Examining the Role of Sphingosine Kinase-2 in the Regulation of Endothelial Cell Barrier Integrity

Microcirculation. 2016 Apr;23(3):248-65. doi: 10.1111/micc.12271.


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.

Keywords: endothelial cell barrier integrity; sphingosine kinase; sphingosine-1-phosphate.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adamantane / analogs & derivatives*
  • Adamantane / pharmacokinetics
  • Animals
  • Capillary Permeability / drug effects*
  • Capillary Permeability / genetics
  • Human Umbilical Vein Endothelial Cells / enzymology*
  • Humans
  • Mice
  • Mice, Knockout
  • Phosphotransferases (Alcohol Group Acceptor) / antagonists & inhibitors*
  • Phosphotransferases (Alcohol Group Acceptor) / genetics
  • Phosphotransferases (Alcohol Group Acceptor) / metabolism*
  • Pyridines / pharmacokinetics*


  • Pyridines
  • 3-(4-chlorophenyl)-adamantane-1-carboxylic acid (pyridin-4-ylmethyl)amide
  • Phosphotransferases (Alcohol Group Acceptor)
  • sphingosine kinase 2, mouse
  • sphingosine kinase 2, human
  • Adamantane