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Nakajima Y, Oda A, Baatartsogt N, Kashiwakura Y, Ohmori T, Nogami K. The combination of Asp519Val/Glu665Val and Lys1813Ala mutations in FVIII markedly increases coagulation potential. Blood Adv 2024; 8:3929-3940. [PMID: 38820442 PMCID: PMC11321387 DOI: 10.1182/bloodadvances.2023012391] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 05/06/2024] [Accepted: 05/18/2024] [Indexed: 06/02/2024] Open
Abstract
ABSTRACT A2 domain dissociation in activated factor VIII (FVIIIa) results in reduced activity. Previous studies demonstrated that some FVIII mutants (D519V/E665V and K1813A) with delayed A2 dissociation enhanced coagulation potential. We speculated, therefore, that FVIII encompassing a combination of these mutations might further enhance coagulant activity. The aim was to assess the D519V/E665V/K1813A-FVIII mutation as a gain of function. The FVIII mutants, D519V/E665V/K1813A, D519V/E665V, and K1813A were expressed in a baby hamster kidney cell system, and global coagulation potential of these mutants was compared with wild-type (WT) FVIII in vitro and in hemophilia A mice in vivo. Kinetic analyses indicated that the apparent Kd for FIXa on the tenase assembly with D519V/E665V and D519V/E665V/K1813A mutants were lower, and that the generated FXa for D519V/E665V/K1813A was significantly greater than WT-FVIII. WT-FVIII activity after thrombin activation increased by ∼12-fold within 5 minutes, and returned to initial levels within 30 minutes. In contrast, The FVIII-related activity of D519V/E665V/K1813A increased further with time after thrombin activation, and showed an ∼25-fold increase at 2 hours. The A2 dissociation rate of D519V/E665V/K1813A was ∼50-fold slower than the WT in a 1-stage clotting assay. Thrombin generation assays demonstrated that D519V/E665V/K1813A (0.125 nM) exhibited coagulation potential comparable with that of the WT (1 nM). In animal studies, rotational thromboelastometry and tail-clip assays showed that the coagulation potential of D519V/E665V/K1813A (0.25 μg/kg) was equal to that of the WT (2 μg/kg). FVIII-D519V/E665V/K1813A mutant could provide an approximately eightfold increase in hemostatic function of WT-FVIII because of increased FVIIIa stability and the association between FVIIIa and FIXa.
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Affiliation(s)
- Yuto Nakajima
- Department of Pediatrics, Nara Medical University, Kashihara, Japan
- Advanced Medical Science of Thrombosis and Hemostasis, Nara Medical University, Kashihara City, Japan
| | - Akihisa Oda
- Department of Pediatrics, Nara Medical University, Kashihara, Japan
| | | | - Yuji Kashiwakura
- Department of Biochemistry, Jichi Medical University School of Medicine, Shimotsuke, Japan
| | - Tsukasa Ohmori
- Department of Biochemistry, Jichi Medical University School of Medicine, Shimotsuke, Japan
| | - Keiji Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Japan
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Sarmiento Doncel S, Díaz Mosquera GA, Cortes JM, Agudelo Rico C, Meza Cadavid FJ, Peláez RG. Haemophilia A: A Review of Clinical Manifestations, Treatment, Mutations, and the Development of Inhibitors. Hematol Rep 2023; 15:130-150. [PMID: 36810557 PMCID: PMC9944491 DOI: 10.3390/hematolrep15010014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2022] [Revised: 09/07/2022] [Accepted: 02/10/2023] [Indexed: 02/18/2023] Open
Abstract
The purpose of this narrative review was to provide an overview that allows readers to improve their understanding of hemophilia A, which is considered a genetic disease with a high impact on the quality of life of people who suffer from it is considered one of the diseases with the highest cost for health systems (In Colombia it is part of the five diseases with the greatest economic impact). After this exhaustive review, we can see that the treatment of hemophilia is on the way to precision medicine, which involves genetic variables specific to each race and ethnicity, pharmacokinetics (PK), as well as environmental factors and lifestyle. Knowing the impact of each of these variables and their relationship with the efficacy of treatment (prophylaxis: regular infusion of the missing clotting factor VIII in order to prevent spontaneous bleeding) will allow for individualizing the medical behavior in a cost-effective way. For this is required to build more strong scientific evidence with statistical power that allows us to infer.
