Interaction of cholesterol with sphingosine: physicochemical characterization and impact on intestinal absorption

Molecular associations between sphingomyelin and cholesterol provide a molecular basis for the colocalization of these lipids in plasma membrane microdomains (lipid rafts) and for the inhibitory effect of sphingomyelin on the intestinal absorption of cholesterol. Using surface pressure measurements...

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Bibliographic Details
Published in:Journal of lipid research 2005, Vol.46 (1), p.36-45
Main Authors: Garmy, Nicolas, Tai̊eb, Nadira, Yahi, Nouara, Fantini, Jacques
Format: Article
Language:English
Subjects:
Binding Sites
Biological Transport
Cell Line
Cholesterol - metabolism
Humans
Intestinal Absorption
Intestinal Mucosa - cytology
Membrane Microdomains - chemistry
Membrane Proteins - genetics
Membrane Transport Proteins
Proteins - genetics
RNA, Messenger - analysis
Sphingosine - analogs & derivatives
Sphingosine - metabolism
Sphingosine - pharmacology
Structure-Activity Relationship
Surface Tension
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Summary:Molecular associations between sphingomyelin and cholesterol provide a molecular basis for the colocalization of these lipids in plasma membrane microdomains (lipid rafts) and for the inhibitory effect of sphingomyelin on the intestinal absorption of cholesterol. Using surface pressure measurements at the air-water interface, we showed that sphingosine, the common sphingoid backbone of most sphingolipids, formed condensed lipid complexes with cholesterol. Structure-activity relationship studies with long-chain analogs of sphingosine, together with molecular mechanics simulations, were consistent with a specific interaction between sphingosine and the [alpha] face of cholesterol. The uptake of micellar cholesterol and the effect of sphingosine on cholesterol absorption were studied with two human model intestinal epithelial cell lines, Caco-2 and HT-29-D4. Real-time PCR quantifications of the putative cholesterol transporter Niemann-Pick C1 like 1 (NPC1L1) mRNA revealed that, in these cell lines, the activity of cholesterol transport correlated with the level of NPC1L1 expression. In both cell lines, sphingosine induced a dose-dependent decrease of cholesterol absorption. Yet the effect of sphingosine was more dramatic in Caco-2 cells, which also displayed the highest expression of NPC1L1 mRNA. Altogether, these data suggested that sphingosine interacts specifically with cholesterol and inhibits the intestinal NPC1L1-dependent transport of micellar cholesterol.
ISSN:0022-2275
1539-7262
DOI:10.1194/jlr.M400199-JLR200