Cholesterol Efflux, Cholesterol Esterification, and Cholesteryl Ester Transfer by LpA-I and LpA-I/A-II in Native Plasma

• Published in: Arteriosclerosis, thrombosis, and vascular biology Vol. 15; no. 9; pp. 1412 - 1418
• Main Authors: Huang, Yadong, von Eckardstein, Arnold, Wu, Shili, Assmann, Gerd
• Format: Journal Article
• Language: English
• Published: Philadelphia, PA American Heart Association, Inc 01.09.1995; Hagerstown, MD Lippincott
• Subjects: Apolipoprotein A-I - blood; Apolipoprotein A-II - blood; Biological and medical sciences; Cells, Cultured; Cholesterol - blood; Cholesterol Esters - blood; Electrophoresis, Gel, Two-Dimensional; Esterification; Fundamental and applied biological sciences. Psychology; Humans; Kinetics; Lipids. Glycolipids; Lipoprotein(a) - analogs & derivatives; Lipoprotein(a) - blood; Metabolisms and neurohumoral controls; Vertebrates: anatomy and physiology, studies on body, several organs or systems; Human; Countercurrent; Lipids; Exploration; Transport; Cholesterol; Esterification; Blood plasma
• ISSN: 1079-5642; 1524-4636
• DOI: 10.1161/01.atv.15.9.1412

HDLs encompass structurally heterogeneous particles that fulfill specific functions in reverse cholesterol transport. Two-dimensional nondenaturing polyacrylamide gradient gel electrophoresis (2D-PAGGE) of normal plasma and subsequent immunoblotting with anti-apolipoprotein (apo) A-I antibodies differentiates an abundant particle with electrophoretic alpha-mobility and less abundant particles with electrophoretic pre-beta-mobility (pre beta1 -LpA-I, pre beta2 -LpA-I, pre beta3 -LpA-I). Immunodetection with anti-apoA-II antibodies identifies a single particle with alpha-mobility. To differentiate alpha-migrating HDL without apo A-II (alpha-LpA-I) from those with apoA-II (alpha-LpA-I/A-II), we combined 2D-PAGGE with immunoadsorption of apoA-II. Incubation of plasma with [sup 3 Hydrogen]cholesterol-labeled fibroblasts in combination with immunosubtracting 2D-PAGGE allowed us to analyze the role of alpha-LpA-I and alpha-LpA-I/A-II in the uptake and esterification of cell-derived cholesterol in native plasma. Depending on the duration of incubations with cells, alpha-LpA-I took up two to four times more [sup 3 Hydrogen]cholesterol than alpha-LpA-I/A-II. Irrespective of the duration of incubation, two to three times more [sup 3 Hydrogen]cholesteryl esters accumulated in alpha-LpA-I than in alpha-LpA-I/A-II. Subsequent incubations in the presence of an inhibitor of lecithin:cholesterol acyltransferase led to preferential accumulation of [sup 3 Hydrogen]cholesteryl esters in alpha-LpA-I/A-II. In conclusion, our data indicate that alpha-LpA-I is more effective than alpha-LpA-I/A-II in both uptake and esterification of cell-derived cholesterol. Moreover, alpha-LpA-I/A-II appears to accumulate cholesteryl esters, at least partially, from alpha-LpA-I. (Arterioscler Thromb Vasc Biol. 1995;15:1412-1418.)