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Affiliation(s)
- Samuel Sarmiento Doncel
- Integral Solutions SD SAS, Integral Solutions Research, Bogota 110121, Colombia
- Life Sciences and Health Research Group, Graduates School, CES University, Medellin 050021, Colombia
| | | | | | - Carol Agudelo Rico
- Integral Solutions SD SAS, Integral Solutions Research, Bogota 110121, Colombia
| | - Francisco Javier Meza Cadavid
- Integral Solutions SD SAS, Integral Solutions Research, Bogota 110121, Colombia
- Hospital Universitario San Jorge, Pereira 660002, Colombia
| | - Ronald Guillermo Peláez
- Life Sciences and Health Research Group, Graduates School, CES University, Medellin 050021, Colombia
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3
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Zamora M, Robles JP, Aguilar MB, Romero-Gómez SDJ, Bertsch T, Martínez de la Escalera G, Triebel J, Clapp C. Thrombin Cleaves Prolactin Into a Potent 5.6-kDa Vasoinhibin: Implication for Tissue Repair. Endocrinology 2021; 162:6356167. [PMID: 34418052 DOI: 10.1210/endocr/bqab177] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Indexed: 12/17/2022]
Abstract
Vasoinhibin is an endogenous prolactin (PRL) fragment with profibrinolytic, antivasopermeability, and antiangiogenic effects. The fact that blood clotting, vascular permeability, and angiogenesis are functionally linked during the wound-healing process led us to investigate whether thrombin, a major protease in tissue repair, generates vasoinhibin. Here, we have incubated human PRL with thrombin and analyzed the resulting proteolytic products by Western blot, mass spectrometry, high-performance liquid chromatography purification, recombinant production, and bioactivity. We unveil a main thrombin cleavage site at R48-G49 that rapidly (< 10 minutes) generates a 5.6-kDa fragment (residues 1-48) with full vasoinhibin activity, that is, it inhibited the proliferation, invasion, and permeability of cultured endothelial cells and promoted the lysis of a fibrin clot in plasma with a similar potency to that of a conventional 14-kDa vasoinhibin (residues 1-123). The R48-G49 cleavage site is highly conserved throughout evolution and precedes the intramolecular disulfide bond (C58-C174), thereby allowing the 5.6-kDa vasoinhibin to be released without a reduction step. Furthermore, the 5.6-kDa vasoinhibin is produced by endogenous thrombin during the clotting process. These findings uncover the smallest vasoinhibin known, add thrombin to the list of PRL-cleaving proteases generating vasoinhibin, and introduce vasoinhibin as a thrombin-activated mechanism for the regulation of hemostasis, vasopermeability, and angiogenesis in response to tissue injury.
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Affiliation(s)
- Magdalena Zamora
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro 76230, México
- Institute for Clinical Chemistry, Laboratory Medicine and Transfusion Medicine, Nuremberg General Hospital and Paracelsus Medical University, Nuremberg 90419, Germany
| | - Juan Pablo Robles
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro 76230, México
| | - Manuel B Aguilar
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro 76230, México
| | | | - Thomas Bertsch
- Institute for Clinical Chemistry, Laboratory Medicine and Transfusion Medicine, Nuremberg General Hospital and Paracelsus Medical University, Nuremberg 90419, Germany
| | | | - Jakob Triebel
- Institute for Clinical Chemistry, Laboratory Medicine and Transfusion Medicine, Nuremberg General Hospital and Paracelsus Medical University, Nuremberg 90419, Germany
| | - Carmen Clapp
- Instituto de Neurobiología, Universidad Nacional Autónoma de México (UNAM), Querétaro 76230, México
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Nakajima Y, Nogami K. The C-terminal acidic region in the A1 domain of factor VIII facilitates thrombin-catalyzed activation and cleavage at Arg 372. J Thromb Haemost 2021; 19:677-688. [PMID: 33369157 DOI: 10.1111/jth.15201] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2020] [Revised: 11/22/2020] [Accepted: 11/23/2020] [Indexed: 12/01/2022]
Abstract
