Effect of selective inhibition of the p38 MAP kinase pathway on platelet aggregation

Athan Kuliopulos; Ramon Mohanlal; Lidija Covic

doi:10.1160/TH04-03-0187

Thrombosis and Haemostasis, Inhaltsverzeichnis

Thromb Haemost 2004; 92(06): 1387-1393
DOI: 10.1160/TH04-03-0187

Platelets and Blood Cells

Schattauer GmbH

Effect of selective inhibition of the p38 MAP kinase pathway on platelet aggregation

Athan Kuliopulos

¹Division of Hematology/Oncology, Molecular Oncology Research Institute, New England Medical Center and Departments of Medicine and Biochemistry Tufts University School of Medicine, Boston, Massachusetts, USA

,

Ramon Mohanlal

²Vertex Pharmaceutical Company, Inc., Cambridge, Massachusetts, USA

,

Lidija Covic

¹Division of Hematology/Oncology, Molecular Oncology Research Institute, New England Medical Center and Departments of Medicine and Biochemistry Tufts University School of Medicine, Boston, Massachusetts, USA

› Institutsangaben

Abstract

Summary

Systemic inflammation has been shown to be a contributing factor to the instability of atherosclerotic plaques in patients with acute coronary syndromes (ACS). VX-702, a novel p38 mitogen-activated protein kinase (MAPK) inhibitor, is currently under investigation in ACS patients with unstable angina to evaluate its safety and efficacy during percutaneous coronary intervention (PCI).The role of p38 MAPK in platelet aggregation of normal individuals was examined using the selective second generation p38 MAPK inhibitor VX-702. Treatment of platelets with thrombin (activates PAR1 and PAR4 thrombin receptors), SFLLRN (PAR1), AYPGKF (PAR4), collagen (α2β1 and GPVI/FCγIIR receptors) and U46619 (TXA₂) resulted in strong activation of p38 MAPK. Activation of the GPIb von Willebrand factor receptor with ristocetin did not stimulate p38 MAPK. Pre-treatment of platelets with 1 μM VX-702 completely inhibited activation of p38 MAPK by thrombin, SFLLRN, AYPGKF, U46619, and collagen. There was no effect of VX-702 on platelet aggregation induced by any of the agonists in the presence or absence of aspirin, heparin or apyrase. It has been postulated that a potential role of p38 MAPK is to activate phospholipase A₂ (cPLA₂) which catalyses formation of arachidonic acid leading to production of thromboxane. Interestingly, we show contrasting effects of p38 MAPK inhibition as compared to aspirin inhibition on platelet aggregation in response to collagen. Blockade of TXA₂ production by aspirin results in significant inhibition of collagen activation. However, VX-702 has no effect on collagen-mediated platelet aggregation, suggesting that blocking p38 MAPK does not effect thromboxane production in human platelets. Therefore, unlike aspirin blockade of thromboxane production in platelets, p38 MAPK inhibitors such as VX-702 do not significantly affect platelet function and would not be expected to contribute to an elevated risk of bleeding side-effects in treated patients.

