Apolipoprotein E exhibits isoform-specific promotion of lipid efflux from astrocytes and neurons in culture

Makoto Michikawa, Qi Wen Fan, Ichiro Isobe, Katsuhiko Yanagisawa

Research output: Contribution to journalArticle

172 Citations (Scopus)

Abstract

Many studies have shown that apolipoprotein E (apoE) plays important roles in maintaining intracellular lipid homeostasis in nonneuronal cells. However, little is known about the extracellular transport of lipids in the CNS. In this study, we determined whether and to what degree lipid efflux from astrocytes and neurons depended on apoE. Our results showed that exogenously added apoE promoted the efflux of cholesterol and phosphatidylcholine from both astrocytes and neurons in culture, resulting in the generation of high-density lipoprotein-like particles. The order of potency of the apoE isoforms as lipid acceptors was apoE2 > apoE3 = apoE4 in astrocytes and apoE2 > apoE3 > apoE4 in neurons. Treatment with brefeldin A, monensin, and a protein kinase C inhibitor, H7, abolished the ability of apoE to promote cholesterol efflux from cultured astrocytes, without altering apoE-mediated phosphatidylcholine efflux. In contrast, the efflux of both cholesterol and phosphatidylcholine promoted by apoE was abolished following treatment with heparinase or lactoferrin, which block the interaction of apoE with heparan sulfate proteoglycans (HSPGs) or low-density lipoprotein receptor-related protein (LRP), respectively. This study suggests that apoE promotes lipid efflux from astrocytes and neurons in an isoform-specific manner and that cell surface HSPGs and/or HSPG-LRP pathway may mediate this apoE-promoted lipid efflux.

Original languageEnglish
Pages (from-to)1008-1016
Number of pages9
JournalJournal of neurochemistry
Volume74
Issue number3
DOIs
Publication statusPublished - 01-03-2000
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biochemistry
  • Cellular and Molecular Neuroscience

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