BACKGROUND Factor VIII (FVIII) is activated by thrombin-catalyzed cleavage at three sites. Previous reports indicated that the A2 domain contained thrombin-interactive sites responsible for cleavage at Arg372 . We have also found that the A1 domain of FVIII bound to the anion-binding exosite I of thrombin. The present study focused, therefore, on thrombin interaction with A1 residues 337-372 containing clustered acidic and hirugen-like sequences. AIM To identify specific thrombin-interactive site(s) within the A1 acidic region of FVIII. METHODS AND RESULTS The synthetic peptide of residues 337-353 with sulfated Tyr346 (337-353S) significantly blocked thrombin-catalyzed FVIII activation and cleavage at Arg372 , while a corresponding peptide of residues 354-372 had no significant effect. Treatment with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide to cross-link thrombin and 340-350S suggested that the 344-349 clustered acidic region was involved in thrombin interaction. Alanine-substituted FVIII mutants, Y346A and D347A/D348A/D349A, depressed thrombin-catalyzed activation and cleavage at Arg372 , with peak activation at ~ 50% and cleavage rates of ~ 10% to 20% compared to wild type (WT). The peak level of thrombin-catalyzed activation and the cleavage rate at Arg372 using FVIII mutants with 337-346 residues substituted with hirugen-sequences (MKNNEEAEDY337-346GDFEEIPEEY) were ~ 1.5- and ~ 2.5-fold of WT, respectively. Surface plasmon resonance-based analysis demonstrated that the Kd for active-site modified thrombin interactions using Y346A and D347A/D348A/D349A mutants was ~ 3- to 6-fold higher than that of WT, and that the hirugen-hybrid mutant facilitated association kinetics ~ 1.8-fold of WT. CONCLUSION Residues 346-349 with sulfated Tyr provided a thrombin-interactive site responsible for activation and cleavage at Arg372 . A hirugen-hybrid A1 mutant showed more efficient thrombin-catalyzed cleavage at Arg372 .
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Affiliation(s)
- Yuto Nakajima
- Department of Pediatrics, Nara Medical University, Kashihara, Japan
| | - Keiji Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Japan
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Nakajima Y, Minami H, Nogami K. Acidic Region Residues 1680-1684 in the A3 Domain of Factor VIII Contain a Thrombin-Interactive Site Responsible for Proteolytic Cleavage at Arg1689. Thromb Haemost 2021; 121:1274-1288. [PMID: 33592631 DOI: 10.1055/s-0041-1723996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
Factor VIII (FVIII) is activated by thrombin-catalyzed cleavage at Arg372, Arg740, and Arg1689. Our previous studies suggested that thrombin interacted with the FVIII C2 domain specific for cleavage at Arg1689. An alternative report demonstrated, however, that a recombinant (r)FVIII mutant lacking the C2 domain retained >50% cofactor activity, indicating the presence of other thrombin-interactive site(s) associated with cleavage at Arg1689. We have focused, therefore, on the A3 acidic region of FVIII, similar to the hirugen sequence specific for thrombin interaction (54-65 residues). Two synthetic peptides, spanning residues 1659-1669 with sulfated Tyr1664 and residues 1675-1685 with sulfated Try1680, inhibited thrombin-catalyzed FVIII activation and cleavage at Arg1689. Treatment with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide to cross-link thrombin with either peptide showed possible contributions of both 1664-1666 and 1683-1684 residues for thrombin interaction. Thrombin-catalyzed activation and cleavage at Arg1689 in the alanine-substituted rFVIII mutants within 1663-1666 residues were similar to those of wild type (WT). Similar studies of 1680-1684 residues, however, demonstrated that activation and cleavage by thrombin of the FVIII mutant with Y1680A or D1683A/E1684A, in particular, were severely or moderately reduced to 20 to 30% or 60 to 70% of WT, respectively. Surface plasmon resonance-based analysis revealed that thrombin interacted with both Y1680A and D1683A/E1684A mutants with approximately sixfold weaker affinities of WT. Cleavage at Arg1689 in the isolated light-chain fragments from both mutants was similarly depressed, independently of the heavy-chain subunit. In conclusion, the 1680-1684 residues containing sulfated Tyr1680 in the A3 acidic region also contribute to a thrombin-interactive site responsible for FVIII activation through cleavage at Arg1689.
