Protective Effect of Activated Protein C in Murine Endotoxemia: Mechanism of Action.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 26-26 ◽  
Author(s):  
Edward J. Kerschen ◽  
Brian C. Cooley ◽  
Francis J. Castellino ◽  
John H. Griffin ◽  
Hartmut Weiler
Keyword(s):  
Mouse Model ◽  
Protective Effect ◽  
Therapeutic Efficacy ◽  
Protein C ◽  
Activated Protein C ◽  
Coagulation Factor ◽  
Factor V ◽  
Wild Type ◽  
Endothelial Protein C Receptor ◽  
Genetically Engineered Mice

Abstract Recombinant activated protein C (APC) reduces mortality of patients with severe inflammatory disease associated with multi-organ failure. APC exerts anticoagulant, anti-inflammatory, and cytoprotective effects. The contribution of these distinct APC activities to the overall therapeutic efficacy in septic patients is unknown. The aim of the study is to delineate the mechanism underlying the protective effect of APC in mouse endotoxemia. We first establish an experimental mouse model to demonstrate that recombinant murine APC reduces 6 day mortality of mice subjected to LPS-induced endotoxemia. APC treatment did not alter the extent of inflammatory cytokine release. Recombinant human APC did not exhibit therapeutic efficacy in this model. In contrast, recombinant human and mouse APC reduced to a similar extent experimentally induced arterial thrombus formation. The therapeutic efficacy of wild type recombinant murine APC was abolished in genetically engineered mice with reduced expression of the endothelial protein C receptor (EPCR). Recombinant mutant murine APC with greatly reduced anticoagulant potency was as effective as wild type murine APC in reducing mortality of mice subjected to LPS-induced septicemia. Mice homozygous for the Leiden polymorphism in the factor V (fV) gene, which renders coagulation factor V partially resistant to the anticoagulant effect of APC secondary to blocked fV proteolysis at R504 (R506 in humans), were refractory to the therapeutic benefit conveyed by administration of recombinant wild type mouse APC. In summary, these findings provide evidence that the therapeutic efficacy of recombinant APC is predominantly based on the ability of APC to interact with the endothelial protein C receptor, and that the anticoagulant activity of APC is not sufficient for achieving protection against mortality in a mouse model of endotoxemia. On the other hand, cleavage of fV at R506 appears necessary for retaining therapeutic efficacy in carriers of the fV Leiden allele.

Coagulation Factor V Leiden Mutation Was Detected in the Patients with Activated Protein C Resistance in Thailand

1998 ◽  
Vol 80 (08) ◽  
pp. 344-345 ◽  
Author(s):  
Pasra Arnutti ◽  
Motofumi Hiyoshi ◽  
Wichai Prayoonwiwat ◽  
Oytip Nathalang ◽  
Chamaiporn Suwanasophon ◽  
...  
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Coagulation Factor ◽  
Factor V ◽  
Activated Protein C Resistance ◽  
Factor V Leiden Mutation ◽  
Coagulation Factor V

The A6936G polymorphism of the endothelial protein C receptor gene is associated with the risk of unexplained foetal loss in Mediterranean European couples

2009 ◽  
Vol 102 (10) ◽  
pp. 656-667 ◽  
Author(s):  
Pascale Fabbro-Peray ◽  
Pierre Marès ◽  
Patrick Mismetti ◽  
Géraldine Lissalde-Lavigne ◽  
Éva Cochery-Nouvellon ◽  
...  
Keyword(s):  
Protein C ◽  
Pregnancy Loss ◽  
Receptor Gene ◽  
Coagulation Factor ◽  
Factor V ◽  
Endothelial Protein C Receptor ◽  
Foetal Loss ◽  
Factor Ii ◽  
Embryonic Loss ◽  
Factor V Gene

SummaryThe endothelial protein C receptor (EPCR) is expressed by trophoblast cells. Mid-gestation pregnancy loss is described in animals with a haemochorial placenta lacking EPCR. The A6936G allele of the EPCR gene (PROCR) may be associated with lower EPCR densities on trophoblasts, but data are lacking for its effect on the risk of pregnancy loss in humans. A 1:2 case-control study on unexplained pregnancy loss was nested in the NOHA First cohort: 3,218 case couples and 6,436 control couples were studied for PROCR A6936G, coagulation factor V gene (F5) G1691A and coagulation factor II gene (F2) G20210A polymorphisms. Ethnicity and time of pregnancy loss defined through biometry-based gestational ages (embryonic loss < 10th week ≥ foetal loss) were analysed. The PROCR A6936G allele, in mothers and fathers, was associated only with foetal loss in both Europeans and non-Europeans. Increasing probability levels of carrying a homozygous child were increasingly associated with the risk of foetal demise. The F5 G1691A and F2 G20210A alleles, only in mothers, were only and independently associated with foetal loss in Europeans. In our population, the PROCR A6936G allele describes women, but also men and thus couples, at risk for first unexplained foetal loss. This risk is independent of the foetal loss risk conferred to our local Mediterranean European women by the F5 G1691A and F2 G20210A alleles. Data confirm that the relationship between thrombophilias and pregnancy loss varies according to ethnicity and loss type.

