Receptor for Advanced Glycation End Products Is Subjected to Protein Ectodomain Shedding by Metalloproteinases

Abstract

The receptor for advanced glycation end products (RAGE) is a 55-kDa type I membrane glycoprotein of the immunoglobulin superfamily. Ligand-induced up-regulation of RAGE is involved in various pathophysiological processes, including late diabetic complications and Alzheimer disease. Application of recombinant soluble RAGE has been shown to block RAGE-mediated pathophysiological conditions. After expression of full-length RAGE in HEK cells we identified a 48-kDa soluble RAGE form (sRAGE) in the culture medium. This variant of RAGE is smaller than a 51-kDa soluble version derived from alternative splicing. The release of sRAGE can be induced by the phorbol ester PMA and the calcium ionophore calcimycin via calcium-dependent protein kinase C subtypes. Hydroxamic acid-based metalloproteinase inhibitors block the release of sRAGE, and by RNA interference experiments we identified ADAM10 and MMP9 to be involved in RAGE shedding. In protein biotinylation experiments we show that membrane-anchored full-length RAGE is the precursor of sRAGE and that sRAGE is efficiently released from the cell surface. We identified cleavage of RAGE to occur close to the cell membrane. Ectodomain shedding of RAGE simultaneously generates sRAGE and a membrane-anchored C-terminal RAGE fragment (RAGE-CTF). The amount of RAGE-CTF increases when RAGE-expressing cells are treated with a ␥-secretase inhibitor, suggesting that RAGE-CTF is normally further processed by ␥-secretase. Identification of these novel mechanisms involved in regulating the availability of cell surface-located RAGE and its soluble ectodomain may influence further research in RAGE-mediated processes in cell biology and pathophysiology.

Receptor for advanced glycation end-products (RAGE) provides a link between genetic susceptibility and environmental factors in type 1 diabetes

“…One cannot discount, however, the possibility that changes in the proteases responsible for the cleavage of membrane RAGE to soluble RAGE [45] may also be altering the circulating soluble RAGE pool in our diabetic individuals and mice, independent of changes in the AGER gene. Indeed, this possibility should be further investigated in subsequent studies, in particular given the effects of AGEs on circulating RAGE concentrations in NODLt mice observed in the present study.…”

RAGE: The Beneficial and Deleterious Effects by Diverse Mechanisms of Actions

“…The proteolysis of RAGE occurs constitutively and is stimulated by protein kinase C (PKC) activation (Zhang et al, 2008). In the sequential cleavage of RAGE, the ectodomain is shed by the α-secretase ADAM10 (a disintegrin and metalloproteinase 10) and metalloproteinase 9 (MMP9) to generate sRAGE, and the remaining membrane domain is proteolyzed by γ-secretage Kojro and Postina, 2009;Raucci et al, 2008;Zhang et al, 2008).…”

“…Soluble RAGE lacks a transmembrane segment, and 2 types of soluble RAGEs exist: endogenous secretary RAGE (esRAGE) and cleaved RAGE (cRAGE). Splice variant encodes the secreted form of soluble RAGE, esRAGE, and cleavage of full-length RAGE by the membrane metalloproteinase ADAM 10 yields another form of soluble RAGE (cRAGE), (Raucci et al, 2008;Yonekura et al, 2003;Zhang et al, 2008).…”

AGE/RAGE as a Mediator of Insulin Resistance or Metabolic Syndrome: Another Aspect of Metabolic Memory?

“…This proteolytic generation of sRAGE was initially described as occurring in mice 103 . Recent studies suggest that ADAM10 and MMP9 to be involved in RAGE shedding 13,14 . ADAM is known as a shedase to shed several inflammatory receptors and can be involved in regulation of RAGE/sRAGE balance.…”