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Affiliation(s)
- Yuto Nakajima
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - Hiroaki Minami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - Keiji Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
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Abstract
Human factor Xa (FXa) is a serine protease of the common coagulation pathway. FXa is known to activate prothrombin to thrombin, which eventually leads to the formation of cross-linked blood clots. While this process is important in maintaining hemostasis, excessive thrombin generation results in a host of thrombotic conditions. FXa has also been linked to inflammation via protease-activated receptors. Together, coagulopathy and inflammation have been implicated in the pathogenesis of viral infections, including the current coronavirus pandemic. Direct FXa inhibitors have been shown to possess anti-inflammatory and antiviral effects, in addition to their established anticoagulant activity. This review summarizes the pharmacological activities of direct FXa inhibitors, their pharmacokinetics, potential drug–drug interactions and adverse effects, and the details of clinical trials involving direct FXa inhibitors in coronavirus disease 2019 (COVID-19) patients.
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Affiliation(s)
- Rami A Al-Horani
- Division of Basic Pharmaceutical Sciences, College of Pharmacy, Xavier University of Louisiana, 1 Drexel Drive, New Orleans, LA, 70125-1089, USA.
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Castaman G. Hemophilia A: different phenotypes may be explained by multiple and variable effects of the causative mutation in the F8 gene. Haematologica 2019; 103:195-196. [PMID: 29386375 DOI: 10.3324/haematol.2017.186353] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Affiliation(s)
- Giancarlo Castaman
- Center for Bleeding Disorders, Department of Oncology, Careggi University Hospital, Florence, Italy
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8
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Mannully S, L.N. R, Pulicherla K. Perspectives on progressive strategies and recent trends in the production of recombinant human factor VIII. Int J Biol Macromol 2018; 119:496-504. [DOI: 10.1016/j.ijbiomac.2018.07.164] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2018] [Revised: 07/11/2018] [Accepted: 07/26/2018] [Indexed: 10/28/2022]
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Mutational Profiles of F8 and F9 in a Cohort of Haemophilia A and Haemophilia B Patients in the Multi-ethnic Malaysian Population. Mediterr J Hematol Infect Dis 2018; 10:e2018056. [PMID: 30210749 PMCID: PMC6131101 DOI: 10.4084/mjhid.2018.056] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2018] [Accepted: 08/10/2018] [Indexed: 12/30/2022] Open
Abstract
Background Haemophilia A (HA) and Haemophilia B (HB) are X-linked blood disorders that are caused by various mutations in the factor VIII (F8) and factor IX (F9) genes respectively. Identification of mutations is essential as some of the mutations are associated with the development of inhibitors. This study is the first comprehensive study of the F8 mutational profile in Malaysia. Materials and methods We analysed 100 unrelated HA and 15 unrelated HB patients for genetic alterations in the F8 and F9 genes by using the long-range PCR, DNA sequencing, and the multiplex-ligation-dependent probe amplification assays. The prediction software was used to confirm the effects of these mutations on factor VIII and IX proteins. Results 44 (53%) of the severe HA patients were positive for F8 intron 22 inversion, and three (3.6%) were positive for intron one inversion. There were 22 novel mutations in F8, including missense (8), frameshift (9), splice site (3), large deletion (1) and nonsense (1) mutations. In HB patients, four novel mutations were identified including the splice site (1), small deletion (1), large deletion (1) and missense (1) mutation. Discussion The mutational spectrum of F8 in Malaysian patients is heterogeneous, with a slightly higher frequency of intron 22 inversion in these severe HA patients when compared to other Asian populations. Identification of these mutational profiles in F8 and F9 genes among Malaysian patients will provide a useful reference for the early detection and diagnosis of HA and HB in the Malaysian population.
