Homocysteine, a thrombogenic agent, suppresses anticoagulant heparan sulfate expression in cultured porcine aortic endothelial cells.
Open Access
- 1 September 1993
- journal article
- Published by American Society for Clinical Investigation in JCI Insight
- Vol. 92 (3), 1381-1386
- https://doi.org/10.1172/jci116712
Abstract
Previous studies showed that homocysteine, a thrombo-atherogenic and atherogenic agent, inhibits an endothelial thrombomodulin-protein C anticoagulant pathway. We examined whether homocysteine might affect another endothelial anticoagulant mechanism; i.e., heparin-like glycosaminoglycan-antithrombin III interactions. Incubations of porcine aortic endothelial cell cultures with homocysteine reduced the amount of antithrombin III bound to the cell surface in a dose- and time-dependent fashion. The inhibitory effect was observed at a homocysteine concentration as low as 0.1 mM, and the maximal suppression occurred at 1 mM of homocysteine after 24 h. In contrast with a marked reduction in the maximal antithrombin III binding capacity (approximately 30% of control), the radioactivity of [35S]sulfate incorporated into heparan sulfate on the cell surface was minimally (< 15%) reduced. The cells remained viable after homocysteine treatment. Although neither net negative charge nor proportion in total glycosaminoglycans of cell surface heparan sulfate was altered by homocysteine treatment, a substantial reduction in antithrombin III binding capacity of heparan sulfate isolated from homocysteine-treated endothelial cells was found using both affinity chromatography and dot blot assay techniques. The antithrombin III binding activity of endothelial cells decreased after preincubation with 1 mM homocysteine, cysteine, or 2-mercaptoethanol; no reduction in binding activity was observed after preincubation with the same concentration of methionine, alanine, or valine. This sulfhydryl effect may be caused by generation of hydrogen peroxide, as incubation of catalase, but not superoxide dismutase, with homocysteine-treated endothelial cells prevented this reduction, whereas copper augmented the inhibitory effects of the metabolite. Thus, our data suggest that the inhibited expression of anticoagulant heparan sulfate may contribute to the thrombogenic property resulting from the homocysteine-induced endothelial cell perturbation, mediated by generation of hydrogen peroxide through alteration of the redox potential.Keywords
This publication has 28 references indexed in Scilit:
- The protein C anticoagulant pathway.Arteriosclerosis and Thrombosis: A Journal of Vascular Biology, 1992
- Inhibition of thrombomodulin surface expression and protein C activation by the thrombogenic agent homocysteine.JCI Insight, 1991
- Human arterial endothelial cell detachment in vitro: its promotion by homocysteine and cysteineAtherosclerosis, 1991
- Hyperhomocysteinemia: An Independent Risk Factor for Vascular DiseaseNew England Journal of Medicine, 1991
- Human recombinant interleukin‐1β‐ and tumor necrosis factor α‐mediated suppression of heparin‐like compounds on cultured porcine aortic endothelial cellsJournal of Cellular Physiology, 1990
- Modulation of glycosaminoglycan production and antithrombin III binding by cultured aortic endothelial cells treated with 4-methylumbelliferyl-beta-D-xyloside.Arteriosclerosis: An Official Journal of the American Heart Association, Inc., 1987
- Evidence that cell surface heparan sulfate is involved in the high affinity thrombin binding to cultured porcine aortic endothelial cells.JCI Insight, 1985
- Natural anticoagulant mechanisms.JCI Insight, 1984
- The production of free radicals during the autoxidation of cysteine and their effect on isolated rat hepatocytesBiochimica et Biophysica Acta (BBA) - General Subjects, 1982
- Homocystine-induced arteriosclerosis. The role of endothelial cell injury and platelet response in its genesis.JCI Insight, 1976