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A Bar-Ilan, T Livnat, M Hoffmann, L Binder, M Zakar, R Guy, Y Felikman, L Moschcovich, B Shenkman, D Monroe, O Hershkovitz, G Kenet, G Hart
INTRODUCTION: Recombinant FVIIa (rFVIIa) is an effective treatment for haemophilia through frequent administration. However, the short half-life of rFVIIa decreases its prophylactic ability to reduce bleeding. Carboxy-terminal peptide (CTP)-modified FVIIa (MOD-5014) is a long-acting rFVIIa developed for on-demand treatment of haemophilia using either an intravenous or subcutaneous injection with the aim of less frequent administrations, as well as for prophylactic use. AIM: The comprehensive evaluation of the activity MOD-5014 vs commercially available rhFVIIa, as well as their interaction with cofactors and inhibitors...
March 14, 2018: Haemophilia: the Official Journal of the World Federation of Hemophilia
Cecilia Augustsson, Anders Svensson, Birgitte Kjaer, Tzu-Yuan Chao, Xia Wenjuan, Berit Olsen Krogh, Jens Breinholt, Jes Thorn Clausen, Ida Hilden, Helle Heibroch Petersen, Lars Christian Petersen
BACKGROUND: Initiation of coagulation is induced by binding of activated factor VII (FVIIa) to tissue factor (TF) and activation of factor X (FX) in a process regulated by tissue factor pathway inhibitor (TFPI). TFPI contains three Kunitz-type protease inhibitor domains (K1-K3) of which K1 and K2 block the active sites of FVIIa and FXa respectively. OBJECTIVE: To produce a monoclonal antibody (mAb) directed towards K1, to characterize the binding epitope, and to study its effect on TFPI inhibition...
March 12, 2018: Journal of Thrombosis and Haemostasis: JTH
Steven P Grover, Nigel Mackman
Tissue factor (TF) is the high-affinity receptor and cofactor for FVII/VIIa. The TF-FVIIa complex is the primary initiator of blood coagulation and plays an essential role in hemostasis. TF is expressed on perivascular and epithelial cells at organ and body surfaces where it forms a hemostatic barrier. TF also provides additional hemostatic protection to vital organs, such as the brain, lung, and heart. Under pathological conditions, TF can trigger both arterial and venous thrombosis. For instance, atherosclerosis plaques contain high levels of TF on macrophage foam cells and microvesicles that drives thrombus formation after plaque rupture...
February 8, 2018: Arteriosclerosis, Thrombosis, and Vascular Biology
D L Beeler, W C Aird, M A Grant
BACKGROUND: Previous studies have provided insight into the molecular basis of human tissue factor (TF) activation of activated factor VII (FVIIa). TF-induced allosteric networks of FVIIa activation have been rationalized through analysis of the dynamic changes and residue connectivities in the human soluble TF (sTF)/FVIIa complex structure during molecular dynamics (MD) simulation. Evolutionary conservation of the molecular mechanisms for TF-induced allosteric FVIIa activation between human and extant vertebrate jawless fish (lamprey), where blood coagulation emerged more than 500 million years ago, is unknown and of considerable interest...
February 8, 2018: Journal of Thrombosis and Haemostasis: JTH
Othman Montacir, Houda Montacir, Murat Eravci, Andreas Springer, Stephan Hinderlich, Fereidoun Mahboudi, Amirhossein Saadati, Maria Kristina Parr
Eptacog alfa (NovoSeven®) is a vitamin K-dependent recombinant Factor VIIa produced by genetic engineering from baby hamster kidney (BHK) cells as a single peptide chain of 406 residues. After activation, it consists of a light chain (LC) of 152 amino and a heavy chain (HC) of 254 amino acids. Recombinant FVIIa undergoes many post-translational modifications (PTMs). The first ten glutamic acids of the N-terminal moiety are γ-carboxylated, Asn145 and Asn322 are N-glycosylated, and Ser52 and Ser60 are O-glycosylated...