Activated Protein C Strengthens Cardiac Tolerance to Ischemic Insults in Aging

2021 ◽  
Author(s):  
Di Ren ◽  
Julia Fedorova ◽  
Kayla Davitt ◽  
Tran Ngoc Van Le ◽  
John H Griffin ◽  
...  
Keyword(s):  
Protein Kinase ◽  
Protein C ◽  
Ex Vivo ◽  
Activated Protein C ◽  
Wild Type ◽  
Endothelial Protein C Receptor ◽  
Cardiac Damage ◽  
Downstream Signaling ◽  
Cardioprotective Effects ◽  
Epcr Shedding

Background: Activated protein C (APC) is a plasma serine protease with anticoagulant and anti-inflammatory activities. Endothelial protein C receptor (EPCR) is associated with APC's activity and mediates its downstream signaling events. APC exerts cardioprotective effects during ischemia and reperfusion (I/R). This study aims to characterize the role of the APC-EPCR axis in ischemic insults in aging. Methods: Young (3-4 months) and aged (24-26 months) wild type C57BL/6J mice, as well as EPCR point mutation (EPCR R84A/R84A ) knock-in C57BL/6J mice incapable of interaction with APC and its wild type of littermate C57BL/6J mice, were subjected to I/R. Wild type APC, signaling-selective APC-2Cys, or anticoagulant-selective APC-E170A were administrated before reperfusion. Results: The results demonstrated that cardiac I/R reduces APC activity, and the APC activity was impaired in the aged versus young hearts possibly attributable to the declined EPCR level with aging. Serum EPCR measurement showed that I/R triggered the shedding of membrane EPCR into circulation, while administration of APC attenuated the I/R-induced EPCR shedding in both young and aged hearts. Subsequent echocardiography showed that APC and APC-2Cys but not APC-E170A ameliorated cardiac dysfunction during I/R in both young and aged mice. Importantly, APC elevated the resistance of the aged heart to ischemic insults through stabilizing EPCR. However, all these cardioprotective effects of APC were blunted in the EPCR R84A/R84A mice versus its wild-type littermates. The ex vivo working heart and metabolomics results demonstrated that AMP-activated protein kinase (AMPK) mediates acute adaptive response while protein kinase B (AKT) is involved in chronic metabolic programming in the hearts with APC treatment. Conclusions: I/R stress causes shedding of the membrane EPCR in the heart, and administration of APC prevents I/R-induced cardiac EPCR shedding that is critical for limiting cardiac damage in aging.

scholarly journals Cryo-EM structures of human coagulation factors V and Va

Blood ◽  
2021 ◽  
Author(s):  
Eliza A Ruben ◽  
Michael J Rau ◽  
James Fitzpatrick ◽  
Enrico Di Cera
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Factor Xa ◽  
Coagulation Factor ◽  
Coagulation Factors ◽  
Proteolytic Processing ◽  
Coagulation Cascade ◽  
Factor V ◽  
Prothrombinase Complex ◽  
A2 Domain

Coagulation factor V is the precursor of factor Va that, together with factor Xa, Ca2+ and phospholipids, defines the prothrombinase complex and activates prothrombin in the penultimate step of the coagulation cascade. Here we present cryo-EM structures of human factors V and Va at atomic (3.3 Å) and near-atomic (4.4 Å) resolution, respectively. The structure of fV reveals the entire A1-A2-B-A3-C1-C2 assembly but with a surprisingly disordered B domain. The C1 and C2 domains provide a platform for interaction with phospholipid membranes and support the A1 and A3 domains, with the A2 domain sitting on top of them. The B domain is highly dynamic and visible only for short segments connecting to the A2 and A3 domains. The A2 domain reveals all sites of proteolytic processing by thrombin and activated protein C, a partially buried epitope for binding factor Xa and fully exposed epitopes for binding activated protein C and prothrombin. Removal of the B domain and activation to fVa exposes the sites of cleavage by activated protein C at R306 and R506 and produces increased disorder in the A1-A2-A3-C1-C2 assembly, especially in the C-terminal acidic portion of the A2 domain responsible for prothrombin binding. Ordering of this region and full exposure of the factor Xa epitope emerge as a necessary step for the assembly of the prothrombin-prothrombinase complex. These structures offer molecular context for the function of factors V and Va and pioneer the analysis of coagulation factors by cryo-EM.

