title: Examining the Role of Sphingosine Kinase-2 in the Regulation of Endothelial Cell Barrier Integrity.
abstract: OBJECTIVE
  A key mediator of vascular EC barrier integrity, S1P, is derived from phosphorylation of sphingosine by the SK-1 and SK-2. While previous work indicates that SK-1 can regulate EC barrier integrity, whether SK-2 has a similar role remains to be determined.
  
  
  METHODS
  A cell impedance assay was used to assess human umbilical vein EC and bone marrow EC barrier integrity in vitro, with application of the SK inhibitors ABC294640, PF543, SKi, and MP-A08. In vivo studies were conducted using intravital microscopy to assess EC barrier integrity in SK-1 (Sphk1(-/-)) and SK-2 (Sphk2(-/-)) knock-out mice.
  
  
  RESULTS
  Only ABC294640 and MP-A08, which can both inhibit SK-2, caused a decrease in EC barrier integrity in vitro in both cell types. Intravital microscopy revealed that Sphk1(-/-) mice had reduced EC barrier integrity compared to WT mice, whereas no change was evident in Sphk2(-/-) mice.
  
  
  CONCLUSIONS
  Our data suggest that in vitro inhibition of SK-2, can compromise the integrity of the EC monolayer, while SK-1 exerts a more dominant control in vivo. These data may have clinical implications and could aid in the development of new treatments for disorders of vascular barrier function.
authors.affiliation: Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia.
authors.forename: David P
authors.initials: DP
authors.lastname: Dimasi
authors.affiliation: Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia.|School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.|School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Stuart M
authors.initials: SM
authors.lastname: Pitson
authors.affiliation: Centre for Cancer Biology, University of South Australia and SA Pathology, Adelaide, South Australia, Australia.|School of Medicine, University of Adelaide, Adelaide, South Australia, Australia.|School of Biological Sciences, University of Adelaide, Adelaide, South Australia, Australia.
authors.forename: Claudine S
authors.initials: CS
authors.lastname: Bonder
mesh_terms: D000218:Adamantane / Q000031:analogs & derivatives* / Q000493:pharmacokinetics; D000818:Animals; D002199:Capillary Permeability / Q000187:drug effects* / Q000235:genetics; D061307:Human Umbilical Vein Endothelial Cells / Q000201:enzymology*; D006801:Humans; D051379:Mice; D018345:Mice, Knockout; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000378:metabolism*; D011725:Pyridines / Q000493:pharmacokinetics*; D000099157:Sphingosine Kinase
chemical_list: D000218:Adamantane; D017853:Phosphotransferases (Alcohol Group Acceptor); D011725:Pyridines; C548780:3-(4-chlorophenyl)-adamantane-1-carboxylic acid (pyridin-4-ylmethyl)amide; C000603447:sphingosine kinase 2, mouse; D000099157:Sphingosine Kinase; C000594250:sphingosine kinase 2, human
keywords: endothelial cell barrier integrity; sphingosine kinase; sphingosine-1-phosphate