Endothelial α2,6-Linked Sialic Acid Inhibits VCAM-1- Dependent Adhesion Under Flow Conditions
| Autor: | Yasunori Abe, C. Wayne Smith, Julie P. Katkin, Lisa M. Thurmon, Xudong Xu, Leonardo H. Mendoza, Christie M. Ballantyne |
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| Rok vydání: | 1999 |
| Předmět: | |
| Zdroj: | The Journal of Immunology. 163:2867-2876 |
| ISSN: | 1550-6606 0022-1767 |
| DOI: | 10.4049/jimmunol.163.5.2867 |
| Popis: | We have previously shown that costimulation of endothelial cells with IL-1 + IL-4 markedly inhibits VCAM-1-dependent adhesion under flow conditions. We hypothesized that sialic acids on the costimulated cell surfaces may contribute to the inhibition. Northern blot analyses showed that Galβ1-4GlcNAc α2,6-sialyltransferase (ST6N) mRNA was up-regulated in cultured HUVEC by IL-1 or IL-4 alone, but that the expression was enhanced by costimulation, whereas the level of Galβ1-4GlcNAc/Galβ1-3GalNAc α2,3-sialyltransferase (ST3ON) mRNA was unchanged. Removing both α2,6- and α2,3-linked sialic acids from IL-1 + IL-4-costimulated HUVEC by sialidase significantly increased VCAM-1-dependent adhesion, whereas removing α2,3-linked sialic acid alone had no effect; adenovirus-mediated overexpression of ST6N with costimulation almost abolished the adhesion, which was reversible by sialidase. The same treatments of IL-1-stimulated HUVEC had no effect. Lectin blotting showed that VCAM-1 is decorated with α2,6- but not α2,3-linked sialic acids. However, overexpression of α2,6-sialyltransferase did not increase α2,6-linked sialic acid on VCAM-1 but did increase α2,6-linked sialic acids on other proteins that remain to be identified. These results suggest that α2,6-linked sialic acids on a molecule(s) inducible by costimulation with IL-1 + IL-4 but not IL-1 alone down-regulates VCAM-1-dependent adhesion under flow conditions. |
| Databáze: | OpenAIRE |
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