Functional role of p38 mitogen activated protein kinase in platelet activation induced by a thromboxane A2 analogue and by 8-iso-prostaglandin F2alpha.
We investigated similarities in the signaling pathways elicited by the F2 isoprostane 8-iso-PGF2alpha and by low doses of U46619 to induce platelet activation. Both 0.01-0.1 micromol/L U46619 and 0.01-1 micromol/L 8-iso-PGF2alpha triggered shape change and filopodia extension, as well as adhesion to immobilized fibrinogen of washed platelets. At these doses the two platelet agonists failed to trigger secretion and aggregation, which were however induced by higher doses of U46619 (0.1-1 micromol/L). SB203580 (1-10 micromol/L), a specific inhibitor of the p38 mitogen activated protein (MAP) kinase blunted platelet shape change and adhesion induced by 0.05-1 micromol/L 8-iso-PGF2alpha and by 0.01 micromol/L U46619. These platelet responses were also inhibited by 20 micromol/L cytochalasin D, an inhibitor of actin polymerization, and 50 micromol/L piceatannol, an inhibitor of the Syk tyrosine kinases. Both 8-iso-PGF2alpha and U46619-induced p38 MAP kinase phosphorylation in suspended platelets and this was inhibited by piceatannol, indicating that Syk activation occurs upstream of p38 MAP kinase phosphorylation. These findings suggest that the signaling pathway triggered by both 8-iso-PGFalpha and low concentrations of U46619 to induce platelet adhesion and shape change implicates Syk, the p38 MAP kinase, and actin polymerization.
Minuz
Pietro
P
Department of Biomedical and Surgical Sciences, Section of Internal Medicine, University of Verona, Italy. minuz@borgoroma.univr.it
Gaino
Stefania
S
Zuliani
Valeria
V
Tommasoli
Rosa Maria
RM
Benati
Donatella
D
Ortolani
Riccardo
R
Zancanaro
Carlo
C
Berton
Giorgio
G
Santonastaso
Clara Lechi
CL
D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid / Q000494:pharmacology*; D008841:Actin Cytoskeleton / Q000187:drug effects; D000199:Actins / Q000187:drug effects; D000328:Adult; D015703:Antigens, CD / Q000096:biosynthesis / Q000235:genetics; D001792:Blood Platelets / Q000187:drug effects / Q000201:enzymology* / Q000648:ultrastructure; D048429:Cell Size / Q000187:drug effects; D015638:Cytochalasin D / Q000494:pharmacology; D015237:Dinoprost / Q000031:analogs & derivatives*; D004789:Enzyme Activation; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004792:Enzyme Precursors / Q000037:antagonists & inhibitors / Q000502:physiology; D028441:F2-Isoprostanes / Q000494:pharmacology*; D006801:Humans; D007093:Imidazoles / Q000494:pharmacology; D039661:Integrin beta3; D047908:Intracellular Signaling Peptides and Proteins; D020935:MAP Kinase Signaling System / Q000187:drug effects / Q000502:physiology*; D008855:Microscopy, Electron, Scanning; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000502:physiology*; D019007:P-Selectin / Q000096:biosynthesis / Q000235:genetics; D015539:Platelet Activation / Q000187:drug effects*; D010973:Platelet Adhesiveness / Q000187:drug effects; D019039:Platelet Glycoprotein GPIIb-IIIa Complex / Q000096:biosynthesis / Q000235:genetics; D010980:Platelet Membrane Glycoproteins / Q000096:biosynthesis / Q000235:genetics; D011505:Protein-Tyrosine Kinases / Q000037:antagonists & inhibitors / Q000502:physiology; D011554:Pseudopodia / Q000187:drug effects / Q000648:ultrastructure; D011725:Pyridines / Q000494:pharmacology; D013267:Stilbenes / Q000494:pharmacology; D000072377:Syk Kinase; D013928:Thromboxane A2 / Q000031:analogs & derivatives; D048051:p38 Mitogen-Activated Protein Kinases
D000199:Actins; D015703:Antigens, CD; D004791:Enzyme Inhibitors; D004792:Enzyme Precursors; D028441:F2-Isoprostanes; D007093:Imidazoles; D039661:Integrin beta3; D047908:Intracellular Signaling Peptides and Proteins; D019007:P-Selectin; D019039:Platelet Glycoprotein GPIIb-IIIa Complex; D010980:Platelet Membrane Glycoproteins; D011725:Pyridines; D013267:Stilbenes; D015638:Cytochalasin D; C075750:8-epi-prostaglandin F2alpha; D013928:Thromboxane A2; C041525:3,3',4,5'-tetrahydroxystilbene; D019796:15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid; D015237:Dinoprost; D011505:Protein-Tyrosine Kinases; C000606896:SYK protein, human; D000072377:Syk Kinase; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases; C093642:SB 203580