scholarly journals A Mosquito Salivary Protein Inhibits Activation of the Plasma Contact System by Binding to Factor XII and High Molecular Weight Kininogen

2002 ◽  
Vol 277 (31) ◽  
pp. 27651-27658 ◽  
Author(s):  
Haruhiko Isawa ◽  
Masao Yuda ◽  
Yuki Orito ◽  
Yasuo Chinzei
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Salivary Protein ◽  
Contact System ◽  
Factor Xii ◽  
High Molecular Weight Kininogen

Fibrinolysis and the Contact System: A Role for Factor XI in the Down-Regulation of Fibrinolysis

1999 ◽  
Vol 82 (08) ◽  
pp. 243-250 ◽  
Author(s):  
Joost Meijers ◽  
Bonno Bouma
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Fibrinolytic System ◽  
Contact System ◽  
Factor Xii ◽  
Charged Surface ◽  
High Molecular Weight Kininogen ◽  
Factor Xi ◽  
Factor Xiia

IntroductionExposure of blood to negatively-charged surfaces, such as collagen, kaolin, or glass, results in the activation of the contact system of the intrinsic pathway of coagulation. Prekallikrein, factor XII, high molecular weight kininogen, and factor XI are the proteins involved in this contact reaction. The assembly of these components on a negatively-charged surface leads to the activation of factor XI, thereby propagating the intrinsic coagulation pathway. Simultaneously, several other reactions occur, such as the activation of factor VII and the initiation of the fibrinolytic system, kinin-forming pathway, and renin-angiotensin pathway.The first step in the contact phase is to bind factor XII to the negatively-charged surface, making it highly susceptible for proteolysis by kallikrein.1-3 Activated factor XII (α-factor XIIa) is formed in a process that may involve autoactivation.4-7 Prekallikrein is bound to high molecular weight kininogen in plasma. High molecular weight kininogen associates with a negatively-charged surface, thereby localizing prekallikrein to the surface. Limited proteolysis by α-factor XIIa converts prekallikrein to kallikrein. Kallikrein can dissociate from the surface and act on surface-bound factor XII at distant sites, thereby propagating the reciprocal cycle.7 Factor XI circulates plasma in a complex with high molcular weight kininogen. High molecular weight kininogen links factor XI to a negatively charged surface where it is activated by surface bound:α-factor XIIa. Although the in vivo, activating, negatively-charged surface is unknown, assembly and activation of the contact system on biological membranes of endothelial cells, platelets, neutrophils, and monocytes can take place, suggesting that these surfaces are the actual activating surfaces in vivo.8 The physiological significance of the contact system in blood coagulation remains unclear, however, because a deficiency of factor XII, prekallikrein, and high molecular weight kininogen does not result in a bleeding disorder. In contrast, patients deficient in factor XI, most common among Ashkenazi Jews, do suffer from variable bleeding abnormalities, especially from tissues with high local fibrinolytic activity (e.g., urinary tract, nose, oral cavity, tonsils).9,10 This suggested that there was an alternative route for the activation of factor XI, and recently, such a route was described.11,12 Thrombin was found to activate factor XI even in the absence of a negatively-charged surface,11-15 and factor XI was shown to play a role in the downregulation of fibrinolysis.16 In this article, the role of the contact system, with an emphasis on factor XI in the regulation of the fibrinolytic system, will be described.

Effect of Heparin on the Activation of Factor XII and the Contact System in Plasma

1991 ◽  
Vol 66 (05) ◽  
pp. 540-547 ◽  
Author(s):  
Robin A Pixley ◽  
Anita Cassello ◽  
Raul A De La Cadena ◽  
Nathan Kaufman ◽  
Robert W Colman
Keyword(s):  
Molecular Weight ◽  
Human Plasma ◽  
High Molecular Weight ◽  
Anticoagulant Therapy ◽  
Human Factor ◽  
Dextran Sulfate ◽  
Contact System ◽  
Factor Xii ◽  
High Molecular Weight Kininogen

SummaryWe examined in purified systems and in human plasma whether heparin serves as a contact system activating compound. Purified human factor XII zymogen was not activated by heparin through an autoactivation mechanism, but was activated in the presence of purified prekallikrein. Zn2+ (12 εM) did not support autoactivation by heparin. The activation of factor XII and the contact system by heparin in plasma anticoagulated with citrate or with hirudin (not chelating ions) was examined by the cleavage of 125I-labeled factor XII and high molecular weight kininogen (HK). Heparin at 1.6 and 16 USP U/ml was not able to produce activation, in contrast to dextran sulfate (20 εg/ml) which supported activation of both factor XII and HK. This study indicates that heparinized plasma does not support activation of the contact system mediated through activation of factor XII. It is not expected that heparin anticoagulant therapy will contribute to activation of the contact system.