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Donadon I, McVey JH, Garagiola I, Branchini A, Mortarino M, Peyvandi F, Bernardi F, Pinotti M. Clustered F8 missense mutations cause hemophilia A by combined alteration of splicing and protein biosynthesis and activity. Haematologica 2017; 103:344-350. [PMID: 29170251 PMCID: PMC5792279 DOI: 10.3324/haematol.2017.178327] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 11/15/2017] [Indexed: 01/01/2023] Open
Abstract
Dissection of pleiotropic effects of missense mutations, rarely investigated in inherited diseases, is fundamental to understanding genotype-phenotype relationships. Missense mutations might impair mRNA processing in addition to protein properties. As a model for hemophilia A, we investigated the highly prevalent F8 c.6046c>t/p.R2016W (exon 19) mutation. In expression studies exploiting lentiviral vectors, we demonstrated that the amino acid change impairs both Factor VIII (FVIII) secretion (antigen 11.0±0.4% of wild-type) and activity (6.0±2.9%). Investigations in patients' ectopic F8 mRNA and with minigenes showed that the corresponding nucleotide change also decreases correct splicing to 70±5%, which is predicted to lower further FVIII activity (4.2±2%), consistently with patients' levels (<1-5%). Masking the mutated exon 19 region by antisense U7snRNA supported the presence of a splicing regulatory element, potentially affected by several missense mutations causing hemophilia A. Among these, the c.6037g>a (p.G2013R) reduced exon inclusion to 41±3% and the c.6053a>g (p.E2018G) to 28±2%, similarly to a variant affecting the 5' splice site (c.6113a>g, p.N2038S, 26±2%), which displayed normal protein features upon recombinant expression. The p.G2013R reduced both antigen (7.0±0.9%) and activity (8.4±0.8%), while the p.E2018G produced a dysfunctional molecule (antigen: 69.0±18.1%; activity: 19.4±2.3%). In conclusion, differentially altered mRNA and protein patterns produce a gradient of residual activity, and clarify genotype-phenotype relationships. Data detail pathogenic mechanisms that, only in combination, account for moderate/severe disease forms, which in turn determine the mutation profile. Taken together we provide a clear example of interplay between mRNA and protein mechanisms of disease that operate in shaping many other inherited disorders.
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Affiliation(s)
- Irving Donadon
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy.,Human Molecular Genetics, International Centre for Genetic Engineering and Biotechnology, Trieste, Italy
| | - John H McVey
- School of Bioscience & Medicine, University of Surrey, Guildford, UK
| | - Isabella Garagiola
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico and Fondazione Luigi Villa, Milan, Italy
| | - Alessio Branchini
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy
| | - Mimosa Mortarino
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico and Fondazione Luigi Villa, Milan, Italy
| | - Flora Peyvandi
- Angelo Bianchi Bonomi Hemophilia and Thrombosis Center, Fondazione IRCCS Ca' Granda Ospedale Maggiore Policlinico and Fondazione Luigi Villa, Milan, Italy.,Department of Pathophysiology and Transplantation, University of Milan, Italy
| | - Francesco Bernardi
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy
| | - Mirko Pinotti
- Department of Life Sciences and Biotechnology, University of Ferrara, Italy .,Laboratorio per le Tecnologie delle Terapie Avanzate, University of Ferrara, Italy
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Yada K, Wakabayashi H, Fay PJ, Shima M, Nogami K. The mild phenotype in severe hemophilia A with Arg1781His mutation is associated with enhanced binding affinity of factor VIII for factor X. Thromb Haemost 2017; 109:1007-15. [DOI: 10.1160/th12-10-0762] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Accepted: 02/12/2013] [Indexed: 12/29/2022]
Abstract
SummaryThe clinical severity in some patients with haemophilia A appears to be unrelated to the levels of factor (F)VIII activity (FVIII:C), but mechanisms are poorly understood. We have investigated a patient with a FVIII gene mutation at Arg1781 to His (R1781H) presenting with a mild phenotype despite FVIII:C of 0.9 IU/dl. Rotational thromboelastometry using the patient’s whole blood demonstrated that the clot time and clot firmness were comparable to those usually observed at FVIII:C 5–10 IU/dl. Thrombin and FXa assays using plasma samples also showed that the peak levels of thrombin formation and the initial rate of FXa generation were comparable to those observed at FVIII:C 5–10 IU/dl. The results suggested a significantly greater haemostatic potential in this individual than in those with severe phenotype. The addition of incremental amounts of FX to control plasma with FVIII:C 0.9 IU/dl in clot waveform analyses suggested that the enhanced functional tenase assembly might have been related to changes in association between FVIII and FX. To further investigate this mechanism, we prepared a stably expressed, recombinant, B-domainless FVIII R1781H mutant. Thrombin generation assays using mixtures of control plasma and FVIII revealed that the coagulation function observed with the R1781H mutant (0.9 IU/dl) was comparable to that seen with wild-type FVIII:C at ∼5 IU/dl. In addition, the R1781H mutant demonstrated an ∼1.9-fold decrease in K m for FX compared to wild type. These results indicated that relatively enhanced binding affinity of FVIII R1781H for FX appeared to moderate the severity of the haemophilia A phenotype.Note: An account of this work was presented, in part, at the 23rd Congress of the International Society of Thrombosis and Haemostasis, July 27, 2011, Kyoto, Japan.
