The Experts below are selected from a list of 11733 Experts worldwide ranked by ideXlab platform
Ralf Reski - One of the best experts on this subject based on the ideXlab platform.
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Critical Evaluation of Strategies for the Production of Blood Coagulation Factors in Plant-Based Systems
Frontiers in Plant Science, 2019Co-Authors: Oguz Top, Ulrich Geisen, Eva L Decker, Ralf ReskiAbstract:The use of plants as alternative production platforms for pharmaceutical proteins has been on the rise for the past two decades. The first marketed plant-made pharmaceutical, taliglucerase alfa against Gaucher`s disease produced in carrot cells by Pfizer/Protalix Biotherapeutics, was approved by the US Food and Drug Administration (FDA) in 2012. Milestones which followed include the successful completion of phase I clinical trial of the HIV-neutralizing human monoclonal antibody 2G12, expressed in Nicotiana tabacum in 2015, and alpha-galactosidase A against Fabry disease produced in Physcomitrella patens in 2017, and the start of phase III efficacy study of the seasonal quadrivalent influenza vaccine manufactured in Nicotiana benthamiana in 2017. The approaches in the field of plant molecular farming are concentrated on the use of different plant species with distinct and overlapping benefits rather than the development of standardized platforms as in microbes and mammalian cells. These benefits might be low cost and highly scalable biomass production compared to the fermentation systems, safety compared with other expression systems, as plant-based systems do not produce endotoxins, and the ability to perform complex eukaryotic post-translational modifications, e.g. N-glycosylation that can be further engineered to achieve humanized N-glycan structures. The necessity of large-scale and less expensive production of human Blood Coagulation Factors, particularly Factors associated with rare bleeding disorders may be an important area for plant-based systems, as they do not fit into the industry-favored production models. In this review, we explore previous studies on recombinant production of Factor II, VIII, IX and XIII in different plant species and discuss potential strategies to overcome bottlenecks in plant-based systems. The impact of plant molecular farming in the production of clotting Factors will increase once plant-made proteins can compete with products in the market in terms of manufacturing costs and product quality.
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Critical Evaluation of Strategies for the Production of Blood Coagulation Factors in Plant-Based Systems
Frontiers Media S.A., 2019Co-Authors: Oguz Top, Ulrich Geisen, Eva L Decker, Ralf ReskiAbstract:The use of plants as production platforms for pharmaceutical proteins has been on the rise for the past two decades. The first marketed plant-made pharmaceutical, taliglucerase alfa against Gaucher’s disease produced in carrot cells by Pfizer/Protalix Biotherapeutics, was approved by the US Food and Drug Administration (FDA) in 2012. The advantages of plant systems are low cost and highly scalable biomass production compared to the fermentation systems, safety compared with other expression systems, as plant-based systems do not produce endotoxins, and the ability to perform complex eukaryotic post-translational modifications, e.g., N-glycosylation that can be further engineered to achieve humanized N-glycan structures. Although bleeding disorders affect only a small portion of the world population, costs of clotting factor concentrates impose a high financial burden on patients and healthcare systems. The majority of patients, ∼75% in the case of hemophilia, have no access to an adequate treatment. The necessity of large-scale and less expensive production of human Blood Coagulation Factors, particularly Factors associated with rare bleeding disorders, may be an important area for plant-based systems, as Coagulation Factors do not fit into the industry-favored production models. In this review, we explore previous studies on recombinant production of Coagulation Factor II, VIII, IX, and XIII in different plant species. Production of bioactive FII and FIX in plants was not achieved yet due to complex post-translational modifications, including vitamin K-dependent γ-carboxylation and propeptide removal. Although plant-made FVIII and FXIII showed specific activities, there are no follow-up studies like pre-clinical/clinical trials. Significant progress has been achieved in oral delivery of bioencapsulated FVIII and FIX to induce immune tolerance in murine models of hemophilia A and B, resp. Potential strategies to overcome bottlenecks in the production systems are also addressed in this review
Oguz Top - One of the best experts on this subject based on the ideXlab platform.
