Human L-selectin preferentially binds synthetic glycosulfopeptides modeled after endoglycan and containing tyrosine sulfate residues and sialyl Lewis x in core 2 O-glycans

Abstract

Endoglycan is a mucin-like glycoprotein expressed by endothelial cells and some leukocytes and is recognized by L-selectin, a C-type lectin important in leukocyte trafficking and extravasation during inflammation. Here, we show that recombinant L-selectin and human T lymphocytes expressing L-selectin bind to synthetic glycosulfopeptides (GSPs). These synthetic glycosulfopeptides contain 37 amino acid residues modeled after the N-terminus of human endoglycan and contain one or two tyrosine sulfates (TyrSO(3)) along with a nearby core-2-based Thr-linked O-glycan with sialyl Lewis x (C2-SLe(x)). TyrSO(3) at position Y118 was more critical for binding than at Y97. C2-SLe(x) at T124 was required for L-selectin recognition. Interestingly, under similar conditions, neither L-selectin nor T lymphocytes showed appreciable binding to the sulfated carbohydrate epitope 6-sulfo-SLe(x). P-selectin also bound to endoglycan-based GSPs but with lower affinity than toward GSPs modeled after PSGL-1, the physiological ligand for P- and L-selectin that is expressed on leukocytes. These results demonstrate that TyrSO(3) residues in association with a C2-SLe(x) moiety within endoglycan and PSGL-1 are preferentially recognized by L-selectin.

P-selectin glycoprotein ligand regulates the interaction of multiple myeloma cells with the bone marrow microenvironment

“…31 Moreover, the differences in the interaction between MM cells and normal plasma cells were apparently due to lower expression of PSGL-1 in normal plasma cells or potentially because of different glycosylation patterns of the PSGL-1, which is known to alter binding of selectins to the ligand. 32,33 To confirm the role of PSGL-1 in the interaction of selectins with MM cells, we knocked down PSGL-1 in MM1s cells using siRNA (as verified by flow cytometry; supplemental Figure 2). Knock-down of PSGL-1 decreased the high level of interaction of L-and P-selectins with MM cells (the effect was stronger for interaction of P-selectin on MM cells).…”

Inactivation of heparan sulfate 2-O-sulfotransferase accentuates neutrophil infiltration during acute inflammation in mice

“…Potential ligands include heparan sulfate [30][31][32] and sulfated ligands on TNF-␣-stimulated microvascular and macrovascular endothelial cells, 33,34 P-selectin glycoprotein ligand-1, 35 and endoglycan. 36 L-selectin interaction with P-selectin glycoprotein ligand-1 also facilitates neutrophil-neutrophil interactions or "secondary capture" of cells, resulting in pavementing of neutrophils. 37,38 In 2005, we provided genetic evidence suggesting that endothelial heparan sulfate facilitates neutrophil rolling on different endothelial beds based on inactivation of Ndst1 in the endothelium in Ndst1 f/f Tie2Cre ϩ mice.…”

Human Synovial Lubricin Expresses Sialyl Lewis x Determinant and Has L-selectin Ligand Activity

“…There are three groups of L-selectin ligands: the orthodox ligands with 6-sulfo sLe x structure on sialomucins and glycoproteins (i.e. GlyCAM-1 (glycosylation cell adhesion molecule-1), CD34, podocalyxin, and MAdCAM-1 (mucosal vascular addressin)); ligands with clusters of sLe x and Tyr-SO 3 like PSGL-1 (P-selectin-glycoprotein ligand-1) and endoglycan; and proteoglycans with predominantly heparan or chondroitin sulfate modifications (57)(58)(59). However, lubricin is different from those identified L-selectin ligands.…”