Keywords

p38 MAPK - platelet function - aspirin

Volltext

Referenzen

References
1 Lee JC, Laydon JT, McDonnell PC. et al. A protein kinase involved in the regulation of inflammatory cytokine biosynthesis. Nature 1994; 372: 739-46.
2 Han J, Lee JD, Bibbs L. et al. A MAP kinase targeted by endotoxin and hyperosmolarity in mammalian cells. Science 1994; 265: 808-11.
3 Rouse J, Cohen P, Trigon S. et al. A novel kinase cascade triggered by stress and heat shock that stimulates MAPKAP kinase-2 and phosphorylation of the small heat shock proteins. Cell 1994; 78: 1027-37.
4 Jiang Y, Chen C, Li Z. Guo et al. Characterization of the structure and function of a new mitogen-activated protein kinase (p38beta). J Biol Chem 1996; 271: 17920-6.
5 Jiang Y, Gram H, Zhao M. et al. Characterization of the structure and function of the fourth member of p38 group mitogenactivated protein kinases, p38delta. J Biol Chem 1997; 272: 30122-8.
6 Young PR, McLaughlin MM, Kumar S. et al. Pyridinyl imidazole inhibitors of p38 mitogenactivated protein kinase bind in the ATP site. 1997; 272: 12116-21.
7 Lee JC, Kumar S, Griswold DE. et al. Inhibition of p38 MAP kinase as a therapeutic strategy. Immunopharmacology 2000; 47: 185-201.
8 Kumar S, McDonnell PC, Gum RJ. et al. Novel homologues of CSBP/p38 MAP kinase: activation, substrate specificity and sensitivity to inhibition by pyridinyl imidazoles. Biochem Biophys Res Commun 1997; 235: 533-8.
9 Wilson KP, Fitzgibbon MJ, Caron PR. et al. Crystal structure of p38 mitogen-activated protein kinase. J Biol Chem 1996; 271: 27696-700.
10 Wang Z, Harkins Ulevitch PC, Han RJ. et al. The structure of mitogen-activated protein kinase p38 at 2.1-A resolution. Proc Natl Acad Sci U S A 1997; 94: 2327-32.
11 Borsch-Haubold AG, Ghomashchi F, Pasquet S. et al. Phosphorylation of cytosolic phospholipase A2 in platelets is mediated by multiple stress-activated protein kinase pathways. Eur J Biochem 1999; 265: 195-203.
12 Kramer RM, Roberts EF, Strifler BA. et al. Thrombin induces activation of p38 MAP kinase in human platelets. J Biol Chem 1995; 270: 27395-8.
13 Kramer RM, Roberts EF, Um SL. et al. p38 Mitogen-activated Protein Kinase Phosphorylates Cytosolic Phospholipase A2 (cPLA2) in Thrombin-stimulated Platelets. J Biol Chem 1996; 271: 27723-9.
14 Dangelmaier C, Jin J, Daniel JL. et al. The P2Y1 receptor mediates ADP-induced p38 kinase-activating factor generation in human platelets. Eur J Biochem 2000; 267: 2283-9.
15 Saklatvala J, Rawlinson L, Waller RJ. et al. Role for p38 mitogen-activated protein kinase in platelet aggregation caused by collagen or a thromboxane analogue. J Biol Chem 1996; 271: 6586-9.
16 Covic L, Gresser AL, Kuliopulos A. Biphasic Kinetics of Activation and Signaling for PAR1 and PAR4 Thrombin Receptors in Platelets. Biochemistry 2000; 39: 5458-67.
17 Laemmli UK. Cleavage of structural proteins during the assembly of the head of bacteriophage T4. Nature 1970; 227: 680-5.
18 Song S, Freedman J, Mody M, Lazarus AH. p38 MAPK is activated but not necessary in porcine von Willebrand factor-dependent platelet activation. Br J Haematol 1999; 107: 532-38.
19 Vu T-KH, DT Hung, Wheaton VI. et al. Molecular Cloning of a Functional Thrombin Receptor Reveals a Novel Proteolytic Mechanism of Receptor Action. Cell 1991; 64: 1057-68.
20 Xu W-F, Andersen H, Whitmore TE. et al. Cloning and characterization of human protease-activated receptor 4. Proc Natl Acad Sci USA 1998; 95: 6642-6.
21 Kahn ML, Zheng Y-W, Huang W. et al. A dual thrombin receptor system for platelet activation. Nature 1998; 394: 690-4.
22 Covic L, Singh C, Smith H. et al. Role of the PAR4 Thrombin Receptor in Stabilizing Platelet-Platelet Aggregates as revealed by a Patient with Hermansky-Pudlak Syndrome. Thromb Haemost 2002; 87: 722-7.
23 Lee DS, Bhatt DL, Moliterno DJ. et al. The combination of enoxaparin, glycoprotein IIb/IIIa inhibitors and an early invasive approach among acute coronary syndrome patients. J Invasive Cardiol 2004; 16: 46-51.
24 Jin J, Quinton TM, Zhang J. et al. Adenosine diphosphate (ADP)-induced thromboxane A(2) generation in human platelets requires coordinated signaling through integrin alpha(IIb)beta(3) and ADP receptors. Blood 2002; 99: 193-8.
25 Andre P, Delaney SM, LaRocca T. et al. P2Y12 regulates platelet adhesion/activation, thrombus growth, and thrombus stability in injured arteries. J Clin Invest 2003; 112: 398-406.