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Critical Evaluation of Strategies for the Production of Blood Coagulation Factors in Plant-Based Systems
Frontiers in Plant Science, 2019Co-Authors: Oguz Top, Ulrich Geisen, Eva L Decker, Ralf ReskiAbstract:The use of plants as alternative production platforms for pharmaceutical proteins has been on the rise for the past two decades. The first marketed plant-made pharmaceutical, taliglucerase alfa against Gaucher`s disease produced in carrot cells by Pfizer/Protalix Biotherapeutics, was approved by the US Food and Drug Administration (FDA) in 2012. Milestones which followed include the successful completion of phase I clinical trial of the HIV-neutralizing human monoclonal antibody 2G12, expressed in Nicotiana tabacum in 2015, and alpha-galactosidase A against Fabry disease produced in Physcomitrella patens in 2017, and the start of phase III efficacy study of the seasonal quadrivalent influenza vaccine manufactured in Nicotiana benthamiana in 2017. The approaches in the field of plant molecular farming are concentrated on the use of different plant species with distinct and overlapping benefits rather than the development of standardized platforms as in microbes and mammalian cells. These benefits might be low cost and highly scalable biomass production compared to the fermentation systems, safety compared with other expression systems, as plant-based systems do not produce endotoxins, and the ability to perform complex eukaryotic post-translational modifications, e.g. N-glycosylation that can be further engineered to achieve humanized N-glycan structures. The necessity of large-scale and less expensive production of human Blood Coagulation Factors, particularly Factors associated with rare bleeding disorders may be an important area for plant-based systems, as they do not fit into the industry-favored production models. In this review, we explore previous studies on recombinant production of Factor II, VIII, IX and XIII in different plant species and discuss potential strategies to overcome bottlenecks in plant-based systems. The impact of plant molecular farming in the production of clotting Factors will increase once plant-made proteins can compete with products in the market in terms of manufacturing costs and product quality.
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Critical Evaluation of Strategies for the Production of Blood Coagulation Factors in Plant-Based Systems
Frontiers Media S.A., 2019Co-Authors: Oguz Top, Ulrich Geisen, Eva L Decker, Ralf ReskiAbstract:The use of plants as production platforms for pharmaceutical proteins has been on the rise for the past two decades. The first marketed plant-made pharmaceutical, taliglucerase alfa against Gaucher’s disease produced in carrot cells by Pfizer/Protalix Biotherapeutics, was approved by the US Food and Drug Administration (FDA) in 2012. The advantages of plant systems are low cost and highly scalable biomass production compared to the fermentation systems, safety compared with other expression systems, as plant-based systems do not produce endotoxins, and the ability to perform complex eukaryotic post-translational modifications, e.g., N-glycosylation that can be further engineered to achieve humanized N-glycan structures. Although bleeding disorders affect only a small portion of the world population, costs of clotting factor concentrates impose a high financial burden on patients and healthcare systems. The majority of patients, ∼75% in the case of hemophilia, have no access to an adequate treatment. The necessity of large-scale and less expensive production of human Blood Coagulation Factors, particularly Factors associated with rare bleeding disorders, may be an important area for plant-based systems, as Coagulation Factors do not fit into the industry-favored production models. In this review, we explore previous studies on recombinant production of Coagulation Factor II, VIII, IX, and XIII in different plant species. Production of bioactive FII and FIX in plants was not achieved yet due to complex post-translational modifications, including vitamin K-dependent γ-carboxylation and propeptide removal. Although plant-made FVIII and FXIII showed specific activities, there are no follow-up studies like pre-clinical/clinical trials. Significant progress has been achieved in oral delivery of bioencapsulated FVIII and FIX to induce immune tolerance in murine models of hemophilia A and B, resp. Potential strategies to overcome bottlenecks in the production systems are also addressed in this review
Hossein Zolfagharian - One of the best experts on this subject based on the ideXlab platform.
