title: The neutral sphingomyelinase-2 is involved in angiogenic signaling triggered by oxidized LDL.
abstract: Capillaries of the external part of the normal arterial wall constitute the vasa vasorum network. In atherosclerotic lesions, neovascularization occurs in areas of intimal hyperplasia where it may promote plaque expansion, and intraplaque hemorrhage. Oxidized LDL that are present in atherosclerotic areas activate various angiogenic signaling pathways, including reactive oxygen species and the sphingosine kinase/sphingosine-1-phosphate pathway. We aimed to investigate whether oxidized LDL-induced angiogenesis requires neutral sphingomyelinase-2 activation and the neutral sphingomyelinase-2/sphingosine kinase-1 pathway. The role of neutral sphingomyelinase-2 in angiogenic signaling was investigated in Human Microvascular Endothelial Cells (HMEC-1) forming capillary tube on Matrigel and in vivo in the Matrigel plug assay in C57BL/6 mice and in the chicken chorioallantoic membrane model. Low concentration of human oxidized LDL elicits HMEC-1 capillary tube formation and neutral sphingomyelinase-2 activation, which were blocked by neutral sphingomyelinase-2 inhibitors, GW4869 and specific siRNA. This angiogenic effect was mimicked by low concentration of C6-Ceramide and was inhibited by sphingosine kinase-1 inhibitors. Upstream of neutral sphingomyelinase-2, oxidized LDL-induced activation required LOX-1, reactive oxygen species generation by NADPH oxidase and p38-MAPK activation. Inhibition of sphingosine kinase-1 blocked the angiogenic response and triggered HMEC-1 apoptosis. Low concentration of oxidized LDL was angiogenic in vivo, both in the Matrigel plug assay in mice and in the chorioallantoic membrane model, and was blocked by GW4869. In conclusion, low oxLDL concentration triggers sprouting angiogenesis that involves ROS-induced activation of the neutral sphingomyelinase-2/sphingosine kinase-1 pathway, and is effectively inhibited by GW4869.
authors: Inserm UMR-1048, CHU Rangueil, BP 84225, 31432 Toulouse Cedex 4, France; University of Toulouse, Faculty of Medicine, Biochemistry Department, Toulouse, France; CHU Toulouse, Rangueil, Toulouse, France.
authors: Caroline
authors: C
authors: Camaré
authors: Inserm UMR-1048, CHU Rangueil, BP 84225, 31432 Toulouse Cedex 4, France.
authors: Nathalie
authors: N
authors: Augé
authors: Inserm UMR-1048, CHU Rangueil, BP 84225, 31432 Toulouse Cedex 4, France.
authors: Mélanie
authors: M
authors: Pucelle
authors: Inserm UMR-1048, CHU Rangueil, BP 84225, 31432 Toulouse Cedex 4, France; University of Toulouse, Faculty of Medicine, Biochemistry Department, Toulouse, France; CHU Toulouse, Rangueil, Toulouse, France.
authors: Bertrand
authors: B
authors: Saint-Lebes
authors: University of Toulouse, Faculty of Medicine, Biochemistry Department, Toulouse, France.
authors: Marie-Hélène
authors: MH
authors: Grazide
authors: Inserm UMR-1048, CHU Rangueil, BP 84225, 31432 Toulouse Cedex 4, France. Electronic address: anne.negre-salvayre@inserm.fr.
authors: Anne
authors: A
authors: Nègre-Salvayre
authors: Inserm UMR-1048, CHU Rangueil, BP 84225, 31432 Toulouse Cedex 4, France; University of Toulouse, Faculty of Medicine, Biochemistry Department, Toulouse, France; CHU Toulouse, Rangueil, Toulouse, France. Electronic address: robert.salvayre@inserm.fr.
authors: Robert
authors: R
authors: Salvayre
mesh_terms: D000814:Aniline Compounds / Q000008:administration & dosage; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D001597:Benzylidene Compounds / Q000008:administration & dosage; D002518:Ceramides / Q000378:metabolism; D042783:Endothelial Cells / Q000378:metabolism; D006801:Humans; D008077:Lipoproteins, LDL / Q000235:genetics / Q000378:metabolism*; D008246:Lysophospholipids / Q000378:metabolism; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000378:metabolism / Q000473:pathology; D019255:NADPH Oxidases / Q000378:metabolism; D009389:Neovascularization, Pathologic / Q000235:genetics* / Q000378:metabolism / Q000473:pathology; D018384:Oxidative Stress; D017853:Phosphotransferases (Alcohol Group Acceptor) / Q000235:genetics* / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics; D013110:Sphingosine / Q000031:analogs & derivatives / Q000378:metabolism; D015533:Transcriptional Activation / Q000187:drug effects; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism; D000099157:Sphingosine Kinase
chemical_list: D000814:Aniline Compounds; D001597:Benzylidene Compounds; D002518:Ceramides; D008077:Lipoproteins, LDL; D008246:Lysophospholipids; D019255:NADPH Oxidases; D017853:Phosphotransferases (Alcohol Group Acceptor); D017382:Reactive Oxygen Species; D013108:Sphingomyelin Phosphodiesterase; D013110:Sphingosine; D048051:p38 Mitogen-Activated Protein Kinases; D000099157:Sphingosine Kinase; C468773:GW 4869; C099252:oxidized low density lipoprotein; C060506:sphingosine 1-phosphate; C491484:SMPD3 protein, human
keywords: Angiogenesis; Cell signaling/signal transduction; Ceramide; Neutral sphingomyelinase type 2; Oxidized LDL; ROS and oxidative stress