PSGL-1 derived from human neutrophils is a high-efficiency ligand for endothelium-expressed E-selectin under flow.
P-selectin glycoprotein ligand-1 (PSGL-1) has been proposed as an important tethering ligand for E-selectin and is expressed at a modest level on human leukocytes. Sialyl Lewis x (sLe(x))-like glycans bind to E-selectin and are expressed at a relatively high level on circulating leukocytes. It is unclear whether PSGL-1 has unique biochemical attributes that contribute to its role as an E-selectin ligand. To probe this issue, we conjugated microspheres with either sLe(x) or PSGL-1 purified from myeloid cells (neutrophils and HL-60) and compared their adhesion to endothelial expressed E-selectin under defined shear conditions. We found that both sLe(x) and PSGL-1 microspheres adhere to 4 h of IL-1beta-activated human umbilical vein endothelial cells predominantly through E-selectin. Analysis of the adhesion revealed that the rate of initial tethering of the PSGL-1 microspheres to E-selectin was significantly greater than the rate of initial tethering of the sLe(x) microspheres despite the fact that the sLe(x) microspheres tested had higher ligand densities than the PSGL-1 microspheres. We also found that pretreatment of the PSGL-1 or sLe(x) microspheres with HECA-452 had no significant effect on initial tethering to E-selectin. These results support the hypotheses that 1) PSGL-1 is a high-efficiency tethering ligand for E-selectin, 2) ligand biochemistry can significantly influence initial tethering to E-selectin, and 3) PSGL-1 tethering to E-selectin can occur via non-HECA-452 reactive epitopes.
Zou
Xiaoyan
X
Department of Chemical Engineering, 172 Stocker Center, Ohio University, Athens, OH 45701, USA.
Shinde Patil
Vivek R
VR
Dagia
Nilesh M
NM
Smith
Lee A
LA
Wargo
Maureen J
MJ
Interliggi
Kimberly A
KA
Lloyd
Christopher M
CM
Tees
David F J
DF
Walcheck
Bruce
B
Lawrence
Michael B
MB
Goetz
Douglas J
DJ
D002448:Cell Adhesion / Q000502:physiology; D002478:Cells, Cultured; D019040:E-Selectin / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D036904:Leukocyte Rolling / Q000502:physiology; D008024:Ligands; D008562:Membrane Glycoproteins / Q000378:metabolism*; D008863:Microspheres; D009363:Neoplasm Proteins / Q000378:metabolism; D009504:Neutrophils / Q000378:metabolism*; D033081:Shear Strength
D019040:E-Selectin; C445125:HECA protein, human; D008024:Ligands; D008562:Membrane Glycoproteins; D009363:Neoplasm Proteins; C084882:P-selectin ligand protein