title: The protective role of high-density lipoprotein on oxidized-low-density-lipoprotein-induced U937/endothelial cell interactions.
abstract: The adherence of monocytes to the endothelium is an early event in atherogenesis. We have investigated this process by examining whether native and oxidized low-density and high-density lipoproteins could modulate this process. Only oxidized low-density lipoprotein caused a significant dose-dependent and time-dependent increase in U937 monocyte-like cell line binding to human endothelial cells, by a process which required de novo protein synthesis. Interestingly, E-selectin, intercellular adhesion molecule-1, vascular cell-adhesion molecule or P-selectin induction was not apparent in this system suggesting the presence of an alternative system for the interaction of endothelial cells with monocyte-like cells in response to oxidized low-density lipoprotein. High-density lipoprotein completely suppressed oxidized low-density-lipoprotein-induced adhesion of U937 cells to the endothelial monolayer, while oxidized high-density lipoprotein did not. These data suggest that the balance between native and oxidized lipoproteins may play a role in the formation of the atherosclerotic lesion by modulating monocyte endothelial interactions.
authors.affiliation: Department of Biomedical Sciences, Technologies-Ospedale San Raffaele, Milan, Italy.
authors.forename: J A
authors.initials: JA
authors.lastname: Maier
authors.forename: L
authors.initials: L
authors.lastname: Barenghi
authors.forename: F
authors.initials: F
authors.lastname: Pagani
authors.forename: S
authors.initials: S
authors.lastname: Bradamante
authors.forename: P
authors.initials: P
authors.lastname: Comi
authors.forename: G
authors.initials: G
authors.lastname: Ragnotti
mesh_terms: D001483:Base Sequence; D002448:Cell Adhesion; D015815:Cell Adhesion Molecules / Q000235:genetics; D002478:Cells, Cultured; D019040:E-Selectin; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D015870:Gene Expression; D006801:Humans; D018799:Intercellular Adhesion Molecule-1; D008075:Lipoproteins, HDL / Q000494:pharmacology*; D008077:Lipoproteins, LDL / Q000494:pharmacology*; D008969:Molecular Sequence Data; D009000:Monocytes / Q000166:cytology* / Q000187:drug effects / Q000502:physiology; D010084:Oxidation-Reduction; D012333:RNA, Messenger / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1
chemical_list: D015815:Cell Adhesion Molecules; D019040:E-Selectin; D008075:Lipoproteins, HDL; D008077:Lipoproteins, LDL; D012333:RNA, Messenger; D019010:Vascular Cell Adhesion Molecule-1; D018799:Intercellular Adhesion Molecule-1