Selective uptake and efflux of cholesteryl linoleate in LDL by macrophages expressing 12/15-lipoxygenase.
Oxidation of low density lipoprotein (LDL) is a critical step for atherogenesis, and the role of the 12/15-lipoxygenase (12/15-LOX) as well as LDL receptor-related protein (LRP) expressed in macrophages in this process has been suggested. The oxygenation of cholesteryl linoleate in LDL by mouse macrophage-like J774A.1 cells overexpressing 12/15-LOX was inhibited by an anti-LRP antibody but not by an anti-LDL receptor antibody. When the cells were incubated with LDL double-labeled by [3H]cholesteryl linoleate and [125I]apoB, association with the cells of [3H]cholesteryl linoleate expressed as LDL protein equivalent exceeded that of [125I]apoB, indicating selective uptake of [3H]cholesteryl linoleate from LDL to these cells. An anti-LRP antibody inhibited the selective uptake of [3H]cholesteryl ester by 62% and 81% with the 12/15-LOX-expressing cells and macrophages, respectively. Furthermore, addition of LDL to the culture medium of the [3H]cholesteryl linoleate-labeled 12/15-LOX-expressing cells increased the release of [3H]cholesteryl linoleate to the medium in LDL concentration- and time-dependent manners. The transport of [3H]cholesteryl linoleate from the cells to LDL was also inhibited by an anti-LRP antibody by 75%. These results strongly suggest that LRP contributes to the LDL oxidation by 12/15-LOX in macrophages by selective uptake and efflux of cholesteryl ester in the LDL particle.
Takahashi
Yoshitaka
Y
Department of Nutritional Science, Faculty of Health and Welfare Science, Okayama Prefectural University, Soja, Okayama 719-1197, Japan. ytaka@fhw.oka-pu.ac.jp
Zhu
Hong
H
Xu
Wanpeng
W
Murakami
Takashi
T
Iwasaki
Tadao
T
Hattori
Hiroaki
H
Yoshimoto
Tanihiro
T
D000818:Animals; D001092:Arachidonate 12-Lipoxygenase / Q000096:biosynthesis*; D001093:Arachidonate 15-Lipoxygenase / Q000096:biosynthesis*; D016466:CHO Cells; D002460:Cell Line; D002462:Cell Membrane / Q000201:enzymology; D002788:Cholesterol Esters / Q000378:metabolism*; D008078:Cholesterol, LDL / Q000378:metabolism*; D002851:Chromatography, High Pressure Liquid; D006224:Cricetinae; D003412:Cricetulus; D026503:Low Density Lipoprotein Receptor-Related Protein-1 / Q000502:physiology; D017737:Macrophages, Peritoneal / Q000201:enzymology* / Q000378:metabolism; D051379:Mice; D010100:Oxygen / Q000378:metabolism; D021381:Protein Transport / Q000502:physiology
D002788:Cholesterol Esters; D008078:Cholesterol, LDL; D026503:Low Density Lipoprotein Receptor-Related Protein-1; C021976:cholesteryl linoleate; D001092:Arachidonate 12-Lipoxygenase; D001093:Arachidonate 15-Lipoxygenase; D010100:Oxygen