title: Distribution and dynamic changes of sphingolipids in blood in response to platelet activation.
abstract: BACKGROUND
  Sphingolipids are signaling molecules in a range of biological processes. While sphingosine-1-phosphate (S1P) is thought to be abundantly stored in platelets and released upon stimulation, knowledge about the distribution and function of other sphingolipids in blood is lacking.
  
  
  OBJECTIVE
  To analyze the sphingolipid content of blood components with special emphasis on dynamic changes in platelets.
  
  
  METHODS
  Blood components from mice and humans were prepared by gradient centrifugation and analyzed by liquid chromatography-mass spectrometry. Additionally, murine platelets were activated in vitro and in vivo.
  
  
  RESULTS
  Isolated non-activated platelets of mice were devoid of S1P, but instead contained dihydrosphingosine-1-phosphate (dhS1P), along with a high concentration of ceramide. Activation of platelets in vitro led to a loss of dhS1P and an increase in sphingosine, accompanied by a reduction of ceramide content. Platelet activation in vivo led to an immediate and continuous rise of dhS1P in plasma, while S1P remained stable. The sphingolipid distribution of human blood was markedly different from mice. Human platelets contained dhS1P in addition to S1P.
  
  
  CONCLUSIONS
  Mouse platelets contain dhS1P instead of S1P. Platelet activation causes loss of dhS1P and breakdown of ceramide, implying ceramidase activation. Release of dhS1P from activated platelets might be a novel signaling pathway. Finally, the sphingolipid composition of mouse and human blood shows large differences, which must be considered when studying sphingolipid biology.
authors.affiliation: Swiss Hepato-Pancreato-Biliary (HPB) Centre, Department of Visceral and Transplantation Surgery, University Hospital Zurich, Zurich, Switzerland.
authors.forename: F
authors.initials: F
authors.lastname: Dahm
authors.forename: A
authors.initials: A
authors.lastname: Nocito
authors.forename: A
authors.initials: A
authors.lastname: Bielawska
authors.forename: K S
authors.initials: KS
authors.lastname: Lang
authors.forename: P
authors.initials: P
authors.lastname: Georgiev
authors.forename: L M
authors.initials: LM
authors.lastname: Asmis
authors.forename: J
authors.initials: J
authors.lastname: Bielawski
authors.forename: J
authors.initials: J
authors.lastname: Madon
authors.forename: Y A
authors.initials: YA
authors.lastname: Hannun
authors.forename: P-A
authors.initials: PA
authors.lastname: Clavien
mesh_terms: D000818:Animals; D000906:Antibodies; D001792:Blood Platelets / Q000187:drug effects / Q000276:immunology / Q000378:metabolism*; D002469:Cell Separation; D002518:Ceramides / Q000097:blood; D002853:Chromatography, Liquid; D004912:Erythrocytes / Q000737:chemistry; D005434:Flow Cytometry; D006801:Humans; D066298:In Vitro Techniques; D007962:Leukocytes / Q000737:chemistry; D008246:Lysophospholipids / Q000097:blood; D051379:Mice; D008807:Mice, Inbred BALB C; D015539:Platelet Activation / Q000187:drug effects / Q000276:immunology; D040201:Platelet Membrane Glycoprotein IIb / Q000276:immunology; D013045:Species Specificity; D021241:Spectrometry, Mass, Electrospray Ionization; D013107:Sphingolipids / Q000097:blood* / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives / Q000097:blood; D013917:Thrombin / Q000494:pharmacology
chemical_list: D000906:Antibodies; D002518:Ceramides; D008246:Lysophospholipids; D040201:Platelet Membrane Glycoprotein IIb; D013107:Sphingolipids; C060504:dihydrosphingosine 1-phosphate; C060506:sphingosine 1-phosphate; D013917:Thrombin; D013110:Sphingosine