Ceramide kinase regulates TNFα-stimulated NADPH oxidase activity and eicosanoid biosynthesis in neuroblastoma cells.
Cell Signal
; 24(6): 1126-33, 2012 Jun.
Article
em En
| MEDLINE
| ID: mdl-22230689
ABSTRACT
A persistent inflammatory reaction is a hallmark of chronic and acute pathologies in the central nervous system (CNS) and greatly exacerbates neuronal degeneration. The proinflammatory cytokine tumor necrosis factor alpha (TNFα) plays a pivotal role in the initiation and progression of inflammatory processes provoking oxidative stress, eicosanoid biosynthesis, and the production of bioactive lipids. We established in neuronal cells that TNFα exposure dramatically increased Mg(2+)-dependent neutral sphingomyelinase (nSMase) activity thus generating the bioactive lipid mediator ceramide essential for subsequent NADPH oxidase (NOX) activation and oxidative stress. Since many of the pleiotropic effects of ceramide are attributable to its metabolites, we examined whether ceramide kinase (CerK), converting ceramide to ceramide-1-phosphate, is implicated both in NOX activation and enhanced eicosanoid production in neuronal cells. In the present study, we demonstrated that TNFα exposure of human SH-SY5Y neuroblastoma caused a profound increase in CerK activity. Depleting CerK activity using either siRNA or pharmacology completely negated NOX activation and eicosanoid biosynthesis yet, more importantly, rescued neuronal viability in the presence of TNFα. These findings provided evidence for a critical function of ceramide-1-phospate and thus CerK activity in directly linking sphingolipid metabolism to oxidative stress. This vital role of CerK in CNS inflammation could provide a novel therapeutic approach to intervene with the adverse consequences of a progressive CNS inflammation.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Fator de Necrose Tumoral alfa
/
Fosfotransferases (Aceptor do Grupo Álcool)
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NADPH Oxidases
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Neuroblastoma
Limite:
Humans
Idioma:
En
Revista:
Cell Signal
Ano de publicação:
2012
Tipo de documento:
Article