Fluid flow regulates E-selectin protein levels in human endothelial cells by inhibiting translation.
OBJECTIVE
The purpose of this study was to determine the mechanism with which fluid flow inhibits endothelial E-selectin expression.


METHODS
Cultured human umbilical vein endothelial cells were stimulated with inflammatory agonists (tumor necrosis factor-alpha [TNF-alpha], interleukin-1beta, oncostatin M, or phorbol ester) in the presence or absence of fluid flow (peak shear stress, approximately 12 dynes/cm(2)) imposed with an orbital shaker. E-selectin expression was assessed with ribonuclease protection assay, immunoblotting, enzyme-linked immunosorbent assay, or metabolic labeling as appropriate.


RESULTS
All agonists caused human umbilical vein endothelial cells to express E-selectin protein. Fluid flow inhibited E-selectin protein levels by about 50% in response to TNF-alpha but had no effect on total E-selectin messenger RNA (mRNA) expression. Flow inhibited E-selectin protein production even after initiation of E-selectin transcription. Flow did not cause E-selectin to be shed from the cell surface nor was E-selectin degradation accelerated. Although fluid flow did not reduce total cellular E-selectin mRNA levels in response to TNF-alpha, the amount of E-selectin mRNA present in the actively translated polysome fraction was markedly attenuated.


CONCLUSIONS
These findings indicate that E-selectin expression is subject to translational and transcriptional control. Fluid mechanical forces can regulate endothelial phenotype by targeting translational control points.
Kraiss
Larry W
LW
Division of Vascular Surgery, Eccles Institute of Human Genetics, University of Utah, 15 North 2030 East, Salt Lake City UT, 84112-5330, USA. larry.kraiss@hmbg.utah.edu
Alto
Neal M
NM
Dixon
Dan A
DA
McIntyre
Thomas M
TM
Weyrich
Andrew S
AS
Zimmerman
Guy A
GA
D001783:Blood Flow Velocity / Q000502:physiology*; D002478:Cells, Cultured; D019040:E-Selectin / Q000032:analysis* / Q000235:genetics; D004730:Endothelium, Vascular / Q000166:cytology*; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D015151:Immunoblotting; D007375:Interleukin-1 / Q000494:pharmacology; D053683:Oncostatin M; D010455:Peptides / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology; D014176:Protein Biosynthesis / Q000502:physiology*; D011506:Proteins; D012333:RNA, Messenger / Q000032:analysis; D014158:Transcription, Genetic / Q000502:physiology; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D014471:Umbilical Veins
D019040:E-Selectin; D007375:Interleukin-1; C508351:OSM protein, human; D010455:Peptides; D010703:Phorbol Esters; D011506:Proteins; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C447606:WFDC12 protein, human; D053683:Oncostatin M