Factor XI and Protection of the Fibrin Clot against Lysis – a Role for the Intrinsic Pathway of Coagulation in Fibrinolysis

1998 ◽  
Vol 80 (07) ◽  
pp. 24-27 ◽  
Author(s):  
Peter von dem Borne ◽  
Joost Meijers ◽  
Bonno Bouma
Keyword(s):  
Molecular Weight ◽  
Blood Coagulation ◽  
High Molecular Weight ◽  
Fibrin Clot ◽  
Contact System ◽  
Activate Factor ◽  
Factor Xii ◽  
High Molecular Weight Kininogen ◽  
Intrinsic Pathway ◽  
Factor Xi

IntroducationBlood coagulation is an important mechanism that maintains the integrity of the vascular system to prevent blood loss after injury. The conceptions on the working mechanism of coagulation are based on the waterfall or cascade model, which was already proposed more than 30 years ago, independently by Davie and Ratnoff (1) and MacFarlane (2). Blood coagulation was viewed as a series of linked proteolytic reactions in which zymogens are converted into serine proteases, ultimately leading to the formation of thrombin, which converts soluble fibrinogen into insoluble fibrin. Coagulation was thought to proceed via two pathways, an extrinsic and an intrinsic pathway. Activation of the extrinsic pathway of coagulation occurs by the exposition of tissue factor at the site of injury (3) whereas the intrinsic system is activated after exposure of plasma to an activating surface. Although the in vivo activating surface is unknown, the contact system was believed to play a role in the initiation of the intrinsic pathway. This system consists of factor XII, prekallikrein, high molecular weight kininogen and factor XI. The physiological relevance of the contact system is unclear, since a deficiency of factor XII, prekallikrein or high molecular weight kininogen does not result in a bleeding disorder. In contrast, patients deficient in factor XI, most common among Ashkenazi Jews, do suffer from variable bleeding abnormalities especially from tissues with high local fibrinolytic activity (urinary tract, nose, oral cavity, tonsils) (4, 5). This suggested there was an alternative route for the activation of factor XI, and recently such a route was described (6, 7). Thrombin was found to activate factor XI, even in the absence of a negatively charged surface (6-11), and factor XI was shown to play a role in the protection of the fibrin clot against lysis (9). In plasma the possibility cannot be excluded that the activation of factor XI by thrombin takes place via an intermediary component. Recently, it was shown that meizothrombin was capable of activating factor XI (12).

The Contact Phase of Blood Coagulation in Diabetes Mellitus and in Patients with Vasculopathy

1984 ◽  
Vol 52 (03) ◽  
pp. 221-223 ◽  
Author(s):  
M Christe ◽  
P Gattlen ◽  
J Fritschi ◽  
B Lämmle ◽  
W Berger ◽  
...  
Keyword(s):  
Diabetes Mellitus ◽  
Molecular Weight ◽  
Blood Coagulation ◽  
High Molecular Weight ◽  
Negative Correlation ◽  
Factor Xii ◽  
C1 Inhibitor ◽  
High Molecular Weight Kininogen ◽  
Contact Phase ◽  
Α2 Macroglobulin

SummaryThe contact phase has been studied in diabetics and patients with macroangiopathy. Factor XII and high molecular weight kininogen (HMWK) are normal. C1-inhibitor and also α2-macroglobulin are significantly elevated in diabetics with complications, for α1-macroglobulin especially in patients with nephropathy, 137.5% ± 36.0 (p <0.001). C1-inhibitor is also increased in vasculopathy without diabetes 113.2 ± 22.1 (p <0.01).Prekallikrein (PK) is increased in all patients’ groups (Table 2) as compared to normals. PK is particularly high (134% ± 32) in 5 diabetics without macroangiopathy but with sensomotor neuropathy. This difference is remarkable because of the older age of diabetics and the negative correlation of PK with age in normals.

Interaction of high molecular weight kininogen binding proteins on endothelial cells

2004 ◽  
Vol 91 (01) ◽  
pp. 61-70 ◽  
Author(s):  
Baby Tholanikunnel ◽  
Berhane Ghebrehiwet ◽  
Allen Kaplan ◽  
Kusumam Joseph
Keyword(s):  
Molecular Weight ◽  
Endothelial Cell ◽  
High Molecular Weight ◽  
Gel Filtration ◽  
Surface Proteins ◽  
Factor Xii ◽  
High Molecular Weight Kininogen ◽  
Dot Blot ◽  
Cell Plasma ◽  
Molecular Weight Peak

