Ceramide structural features required to stimulate ABCA1-mediated cholesterol efflux to apolipoprotein A-I

J Lipid Res. 2006 Dec;47(12):2781-8. doi: 10.1194/jlr.M600380-JLR200. Epub 2006 Sep 21.

Abstract

Ceramide is a component of the sphingomyelin cycle and a well-established lipid signaling molecule. We recently reported that ceramide specifically increased ABCA1-mediated cholesterol efflux to apolipoprotein A-I (apoA-I), a critical process that leads to the formation of cardioprotective HDL. In this report, we characterize the structural features of ceramide required for this effect. C2 dihydroceramide, which contains a fully saturated acyl chain and is commonly used as a negative control for ceramide apoptotic signaling, stimulated a 2- to 5-fold increase in ABCA1-mediated cholesterol efflux to apoA-I over a 0-60 muM concentration range without the cell toxicity apparent with native C2 ceramide. Compared with C2 ceramide, C6 and C8 ceramides with medium-length N-acyl chains showed a similar extent of efflux stimulation (a 2- to 5-fold increase) but at a higher onset concentration than the less hydrophobic C2 ceramide. In contrast, the reduced and methylated ceramide analogs, N,N-dimethyl sphingosine and N,N,N-trimethyl sphingosine, failed to stimulate cholesterol efflux. We found that changes in the native spatial orientation at either of two chiral carbon centers (or both) resulted in an approximately 50% decrease compared with native ceramide-stimulated cholesterol efflux. These data show that the overall ceramide shape and the amide bond are critical for the cholesterol efflux effect and suggest that ceramide acts through a protein-mediated pathway to affect ABCA1 activity.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • ATP Binding Cassette Transporter 1
  • ATP-Binding Cassette Transporters / metabolism*
  • Animals
  • Apolipoprotein A-I / metabolism*
  • Apoptosis / drug effects
  • Biological Transport, Active / drug effects
  • CHO Cells
  • Ceramides / chemistry*
  • Ceramides / metabolism*
  • Ceramides / pharmacology
  • Cholesterol / metabolism*
  • Cricetinae
  • Molecular Structure
  • Signal Transduction
  • Sphingosine / analogs & derivatives
  • Sphingosine / chemistry
  • Sphingosine / metabolism
  • Sphingosine / pharmacology
  • Stereoisomerism

Substances

  • ATP Binding Cassette Transporter 1
  • ATP-Binding Cassette Transporters
  • Apolipoprotein A-I
  • Ceramides
  • N-acetylsphingosine
  • Cholesterol
  • Sphingosine