MATHEMATICAL MODEL FOR THE CENTRAL REACTION OF PROTEIN C IN BLOOD COAGULATION CASCADE

2019 ◽  
Vol 101 (1) ◽  
pp. 1-17
Author(s):  
Chuanqing Xu ◽  
Yejuan Feng ◽  
Dashun Xu
2008 ◽  
Vol 389 (8) ◽  
Author(s):  
James A. Huntington

Abstract Thrombin is the ultimate coagulation factor; it is the final protease generated in the blood coagulation cascade and is the effector of clot formation. Regulation of thrombin activity is thus of great relevance to determining the correct haemostatic balance, with dysregulation leading to bleeding or thrombosis. One of the most enigmatic and controversial regulators of thrombin activity is the monovalent cation Na+. When bound to Na+, thrombin adopts a ‘fast’ conformation which cleaves all procoagulant substrates more rapidly, and when free of Na+, thrombin reverts to a ‘slow’ state which preferentially activates the protein C anticoagulant pathway. Thus, Na+-binding allosterically modulates the activity of thrombin and helps determine the haemostatic balance. Over the last 30 years, there has been much research investigating the structural basis of thrombin allostery. Biochemical and mutagenesis studies established which regions and residues are involved in the slow→fast conformational change, and recently several crystal structures of the putative slow form have been solved. In this article, the biochemical and crystallographic data are reviewed to see if we are any closer to understanding the conformational basis of the Na+ activation of thrombin.


1999 ◽  
Vol 82 (08) ◽  
pp. 718-721 ◽  
Author(s):  
Ikuro Maruyama

IntroductionThe blood coagulation cascade is regulated by the luminal surface of the endothelial cell lining.1 Endothelial cells synthesize tissue factor pathway inhibitor (TFPI), which, in part, binds to the cell surface glycosaminoglycans and inhibits factors Xa, VIIa, and tissue factor.2 Endothelial cells also produce and exhibit thrombomodulin (TM) on their luminal surface.3 TM is a kind of thrombin receptor that forms a 1:1 complex with thrombin. In this complex, thrombin activates protein C (PC) more than 1,000-fold more than thrombin alone. TM then loses its procoagulant activities, which include fibrinogen clotting, activation of factors V and VIII, and platelet activation. Thus, TM converts thrombin from a procoagulant protease to an anticoagulant. Pathologic states, such as an endothelial injury or perturbation or continuous rapid coagulation cascade activation, overcomes the endothelial regulating activity, resulting in the development of intravascular coagulation and the induction of disseminated intravascular coagulation (DIC). Theoretically, then, supplementing soluble TM or activated PC (APC) to reconstitute the endothelial coagulation regulation system in the circulation and regulate pathologically-activated blood coagulation could be beneficial. In this chapter, application of soluble TM and APC in the treatment of DIC is reviewed.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
PEYRAFITTE MARIE ◽  
VISSAC MARIE ◽  
AMIRAL JEAN

Coagulation Factor V (FV) is a key factor for regulating blood coagulation cascade, and it acts at the crossroads of the intrinsic and extrinsic pathways. It shows a dual activity as the procoagulant cofactor for Factor Xa in the prothrombinase complex, but it also supports an anticoagulant activity in combination with TFPI and Protein S. Its rapid cleavage by Activated Protein C (APC) complexed with Free Protein S (FPS), in presence of phospholipids and calcium, inhibits its activity and limits the propagation of blood coagulation, keeping it to where it is beneficial. Rapid inactivation of active FV by APC-FPS is essential for preventing the risk of thrombosis development. In 1993, Dahlbäck and coworkers reported an inherited disorder characterized by activated protein C resistance (APC-R) and associated to an increased occurrence of thromboembolic events in affected families. In 1994 Bertina demonstrated that this diathesis resulted from a Factor V mutation (R506Q), rendering this factor resistant to inactivation by APC. This mutated Factor V was called Factor V Leiden (FV-L). APTT based assays and molecular biology methods for detecting the mutation were developed, but these methods are only qualitative and classify tested individuals as normals, heterozygous or homozygous for the coagulation defect. Our group developed a quantitative assay for FV-L, which is described in this report, along with its performances. This assay allows to quantitate specifically FV-L coagulant activity, and to graduate its amount in heterozygous or homozygous patients. FV-L is absent in normal individuals and present in homozygous or heterozygous patients, accounting respectively for 100 % or 50 % of blood FV. Its amount is compared with FV clotting activity or antigenic concentration. Measured FV-L activities overlap between heterozygous patients with high FV and homozygous ones with low FV levels. This assay allows to better discriminate for the FV-L associated thrombotic risk, which depends on the effective FV-L concentration rather than on patients’ genetic status. This expectation is supported by literature review, which shows that FV-L concentrations correlate with presence of platelet released microparticles in patients carrying that mutation.