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Article type: Original article
2016Co-Authors: Mahdi Babaie, Hossein Salmanizadeh, Hossein ZolfagharianAbstract:Objective(s): Echis carinatus is one of the venomous snakes in Iran. The venom of Iranian Echis carinatus is a rich source of protein with various Factors affecting the plasma protein and Blood Coagulation factor. Some of these proteins exhibit types of enzymatic activities. However, other items are proteins with no enzymatic activity. Materials and Methods: In order to study the mechanism and effect of the venom on human plasma proteins, the present study has evaluated the effect of crude venom and all fractions. A procoagulant factor (prothrombin activator) was isolated from the venom of the Iranian snake Echis carinatus with a combination of gel filtration (Sephadex G-75), ion-exchange chromatography (DEAE- Sepharose) and reverse phase HPLC. Furthermore, proteolytic activity of the crude venom and all fractions on Blood Coagulation Factors such as prothrombin time (PT) was studied. Results: In the present study, the PT test was reduced from 13.4 s to 8.6 s when human plasma was treated with crude venom (concentraion of venom was 1 mg/ml). The purified procoagulant factor revealed a single protein band in SDS polyacrylamide electrophoresis under reducing conditions and its molecular weight was estimated at about 65 kDa. A single-band protein showed fragmen
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Blood Coagulation Induced by Iranian Saw-Scaled Viper (Echis Carinatus) Venom: Identification, Purification and Characterization of a Prothrombin Activator
Mashhad University of Medical Sciences, 2013Co-Authors: Mahdi Babaie, Hossein Salmanizadeh, Hossein ZolfagharianAbstract:Objective(s): Echis carinatus is one of the venomous snakes in Iran. The venom of Iranian Echis carinatus is a rich source of protein with various Factors affecting the plasma protein and Blood Coagulation factor. Some of these proteins exhibit types of enzymatic activities. However, other items are proteins with no enzymatic activity. Materials and Methods: In order to study the mechanism and effect of the venom on human plasma proteins, the present study has evaluated the effect of crude venom and all fractions. A procoagulant factor (prothrombin activator) was isolated from the venom of the Iranian snake Echis carinatus with a combination of gel filtration (Sephadex G-75), ion-exchange chromatography (DEAE- Sepharose) and reverse phase HPLC. Furthermore, proteolytic activity of the crude venom and all fractions on Blood Coagulation Factors such as prothrombin time (PT) was studied. Results: In the present study, the PT test was reduced from 13.4 s to 8.6 s when human plasma was treated with crude venom (concentraion of venom was 1 mg/ml). The purified procoagulant factor revealed a single protein band in SDS polyacrylamide electrophoresis under reducing conditions and its molecular weight was estimated at about 65 kDa. A single-band protein showed fragment patterns similar to those generated by the group A prothrombin activators, which convert prothrombin into meizothrombin independent of the prothrombinase complex. Conclusion: This study showed that the fraction which separated from Iranian snake Echis carinatus venom can be a prothrombin activators. It can be concluded that this fraction is a procoagulant factor
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Blood Coagulation induced by Iranian saw-scaled viper (echis carinatus) venom: identification, purification and characterization of a prothrombin activator.
Iranian journal of basic medical sciences, 2013Co-Authors: Babaie, Hossein Salmanizadeh, Hossein ZolfagharianAbstract:A B S T R A C T Article type: Original article Objective(s): Echis carinatus is one of the venomous snakes in Iran. The venom of Iranian Echis carinatus is a rich source of protein with various Factors affecting the plasma protein and Blood Coagulation factor. Some of these proteins exhibit types of enzymatic activities. However, other items are proteins with no enzymatic activity. Materials and Methods: In order to study the mechanism and effect of the venom on human plasma proteins, the present study has evaluated the effect of crude venom and all fractions. A procoagulant factor (prothrombin activator) was isolated from the venom of the Iranian snake Echis carinatus with a combination of gel filtration (Sephadex G-75), ion-exchange chromatography (DEAE- Sepharose) and reverse phase HPLC. Furthermore, proteolytic activity of the crude venom and all fractions on Blood Coagulation Factors such as prothrombin time (PT) was studied. Results: In the present study, the PT test was reduced from 13.4 s to 8.6 s when human plasma was treated with crude venom (concentraion of venom was 1 mg/ml). The purified procoagulant factor revealed a single protein band in SDS polyacrylamide electrophoresis under reducing conditions and its molecular weight was estimated at about 65 kDa. A single-band protein showed fragment patterns similar to those generated by the group A prothrombin activators, which convert prothrombin into meizothrombin independent of the prothrombinase complex. Conclusion: This study showed that the fraction which separated from Iranian snake Echis carinatus venom can be a prothrombin activators. It can be concluded that this fraction is a procoagulant factor.
Steven T. Olson - One of the best experts on this subject based on the ideXlab platform.
