Sialyl Lewis(x)-mediated, PSGL-1-independent rolling adhesion on P-selectin

Biophys J. 2000 Aug;79(2):694-706. doi: 10.1016/S0006-3495(00)76328-4.

Abstract

Selectin-mediated cell adhesion is an essential component of the inflammatory response. In an attempt to unambiguously identify molecular features of ligands that are necessary to support rolling adhesion on P-selectin, we have used a reconstituted ("cell-free") system in which ligand-coated beads are perfused over soluble P-selectin surfaces. We find that beads coated with the saccharides sialyl Lewis(x) (sLe(x)), sialyl Lewis(a) (sLe(a)), and sulfated Lewis(x) (HSO(3)Le(x) support rolling adhesion on P-selectin surfaces. Although it has been suggested that glycosylation and sulfation of P-selectin glycoprotein ligand-1 (PSGL-1) is required for high-affinity binding and rolling on P-selectin, our findings indicate that sulfation of N-terminal tyrosine residues is not required for binding or rolling. However, beads coated with a tyrosine-sulfated, sLe(x)-modified, PSGL-1-Fc chimera support slower rolling on P-selectin than beads coated with sLe(x) alone, suggesting that sulfation improves rolling adhesion by modulating binding to P-selectin. In addition, we find it is not necessary that P-selectin carbohydrate ligands be multivalent for robust rolling to occur. Our results demonstrate that beads coated with monovalent sLe(x), exhibiting a more sparse distribution of carbohydrate than a similar amount of the multivalent form, are sufficient to yield rolling adhesion. The relative abilities of various ligands to support rolling on P-selectin are quantitatively examined among themselves and in comparison to human neutrophils. Using stop-time distributions, rolling dynamics at video frame rate resolution, and the average and variance of the rolling velocity, we find that P-selectin ligands display the following quantitative trend, in order of decreasing ability to support rolling adhesion on P-selectin: PSGL-1-Fc > sLe(a) approximately sLe(x) > HSO(3)Le(x).

Publication types

  • Research Support, U.S. Gov't, Non-P.H.S.
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Adult
  • Animals
  • CHO Cells
  • Cell Adhesion
  • Cricetinae
  • Humans
  • In Vitro Techniques
  • Lewis X Antigen / chemistry
  • Membrane Glycoproteins / chemistry*
  • Membrane Glycoproteins / physiology
  • Neutrophils / physiology*
  • Oligosaccharides / chemistry*
  • P-Selectin / chemistry*
  • P-Selectin / physiology
  • Recombinant Proteins / chemistry
  • Sialyl Lewis X Antigen
  • Stress, Mechanical
  • Transfection

Substances

  • Lewis X Antigen
  • Membrane Glycoproteins
  • Oligosaccharides
  • P-Selectin
  • P-selectin ligand protein
  • Recombinant Proteins
  • Sialyl Lewis X Antigen