The role of diacylglyceride generation by phospholipase D and phosphatidic acid phosphatase in the activation of 5-lipoxygenase in polymorphonuclear leukocytes.
J Leukoc Biol
; 83(4): 1019-27, 2008 Apr.
Article
em En
| MEDLINE
| ID: mdl-18218859
ABSTRACT
Diacylglycerides (DAGs) such as 1-oleoyl-2-acetyl-sn-glycerol (OAG) stimulate 5-lipoxygenase (5-LO) enzyme activity and function as agonists for human polymorphonuclear leukocytes (PMNL) to induce 5-LO product synthesis. Here, we addressed the role of endogenous DAG generation in agonist-induced 5-LO activation in human PMNL. Preincubation of PMNL with the phospholipase D (PLD) inhibitor 1-butanol potently suppressed 5-LO product synthesis induced by the Ca(2)(+) ionophore A23187 or thapsigargin (TG) and blocked A23187-evoked translocation of 5-LO from the cytosol to the nuclear membrane, analyzed by subcellular fractionation as well as by indirect immunofluorescence microscopy. Tertiary-butanol, a rather poor inhibitor of PLD, caused only moderate suppression of 5-LO and hardly inhibited 5-LO translocation. Interestingly, 1-butanol failed to inhibit 5-LO product formation when PMNL were stimulated with OAG (30 microM). Moreover, coincubation of A23187- or TG-stimulated PMNL with OAG reversed inhibition of 5-LO product formation by 1-butanol in a concentration-dependent manner (EC(50), approximately 1 muM) and also restored 5-LO translocation. In addition, inhibition of phosphatidic acid phosphatase (PA-P) by propranolol or bromoenol lactone caused suppression of 5-LO product formation and of translocation, which could be reversed by addition of exogenous OAG. Together, our data suggest that in agonist-stimulated PMNL, the endogenous formation of DAGs via the PLD/PA-P pathway determines 5-LO activation.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Fosfolipase D
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Araquidonato 5-Lipoxigenase
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Fosfatidato Fosfatase
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Diglicerídeos
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Neutrófilos
Limite:
Adult
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Humans
Idioma:
En
Ano de publicação:
2008
Tipo de documento:
Article