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heparin is a major activator of the anticoagulant serpin protein z dependent protease inhibitor
Journal of Biological Chemistry, 2011Co-Authors: Xin Huang, Alireza R Rezaie, George J Broze, Steven T. OlsonAbstract:Protein Z-dependent protease inhibitor (ZPI) is a recently identified member of the serpin superfamily that functions as a cofactor-dependent regulator of Blood Coagulation Factors Xa and XIa. Here we provide evidence that, in addition to the established coFactors, protein Z, lipid, and calcium, heparin is an important cofactor of ZPI anticoagulant function. Heparin produced 20–100-fold accelerations of ZPI reactions with factor Xa and factor XIa to yield second order rate constants approaching the physiologically significant diffusion limit (ka = 106 to 107 m−1 s−1). The dependence of heparin accelerating effects on heparin concentration was bell-shaped for ZPI reactions with both Factors Xa and XIa, consistent with a template-bridging mechanism of heparin rate enhancement. Maximal accelerations of ZPI-factor Xa reactions required calcium, which augmented the heparin acceleration by relieving Gla domain inhibition as previously shown for heparin bridging of the antithrombin-factor Xa reaction. Heparin acceleration of both ZPI-protease reactions was optimal at heparin concentrations and heparin chain lengths comparable with those that produce physiologically significant rate enhancements of other serpin-protease reactions. Protein Z binding to ZPI minimally affected heparin rate enhancements, indicating that heparin binds to a distinct site on ZPI and activates ZPI in its physiologically relevant complex with protein Z. Taken together, these results suggest that whereas protein Z, lipid, and calcium coFactors promote ZPI inhibition of membrane-associated factor Xa, heparin activates ZPI to inhibit free factor Xa as well as factor XIa and therefore may play a physiologically and pharmacologically important role in ZPI anticoagulant function.
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kinetic characterization of the protein z dependent protease inhibitor reaction with Blood Coagulation factor xa
Journal of Biological Chemistry, 2008Co-Authors: Xin Huang, George J Broze, Richard Swanson, Steven T. OlsonAbstract:Protein Z-dependent protease inhibitor (ZPI) is a recently identified member of the serpin superfamily that functions as a cofactor-dependent regulator of Blood Coagulation Factors Xa (FXa) and XIa. Here we show that ZPI and its cofactor, protein Z (PZ), inhibit procoagulant membrane-bound factor Xa by the branched pathway acyl-intermediate trapping mechanism used by other serpins, but with significant variations of this mechanism that are unique to ZPI. Rapid kinetic analyses showed that the reaction proceeded by the initial assembly of a membrane-associated PZ-ZPI-FXa Michaelis complex (KM 53 ± 5 nm) followed by conversion to a stable ZPI-FXa complex (klim 1.2 ± 0.1 s–1). Cofactor premixing experiments together with independent kinetic analyses of ZPI-PZ and factor Xa-PZ-membrane complex formation suggested that assembly of the Michaelis complex through either ZPI-PZ-lipid or factor Xa-PZ-lipid intermediates was rate-limiting. Reaction stoichiometry analyses and native PAGE showed that for every factor Xa molecule inhibited by ZPI, two serpin molecules were cleaved. Native PAGE and immunoblotting showed that PZ dissociated from ZPI once ZPI forms a stable complex with FXa, and kinetic analyses confirmed that PZ acted catalytically to accelerate the membrane-dependent ZPI-factor Xa reaction. The ZPI-FXa complex was only transiently stable and dissociated with a rate constant that showed a bell-shaped pH dependence indicative of participation of factor Xa active-site residues. The complex was detectable by SDS-PAGE when denatured at low pH, consistent with it being a kinetically trapped covalent acyl-intermediate. Together our findings show that ZPI functions like other serpins to regulate the activity of FXa but in a manner uniquely dependent on protein Z, procoagulant membranes, and pH.
Johannes Oldenburg - One of the best experts on this subject based on the ideXlab platform.
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compound heterozygous mutations in the γ glutamyl carboxylase gene cause combined deficiency of all vitamin k dependent Blood Coagulation Factors
British Journal of Haematology, 2004Co-Authors: Simone Rost, Andreas Fregin, Dieter Koch, Markus Compes, C R Muller, Johannes OldenburgAbstract:Summary Hereditary combined deficiency of the vitamin K-dependent Coagulation Factors II, VII, IX, X, protein C, S and protein Z (VKCFD) is a very rare autosomal recessive inherited bleeding disorder. The phenotype may result from functional deficiency of either the γ-glutamyl carboxylase (GGCX) or the vitamin K epoxide reductase (VKOR) complex. We report on the third case of VKCFD1 with mutations in the γ-glutamyl carboxylase gene, which is remarkable because of compound heterozygosity. Two mutations were identified: a splice site mutation of exon 3 and a point mutation in exon 11, resulting in the replacement of arginine 485 by proline. Screening of 100 unrelated normal chromosomes by restriction fragment length polymorphism and denaturing high-performance liquid chromatography analysis excluded either mutation as a frequent polymorphism. Substitution of vitamin K could only partially normalize the levels of Coagulation Factors. It is suggested that the missense mutation affects either the propeptide binding site or the vitamin K binding site of GGCX.