Open AccessPartially reassembled high density lipoproteins. Effects on cholesterol flux, synthesis, and esterification in normal human skin fibroblasts.
Author(s) -
Martino Picardo,
John B. Massey,
Donald E. Kuhn,
Antonio M. Gotto,
Sandra H. Gianturco,
Henry J. Pownall
Publication year - 1986
Publication title -
arteriosclerosis
Language(s) - English
Resource type - Journals
eISSN - 2330-9180
pISSN - 0276-5047
DOI - 10.1161/01.atv.6.4.434
Subject(s) - sterol o acyltransferase , cholesterol , chemistry , reductase , popc , coenzyme a , reverse cholesterol transport , apolipoprotein b , biochemistry , lipoprotein , enzyme , phospholipid , membrane
The effects of a partially reassembled high density lipoprotein (PR-HDL) prepared by a detergent removal method on the cholesterol metabolism of fibroblasts has been tested under conditions of lipid depletion. The PR-HDL were composed of apolipoprotein A-I (1 mol) from human plasma HDL, 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC) 100 mol, and varying amounts of cholesterol. Below 15 mol%, the PR-HDL effected a net efflux of cholesterol from the fibroblasts; as a consequence, the activities of 3-hydroxy-3-methylglutaryl coenzyme A reductase and acyl coenzyme A acyltransferase, respectively, were increased and decreased. Above 15 mol% cholesterol in the PR-HDL, net influx of cholesterol was observed and 3-hydroxy-3-methyl-glutaryl coenzyme A reductase activity was decreased, while acyl coenzyme A acyltransferase activity was increased. The uptake of several phosphatidylcholines, apo A-I, and cholesterol were measured as a function of time. The rates of lipid transfer to the cells decreased with increasing hydrophobicity of the transferring lipid. By contrast, in parallel experiments a relatively small quantity of 125I apo A-I was associated with the cells. Our results suggest that a component of lipid transfer from PR-HDL to fibroblasts occurs via monomeric transfer through the aqueous phase that is independent of apo A-I binding.