title: Early-glycation of apolipoprotein E: effect on its binding to LDL receptor, scavenger receptor A and heparan sulfates.
abstract: Glycation is responsible for disruption of lipoprotein functions leading to the development of atherosclerosis in diabetes. The effects of apolipoprotein E (apoE) glycation were investigated with respect to its interaction with receptors. The interaction of apoE with the low density lipoprotein receptor (LDL-R) and scavenger receptor A (SR-A) was measured by competition experiments performed using, respectively, on a human fibroblast cell line 125I-LDL, and on a murine macrophage cell line (J774) 125I-acetylated LDL, and unlabeled apoE/phospholipid complexes. Glycated apoE binding to heparin and heparan sulfates (HS) was assessed by surface plasmon resonance (SPR) technology. Site-directed mutagenesis was then performed on Lys-75, the major glycation site of the protein. The prepared mutant protein proved to be useful as a tool to study the role of Lys-75 in apoE glycation. The findings showed that, although glycation has no effect on apoE binding either to the LDL-R or to SR-A, it impairs its binding to immobilized heparin and HS. The glycation of Lys-75 was found to be proceed rapidly and contributed significantly to total protein glycation. We propose that, in the case of diabetes, glycation may lead to the atherogenicity of apoE-containing lipoproteins disturbing their uptake via the HS proteoglycan pathway.
authors.affiliation: INSERM U525 (Equipe 4), Centre du Médicament, Université Henri Poincaré Nancy 1, 30, rue Lionnois, France.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Laffont
authors.forename: Vladimir V
authors.initials: VV
authors.lastname: Shuvaev
authors.forename: Olivier
authors.initials: O
authors.lastname: Briand
authors.forename: Sophie
authors.initials: S
authors.lastname: Lestavel
authors.forename: Anne
authors.initials: A
authors.lastname: Barbier
authors.forename: Naoyuki
authors.initials: N
authors.lastname: Taniguchi
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Fruchart
authors.forename: Véronique
authors.initials: V
authors.lastname: Clavey
authors.forename: Gérard
authors.initials: G
authors.lastname: Siest
mesh_terms: D001057:Apolipoproteins E / Q000235:genetics / Q000378:metabolism*; D001483:Base Sequence; D002478:Cells, Cultured; D017931:DNA Primers; D005947:Glucose / Q000378:metabolism*; D006497:Heparan Sulfate / Q000378:metabolism*; D006801:Humans; D008565:Membrane Proteins; D016297:Mutagenesis, Site-Directed; D011485:Protein Binding; D011971:Receptors, Immunologic / Q000378:metabolism*; D011973:Receptors, LDL / Q000378:metabolism*; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D011994:Recombinant Proteins / Q000378:metabolism; D051117:Scavenger Receptors, Class A; D051122:Scavenger Receptors, Class B
chemical_list: D001057:Apolipoproteins E; D017931:DNA Primers; D005947:Glucose; D006497:Heparan Sulfate; D008565:Membrane Proteins; D011971:Receptors, Immunologic; D011973:Receptors, LDL; D018110:Receptors, Lipoprotein; D051116:Receptors, Scavenger; D011994:Recombinant Proteins; D051117:Scavenger Receptors, Class A; D051122:Scavenger Receptors, Class B; C454739:Scarb1 protein, mouse