Lysophosphatidylcholine promotes cholesterol efflux from mouse macrophage foam cells.
We examined the effects of lysophosphatidylcholine (lyso-PC) on promoting cholesterol efflux from macrophage foam cells. Mouse peritoneal macrophages were converted to foam cells by incubation with [3H]cholesteryl linoleate-labeled or unlabeled acetyl-LDL. When these cells were incubated with lyso-PC, [3H]cholesterol release was promoted in relation to both dose and time, and cellular cholesterol mass was decreased, while medium cholesterol mass was increased. These cholesterol efflux-promotive effects of lyso-PC were confirmed by the fact that the lyso-PC-treated cells showed less oil red O staining than the control cells. ApoE secretion, estimated by Western blotting of the medium, was also augmented by lyso-PC. Both the cholesterol and apoE released by lyso-PC treatment were floated by ultracentrifugation of the medium after its density had been adjusted to 1.210 g/mL. By electron microscopic analysis, vesicular lipoproteins were observed in ultracentrifugally concentrated conditioned medium of lyso-PC. Monensin, a protein secretion inhibitor, effectively inhibited [3H]cholesterol release induced by lyso-PC but not by apoA-I. These results suggest that lyso-PC may inhibit the development of atherosclerosis or enhance its regression by stimulating cholesterol efflux from macrophage foam cells.
Hara
S
S
Discovery Research Laboratories II, Shionogi & Co, Ltd, Osaka, Japan. seijiro.hara@shionogi.co.jp
Shike
T
T
Takasu
N
N
Mizui
T
T
D000818:Animals; D001057:Apolipoproteins E / Q000494:pharmacology; D001692:Biological Transport / Q000187:drug effects; D003994:Bucladesine / Q000494:pharmacology; D002784:Cholesterol / Q000378:metabolism*; D005260:Female; D005487:Foam Cells / Q000378:metabolism*; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008244:Lysophosphatidylcholines / Q000494:pharmacology*; D017737:Macrophages, Peritoneal / Q000378:metabolism*; D051379:Mice; D008985:Monensin / Q000494:pharmacology; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D001057:Apolipoproteins E; D008244:Lysophosphatidylcholines; D003994:Bucladesine; D008985:Monensin; D002784:Cholesterol; D007770:L-Lactate Dehydrogenase; D013755:Tetradecanoylphorbol Acetate