Tag Archives: urokinase

Fibrinolysis regulation by platelets retaining plasminogen and tissue-type plasminogen activator on their surface

T. Grinenko, О. Yusova, O. Revka, I. Patalakh, T. Yatsenko

Palladin Institute of Biochemistry, National Academy of Sciences of Ukraine, Kyiv;
e-mail: sedrickedel@gmail.com

Received: 22 July 2019; Accepted: 18 October 2019

Platelets play a key role in hemostasis as cofactors of thrombin generation, fibrin polymerization centers­, and initiators of clot retraction, while their ability to modulate clot dissolution remains less understood. The aim of this study was to investigate the interaction of plasminogen and tissue plasminogen activator with native and activated platelets, to determine the amount of plasmin generated by various activators in the presence of platelets, and the ability of platelets to modulate the rate of polymer fibrin hydrolysis. Spectrometric and immunofluorometric methods were used in the study. It was shown that intact circulating platelets carry a small amount of plasminogen on their surface, whereas thrombin-induced activation led to the exposure of plasminogen-binding sites on their plasma membrane. Activated platelets stimulated plasminogen activation by tissue plasminogen activator, urokinase, and streptokinase. Components of prothrombin complex enhanced plasminogen activation by tissue plasminogen activator on the surface of activated platelets. Model system with desAB-fibrin revealed the ability of platelets to stimulate fibrinolysis. These results suggest that the regulation of fibrinolysis by platelets is provided by the binding of plasminogen and plasminogen activators on their surface, acceleration of plasmin generation and, consequently, acceleration of the onset of fibrin lysis and reducing of the clot lifetime, which is important to maintain hemostatic balance.

Role of multidomain structure of urokinase in regulation of growth and remodeling of vessels

V. A. Tkachuk1,2, O. S. Plekhanova1, I. B. Beloglazova1, E. V. Parfenova1

1Russian Cardiologic Research-Production Complex,
RF Ministry of Public Health, Moscow, Russia;
2Faculty of Fundamental Medicine, M.V. Lomonosov Moscow
State University, Russia;
e-mail: plekhanova@mail.ru

Urokinase type plasminogen activator, or urokinase (uPA), is a multifunctional protein which plays special regulatory role in the vascular wall and can actuate the proteolytic and signal cascades. The authors’ results and literature data concerning the role of urokinase in remodeling blood vessels and angiogenesis are summarized in the paper. At the present stage urokinase may be conside­red as a promising target for the effects directed to prophylaxis of restenoses, to preventing of negative remodeling of arteries­, stimulation of vessels growth under the ischemic diseases and suppression of angiogenesis under oncologic diseases.