Article date: August 2010
By: Stephanie Schwalm, Josef Pfeilschifter, Andrea Huwiler in Volume 160, Issue 7, pages 1641-1651
Background and purpose: Sphingosine kinases (SKs) convert sphingosine to sphingosine 1‐phosphate (S1P), which is a bioactive lipid that regulates a variety of cellular processes including proliferation, differentiation and migration.
Experimental approach: We used the human endothelial cell line EA.hy926 to investigate the effect of nitric oxide (NO) donors on SK‐1 expression, and on cell migration and tube formation.
Key results: We showed that exposure of EA.hy926 cells to Deta‐NO (125–1000 µM) resulted in a time‐ and concentration‐dependent up‐regulation of SK‐1 mRNA and protein expression, and activity with a first significant effect at 250 µM of Deta‐NO. The increased SK‐1 mRNA expression resulted from an enhanced SK‐1 promoter activity. A similar effect was also seen with various other NO donors. In mechanistic terms, the NO‐triggered effect occurred independently of cGMP, but involved the classical mitogen‐activated protein kinase cascade because the MEK inhibitor U0126 abolished the NO‐induced SK‐1 expression. The effect of NO was also markedly reduced by the thiol‐reducing agent N‐acetylcysteine, suggesting a redox‐dependent mechanism. Functionally, Deta‐NO triggered an increase in the migration of endothelial cells in an adapted Boyden chamber assay, and also increased endothelial tube formation in a Matrigel assay. These responses were both abolished in cells depleted of SK‐1.
Conclusions and implications: These data show that NO donors up‐regulate specifically SK‐1 expression and activity in human endothelial cells, and SK‐1 in turn critically contributes to the migratory capability and tube formation of endothelial cells. Thus, SK‐1 may be considered an attractive novel target to interfere with pathological processes involving angiogenesis.
DOI: 10.1111/j.1476-5381.2010.00818.x
View this article