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pubmed:abstractText |
The extended interaction of aldoses with proteins or lipids results in nonenzymatic glycation and oxidation, ultimately forming AGEs, the presence of which in the plasma and vessel wall is associated with diabetic vascular complications. We show here that AGE albumin in the intravascular space interacts with the vessel wall via binding to an integral membrane protein, receptor for AGE (RAGE), a member of the immunoglobulin superfamily, resulting in clearance from the plasma and induction of interleukin 6 mRNA. Intravenously infused 125I-AGE albumin showed a rapid phase of plasma clearance with deposition in several organs. Rapid removal of 125I-AGE albumin from the plasma was prevented by administration of a soluble, truncated form of RAGE, which blocked binding of 125I-labeled AGE albumin to cultured endothelial cells and mononuclear phagocytes, as well as by pretreatment with anti-RAGE IgG. Ultrastructural studies with AGE albumin-colloidal gold conjugates perfused in situ showed that in murine coronary vasculature this probe was taken up by endothelial plasmalemmal vesicles followed by transport either to the abluminal surface or by accumulation in intracellular vesicular structures reminiscent of endosomes and lysosomes. Consequences of AGE-RAGE interaction included induction of interleukin 6 mRNA expression in mice. These data indicate that RAGE mediates the interaction of AGEs with the vessel wall, both for removal of these glycated proteins from the plasma and for changes in gene expression.
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