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12
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Crawford B, Ozelo MC, Ogiwara K, Ahlin J, Albanez S, Hegadorn C, Harpell L, Hough C, Lillicrap D. Transgene-host cell interactions mediate significant influences on the production, stability, and function of recombinant canine FVIII. MOLECULAR THERAPY-METHODS & CLINICAL DEVELOPMENT 2015; 2:15033. [PMID: 26636112 PMCID: PMC4650998 DOI: 10.1038/mtm.2015.33] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/12/2015] [Revised: 07/14/2015] [Accepted: 07/19/2015] [Indexed: 01/23/2023]
Abstract
Recombinant FVIII manufacturing is characterized by poor product stability and low yields. Codon-optimization of transgenes accelerates translation by exploiting the synonymous codon usage bias of a species. However, this can alter the performance of the final product. Additionally, the effects of transgene design across diverse cell types are not well understood and are of interest for next-generation protein and gene therapies. To investigate the effects of transgene design across different host cells, B-domain-deleted (BDD) and modified codon-optimized (CO-N6) transgenes were inserted via lentiviral delivery into cBOECs, HEK293T, and MDCK cells. The CO-N6 cFVIII transgene produced threefold more protein per transgene in HEK293T cells, and sixfold more protein in the two canine cell lines. However, pharmacokinetic analysis in hemophilia A dogs demonstrated that cFVIII produced from cBOECs transduced with the CO-N6 transgene had significantly reduced in vivo recovery. Furthermore, this product showed reduced in vitro stability and activity on thrombin activation versus the BDD product. This trend was reversed in HEK293T lines. Overall, our results demonstrate the need for an integrated approach that not only assesses protein expression levels but also considers the influence that host-cells have on preserving the molecular and biochemical properties of the naturally occurring FVIII.
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Affiliation(s)
- Bredon Crawford
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
| | - Margareth C Ozelo
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada ; INCT do Sangue Hemocentro UNICAMP, INCT do Sangue Hemocentro UNICAMP, University of Campinas , Campinas, Brazil
| | - Kenichi Ogiwara
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
| | - James Ahlin
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
| | - Silvia Albanez
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
| | - Carol Hegadorn
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
| | - Lori Harpell
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
| | - Christine Hough
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
| | - David Lillicrap
- Department of Pathology and Molecular Medicine, Queen's University , Kingston, Ontario, Canada
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13
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Yada K, Nogami K, Takeyama M, Ogiwara K, Wakabayashi H, Shima M. Mild hemophilia A patient with novel Pro1809Leu mutation develops an anti-C2 antibody inhibiting allogeneic but not autologous factor VIII activity. J Thromb Haemost 2015; 13:1843-53. [PMID: 26278069 DOI: 10.1111/jth.13118] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2015] [Accepted: 08/10/2015] [Indexed: 11/26/2022]
Abstract
BACKGROUND In mild hemophilia A (MHA) patients, the risk of inhibitor development is generally low, but some factor VIII (FVIII) gene missense mutations are associated with a higher inhibitor incidence. OBJECTIVE To investigate the mechanism(s) of inhibitor development in MHA. METHODS AND RESULTS A patient, HA78, with MHA with a novel P1809L missense mutation in the A3 domain, exhibited significant residual FVIII activity ( FVIII C ~10 IU dL(-1) ), despite the development of an inhibitor (5.6 BU mL(-1) ). Purified HA78-IgG significantly depressed FVIII C from normal plasma but not from patient's plasma without inhibitor, indicating that this IgG inhibited allogeneic but not autologous FVIII. The HA78-IgG blocked thrombin and FXa-catalyzed FVIII cleavage but had little effect on FVIII binding to von Willebrand factor and phospholipid. The IgG recognized a C2 epitope close or overlapping the previously described anti-C2 ESH8 epitope. Similarly, a recombinant FVIII-P1809L mutant was little inactivated by HA78-IgG. This mutant demonstrated ~3-fold lower binding affinities to von Willebrand factor and phospholipid compared with wild-type, while reactions with thrombin or FXa were not impaired. Reaction of FVIII-P1809L with the alternative anti-C2 ESH4 showed only an ~20% inhibition compared with wild-type FVIII but was similar to wild-type after incubation with ESH8. A surface plasmon resonance-based assay demonstrated that anti-C2 ESH4 bound to FVIII-P1809L with ~10(2) -fold lower affinity compared with ESH8. CONCLUSION These results indicated that the P1809L mutation in A3 induced the conformational change in the FVIII molecule that hampered antigenic determinant(s) located in the C2 domain and might result in the inhibitor development.