January 19, 2018: Bioengineering
Yunn-Hwa Ma, Chao-Wei Huang, Chih-Jen Wen, Yi-Ching Lu, Shiaw-Pyng Wey, Tze-Chein Wun
Without conjunctive administration of an anticoagulant, endothelial injury-induced thrombosis is resistant to thrombolysis and prone to re-thrombosis. We hypothesized that co-delivery of recombinant tissue plasminogen activator (rtPA) with annexin V-containing anticoagulants that specifically target the injured endothelium may passivate the thrombogenic elements of the vascular injury site and enhance rtPA-induced thrombolysis. In this study, the effects of conjunctive administration of Kinexins (Kunitz inhibitor-annexin V fusion proteins) with rtPA on thrombolysis were determined in vitro and in vivo...
January 2018: Thrombosis and Haemostasis
Andrea S Rothmeier, Enbo Liu, Sagarika Chakrabarty, Jennifer Disse, Barbara M Mueller, Henrik Østergaard, Wolfram Ruf
The tissue factor (TF) pathway serves both hemostasis and cell signaling, but how cells control these divergent functions of TF remains incompletely understood. TF is the receptor and scaffold of coagulation proteases cleaving protease activated receptor (PAR) 2 that plays pivotal roles in angiogenesis and tumor development. Here we demonstrate that coagulation factor (F) VIIa elicits TF cytoplasmic domain-dependent pro-angiogenic cell signaling independent of the alternative PAR2 activator matriptase. We identify a Lys-Gly-Glu (KGE) integrin binding motif in the FVIIa protease domain that is required for association of the TF-FVIIa complex with the active conformer of integrin β1...
December 15, 2017: Blood
Muriel Giansily-Blaizot, Jean-François Schved
Recombinant activated factor VII (rFVIIa) is a bypassing agent widely used both in the treatment and prevention of hemorrhagic complications due to hemophilia with inhibitor. In such cases, antihemophilic factors cannot be used. The normal physiology of factor VII/ factor VIIa (FVII/FVIIa) in the hemostatic process requires the presence of tissue factor (TF) that links to FVII leading to a FVIIa-TF complex which activates both factor X and factor IX. The therapeutic use of rFVIIa requires high amount of FVIIa...
December 2017: Therapeutic Advances in Hematology
William E Winter, Sherri D Flax, Neil S Harris
Primary hemostasis begins with endothelial injury. VWF, produced by endothelial cells, binds to platelets and links them to subendothelial collagen. Platelet-derived ADP and thromboxane activate non-adhered platelets via their GPIIb/IIIa receptors, allowing these platelets to participate in platelet aggregation. Secondary hemostasis is initiated with the binding of factor VII to extravascular tissue factor (TF). Factors II, VII, IX and X are vitamin K-dependent factors. The role of vitamin K is to assist in the addition of gamma carboxylate groups to glutamic acids in the "GLA" domains of these factors...
November 8, 2017: Laboratory Medicine
N C Olson, L M Raffield, L A Lange, E M Lange, W T Longstreth, G Chauhan, S Debette, S Seshadri, A P Reiner, R P Tracy
ESSENTIALS: Essentials A fraction of coagulation factor VII circulates in blood as an activated protease (FVIIa). We evaluated FVIIa and FVIIa-antithrombin (FVIIa-AT) levels in the Cardiovascular Health Study. Polymorphisms in the F7 and PROCR loci were associated with FVIIa and FVIIa-AT levels. FVIIa may be an ischemic stroke risk factor in older adults and FVIIa-AT may assess mortality risk. SUMMARY: Background A fraction of coagulation factor (F) VII circulates as an active protease (FVIIa)...
January 2018: Journal of Thrombosis and Haemostasis: JTH
Esterina D'Asti, G Mark Anderson, Janusz Rak
Tissue factor (TF) is a transmembrane receptor for coagulation factor VII/VIIa and is frequently overexpressed by cancer cells. The TF/VIIa complex acts as the main initiator of the clotting cascade in blood and a trigger of intracellular signaling that changes gene expression and the cellular phenotype. However, pathways mediating these changes are still poorly characterized and especially the impact of TF signals on regulatory microRNA (miR) networks in cancer remains unknown. We show that the monoclonal antibody that selectively neutralises the signaling (but not coagulant) function of human TF (CNTO 2559) inhibits progression of MDA-MB-231 breast cancer xenografts in mice and prolongs animal survival...
