title: Phosphatidylinositol 3-kinase and xanthine oxidase regulate nitric oxide and reactive oxygen species productions by apoptotic lymphocyte microparticles in endothelial cells.
abstract: Microparticles (MPs) are membrane vesicles released during cell activation and apoptosis. We have previously shown that MPs from apoptotic T cells induce endothelial dysfunction, but the mechanisms implicated are not completely elucidated. In this study, we dissect the pathways involved in endothelial cells with respect to both NO and reactive oxygen species (ROS). Incubation of endothelial cells with MPs decreased NO production that was associated with overexpression and phosphorylation of endothelial NO synthase (eNOS). Also, MPs enhanced expression of caveolin-1 and decreased its phosphorylation. Microparticles enhanced ROS by a mechanism sensitive to xanthine oxidase and P-IkappaBalpha inhibitors. PI3K inhibition reduced the effects of MPs on eNOS, but not on caveolin-1, whereas it enhanced the effects of MPs on ROS production. Microparticles stimulated ERK1/2 phosphorylation via a PI3K-depedent mechanism. Inhibition of MEK reversed eNOS phosphorylation but had no effect on ROS production induced by MPs. In vivo injection of MPs in mice impaired endothelial function. In summary, MPs activate pathways related to NO and ROS productions through PI3K, xanthine oxidase, and NF-kappaB pathways. These data underscore the pleiotropic effects of MPs on NO and ROS, leading to an increase oxidative stress that may account for the deleterious effects of MPs on endothelial function.
authors: Centre National de la Recherche Scientifique Unité Mixte de Recherche 6214, INSERM Unité 771, and Université d'Angers, Angers, France.
authors: H Ahmed
authors: HA
authors: Mostefai
authors: Abdelali
authors: A
authors: Agouni
authors: Nunzia
authors: N
authors: Carusio
authors: M Letizia
authors: ML
authors: Mastronardi
authors: Christophe
authors: C
authors: Heymes
authors: Daniel
authors: D
authors: Henrion
authors: Ramaroson
authors: R
authors: Andriantsitohaina
authors: M Carmen
authors: MC
authors: Martinez
mesh_terms: D000818:Animals; D001011:Aorta / Q000378:metabolism; D017209:Apoptosis; D002460:Cell Line; D042783:Endothelial Cells / Q000378:metabolism*; D006801:Humans; D008214:Lymphocytes / Q000166:cytology / Q000378:metabolism*; D020935:MAP Kinase Signaling System; D051379:Mice; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000378:metabolism; D009569:Nitric Oxide / Q000096:biosynthesis*; D019869:Phosphatidylinositol 3-Kinases / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*; D014969:Xanthine Oxidase / Q000378:metabolism*
chemical_list: D016328:NF-kappa B; D017382:Reactive Oxygen Species; D009569:Nitric Oxide; D014969:Xanthine Oxidase; D019869:Phosphatidylinositol 3-Kinases; D020928:Mitogen-Activated Protein Kinases