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Affiliation(s)
- K Yada
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - K Nogami
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - M Takeyama
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - K Ogiwara
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
| | - H Wakabayashi
- Department of Biochemistry and Biophysics, University of Rochester School, Rochester, NY, USA
| | - M Shima
- Department of Pediatrics, Nara Medical University, Kashihara, Nara, Japan
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14
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Haji-Valizadeh H, Modery-Pawlowski CL, Sen Gupta A. A factor VIII-derived peptide enables von Willebrand factor (VWF)-binding of artificial platelet nanoconstructs without interfering with VWF-adhesion of natural platelets. NANOSCALE 2014; 6:4765-73. [PMID: 24658160 PMCID: PMC4300948 DOI: 10.1039/c3nr06400j] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/20/2023]
Abstract
There is substantial clinical interest in synthetic platelet analogs for potential application in transfusion medicine. To this end, our research is focused on self-assembled peptide-lipid nanoconstructs that can undergo injury site-selective adhesion and subsequently promote site-directed active platelet aggregation, thus mimicking platelet's primary hemostatic actions. For injury site-selective adhesion, we have utilized a coagulation factor FVIII-derived VWF-binding peptide (VBP). FVIII binds to VWF's D'-D3 domain while natural platelet GPIbα binds to VWF's A1 domain. Therefore, we hypothesized that the VBP-decorated nanoconstructs will adhere to VWF without mutual competition with natural platelets. We further hypothesized that the adherent VBP-decorated constructs can enhance platelet aggregation when co-decorated with a fibrinogen-mimetic peptide (FMP). To test these hypotheses, we used glycocalicin to selectively block VWF's A1 domain and, using fluorescence microscopy, studied the binding of fluorescently labeled VBP-decorated nanoconstructs versus platelets to ristocetin-treated VWF. Subsequently, we co-decorated the nanoconstructs with VBP and FMP and incubated them with human platelets to study construct-mediated enhancement of platelet aggregation. Decoration with VBP resulted in substantial construct adhesion to ristocetin-treated VWF even if the A1-domain was blocked by glycocalicin. In comparison, such A1-blocking resulted in significant reduction of platelet adhesion. Without A1-blocking, the VBP-decorated constructs and natural platelets could adhere to VWF concomitantly. Furthermore, the constructs co-decorated with VBP and FMP enhanced active platelet aggregation. The results indicate significant promise in utilizing the FVIII-derived VBP in developing synthetic platelet analogs that do not interfere with VWF-binding of natural platelets but allow site-directed enhancement of platelet aggregation when combined with FMP.
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Affiliation(s)
- Hassan Haji-Valizadeh
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio 44106, USA.