December 16, 2017: Biochemical and Biophysical Research Communications
Anders L Nielsen, Anders B Sorensen, Heidi L Holmberg, Prafull S Gandhi, Johan Karlsson, Jens Buchardt, Kasper Lamberth, Mads Kjelgaard-Hansen, Carsten Dan Ley, Brit B Sørensen, Wolfram Ruf, Ole H Olsen, Henrik Østergaard
Recombinant factor VIIa (FVIIa) variants with increased activity offer the promise to improve the treatment of bleeding episodes in patients with inhibitor-complicated hemophilia. Here, an approach was adopted to enhance the activity of FVIIa by selectively optimizing substrate turnover at the membrane surface. Under physiological conditions, endogenous FVIIa engages its cell-localized cofactor tissue factor (TF), which stimulates activity through membrane-dependent substrate recognition and allosteric effects...
November 21, 2017: Proceedings of the National Academy of Sciences of the United States of America
J Ducore, J B Lawrence, M Simpson, L Boggio, A Bellon, J Burggraaf, J Stevens, M Moerland, J Frieling, J Reijers, M Wang
INTRODUCTION: Varying initial doses of activated eptacog beta (recombinant human FVIIa, rhFVIIa) may provide therapeutic options when treating bleeding in patients with congenital haemophilia who have developed inhibitory antibodies to factor VIII (FVIII) or factor IX (FIX). This study evaluated escalated doses of a new rhFVIIa product as a prelude to selecting the doses for clinical efficacy evaluation in haemophilia patients. AIM: To assess the safety, pharmacokinetics, and laboratory pharmacodynamics of 3 doses of rhFVIIa in non-bleeding patients with congenital haemophilia A or B with or without inhibitors...
November 2017: Haemophilia: the Official Journal of the World Federation of Hemophilia
Tatiana A Kovalenko, Mikhail A Panteleev, Anastasia N Sveshnikova
Membrane-bound enzyme complex of extrinsic tenase (VIIa/TF) is believed to be the primary activator of blood clotting in vivo. This complex (where factor VIIa (FVIIa) is a catalytically active part and tissue factor (TF) is its essential cofactor) activates its primary substrate factor X (FX) leading to factor Xa (FXa) ('a' stands for 'activated'). Both FX and FXa are able to bind to phospholipid membrane and, therefore, are distributed between solution and membrane surface. As a result, two possible mechanisms of substrate delivery to the extrinsic tenase exist: via lateral diffusion on the membrane surface or directly from the solution...
December 21, 2017: Journal of Theoretical Biology
Shiva Keshava, Jagan Sundaram, Anuradha Rajulapati, Charles Esmon, Usha Pendurthi, L Vijaya Mohan Rao
Recent studies established that clotting factor VIIa (FVIIa) binds endothelial cell protein C receptor (EPCR). It has been speculated that FVIIa interaction with EPCR might augment the hemostatic effect of rFVIIa in therapeutic conditions. The present study is carried out to investigate the mechanism by which FVIIa interaction with EPCR contributes to the hemostatic effect of rFVIIa in hemophilia therapy. Active-site inhibited FVIIa, which is capable of binding to EPCR but has no ability to activate factor X, reduced the concentration of rFVIIa required to correct the bleeding following the saphenous vein injury in mouse hemophilia model systems...
