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N-cholesteryl sphingomyelin-A Synthetic Sphingolipid With Unique Membrane Properties

Christian Sergelius, Shou Yamaguchi, Tetsuya Yamamoto, J Peter Slotte, Shigeo Katsumura

Biochim Biophys Acta. 2011 Apr;1808(4):1054-62.

PMID: 21194522

Abstract:

A sphingomyelin chimera in which the amide-linked acyl chain was replaced with cholesterol carbamate was prepared and its properties examined. The sphingomyelin/cholesterol chimera (N-cholesterol-D-erythro-sphingomyelin) was able to form unilamellar vesicles of defined size when extruded through 200nm pore size membranes. These N-cholesteryl sphingomyelin bilayers were resistant to solubilization by Triton X-100. When N-cholesteryl sphingomyelin was added to N-palmitoyl sphingomyelin (N-palmitoyl-d-erythro-sphingomyelin) bilayers, it increased acyl chain order as determined by 1,6-diphenyl-1,3,5-hexatriene fluorescence anisotropy. N-cholesteryl sphingomyelin was, however, not as good an inducer of membrane order compared to cholesterol on a molar basis. Differential scanning calorimetry studies further showed that the miscibility of N-cholesteryl sphingomyelin with N-palmitoyl-d-erythro-sphingomyelin bilayers was non-ideal, and the effect of N-cholesteryl sphingomyelin on the N-palmitoyl-d-erythro-sphingomyelin gel-fluid transition enthalpy differed from that seen with cholesterol. Together with N-palmitoyl-d-erythro-sphingomyelin, the N-cholesteryl sphingomyelin chimera was able to form sterol-enriched ordered domains in a fluid 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer. N-cholesteryl sphingomyelin in the absence of N-palmitoyl-d-erythro-sphingomyelin was unable to form such sterol-enriched ordered domains in a 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayer. However, N-cholesteryl sphingomyelin markedly increased the affinity of cholestatrienol for N-cholesteryl sphingomyelin containing 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine bilayers, suggesting that N-cholesteryl sphingomyelin was able to somehow stabilize sterol interaction in fluid bilayers. Based on our results, we conclude that N-cholesteryl sphingomyelin behaved more like a cholesterol than a sphingolipid in fluid bilayer membranes. Because N-cholesteryl sphingomyelin increased bilayer order, conferred resistance against detergent solubilization, and is not degradable by phospholipases A(2), it could constitute a good lipocomplex matrix for drug delivery vehicles.

Chemicals Related in the Paper:

Catalog Number Product Name Structure CAS Number Price
IAR4247490 N-(NBD-Aminolauroyl)sphingomyelin N-(NBD-Aminolauroyl)sphingomyelin Price
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