Miroslava Požgajovà

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Integrin-mediated platelet adhesion and aggregation are essential for sealing injured blood vessels and preventing blood loss, and excessive platelet aggregation can initiate arterial thrombosis, causing heart attacks and stroke. To ensure that platelets aggregate only at injury sites, integrins on circulating platelets exist in a low-affinity state and(More)
Blood coagulation is thought to be initiated by plasma protease factor VIIa in complex with the membrane protein tissue factor. In contrast, coagulation factor XII (FXII)-mediated fibrin formation is not believed to play an important role for coagulation in vivo. We used FXII-deficient mice to study the contributions of FXII to thrombus formation in vivo.(More)
Platelets play a crucial role in the physiology of primary hemostasis and pathophysiologic processes such as arterial thrombosis. Accumulating evidence suggests a role of reactive oxygen species (ROSs) in platelet activation. Here we show that platelets activated with different agonists produced intracellular ROSs, which were reduced by reduced nicotinamide(More)
BACKGROUND Ischemic stroke is a frequent and serious disease with limited treatment options. Platelets can adhere to hypoxic cerebral endothelial cells by binding of their glycoprotein (GP) Ib receptor to von Willebrand factor. Exposure of subendothelial matrix proteins further facilitates firm attachment of platelets to the vessel wall by binding of(More)
Platelet activation at sites of vascular injury is triggered through different signaling pathways leading to activation of phospholipase (PL) Cβ or PLCγ2. Active PLCs trigger Ca2+ mobilization and entry, which is a prerequisite for adhesion, secretion, and thrombus formation. PLCβ isoenzymes are activated downstream of G protein-coupled receptors (GPCRs),(More)
Metastatic dissemination of cancer cells is the ultimate hallmark of malignancy and accounts for approximately 90% of human cancer deaths. We investigated the role of acid sphingomyelinase (Asm) in the hematogenous metastasis of melanoma cells. Intravenous injection of B16F10 melanoma cells into wild-type mice resulted in multiple lung metastases, while(More)
Platelet activation plays a central role in hemostasis and thrombosis. Many platelet agonists function through G-protein-coupled receptors. Epinephrine activates the alpha(2A)-adrenergic receptor (alpha(2A)) that couples to G(z) in platelets. Although alpha(2A) was originally cloned from platelets, its role in thrombosis and hemostasis is still unclear.(More)
Blood coagulation factor XII (FXII, Hageman factor) is a plasma serine protease which is autoactivated following contact with negatively charged surfaces in a reaction involving plasma kallikrein and high-molecular-weight kininogen (contact phase activation). Active FXII has the ability to initiate blood clotting via the intrinsic pathway of coagulation and(More)
Aspirin is effective in the therapy of cardiovascular diseases, because it causes acetylation of cyclooxygenase 1 (COX-1) leading to irreversible inhibition of platelets. Additional mechanisms can be suspected, because patients treated with other platelet COX inhibitors such as indomethacin do not display an increased bleeding tendency as observed for(More)
OBJECTIVE Collagen and thrombin are the strongest physiological platelet agonists, acting through different receptors, among which glycoprotein VI (GPVI) and protease-activated receptors, respectively, are the essential ones. In mice, targeting of GPVI with the monoclonal antibody JAQ1 induces depletion of the receptor from circulating platelets, resulting(More)