SummaryCell surface proteins reported to participate in the binding and activation of the plasma kinin-forming cascade includes gC1qR, cytokeratin 1 and u-PAR. Each of these proteins binds high molecular weight kininogen (HK) as well as Factor XII. The studies on the interaction of these proteins, using dot-blot analysis, revealed that cytokeratin 1 binds to both gC1qR and u-PAR while gC1qR and u-PAR do not bind to each other. The binding properties of these proteins were further analyzed by gel filtration. When biotinylated cytokeratin 1 was incubated with either gC1qR or u-PAR and gel filtered, a new, higher molecular weight peak containing biotin was observed indicating complex formation. The protein shift was also similar to the biotin shift. Further, immunoprecipitation of solubilized endothelial cell plasma membrane proteins with anti-gC1qR recovered both gC1qR and cytokeratin 1, but not u-PAR. Immunoprecipitation with anti-u-PAR recovered only u-PAR and cytokeratin 1. By competitive ELISA, gC1qR inhibits u-PAR from binding to cytokeratin 1; u-PAR inhibits gC1qR binding to a lesser extent and requires a 10-fold molar excess. Our data suggest that formation of HK (and Factor XII) binding sites along endothelial cell membranes consists of bimolecular complexes of gC1qR-cytokeratin 1 and u-PAR-cytokeratin 1, with gC1qR binding being favored.

scholarly journals Interaction of high molecular weight kininogen, factor XII, and fibrinogen in plasma at interfaces

Blood ◽  
1980 ◽  
Vol 55 (1) ◽  
pp. 156-159 ◽  
Author(s):  
L Vroman ◽  
AL Adams ◽  
GC Fischer ◽  
PC Munoz
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Marked Change ◽  
Human Platelets ◽  
Blue Staining ◽  
Factor Xii ◽  
High Molecular Weight Kininogen ◽  
Contact Activation ◽  
Coomassie Blue Staining ◽  
Coated Surfaces

Abstract Using ellipsometry, anodized tantalum interference color, and Coomassie blue staining in conjunction with immunologic identification of proteins adsorbed at interfaces, we have previously found that fibrinogen is the main constituent deposited by plasma onto many man- made surfaces. However, the fibrinogen deposited from normal plasma onto glass and similar wettable materials is rapidly modified during contact activation until it can no longer be identified antigenically. In earlier publications, we have called this modification of the fibrinogen layer “conversion,” to indicate a process of unknown nature. Conversion of adsorbed fibrinogen by the plasma was not accompanied by marked change in film thickness, so that we presumed that this fibrinogen was not covered but replaced by other protein. Conversion is now showen to be markedly delayed in plasma lacking high molecular weight kininogen, slightly delayed in plasma lacking factor XII, and normal in plasma that lack factor XI or prekallikrein. We conclude that intact plasma will quickly replace the fibrinogen it has deposited on glass-like surfaces by high molecular weight kininogen and, to a smaller extent, by factor XII. Platelets adhere preferentially to fibrinogen-coated surfaces; human platelets adhere to hydrophobic nonactivating surfaces, since on these, adsorbed firbinogen is not exchanged by the plasma. The adsorbed fibrinogen will be replaced on glass-like surfaces during surface activation of clotting, and platelets failing to find fibrinogen will not adhere.

Intraindividual Comparison of the Impact of two Selective Apheresis Methods (DALI and HELP) on the Coagulation System

2000 ◽  
Vol 23 (3) ◽  
pp. 199-206 ◽  
Author(s):  
U. Julius ◽  
G. Siegert ◽  
S. Gromeier
Keyword(s):  
Molecular Weight ◽  
High Molecular Weight ◽  
Protein S ◽  
Binding Activity ◽  
Coagulation System ◽  
Factor Xii ◽  
High Molecular Weight Kininogen ◽  
Prothrombin Fragment ◽  
Intraindividual Comparison ◽  
The Impact

We performed an intraindividual comparison of the effect on the coagulation system of two selective apheresis procedures: Direct Adsorption of Lipoproteins (DALI) and Heparin-induced Lipoprotein Fibrinogen Precipitation (HELP). Six patients suffering from heterozygous familial hypercholesterolemia have been treated with 2 sessions of each procedure. Anticoagulation was carried out according to usual recommendations. Blood samples were taken before, immediately after and on the second day after the sessions. We assessed global coagulation tests (prothrombin time, activated partial thromboplastin time), fibrinogen, prothrombin fragment F 1 + 2 and a variety of factors (Factors II, V, VII, XIII, IX, X, XI, XII, XIIa; von Willebrand Factor; collagen-binding activity, prekallikrein, high-molecular weight kininogen) and antagonists (antithrombin III, protein S activity, free protein S). In fact, all parameters measured have been influenced by the apheresis treatment. Fibrinogen is lowered more by HELP, which also has a more definite impact on factors belonging to the prothrombin complex (II, VII, X). In contrast, the major effects of the DALI system have been seen on the intrinsic pathway of the coagulation system (IX, XI, prekallikrein, high-molecular-weight kininogen). With both systems, no increases in activated Factor XII or in prothrombin fragment F1 + 2 have been observed. These data provide a solid basis for individual adaptations of anticoagulant doses.

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