RECEPTOR-BINDING OF AN APOLIPOPROTEIN E-RICH SUBFRACTION OF HIGH-DENSITY-LIPOPROTEIN TO RAT AND HUMAN BRAIN MEMBRANES

Citation
Je. Stewart et al., RECEPTOR-BINDING OF AN APOLIPOPROTEIN E-RICH SUBFRACTION OF HIGH-DENSITY-LIPOPROTEIN TO RAT AND HUMAN BRAIN MEMBRANES, International journal of biochemistry & cell biology, 30(3), 1998, pp. 407-415
Citations number
38
Categorie Soggetti
Biology,"Cell Biology
ISSN journal
13572725
Volume
30
Issue
3
Year of publication
1998
Pages
407 - 415
Database
ISI
SICI code
1357-2725(1998)30:3<407:ROAAES>2.0.ZU;2-H
Abstract
During nerve cell degeneration, cholesterol released from the degradin g cells is conserved through the formation of a cholesterol-apolipopro tein (apo) E complex which is subsequently taken up by regenerating ne rve cells. The aim of the present project was to identify the physiolo gically relevant lipoprotein receptor for this lipoprotein complex whi ch has remained elusive. HDL was separated into apo E-rich and apo E-p oor subfractions and labelled with [C-14]-sucrose. Labelled apo E-rich HDL bound to rat brain membranes in a time-and ligand concentration-d ependent manner and was a saturable process. Essentially no binding oc curred with [C-14]-apo E-poor HDL or with free apo E. Binding was part ially inhibited by low density lipoprotein (LDL) and by alpha(2)-macro globulin. These results provide new evidence that native apoE-rich HDL particles resembling those present in the brain bind to rat brain mem branes and that the binding may be due, at least in part, to the LDL r eceptor and to the LDL-receptor related protein. Evidence was also pro vided for the presence of a receptor which binds [C-14]-sucrose human apoE-rich HDL in human brain. Characterisation of the receptor which m ediates the uptake of cholesterol from HDL-like complexes by brain cel ls is important in understanding the role of apoE in the central nervo us system and of the alterations which occur in disorders such as Alzh eimer's disease. (C) 1998 Elsevier Science Ltd. All rights reserved.