Here we have studied the involvement of endothelial heparan sulfate in inflammation by inactivating the enzyme N-acetyl glucosamine N-deacetylase-N-sulfotransferase-1 in endothelial cells and leukocytes, which is required for the addition of sulfate to the heparin sulfate chains. Mutant mice developed normally but showed impaired neutrophil infiltration in various inflammation models. These effects were due to changes in heparan sulfate specifically in endothelial cells. Decreased neutrophil infiltration was partially due to altered rolling velocity correlated with weaker binding of L-selectin to endothelial cells. Chemokine transcytosis across endothelial cells and presentation on the cell surface were also reduced, resulting in decreased neutrophil firm adhesion and migration. Thus, endothelial heparan sulfate has three functions in inflammation: by acting as a ligand for L-selectin during neutrophil rolling; in chemokine transcytosis; and by binding and presenting chemokines at the lumenal surface of the endothelium.
Bibliographical noteFunding Information:
We thank J. Castagnola, M. Raguseo and L. Sikora for technical help; D. Ditto and D. Le of the Hematology Core and N. Varki of the Histology Core (National Institutes of Health, HL57345); and A. Varki for comments. Supported by the US Department of Veteran’s Affairs (Research Career Development Award to M.M.F.) and National Institutes of Health (HL57345, HL23594 and GM33063 to J.D.E. and AI35796 and AI50498 Core C to P.S.).