2020 ◽  
Vol 26 (18) ◽  
pp. 2109-2115 ◽  
Author(s):  
Mikhail A. Panteleev ◽  
Anna A. Andreeva ◽  
Alexey I. Lobanov

Discovery and selection of the potential targets are some of the important issues in pharmacology. Even when all the reactions and the proteins in a biological network are known, how does one choose the optimal target? Here, we review and discuss the application of the computational methods to address this problem using the blood coagulation cascade as an example. The problem of correct antithrombotic targeting is critical for this system because, although several anticoagulants are currently available, all of them are associated with bleeding risks. The advantages and the drawbacks of different sensitivity analysis strategies are considered, focusing on the approaches that emphasize: 1) the functional modularity and the multi-tasking nature of this biological network; and 2) the need to normalize hemostasis during the anticoagulation therapy rather than completely suppress it. To illustrate this effect, we show the possibility of the differential regulation of lag time and endogenous thrombin potential in the thrombin generation. These methods allow to identify the elements in the blood coagulation cascade that may serve as the targets for the differential regulation of this system.


1987 ◽  
Author(s):  
H J Hassan ◽  
A Leonardi ◽  
C Chelucci ◽  
R Guerriero ◽  
P M Mannucci ◽  
...  

We have analyzed the expression of several blood coagulation factors (IX, VIII, X, fibrinogen chains) and inhibitors (antithrombin III, protein C) in human embryonic and fetal livers, obtained from legal abortions at 6-11 week post-conception. The age was established by morphologic staging and particularly crown-rump lenght measurement.Total cellular RNA was isolated from partially purified hepatocytes or total liver homogenate using the guanidine isothiocyanate method. Poly(A)+ RNA was selected by oligodT cellulose chromatography. The size and the number of the embryonic and fetal transcripts are equivalent to those observed in adult liver, as evaluated by Northern blot analysis of total or poly(A)+ RNA hybridized to human cDNA probes.The level of coagulation factor transcripts in embryonic and fetal liver was evaluated by dot hybridization of total RNA (0.5-10 ug), as compared to RNA extracted from normal adult liver biopsies. The expression of blood coagulation factors in embryos is generally reduced for all factors, but at a different degree. In 5-11 wk liver, the level of factor IX is 5-10% of that observed in adults, while fibrinogen, protein C, antithrombin III RNA level rises from 25 to 50% and factor X is expressed at a level comparable to that observed in adult liver.We conclude that during these stages of development blood coagulation factors are expressed according to three different time, curves, possibly due to the effect of different types of regulatory mechanisms.


Blood ◽  
2020 ◽  
Vol 136 (Supplement 1) ◽  
pp. 22-22
Author(s):  
Chia-Jui Ku ◽  
Steven Grzegorski ◽  
Jordan A. Shavit

Hemostasis is a natural protective process that developed to retain a circulating blood system, conferred by a complicated yet sophisticated balance of factors. Disturbances of this network result in thrombosis or hemorrhage. Among many well-characterized coagulation factors, protein C (PC) exhibits multifunctional roles including anticoagulant, cytoprotective, and anti-inflammatory activities. The importance of PC has been demonstrated not only by the increased risk of venous thrombosis in individuals with heterozygous deficiency, but also the observed neonatal lethality in patients. Knockout mice exhibit similar neonatal lethality, which has made it difficult to further study complete deficiency. The zebrafish is a vertebrate organism that is characterized by a powerful genetic system, prolific breeding, rapid and transparent development, and a well described and highly conserved coagulation cascade. Here we utilize genome editing to generate a null allele of the PC gene (proc) in zebrafish and discover that its loss not only impairs hemostatic balance, but also affects neutrophil recruitment to sites of tissue injury. Through examination of publicly available zebrafish genome sequence, we determined that the proc locus is duplicated in tandem, resulting in two closely adjacent copies with nearly identical sequences. We used CRISPR/Cas9 with two single guide RNAs flanking the entire locus to produce a 17.3 kilobase deletion that knocks out both copies of proc to produce a complete null mutation, verified by sequencing and quantitative PCR. proc-/- mutants survived well into adulthood, with ~50% lethality by seven months of age. The embryonic survival and accessibility enabled us to perform intravital microscopy to evaluate the hemostatic effects of PC deficiency. We used laser-induced endothelial injury on the posterior cardinal vein (PCV) at 3 days post fertilization (dpf), which typically results in rapid formation of an occlusive fibrin-rich thrombus. proc-/- mutants had an average time to occlusion of 60 seconds versus 13 seconds in controls (p < 0.0001), consistent with a consumptive coagulopathy, as previously seen in antithrombin III (at3) mutants. A transgenic background with fluorescently labeled fibrinogen showed that more than 95% of proc-/- mutants had spontaneous thrombi in the PCV, which was not present in controls. To assess the role of PC in inflammation, we used two different injury strategies, non-vascular tail transection and chemical treatment (copper sulfate), on 3 dpf zebrafish larvae. Staining for neutrophil granules revealed homing to the site of injury within 60-75 minutes. In proc-/- mutants we found an average 50% reduction in the number of neutrophils recruited to the site of injury yet counts in the caudal hematopoietic tissue (the site of larval hematopoiesis) were unchanged. Since protein S (PS) is a cofactor for PC anticoagulant function, we hypothesized that the consumptive coagulopathy, but not the neutrophil recruitment, would be PS-dependent. We used genome editing to disrupt the PS gene (pros1) and found that loss of PS also results in a mild consumptive coagulopathy, but spontaneous thrombus formation was less common in the PCV (25%) and was often in the heart instead (80%). Neutrophil recruitment was unaffected in pros1 mutants, and evaluation of double proc/pros1 mutants revealed no synergy in any of the phenotypes. In conclusion, PC and PS deficiency in zebrafish show some similarity to our previously reported model of AT3 deficiency, but the effects are less potent, allowing robust survival that enables in vivo analyses. Our data suggest that the thrombotic phenotypes of PC and PS deficiency are not identical, and display tissue-specific phenotypes. We also found evidence for PS-independent functions of PC in neutrophil migration. We speculate this is due to the role that PC plays in inflammation and signaling but cannot exclude a role in neutrophil extracellular trap (NET) formation. This model of complete proc-/- deficiency in an accessible organism will facilitate further in vivo study of PS-dependent and independent functions of PC, as well as interplay between the two factors. Disclosures Shavit: Bayer: Consultancy; Taked: Consultancy.


