fMLP-induced arachidonic acid release in db-cAMP-differentiated HL-60 cells is independent of phosphatidylinositol-4, 5-bisphosphate-specific phospholipase C activation and cytosolic phospholipase A(2) activation

Autor: Frank Thévenod, Irene Schulz, Lutz Sternfeld
Rok vydání: 2000
Předmět:
Phosphatidylinositol 4
5-Diphosphate
Indoles
Time Factors
Phosphodiesterase Inhibitors
Phospholipase
Biochemistry
chemistry.chemical_compound
Cytosol
Phosphoinositide Phospholipase C
Enzyme Inhibitors
Estrenes
Phosphorylation
Egtazic Acid
Calcimycin
Arachidonic Acid
Norbornanes
Pyrrolidinones
N-Formylmethionine Leucyl-Phenylalanine
lipids (amino acids
peptides
and proteins)
Arachidonic acid
Bridged-Ring Compounds
Bacterial Toxins
Biophysics
HL-60 Cells
Arachidonic Acids
Biology
Models
Biological
Phospholipases A
Phospholipase A2
1-Butanol
Bacterial Proteins
Thiocarbamates
Phospholipase D
Humans
Molecular Biology
Protein kinase C
Arachidonyl trifluoromethyl ketone
Phospholipase A
Phospholipase C
Ionophores
Phosphoric Diester Hydrolases
Cell Membrane
Thiones
Molecular biology
Precipitin Tests
Enzyme Activation
chemistry
Bucladesine
Type C Phospholipases
biology.protein
Calcium
Zdroj: Archives of biochemistry and biophysics. 378(2)
ISSN: 0003-9861
Popis: In inflammatory cells, agonist-stimulated arachidonic acid (AA) release is thought to be induced by activation of group IV Ca(2+)-dependent cytosolic phospholipase A(2) (cPLA(2)) through mitogen-activated protein kinase (MAP kinase)- and/or protein kinase C (PKC)-mediated phosphorylation and Ca(2+)-dependent translocation of the enzyme to the membrane. Here we investigated the role of phospholipases in N-formylmethionyl-l-leucyl-l-phenylalanine (fMLP; 1 nM-10 microM)-induced AA release from neutrophil-like db-cAMP-differentiated HL-60 cells. U 73122 (1 microM), an inhibitor of phosphatidyl-inositol-4,5-biphosphate-specific phospholipase C, or the membrane-permeant Ca(2+)-chelator 1, 2-bis¿2-aminophenoxyĕthane-N,N,N',N'-tetraacetic acid (10 microM) abolished fMLP-mediated Ca(2+) signaling, but had no effect on fMLP-induced AA release. The protein kinase C-inhibitor Ro 318220 (5 microM) or the inhibitor of cPLA(2) arachidonyl trifluoromethyl ketone (AACOCF(3); 10-30 microM) did not inhibit fMLP-induced AA release. In contrast, AA release was stimulated by the Ca(2+) ionophore A23187 (10 microM) plus the PKC activator phorbol myristate acetate (PMA) (0.2 microM). This effect was inhibited by either Ro 318220 or AACOCF(3). Accordingly, a translocation of cPLA(2) from the cytosol to the membrane fraction was observed with A23187 + PMA, but not with fMLP. fMLP-mediated AA release therefore appeared to be independent of Ca(2+) signaling and PKC and MAP kinase activation. However, fMLP-mediated AA release was reduced by approximately 45% by Clostridium difficile toxin B (10 ng/ml) or by 1-butanol; both block phospholipase D (PLD) activity. The inhibitor of phosphatidylcholine-specific phospholipase C (PC-PLC), D609 (100 microM), decreased fMLP-mediated AA release by approximately 35%. The effect of D609 + 1-butanol on fMLP-induced AA release was additive and of a magnitude similar to that of propranolol (0.2 mM), an inhibitor of phosphatidic acid phosphohydrolase. This suggests that the bulk of AA generated by fMLP stimulation of db-cAMP-differentiated HL-60 cells is independent of the cPLA(2) pathway, but may originate from activation of PC-PLC and PLD.
Databáze: OpenAIRE
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