June 27, 2017: Blood Advances
Andrea Roxanne J Anas, Akane Mori, Mineka Tone, Chiaki Naruse, Anna Nakajima, Hirohiko Asukabe, Yoshiaki Takaya, Susumu Y Imanishi, Tomoyasu Nishizawa, Makoto Shirai, Ken-Ichi Harada
The rise of bleeding and bleeding complications caused by oral anticoagulant use are serious problems nowadays. Strategies that block the initiation step in blood coagulation involving activated factor VII-tissue factor (fVIIa-TF) have been considered. This study explores toxic Microcystis aeruginosa K-139, from Lake Kasumigaura, Ibaraki, Japan, as a promising cyanobacterium for isolation of fVIIa-sTF inhibitors. M. aeruginosa K-139 underwent reversed-phase solid-phase extraction (ODS-SPE) from 20% MeOH to MeOH elution with 40%-MeOH increments, which afforded aeruginosin K-139 in the 60% MeOH fraction; micropeptin K-139 and microviridin B in the MeOH fraction...
August 30, 2017: Marine Drugs
Wei Yang, Søren Berg Padkjær, Jishu Wang, Zhe Sun, Bing Shan, Li Yang, Haibin Chen, Lishan Kang, Dennis Madsen, Xun Li, Chenxi Shen, Bingke Yu, Haisun Zhu, Tzu-Yuan Chao, Zhuoxiao Cao, Dapeng Li, Wei Liu, Yanping Du, Jinjing Xu, Dongxia Hao, Fengting Xu, Lujia Peng, Tengkun Li, Lin Wang, Lin Li, Haimei Xing, Di Liu, Zibing Liu, Zhishuang Guan, Wan Wang, Hong Cheng, Henrik Østergaard, Chihchuan Chang, Zhiru Yang, Esper Boel, Jing Su
Interactions between protein ligands and receptors play crucial roles in cell-cell signalling. Most of the human cell surface receptors have been identified in the post-Human Genome Project era but many of their corresponding ligands remain unknown. To facilitate the pairing of orphan receptors, 2762 sequences encoding all human single-pass transmembrane proteins were selected for inclusion into a mammalian-cell expression library. This expression library, consisting of all the individual extracellular domains (ECDs), was constructed as a Fab fusion for each protein...
September 1, 2017: Journal of Biotechnology
V S De Paula, F H S Silva, I M B Francischetti, R Q Monteiro, A P Valente
Ixolaris is a two-Kunitz tick salivary gland protein identified in Ixodes scapularis that presents sequence homology to TFPI (tissue factor pathway inhibitor). It binds to the coagulation enzyme factor Xa (FXa) or to its zymogen form, FX, and further inhibits tissue factor/FVIIa complex (extrinsic Xnase compex). Differently from TFPI, Ixolaris does not bind to the active site cleft of FXa. Instead, complex formation is mediated by the FXa heparin-binding exosite, which may also results in decreased FXa activity into the prothrombinase complex...
October 2017: Biomolecular NMR Assignments
Ramesh Prasad, Prosenjit Sen
During blood-coagulation, the transmembrane protein tissue factor (TF) binds to its ligand, factor (F)VII, activating and allosterically modifying it to form a mature active binary complex (TF-FVIIa). Although the extracellular domain of TF (sTF) can bind to FVII, it fails to activate it. Binding of TF with FVIIa only partially enhances FVIIa proteolytic activity. Our previous kinetic study revealed that sTF has a lower binding capacity with FVIIa compared to membrane bound full-length (fl)TF. The reason behind this incapability of FVII activation and reduced catalytic activity remains unexplored due to the lack of an flTF crystal structure...
August 23, 2017: Physical Chemistry Chemical Physics: PCCP
M P Muller, Y Wang, J H Morrissey, E Tajkhorshid
Essentials Membrane-binding GLA domains of coagulation factors are essential for proper clot formation. Factor X (FX) is specific to phosphatidylserine (PS) lipids through unknown atomic-level interactions. Molecular dynamics simulations were used to develop the first membrane-bound model of FX-GLA. PS binding modes of FX-GLA were described, and potential PS-specific binding sites identified. SUMMARY: Background Factor X (FX) binds to cell membranes in a highly phospholipid-dependent manner and, in complex with tissue factor and factor VIIa (FVIIa), initiates the clotting cascade...
October 2017: Journal of Thrombosis and Haemostasis: JTH
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