E-selectin is upregulated in proliferating endothelial cells in vitro.
OBJECTIVE
E-selectin is an endothelial cell-specific membrane glycoprotein that participates in leukocyte adhesion and has also been suggested to function in angiogenesis. To gain further insights into E-selectin, we analyzed E-selectin polypeptide in proliferating versus quiescent bovine capillary endothelial cells and its expression as a function of the cell cycle.


METHODS
E-selectin polypeptide was analyzed by immunoadsorption from 35Scysteine-labeled endothelial cells, by enzyme-linked immunosorbent assay, and by fluorescence-activated cell sorting. The distribution of endothelial cells in Gzero/G1, S, and G2/M phases of the cell cycle was determined using propidium iodide staining of DNA.


RESULTS
E-selectin was upregulated in subconfluent proliferating bovine capillary endothelial cells compared to confluent quiescent cultures. The upregulation was independent of activation in that E-selectin was further increased by treatment with tumor necrosis factor alpha or lipopolysaccharide. In contrast to E-selectin, P-selectin and platelet-endothelial cell adhesion molecule-1 did not appear to be regulated by the growth state of the endothelial cells. The distribution of E-selectin-positive cells in GzeroG1, S, and G2/M phases of the cell cycle differed from E-selectin-negative cells in that more of the E-selectin-positive cells were in G2 and M.


CONCLUSIONS
Increased E-selectin expression under noninflammatory conditions is correlated with cellular proliferation and G2/M phases of the cell cycle. The expression of E-selectin in proliferating endothelial cells in vitro is consistent with the presence of E-selectin in proliferating endothelial cells in vivo (Kräling et al. [18]).
Bischoff
J
J
Surgical Research Laboratory, Children's Hospital, Boston, MA 02115, USA.
Brasel
C
C
Kräling
B
B
Vranovska
K
K
D000818:Animals; D000918:Antibody Specificity; D002417:Cattle; D002448:Cell Adhesion; D002455:Cell Division; D002478:Cells, Cultured; D019040:E-Selectin / Q000737:chemistry* / Q000276:immunology / Q000378:metabolism*; D004730:Endothelium, Vascular / Q000737:chemistry / Q000166:cytology / Q000378:metabolism*; D015854:Up-Regulation
D019040:E-Selectin