Endothelial inflammation: the role of differential expression of N-deacetylase/N-sulphotransferase enzymes in alteration of the immunological properties of heparan sulphate.
Heparan sulphate N-deacetylase/N-sulphotransferase (NDST) enzymes catalyse the reaction that initiates sulphation and subsequent modification of the oligosaccharide, heparan sulphate (HS). The extent and distribution of sulphate substitution on HS plays a vital role in regulation of the binding of a range of proteins, including IFN-gamma, several interleukins and most chemokines. In this study, the expression of NDST transcripts was found to be non-uniform between a range of cell types, suggesting that different cells produce characteristic HS species. It was found that stimulation of the HMEC-1 microvascular endothelial cell line with the pro-inflammatory cytokines IFN-gamma and TNF-alpha caused a transient decrease in the level of NDST-1 and -2 transcripts after 4 hours (P < 0.05 and P < 0.01 respectively), but the expression of NDST-1 increased above control levels after 16 hours (P < 0.01). The change in NDST expression was concurrent with an increase in the abundance of sulphated HS epitopes on the cell surface; this was not caused by variation in the expression of proteoglycans or by changes in the rate of GAG turnover. Cytokine-stimulated endothelial cells also showed an increase in their potential to bind RANTES (CCL5); this was abrogated by chlorate blockade of sulphotransferase activity or by heparitinase cleavage of cell surface HS. Monolayers of cytokine-stimulated HMEC-1 also supported an enhanced leukocyte chemotactic response towards RANTES. This study demonstrated that pro-inflammatory cytokines can increase NDST expression leading to increased sulphation of HS and a corresponding increase in sequestration of functional RANTES at the apical surface of endothelial cells. This may enhance leukocyte extravasation at sites of inflammation.
Carter
Noel M
NM
Institute of Pharmacy, Chemistry and Biomedical Science, University of Sunderland, Sunderland SR1 3SD, UK.
Ali
Simi
S
Kirby
John A
JA
D000581:Amidohydrolases / Q000378:metabolism*; D000818:Animals; D002462:Cell Membrane / Q000201:enzymology; D002478:Cells, Cultured; D018946:Chemokine CCL5 / Q000378:metabolism; D002633:Chemotaxis / Q000502:physiology; D004730:Endothelium, Vascular / Q000378:metabolism*; D006025:Glycosaminoglycans / Q000378:metabolism; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D007371:Interferon-gamma / Q000378:metabolism; D007962:Leukocytes / Q000378:metabolism; D011133:Polysaccharide-Lyases / Q000378:metabolism; D011509:Proteoglycans / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015238:Sulfotransferases / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D014657:Vasculitis / Q000378:metabolism*
D000581:Amidohydrolases; D018946:Chemokine CCL5; D006025:Glycosaminoglycans; D006497:Heparan Sulfate; D007371:Interferon-gamma; D011133:Polysaccharide-Lyases; D011509:Proteoglycans; D015238:Sulfotransferases; D014409:Tumor Necrosis Factor-alpha; C113066:NDST2 protein, human; C021350:heparitin sulfotransferase; C021349:heparitinsulfate lyase