Sphingosine 1-phosphate activates Akt, nitric oxide production, and chemotaxis through a Gi protein/phosphoinositide 3-kinase pathway in endothelial cells.
Sphingosine 1-phosphate (SPP) binds to members of the endothelial differentiation gene family (EDG) of receptors and leads to diverse signaling events including cell survival, growth, migration and differentiation. However, the mechanisms of how SPP activates these proangiogenic pathways are poorly understood. Here we show that SPP signals through the EDG-1 receptor to the heterotrimeric G protein G(i), leading to activation of the serine/threonine kinase Akt and phosphorylation of the Akt substrate, endothelial nitric-oxide synthase (eNOS). Inhibition of G(i) signaling, and phosphoinositide 3-kinase (PI 3-kinase) activity resulted in a decrease in SPP-induced endothelial cell chemotaxis. SPP also stimulates eNOS phosphorylation and NO release and these effects are also attenuated by inhibition of G(i) signaling, PI 3-kinase, and Akt. However, inhibition of NO production did not influence SPP-induced chemotaxis but effectively blocked the chemotactic actions of vascular endothelial growth factor. Thus, SPP signals through G(i) and PI 3-kinase leading to Akt activation and eNOS phosphorylation.
Department of Pharmacology, Boyer Center for Molecular Medicine, Yale University School of Medicine, New Haven, Connecticut 06536, USA.
M
M
Morales-Ruiz
M J
MJ
Lee
S
S
Zöllner
J P
JP
Gratton
R
R
Scotland
I
I
Shiojima
K
K
Walsh
T
T
Hla
W C
WC
Sessa
D000818:Animals; D015152:Blotting, Northern; D015153:Blotting, Western; D002417:Cattle; D002465:Cell Movement; D002633:Chemotaxis; D016895:Culture Media, Serum-Free / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D016228:Endothelial Growth Factors / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000166:cytology* / Q000201:enzymology; D004789:Enzyme Activation; D019206:GTP-Binding Protein alpha Subunits, Gi-Go / Q000378:metabolism*; D005799:Genes, Dominant; D008168:Lung / Q000378:metabolism; D008222:Lymphokines / Q000494:pharmacology; D008246:Lysophospholipids; D018919:Neovascularization, Physiologic; D009569:Nitric Oxide / Q000096:biosynthesis*; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D010766:Phosphorylation; D011485:Protein Binding; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins / Q000235:genetics / Q000378:metabolism*; D051057:Proto-Oncogene Proteins c-akt; D011956:Receptors, Cell Surface / Q000096:biosynthesis; D015398:Signal Transduction; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism* / Q000502:physiology*; D013997:Time Factors; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D010566:Virulence Factors, Bordetella / Q000494:pharmacology
D016895:Culture Media, Serum-Free; D016228:Endothelial Growth Factors; D019206:GTP-Binding Protein alpha Subunits, Gi-Go; D008222:Lymphokines; D008246:Lysophospholipids; D009569:Nitric Oxide; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D019869:Phosphatidylinositol 3-Kinases; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D051057:Proto-Oncogene Proteins c-akt; D011956:Receptors, Cell Surface; D013110:Sphingosine; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D010566:Virulence Factors, Bordetella; C060506:sphingosine 1-phosphate