scholarly journals Improved Distinction of Factor V Wild-Type and Factor V Leiden Using a Novel Prothrombin-Based Activated Protein C Resistance Assay

2004 ◽  
Vol 122 (6) ◽  
pp. 836-842 ◽  
Author(s):  
Marianne Wilmer ◽  
Christoph Stocker ◽  
Beatrice Bühler ◽  
Brigitte Conell ◽  
Andreas Calatzis
Keyword(s):  
Protein C ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Factor V ◽  
Wild Type ◽  
Activated Protein C Resistance

scholarly journals High risk of thrombosis in patients homozygous for factor V Leiden (activated protein C resistance) [see comments]

Blood ◽  
1995 ◽  
Vol 85 (6) ◽  
pp. 1504-1508 ◽  
Author(s):  
FR Rosendaal ◽  
T Koster ◽  
JP Vandenbroucke ◽  
PH Reitsma
Keyword(s):  
Venous Thrombosis ◽  
Protein C ◽  
Absolute Risk ◽  
Thrombotic Event ◽  
Activated Protein C ◽  
Factor V Leiden ◽  
Coagulation Factor ◽  
Factor V ◽  
Increased Risk ◽  
The Absolute

Resistance to activated protein C (APC) is a common inherited risk factor for venous thrombosis, which is associated with a mutation in coagulation factor V (factor V Leiden). We investigated the risk of venous thrombosis in individuals homozygous for this abnormality. We determined the factor V Leiden genotype in 471 consecutive patients aged less than 70 years with a first objectively confirmed deep-vein thrombosis and in 474 healthy controls. We found 85 heterozygous and seven homozygous individuals among the cases with thrombosis and 14 heterozygous individuals among the control subjects. The expected number of homozygous individuals among the controls was calculated from Hardy-Weinberg equilibrium and estimated at 0.107 (allele frequency, 1.5%). Whereas the relative risk was increased sevenfold for heterozygous individuals, it was increased 80-fold for homozygous individuals. These patients experienced their thrombosis at a much younger age (31 v 44 years). The homozygous individuals were predominantly women, most likely due to the effect of oral contraceptives. Because of the increased risk of thrombosis with age, the absolute risk becomes most pronounced in older patients, both for heterozygous and homozygous individuals. For the homozygous individuals, the absolute risk may become several percentage points per year. This implies that most individuals homozygous for factor V Leiden will experience at least one thrombotic event in their lifetime.

Cleavage of Factor V at Arg 506 by Activated Protein C and the Expression of Anticoagulant Activity of Factor V

Blood ◽  
1999 ◽  
Vol 93 (8) ◽  
pp. 2552-2558 ◽  
Author(s):  
Elisabeth Thorelli ◽  
Randal J. Kaufman ◽  
Björn Dahlbäck
Keyword(s):  
Protein C ◽  
Anticoagulant Activity ◽  
Activated Protein C ◽  
Protein S ◽  
Factor V ◽  
Wild Type ◽  
Apc Resistance ◽  
S 100 ◽  
Negative Effect ◽  
Cofactor Activity

Activated protein C (APC) inhibits coagulation by cleaving and inactivating procoagulant factor Va (FVa) and factor VIIIa (FVIIIa). FV, in addition to being the precursor of FVa, has anticoagulant properties; functioning in synergy with protein S as a cofactor of APC in the inhibition of the FVIIIa-factor IXa (FIXa) complex. FV:Q506 isolated from an individual homozygous for APC-resistance is less efficient as an APC-cofactor than normal FV (FV:R506). To investigate the importance of the three APC cleavage sites in FV (Arg-306, Arg-506, and Arg-679) for expression of its APC-cofactor activity, four recombinant FV mutants (FV:Q306, FV:Q306/Q506, FV:Q506, and FV:Q679) were tested. FV mutants with Gln (Q) at position 506 instead of Arg (R) were found to be poor APC-cofactors, whereas Arg to Gln mutations at positions 306 or 679 had no negative effect on the APC-cofactor activity of FV. The loss of APC-cofactor activity as a result of the Arg-506 to Gln mutation suggested that APC-cleavage at Arg-506 in FV is important for the ability of FV to function as an APC-cofactor. Using Western blotting, it was shown that both wild-type FV and mutant FV was cleaved by APC during the FVIIIa inhibition. At optimum concentrations of wild-type FV (11 nmol/L) and protein S (100 nmol/L), FVIIIa was found to be highly sensitive to APC with maximum inhibition occurring at less than 1 nmol/L APC. FV:Q506 was inactive as an APC-cofactor at APC-concentrations ≤ 1 nmol/L and only partially active at higher APC concentrations. Our results show that increased expression of FV anticoagulant activity correlates with APC-mediated cleavage at Arg-506 in FV, but not with cleavage at Arg-306 nor at Arg-679.

Sign in / Sign up

Export Citation Format

Share Document