Regulation of the concentration of pre beta high-density lipoprotein in normal plasma by cell membranes and lecithin-cholesterol acyltransferase activity.
A minor fraction of plasma high-density lipoprotein (pre beta-1 HDL) has been shown to promote cholesterol efflux from peripheral cell membranes [Castro, G. R., & Fielding, C. J. (1988) Biochemistry 27, 25-29]. When isolated native plasma is incubated at 37 degrees C, this fraction is specifically decreased. On the other hand, the level of plasma pre beta-1 HDL is fully protected in the presence of even very low levels of fibroblasts, vascular smooth muscle cells, or macrophages. Blood cells were completely inactive in maintaining plasma pre beta-1 HDL levels in the absence of peripheral cells, even at the relatively high levels present in whole blood. The loss of pre beta-1 observed in isolated plasma was dependent upon lecithin-cholesterol acyltransferase (LCAT) activity. These data suggest that reverse cholesterol transport catalyzed by pre beta-1 HDL, and subsequent LCAT-mediated cholesterol esterification, is directly dependent upon the interaction between this HDL species and competent peripheral cells.
Miida
T
T
Cardiovascular Research Institute, University of California, San Francisco 94143.
Kawano
M
M
Fielding
C J
CJ
Fielding
P E
PE
D002462:Cell Membrane / Q000378:metabolism; D002478:Cells, Cultured; D004587:Electrophoresis, Agar Gel; D015180:Electrophoresis, Gel, Two-Dimensional; D053442:High-Density Lipoproteins, Pre-beta; D006801:Humans; D008075:Lipoproteins, HDL / Q000378:metabolism*; D007862:Phosphatidylcholine-Sterol O-Acyltransferase / Q000378:metabolism*
D053442:High-Density Lipoproteins, Pre-beta; D008075:Lipoproteins, HDL; D007862:Phosphatidylcholine-Sterol O-Acyltransferase