title: Endothelial lipase is a critical determinant of high-density lipoprotein-stimulated sphingosine 1-phosphate-dependent signaling in vascular endothelium.
abstract: OBJECTIVE
  In addition to an extensively characterized role of high-density lipoprotein (HDL) in reverse cholesterol transport, bioactive lipids bound to HDL can also exert diverse vascular effects. Despite this, integration of HDL action in the vasculature with pathways that metabolize HDL and release bioactive lipids has been much less explored. The effects of HDL on endothelial cells are mediated in part by HDL-associated sphingosine 1-phosphate (S1P), which binds to S1P1 receptors and promotes activation of endothelial NO synthase (eNOS) and the kinase Akt. In these studies, we characterized the role of endothelial lipase (EL) in the control of endothelial signaling and biology, including those mediated by HDL-associated S1P.
  
  
  RESULTS
  HDL-induced angiogenesis in aortic rings from EL-deficient (EL(-/-)) mice was markedly decreased compared with wild-type controls. In cultured endothelial cells, small interfering RNA-mediated knockdown of EL abrogated HDL-promoted endothelial cell migration and tube formation. Small interfering RNA-mediated EL knockdown also attenuated HDL-induced phosphorylation of eNOS(1179) and Akt(473). S1P stimulation restored HDL-induced endothelial migration and Akt/eNOS phosphorylation that had been blocked by small interfering RNA-mediated EL knockdown. HDL-induced endothelial cell migration and Akt/eNOS phosphorylation were completely inhibited by the S1P1 antagonist W146 but not by the S1P3 antagonist CAY10444.
  
  
  CONCLUSIONS
  EL is a critical determinant of the effects of HDL on S1P-mediated vascular responses and acts on HDL to promote activation of S1P1, leading to Akt/eNOS phosphorylation and subsequent endothelial migration and angiogenesis. The role of EL in HDL-associated S1P effects provides new insights into EL action, the responses seen through EL and HDL interaction, and S1P signaling.
authors.affiliation: Division of Cardiovascular Medicine, Department of Medicine, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
authors.forename: Satoru
authors.initials: S
authors.lastname: Tatematsu
authors.forename: Sanjeev A
authors.initials: SA
authors.lastname: Francis
authors.forename: Pradeep
authors.initials: P
authors.lastname: Natarajan
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: Rader
authors.forename: Alan
authors.initials: A
authors.lastname: Saghatelian
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Brown
authors.forename: Thomas
authors.initials: T
authors.lastname: Michel
authors.forename: Jorge
authors.initials: J
authors.lastname: Plutzky
mesh_terms: D000813:Anilides / Q000494:pharmacology; D000818:Animals; D002465:Cell Movement / Q000502:physiology; D049109:Cell Proliferation; D002478:Cells, Cultured; D002784:Cholesterol / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism*; D008075:Lipoproteins, HDL / Q000378:metabolism*; D008246:Lysophospholipids / Q000037:antagonists & inhibitors / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D018919:Neovascularization, Physiologic / Q000502:physiology; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D063065:Organophosphonates / Q000494:pharmacology; D010766:Phosphorylation / Q000502:physiology; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D034741:RNA, Small Interfering / Q000235:genetics; D049349:Receptors, Lysosphingolipid / Q000037:antagonists & inhibitors / Q000378:metabolism; D015398:Signal Transduction / Q000502:physiology*; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000037:antagonists & inhibitors / Q000378:metabolism
chemical_list: C513113:3-amino-4-(3-hexylphenylamino)-4-oxobutylphosphonic acid; D000813:Anilides; D008075:Lipoproteins, HDL; D008246:Lysophospholipids; D063065:Organophosphonates; D034741:RNA, Small Interfering; D049349:Receptors, Lysosphingolipid; C060506:sphingosine 1-phosphate; D002784:Cholesterol; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse; C514862:Akt1 protein, mouse; D051057:Proto-Oncogene Proteins c-akt; D008049:Lipase; C498741:Lipg protein, mouse; D013110:Sphingosine
keywords: HDL cholesterol; angiogenesis; endothelial cells; endothelial lipase, mouse; sphingosine 1-phosphate