Transport of lipids from high and low density lipoproteins via scavenger receptor-BI

Citation
H. Stangl et al., Transport of lipids from high and low density lipoproteins via scavenger receptor-BI, J BIOL CHEM, 274(46), 1999, pp. 32692-32698
Citations number
40
Categorie Soggetti
Biochemistry & Biophysics
Journal title
JOURNAL OF BIOLOGICAL CHEMISTRY
ISSN journal
00219258 → ACNP
Volume
274
Issue
46
Year of publication
1999
Pages
32692 - 32698
Database
ISI
SICI code
0021-9258(19991112)274:46<32692:TOLFHA>2.0.ZU;2-0
Abstract
The scavenger receptor-BI (SR-BI) delivers sterols from circulating lipopro teins to tissues, but the relative potency of individual lipoproteins and t he transported cholesterol has not been studied in detail. In this study, w e used Chinese hamster ovary cells that express recombinant mouse SR-BI but have no functional low density lipoprotein (LDL) receptors (ldlA7-SRBI cel ls) to compare the fate of lipids transferred from high or low density lipo proteins to cells by SR-BI. HDL and LDL were equally effective in mediating the transfer of [H-3]cholesterol to cells. Only 5% of the free cholesterol transferred to cells was esterified, in direct contrast to the findings in the cells that express I;DL receptors in which 50% of the transported chol esterol was esterified. Almost all the free cholesterol transferred from li poproteins to cells was rapidly excreted when the ldlA7-SRBI cells were swi tched to media containing unlabeled lipoproteins. SR-BI expression was asso ciated with an increase in selective cholesteryl ester uptake from both lip oproteins, but HDL was a more effective donor. HDL and LDL were equally eff ective in delivering cholesterol to the intracellular regulatory pool via S R-EI. These data indicate that SR-BI is able to exchange cholesterol rapidl y between lipoproteins and cell membranes and can mediate the uptake of cho lesteryl esters from both classes of lipoproteins.