Blood ◽  
2003 ◽  
Vol 101 (12) ◽  
pp. 4802-4807 ◽  
Author(s):  
Chandrashekhara Manithody ◽  
Philip J. Fay ◽  
Alireza R. Rezaie

AbstractActivated protein C (APC) is a natural anticoagulant serine protease in plasma that down-regulates the coagulation cascade by degrading cofactors Va and VIIIa by limited proteolysis. Recent results have indicated that basic residues of 2 surface loops known as the 39-loop (Lys37-Lys39) and the Ca2+-binding 70-80–loop (Arg74 and Arg75) are critical for the anticoagulant function of APC. Kinetics of factor Va degradation by APC mutants in purified systems have demonstrated that basic residues of these loops are involved in determination of the cleavage specificity of the Arg506 scissile bond on the A2 domain of factor Va. In this study, we characterized the properties of the same exosite mutants of APC with respect to their ability to interact with factor VIIIa. Time course of the factor VIIIa degradation by APC mutants suggested that the same basic residues of APC are also critical for recognition and degradation of factor VIIIa. Sodium dodecyl sulfate–polyacrylamide gel electrophoresis (SDS-PAGE) of the factor VIIIa cleavage reactions revealed that these residues are involved in determination of the specificity of both A1 and A2 subunits in factor VIIIa, thus facilitating the cleavages of both Arg336 and Arg562 scissile bonds in the cofactor.


2022 ◽  
Vol 8 ◽  
Author(s):  
Eizo Watanabe ◽  
Osamu Takasu ◽  
Youichi Teratake ◽  
Teruo Sakamoto ◽  
Toshiaki Ikeda ◽  
...  

Objective: Disseminated intravascular coagulation plays a key role in the pathophysiology of sepsis. Thrombomodulin is essential in the protein C system of coagulation cascade, and functional polymorphisms influence the human thrombomodulin gene (THBD). Therefore, we conducted a multicenter study to evaluate the influence of such polymorphisms on the pathophysiology of sepsis.Methods: A collaborative case-control study in the intensive care unit (ICU) of each of five tertiary emergency centers. The study included 259 patients (of whom 125 displayed severe sepsis), who were admitted to the ICU of Chiba University Hospital, Chiba, Japan between October 2001 and September 2008 (discovery cohort) and 793 patients (of whom 271 patients displayed severe sepsis), who were admitted to the five ICUs between October 2008 and September 2012 (multicenter validation cohort). To assess the susceptibility to severe sepsis, we further selected 222 critically ill patients from the validation cohort matched for age, gender, morbidity, and severity with the patients with severe sepsis, but without any evidence of sepsis.Results: We examined whether the eight THBD single nucleotide polymorphisms (SNPs) were associated with susceptibility to and/or mortality of sepsis. Higher mortality on severe sepsis in the discovery and combined cohorts was significantly associated with the CC genotype in a THBD promoter SNP (−1920*C/G; rs2239562) [odds ratio [OR] 2.709 (1.067–6.877), P = 0.033 and OR 1.768 (1.060–2.949), P = 0.028]. Furthermore, rs2239562 SNP was associated with susceptibility to severe sepsis [OR 1.593 (1.086–2.338), P = 0.017].Conclusions: The data demonstrate that rs2239562, the THBD promoter SNP influences both the outcome and susceptibility to severe sepsis.


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