Translational inhibition of E-selectin expression stimulates P-selectin-dependent neutrophil recruitment.
Although known for its role in hemostasis, there is a growing body of evidence that thrombin can induce leukocyte recruitment and contribute to the inflammatory response. An in vitro parallel-plate flow chamber was used to systematically examine thrombin-induced neutrophil interactions with human endothelium. Stimulation of endothelial cells with thrombin (1 U/ml) resulted in an immediate, P-selectin-dependent increase in neutrophil rolling and adhesion that was comparable in magnitude to optimal levels of histamine (the classical inducer of P-selectin). However, thrombin, but not histamine, induced a delayed (4 h) E-selectin-dependent rolling similar to that of tumor necrosis factor-alpha, suggesting that thrombin has the unique ability to recruit neutrophils by an early P-selectin and a delayed E-selectin pathway. Surprisingly, inhibition of E-selectin expression with the general protein synthesis inhibitor cycloheximide induced P-selectin expression 4 h after thrombin stimulation. Cycloheximide and thrombin (4 h) induced sufficient P-selectin-dependent rolling to recruit as many neutrophils as were recruited with 4 h of stimulation with thrombin alone. Histamine in the presence of cycloheximide or cycloheximide alone did not evoke the P-selectin response at 4 h, suggesting that this was not due to direct cycloheximide induction of P-selectin. Treatment of endothelium with tumor necrosis factor-alpha (an E-selectin inducer) and cycloheximide also eliminated E-selectin expression but, much like thrombin, induced P-selectin expression and neutrophil recruitment. In conclusion, inhibition of E-selectin via protein synthesis inhibition activates the protein synthesis-independent pathway of P-selectin expression to support adequate leukocyte recruitment.
Ostrovsky
L
L
Immunology Research Group and Departments of Physiology and Biophysics and Medicine, University of Calgary, Calgary, Alberta, Canada T2N 4N1.
Carvalho-Tavares
J
J
Woodman
R C
RC
Kubes
P
P
D002448:Cell Adhesion / Q000187:drug effects / Q000276:immunology; D002465:Cell Movement / Q000187:drug effects / Q000276:immunology*; D003513:Cycloheximide / Q000494:pharmacology; D019040:E-Selectin / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000166:cytology / Q000276:immunology / Q000378:metabolism*; D018922:HL-60 Cells; D006490:Hemostatics / Q000494:pharmacology; D006632:Histamine / Q000494:pharmacology; D006801:Humans; D008565:Membrane Proteins / Q000378:metabolism; D009504:Neutrophils / Q000166:cytology*; D019007:P-Selectin / Q000378:metabolism*; D011500:Protein Synthesis Inhibitors / Q000494:pharmacology; D020239:Receptor Cross-Talk / Q000502:physiology; D013917:Thrombin / Q000494:pharmacology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology; D015854:Up-Regulation / Q000187:drug effects
D019040:E-Selectin; D006490:Hemostatics; D008565:Membrane Proteins; D019007:P-Selectin; D011500:Protein Synthesis Inhibitors; D014409:Tumor Necrosis Factor-alpha; D006632:Histamine; D003513:Cycloheximide; D013917:Thrombin