Lipids

, Volume 46, Issue 4, pp 323–332

Presence of Apolipoprotein C-III Attenuates Apolipoprotein E-Mediated Cellular Uptake of Cholesterol-Containing Lipid Particles by HepG2 Cells

Authors

    • Kobe Pharmaceutical University
  • Atsushi Sakurai
    • Graduate School of Pharmaceutical SciencesKyoto University
  • Minoru Nakano
    • Graduate School of Pharmaceutical SciencesKyoto University
  • Shuji Kitagawa
    • Kobe Pharmaceutical University
  • Tetsurou Handa
    • Graduate School of Pharmaceutical SciencesKyoto University
    • Faculty of Pharmaceutical SciencesSuzuka University of Medical Science
Original Article

DOI: 10.1007/s11745-010-3498-9

Cite this article as:
Morita, S., Sakurai, A., Nakano, M. et al. Lipids (2011) 46: 323. doi:10.1007/s11745-010-3498-9

Abstract

Apolipoprotein C-III (apoC-III) decreases the apolipoprotein E (apoE)-mediated uptake of lipoprotein remnants by the liver, and a high plasma concentration of apoC-III in VLDL is associated with hypertriglyceridemia and the risk of coronary heart disease. In this study, we prepared lipid emulsions containing triolein, phosphatidylcholine and cholesterol as model particles of lipoproteins, and examined the roles of apoC-III in apoE-mediated uptake of emulsions by HepG2 cells. Cholesterol in emulsion particles enhanced the apoE-mediated uptake via heparan sulfate proteoglycan and LDL receptor-related protein pathways. The amount of apoE bound to emulsion particles was increased by the presence of cholesterol at the particle surface, whereas cholesterol had no effect on the binding amount of apoC-III. Surface cholesterol alleviated the inhibitory effect of apoC-III on apoE incorporation into the emulsion surface. However, ApoC-III almost completely inhibited the apoE-mediated uptake of cholesterol-containing emulsions despite sufficient binding of apoE to emulsions. These findings suggest that apoC-III attenuates the binding of apoE to the lipoprotein surface and apoE-mediated cellular uptake of lipoprotein remnants. Furthermore, cholesterol may affect these functions of apoC-III and apoE involved in the clearance of lipoprotein remnants.

Keywords

Apolipoprotein C-IIIApolipoprotein ECholesterolLipid emulsions

Abbreviations

apoC-III

Apolipoprotein C-III

apoE

Apolipoprotein E

HSPG

Heparan sulfate proteoglycan

LRP

LDL receptor-related protein

PL

Phospholipid

PMC oleate

Pyrenemethyl 3β-(cis-9-octadecenoyloxy)-22,23-bisnor-5-cholenate

PtdCho

Phosphatidylcholine

TAG

Triacylglycerol

Copyright information

© AOCS 2010