sites of acute inflammation is regulated by both chemotactic peptides and lipid-derived mediators. Tumour necrosis factor-alpha (TNF-alpha) is a pro-inflammatory peptide that up-regulates endothelial expression of intercellular adhesion molecule-1 (ICAM-1) and endothelial leucocyte adhesion molecule-1 (E-selectin), while platelet-activating factor (PAF) is a potent lipid mediator that induces vascular changes via an unknown mechanism. Both have been shown to increase leucocyte-endothelial adhesion in various in vitro models of acute inflammation; however, the combined effects of recombinant TNF-alpha (rTNF-alpha) and PAF on neutrophil-endothelium adhesion have not been well described. In this study, we found rTNF-alpha at 0.5 ng/ml and PAF at 10 microM acted synergistically to increase neutrophil adherence to cultured umbilical vein endothelial cells 4 hr after stimulation. This increased neutrophil-endothelial adhesion was, in part, dependent on up-regulated expression of ICAM-1 and E-selectin since application of anti-ICAM1 and anti-E-selectin F(ab')2 fragments markedly diminished adhesion. Cultures stimulated with rTNF-alpha (0.5 ng/ml) or PAF (10 microM) alone did not show a significant increase in neutrophil adhesion, and neither ICAM-1 nor E-selectin expression was up-regulated as determined by flow cytometric analysis of endothelial cells. These results indicate that rTNF-alpha and PAF act synergistically to increase neutrophil-endothelial adhesion by stimulating endothelial expression of ICAM-1 and E-selectin and, thus, may play important roles in the onset and severity of acute inflammatory reactions.
Sterner-Kock
A
A
Department of Anatomy, Physiology and Cell Biology, University of California, Davis, 95616, USA.
Braun
R K
RK
Schrenzel
M D
MD
Hyde
D M
DM
D002448:Cell Adhesion / Q000187:drug effects; D002478:Cells, Cultured; D004357:Drug Synergism; D019040:E-Selectin / Q000502:physiology*; D004730:Endothelium, Vascular / Q000502:physiology*; D006801:Humans; D018799:Intercellular Adhesion Molecule-1 / Q000502:physiology*; D009504:Neutrophils / Q000187:drug effects* / Q000502:physiology; D010972:Platelet Activating Factor / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000494:pharmacology; D013268:Stimulation, Chemical; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D015854:Up-Regulation
D019040:E-Selectin; D010972:Platelet Activating Factor; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D018799:Intercellular Adhesion Molecule-1