Recent studies suggested that interruption of the interaction of advanced glycation end products (AGEs), with the signal-transducing receptor receptor for AGE (RAGE), by administration of the soluble, extracellular ligand-binding domain of RAGE, reversed vascular hyperpermeability and suppressed accelerated atherosclerosis in diabetic rodents. Since the precise molecular target of soluble RAGE in those settings was not elucidated, we tested the hypothesis that predominant specific AGEs within the tissues in disorders such as diabetes and renal failure, N ⑀ -(carboxymethyl)lysine (CML) adducts, are ligands of RAGE. We demonstrate here that physiologically relevant CML modifications of proteins engage cellular RAGE, thereby activating key cell signaling pathways such as NF-B and modulating gene expression. Thus, CML-RAGE interaction triggers processes intimately linked to accelerated vascular and inflammatory complications that typify disorders in which inflammation is an established component.Receptor for AGE 1 (RAGE), a member of the immunoglobulin superfamily, was first described as a cell surface interaction site for advanced glycation end products (AGEs), products of glycation and oxidation of proteins and lipids (1-2). AGEs are a heterogeneous class of compounds, whose accumulation in disorders such as diabetes, renal failure, Alzheimer's disease, and, indeed, natural aging, albeit to a lesser degree, has suggested their potential contribution to the pathogenesis of complications that typify these conditions (3-7). Our previous studies demonstrated that both in vitro and in vivo derived heterogeneous AGEs ligate cell surface RAGE on endothelium (ECs), mononuclear phagocytes (MPs), vascular smooth muscle (VSMC), and neurons to activate cell signaling pathways such as ERK1/ERK2 kinases and NF-B (8 -9), thereby redirecting cellular function in a manner linked to expression of inflammatory and prothrombotic genes important in the pathogenesis of chronic disorders as apparently diverse as diabetic macrovascular disease and amyloidosis (10 -20).Our recent studies suggested that interruption of the interaction of AGEs with RAGE in vivo, by administration of soluble RAGE (sRAGE), the extracellular ligand-binding domain of RAGE, reversed vascular hyperpermeability and suppressed accelerated atherosclerotic lesion development and complexity in diabetic rodents (19 -20). In the latter studies, analysis of plasma demonstrated evidence of an sRAGE⅐AGE complex; immunoprecipitation of plasma obtained from diabetic sRAGEtreated mice with anti-RAGE IgG yielded species immunoreactive with both anti-RAGE IgG or affinity purified anti-AGE IgG, suggesting that sRAGE might bind up AGEs and limit their interaction with and activation of cell surface RAGE. The beneficial effects of sRAGE were independent of alterations in other risk factors, such as hyperglycemia and hyperlipidemia, implicating a role for AGE-RAGE interaction in the development of vascular dysfunction in diabetes (20).These past studies, however, did not elucidate ...