title: Ceramide binding to anandamide increases its half-life and potentiates its cytotoxicity in human neuroblastoma cells.
abstract: Anandamide (AEA) is a ubiquitous lipid that exerts neurotransmitter functions but also controls important biological functions such as proliferation, survival, or programmed cell death. The latter effects are also regulated by ceramide, a lipid enzymatically generated from sphingomyelin hydrolysis by sphingomyelinase. Ceramide has been shown to increase the cellular toxicity of AEA, but the mechanisms controlling this potentiating effect remained unclear. Here we have used a panel of in silico, physicochemical, biochemical and cellular approaches to study the crosstalk between AEA and ceramide apoptotic pathways. Molecular dynamics simulations indicated that AEA and ceramide could form a stable complex in phosphatidylcholine membranes. Consistent with these data, we showed that AEA can specifically insert into ceramide monolayers whereas it did not penetrate into sphingomyelin membranes. Then we have studied the effects of ceramide on AEA-induced toxicity of human neuroblastoma cells. In these experiments, the cells have been either naturally enriched in ceramide by neutral sphingomyelinase pre-incubation or treated with C2-ceramide, a biologically active ceramide analog. Both treatments significantly increased the cytotoxicity of AEA as assessed by the MTS mitochondrial toxicity assay. This effect was correlated with the concomitant accumulation of natural ceramide (or its synthetic analog) and AEA in the cells. A kinetic study of AEA hydrolysis showed that ceramide inhibited the fatty acid amino hydrolase (FAAH) activity in cell extracts. Taken together, these data suggested that ceramide binds to AEA, increases its half-life and potentiates its cytotoxicity. Overall, these mechanisms account for a functional cross-talk between AEA and ceramide apoptotic pathways.
authors.affiliation: Faculté des Sciences, Aix-Marseille Université, EA4674, Marseille, France.
authors.forename: Coralie
authors.initials: C
authors.lastname: Di Scala
authors.affiliation: Faculté des Sciences, Aix-Marseille Université, EA4674, Marseille, France.
authors.forename: Morgane
authors.initials: M
authors.lastname: Mazzarino
authors.affiliation: Faculté des Sciences, Aix-Marseille Université, EA4674, Marseille, France.
authors.forename: Nouara
authors.initials: N
authors.lastname: Yahi
authors.affiliation: Aix-Marseille Université, CNRS UMR7259, Marseille, France.
authors.forename: Karine
authors.initials: K
authors.lastname: Varini
authors.affiliation: Faculté des Sciences, Aix-Marseille Université, EA4674, Marseille, France.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Garmy
authors.affiliation: Faculté des Sciences, Aix-Marseille Université, EA4674, Marseille, France.
authors.forename: Jacques
authors.initials: J
authors.lastname: Fantini
authors.affiliation: Faculté des Sciences, Aix-Marseille Université, EA4674, Marseille, France. Electronic address: h.chahinian@univ-amu.fr.
authors.forename: Henri
authors.initials: H
authors.lastname: Chahinian
mesh_terms: D017209:Apoptosis; D001095:Arachidonic Acids / Q000737:chemistry* / Q000378:metabolism; D045744:Cell Line, Tumor; D002462:Cell Membrane / Q000737:chemistry* / Q000378:metabolism; D002470:Cell Survival; D002518:Ceramides / Q000737:chemistry* / Q000378:metabolism; D002784:Cholesterol / Q000378:metabolism; D063388:Endocannabinoids / Q000737:chemistry* / Q000378:metabolism; D006207:Half-Life; D006801:Humans; D006867:Hydrolases / Q000378:metabolism; D006868:Hydrolysis; D008563:Membrane Lipids / Q000737:chemistry* / Q000378:metabolism; D008567:Membranes, Artificial; D008958:Models, Molecular; D056004:Molecular Dynamics Simulation; D009447:Neuroblastoma / Q000378:metabolism / Q000473:pathology*; D053284:Polyunsaturated Alkamides / Q000737:chemistry* / Q000378:metabolism
chemical_list: D001095:Arachidonic Acids; D002518:Ceramides; D063388:Endocannabinoids; D008563:Membrane Lipids; D008567:Membranes, Artificial; D053284:Polyunsaturated Alkamides; D002784:Cholesterol; D006867:Hydrolases; C078814:anandamide
keywords: Anandamide; Ceramide; Cholesterol; Endocannabinoid; FAAH; Lipid domain