文章基本信息

标题：Interaction with proteoglycans enhances the sterol efflux produced by endogenous expression of macrophage apoE
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作者：Chen-Yi Lin ; Zhi Hua Huang ; Theodore Mazzone 等
期刊名称：JLR Papers In Press
印刷版ISSN：0022-2275
电子版ISSN：1539-7262
出版年度：2001
卷号：42
期号：7
页码：1125-1133
语种：English
出版社：American Society for Biochemistry and Molecular Biology
摘要：Endogenous expression of apolipoprotein (apo)E in macrophages facilitates cholesterol efflux in the presence and absence of extracellular sterol acceptors. A proteoglycan-associated pool of apoE has also been described. The relationship between a proteoglycan-associated pool of apoE and enhanced cholesterol efflux was investigated in these studies. Inhibition of proteoglycan expression reduced cholesterol efflux from apoE-expressing cells (J774E⁺) in the presence and absence of HDL, but did not do so from non-expressing cells (J774E⁻). The effect of proteoglycan depletion on sterol efflux from J774E⁺ cells was confirmed by measuring differences in cell sterol mass, secreted sterol mass, and sterol efflux rates. Furthermore, apoE-containing particles secreted from proteoglycan-depleted J774E⁺ cells were denser than those secreted from J774E⁺ cells with intact proteoglycan expression. Also, in J774E⁺ cells with intact proteoglycans, apoE particles isolated from the cell surface proteoglycan layer were denser than secreted particles. The apoE-lipid particles isolated from the cell surface proteoglycan layer had a lower lipid-to-apoE and cholesterol-to-apoE ratio compared with secreted particles. In distinction, proteoglycan depletion of J774E⁻ cells did not reduce sterol efflux produced by the exogenous addition of apoE. These observations indicate that one mechanism by which endogenous expression of apoE facilitates effective cholesterol efflux from macrophages is related to its retention at the cell surface in a proteoglycan-associated pool. Further, our data suggest that apoE arrives at the cell surface in a relatively lipid-poor state, and that a proximate source of lipid available to the proteoglycan-bound apoE at the cell surface resides in the plasma membrane. —Lin, C-Y., Z. H. Huang, and T. Mazzone. Interaction with proteoglycans enhances the sterol efflux produced by endogenous expression of macrophage apoE. J. Lipid Res. 2001. 42: 1125–1133.
关键词：apolipoprotein ; atherosclerosis ; vascular biology