Structural characterization and dynamics  of globotetraosylceramide in vascular endothelial  cells under TNF-alpha stimulation.
In several vascular inflammatory reactions (i.e. immunity and thrombosis) inflammatory mediators lead to the activation of vascular endothelial cells (EC). To date, a number of functional molecules induced on the surface of activated-EC have been identified. We report here that Globotetraosylceramide (Gb4), a glycosphingolipid expressed in EC, is a novel inducible molecule on EC activated by TNF-alpha. The cell surface expression of Gb4 is increased in a time-dependent manner under TNF-alpha stimulation, which shows distinct expression kinetics of major proteins induced by TNF-alpha on EC. MALDI-TOFMS analysis revealed that the enhanced Gb4 predominantly contains C24:0 fatty acid in the ceramide moiety. Isolated caveolae/lipid raft-enriched detergent insoluble membrane domains in activated-EC predominantly contain this molecular species of Gb4. Gb4 containing C16:0 fatty acid in the ceramide moiety, which is known to constitute the major species of Gb4 in plasma, is also found as a major molecular species in EC. These observations indicate that Gb4, especially with very long fatty acid, is enhanced in EC during its inflammatory reaction, and suggest the potential utility of Gb4 as a biomarker for monitoring inflammation status of EC involving its related diseases.
Okuda
Tetsuya
T
Glycolipids Function Analysis Team, Health Technology Research Center, National Institute of Advanced Industrial Science and Technology (AIST), 2217-14 Hayashi, Takamatsu, Kagawa 761-0395, Japan. t-okuda@aist.go.jp
Nakakita
Sin-ichi
S
Nakayama
Ken-ichi
K
D015815:Cell Adhesion Molecules / Q000378:metabolism; D002478:Cells, Cultured; D002851:Chromatography, High Pressure Liquid; D003902:Detergents / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism*; D004912:Erythrocytes / Q000187:drug effects / Q000378:metabolism; D005434:Flow Cytometry; D005455:Fluorescent Antibody Technique; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects; D005915:Globosides / Q000737:chemistry* / Q000378:metabolism*; D016695:Glycosyltransferases / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007700:Kinetics; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D012995:Solubility / Q000187:drug effects; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology*; D014471:Umbilical Veins / Q000166:cytology
D015815:Cell Adhesion Molecules; D003902:Detergents; D005915:Globosides; D012333:RNA, Messenger; D014409:Tumor Necrosis Factor-alpha; C024032:globotetraosylceramide; D016695:Glycosyltransferases