A downstream role for protein kinase Calpha in the cytosolic phospholipase A2-dependent protective signalling mediated by peroxynitrite in U937 cells.
Exposure to an otherwise non-toxic concentration of peroxynitrite (ONOO-) promotes toxicity in U937 cells supplemented with pharmacological inhibitors of protein kinase C (PKC). This effect is not associated with enhanced formation of H2O2 and is in fact causally linked to inhibition of the cytoprotective signalling driven by endogenous arachidonic acid (AA). The outcome of various approaches using PKC or phospholipase A2 inhibitors, cytosolic phospholipase A2 or PKCalpha antisense-oligonucleotide-transfected cells and supplementation with exogenous AA or tetradecanoylphorbol acetate, as well as PKC down-regulated cells, indicated that ONOO- promotes AA-dependent cytosol to membrane translocation of PKCalpha, an event critical for the cytoprotective signalling under investigation. Evidence for a similar mechanism regulating survival of human monocytes exposed to ONOO- is also presented. These results, along with our previous work on this topic, contribute to the definition of the mechanism whereby monocytes survive to ONOO- in inflamed tissues.
Guidarelli
Andrea
A
Istituto di Farmacologia e Farmacognosia, Università degli Studi di Urbino "Carlo Bo", Via S. Chiara, 27-61029 Urbino (PU), Italy.
Cerioni
Liana
L
Tommasini
Ilaria
I
Brüne
Bernhard
B
Cantoni
Orazio
O
D016718:Arachidonic Acid / Q000494:pharmacology; D015153:Blotting, Western; D016923:Cell Death / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D003600:Cytosol / Q000187:drug effects / Q000201:enzymology; D015536:Down-Regulation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005452:Fluoresceins / Q000494:pharmacology; D005456:Fluorescent Dyes / Q000494:pharmacology; D006801:Humans; D007150:Immunohistochemistry; D007963:Leukocytes, Mononuclear / Q000187:drug effects; D016376:Oligonucleotides, Antisense / Q000494:pharmacology; D030421:Peroxynitrous Acid / Q000494:pharmacology*; D010741:Phospholipases A / Q000037:antagonists & inhibitors* / Q000378:metabolism; D054467:Phospholipases A2; D011493:Protein Kinase C / Q000378:metabolism*; D051571:Protein Kinase C-alpha; D020112:Rhodamine 123 / Q000494:pharmacology; D015398:Signal Transduction; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014162:Transfection; D014316:Tritium; D014407:Tumor Cells, Cultured; D020298:U937 Cells
D004791:Enzyme Inhibitors; D005452:Fluoresceins; D005456:Fluorescent Dyes; D016376:Oligonucleotides, Antisense; D014316:Tritium; D030421:Peroxynitrous Acid; D020112:Rhodamine 123; D016718:Arachidonic Acid; C496628:PRKCA protein, human; D011493:Protein Kinase C; D051571:Protein Kinase C-alpha; D010741:Phospholipases A; D054467:Phospholipases A2; D013755:Tetradecanoylphorbol Acetate; C007740:fluorexon