title: Ceramide triggers Weibel-Palade body exocytosis.
abstract: The sphingolipid ceramide mediates a variety of stress responses, including vascular inflammation and thrombosis. Activated endothelial cells release Weibel-Palade bodies, granules containing von Willebrand factor (vWF) and P-selectin, which induce leukocyte rolling and platelet adhesion and aggregation. We hypothesized that ceramide induces vascular inflammation and thrombosis in part by triggering Weibel-Palade body exocytosis. We added ceramide to human aortic endothelial cells and assayed Weibel-Palade body exocytosis by measuring the concentration of vWF released into the media. Exogenous ceramide induces vWF release from endothelial cells in a dose-dependent manner. Activators of endogenous ceramide production, neutral sphingomyelinase, or tumor necrosis factor-alpha also induce Weibel-Palade body exocytosis. We next studied NO effects on ceramide-induced Weibel-Palade body exocytosis because NO can inhibit vascular inflammation. The NO donor S-nitroso-N-acetylpenicillamine decreases ceramide-induced vWF release in a dose-dependent manner, whereas the NO synthase inhibitor N(G)-nitro-L-arginine methyl ester increases ceramide-induced vWF release. In summary, our findings show that endogenous ceramide triggers Weibel-Palade body exocytosis, and that endogenous NO inhibits ceramide-induced exocytosis. These data suggest a novel mechanism by which ceramide induces vascular inflammation and thrombosis.
authors.affiliation: Division of Cardiology, Department of Medicine, The Johns Hopkins University School of Medicine, Baltimore, Md 21205, USA.
authors.forename: Rinky
authors.initials: R
authors.lastname: Bhatia
authors.forename: Kenji
authors.initials: K
authors.lastname: Matsushita
authors.forename: Munekazu
authors.initials: M
authors.lastname: Yamakuchi
authors.forename: Craig N
authors.initials: CN
authors.lastname: Morrell
authors.forename: Wangsen
authors.initials: W
authors.lastname: Cao
authors.forename: Charles J
authors.initials: CJ
authors.lastname: Lowenstein
mesh_terms: D001011:Aorta; D002478:Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D002518:Ceramides / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D003891:Desipramine / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D004533:Egtazic Acid / Q000031:analogs & derivatives* / Q000494:pharmacology; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism; D004730:Endothelium, Vascular / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005089:Exocytosis / Q000187:drug effects*; D006801:Humans; D016209:Interleukin-8 / Q000378:metabolism; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D009569:Nitric Oxide / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052250:Nitric Oxide Synthase Type III; D013108:Sphingomyelin Phosphodiesterase / Q000037:antagonists & inhibitors / Q000378:metabolism; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology; D020302:Weibel-Palade Bodies / Q000187:drug effects / Q000378:metabolism*
chemical_list: D002518:Ceramides; D004791:Enzyme Inhibitors; D016209:Interleukin-8; D014409:Tumor Necrosis Factor-alpha; C109343:dihydroceramide; C070379:1,2-bis(2-aminophenoxy)ethane N,N,N',N'-tetraacetic acid acetoxymethyl ester; D009569:Nitric Oxide; D004533:Egtazic Acid; C496314:NOS3 protein, human; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; D013108:Sphingomyelin Phosphodiesterase; D003891:Desipramine; D019331:NG-Nitroarginine Methyl Ester