An induction in hepatic HDL secretion associated with reduced ATPase expression

Am J Pathol. 2009 Oct;175(4):1777-87. doi: 10.2353/ajpath.2009.090082. Epub 2009 Aug 28.

Abstract

Linoleic acid-phospholipids stimulate high-density lipoprotein (HDL) net secretion from liver cells by blocking the endocytic recycling of apoA-I. Experiments were undertaken to determine whether apoA-I accumulation in the cell media is associated with membrane ATPase expression. Treatment of HepG2 cells with dilinoeoylphosphatidylcholine (DLPC) increased apoA-I secretion fourfold. DLPC also significantly reduced cell surface F1-ATPase expression and reduced cellular ATP binding cassette (ABC)A1 and ABCG1 protein levels by approximately 50%. In addition, treatment of HepG2 cells with the ABC transporter inhibitor, glyburide, stimulated the apoA-I secretory effects of both DLPC and clofibrate. Pretreatment of HepG2 cells with compounds that increased ABC transport protein levels (TO901317, N-Acetyl-L-leucyl-L-leucyl-L-norleucinal, and resveratrol) blocked the DLPC-induced stimulation in apoA-I net secretion. Furthermore, whereas HepG2 cells normally secrete nascent prebeta-HDL, DLPC treatment promoted secretion of alpha-migrating HDL particles. These data show that an linoleic acid-phospholipid induced stimulation in hepatic HDL secretion is related to the expression and function of membrane ATP metabolizing proteins.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter 1
  • ATP Binding Cassette Transporter, Subfamily G, Member 1
  • ATP-Binding Cassette Transporters / metabolism
  • Apolipoprotein A-I / metabolism
  • Culture Media
  • Glyburide / pharmacology
  • Hep G2 Cells
  • Humans
  • Leucine / analogs & derivatives
  • Leucine / pharmacology
  • Linoleic Acid / pharmacology
  • Lipoproteins, HDL / metabolism*
  • Liver / drug effects
  • Liver / enzymology*
  • Liver X Receptors
  • Models, Biological
  • Orphan Nuclear Receptors / agonists
  • Phospholipids / metabolism
  • Protein Processing, Post-Translational / drug effects
  • Proton-Translocating ATPases / metabolism*
  • RNA, Small Interfering / metabolism

Substances

  • ABCG1 protein, human
  • ATP Binding Cassette Transporter 1
  • ATP Binding Cassette Transporter, Subfamily G, Member 1
  • ATP-Binding Cassette Transporters
  • Apolipoprotein A-I
  • Culture Media
  • Lipoproteins, HDL
  • Liver X Receptors
  • Orphan Nuclear Receptors
  • Phospholipids
  • RNA, Small Interfering
  • acetyl-leucinal-nor-leucinal
  • Linoleic Acid
  • Proton-Translocating ATPases
  • Leucine
  • Glyburide