出版社：American Society for Biochemistry and Molecular Biology
摘要：Ceramide is a component of the sphingomyelin cycle and a well-establishedlipid signaling molecule. We recently reported that ceramidespecifically increased ABCA1-mediated cholesterol efflux toapolipoprotein A-I (apoA-I), a critical process that leads tothe formation of cardioprotective HDL. In this report, we characterizethe structural features of ceramide required for this effect.C2 dihydroceramide, which contains a fully saturated acyl chainand is commonly used as a negative control for ceramide apoptoticsignaling, stimulated a 2- to 5-fold increase in ABCA1-mediatedcholesterol efflux to apoA-I over a 0–60 µM concentrationrange without the cell toxicity apparent with native C2 ceramide.Compared with C2 ceramide, C6 and C8 ceramides with medium-lengthN-acyl chains showed a similar extent of efflux stimulation(a 2- to 5-fold increase) but at a higher onset concentrationthan the less hydrophobic C2 ceramide. In contrast, the reducedand methylated ceramide analogs, N,N-dimethyl sphingosine andN,N,N-trimethyl sphingosine, failed to stimulate cholesterolefflux. We found that changes in the native spatial orientationat either of two chiral carbon centers (or both) resulted inan 50% decrease compared with native ceramide-stimulated cholesterolefflux. These data show that the overall ceramide shape andthe amide bond are critical for the cholesterol efflux effectand suggest that ceramide acts through a protein-mediated pathwayto affect ABCA1 activity.Supplementary key words chemical structure • stereochemistry • ATP binding cassette type A1
Abbreviations: apoA-I, apolipoprotein A-I; CAPK, ceramide-activated protein kinase; CAPP, ceramide-activated protein phosphatase; DMS, N,N-dimethyl sphingosine; PVDF, polyvinylidene difluoride; TMS, N,N,N-trimethyl sphingosine
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.
Supplementary key words chemical structure • stereochemistry • ATP binding cassette type A1
Abbreviations: apoA-I, apolipoprotein A-I; CAPK, ceramide-activated protein kinase; CAPP, ceramide-activated protein phosphatase; DMS, N,N-dimethyl sphingosine; PVDF, polyvinylidene difluoride; TMS, N,N,N-trimethyl sphingosine