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15
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DeAngelis JP, Wakabayashi H, Fay PJ. Sequences flanking Arg336 in factor VIIIa modulate factor Xa-catalyzed cleavage rates at this site and cofactor function. J Biol Chem 2012; 287:15409-17. [PMID: 22411993 DOI: 10.1074/jbc.m111.333948] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Factor (F)VIII can be activated to FVIIIa by FXa following cleavages at Arg(372), Arg(740), and Arg(1689). FXa also cleaves FVIII/FVIIIa at Arg(336) and Arg(562) resulting in inactivation of the cofactor. These inactivating cleavages occur on a slower time scale than the activating ones. We assessed the contributions to cleavage rate and cofactor function of residues flanking Arg(336), the primary site yielding FVIII(a) inactivation, following replacement of these residues with those flanking the faster-reacting Arg(740) and Arg(372) sites and the slower-reacting Arg(562) site. Replacing P4-P3' residues flanking Arg(336) with those from Arg(372) or Arg(740) resulted in ∼4-6-fold increases in rates of FXa-catalyzed inactivation of FVIIIa, which paralleled the rates of proteolysis at Arg(336). Examination of partial sequence replacements showed a predominant contribution of prime residues flanking the scissile bonds to the enhanced rates. Conversely, replacement of this sequence with residues flanking the slow-reacting Arg(562) site yielded inactivation and cleavage rates that were ∼40% that of the WT values. The capacity for FXa to activate FVIII variants where cleavage at Arg(336) was accelerated due to flanking sequence replacement showed marked reductions in peak activity, whereas reducing the cleavage rate at this site enhanced peak activity. Furthermore, plasma-based thrombin generation assays employing the variants revealed significant reductions in multiple parameter values with acceleration of Arg(336) cleavage suggesting increased down-regulation of FXase. Overall, these results are consistent with a model of competition for activating and inactivating cleavages catalyzed by FXa that is modulated in large part by sequences flanking the scissile bonds.
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Affiliation(s)
- Jennifer P DeAngelis
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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16
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DeAngelis JP, Varfaj F, Wakabayashi H, Fay PJ. The role of P4-P3' residues flanking Arg336 in facilitating activated protein C-catalyzed cleavage and inactivation of factor VIIIa. Thromb Res 2011; 128:470-6. [PMID: 21470668 DOI: 10.1016/j.thromres.2011.03.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2011] [Revised: 03/02/2011] [Accepted: 03/09/2011] [Indexed: 10/18/2022]
Abstract
INTRODUCTION Activated protein C (APC) inactivates factor VIIIa (FVIIIa) through cleavages at Arg336 in the A1 subunit and Arg562 in the A2 subunit. Proteolysis at Arg336 occurs 25-fold faster than at Arg562. Replacing residues flanking Arg336 en bloc with the corresponding residues surrounding Arg562 markedly reduced the rate of cleavage at Arg336, indicating a role for these residues in the catalysis mechanism. MATERIALS AND METHODS To assess the contributions of individual P4-P3' residues flanking the Arg336 site to cleavage efficiency, point mutations were made based upon those flanking Arg562 of FVIIIa (Pro333Val, Gln334Asp, Leu335Gln, Met337Gly, Lys338Asn, Asn339Gln) and selected residues flanking Arg506 of FVa (Leu335Arg, and Lys338Ile). APC-catalyzed inactivation of the FVIII variants and cleavage of FVIIIa subunits were monitored by FXa generation assays and Western blotting. RESULTS Specific activity values of the variants were 60-135% of the wild type (WT) value. APC-catalyzed rates of cleavage at Arg336 remained similar to WT for the Pro333Val and Lys338Ile variants and was modestly increased for the Asn339Gln variant; while rates were reduced ~2-3-fold for the Gln334Asp, Leu335Gln, Leu335Arg, and Lys338Asn variants, and 5-fold for the Met337Gly variant. Rates for cofactor inactivation paralleled cleavage at the A1 site. APC slowly cleaves Arg372 in FVIII, a site responsible for procofactor activation. Using FVIII as substrate for APC, the Met337Gly variant yielded significantly greater activation compared with WT FVIII. CONCLUSIONS These results show that individual P4-P3' residues surrounding Arg336 are in general more favorable to cleavage than those surrounding the Arg562 site.
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Affiliation(s)
- Jennifer P DeAngelis
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, NY 14642, USA
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17
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Bos MH, Camire RM. Blood coagulation factors V and VIII: Molecular Mechanisms of Procofactor Activation. JOURNAL OF COAGULATION DISORDERS 2010; 2:19-27. [PMID: 21165149 PMCID: PMC3001592] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
A hallmark of hemostasis is that cells and proteins involved in the formation of a blood clot remain in a quiescent state and are only activated following an appropriate stimulus. The homologous proteins factors V and VIII cannot participate to any significant degree in their macromolecular enzyme complexes and are thus considered procofactors. Activity is generated following limited proteolysis, indicating that the conversion of the procofactors to factor Va and factor VIIIa must result in structural changes that impart cofactor function. The proteolytic events that lead to the activation of these proteins have been extensively characterized over the past three decades. However, a fundamental understanding of the mechanism(s) by which these proteins are kept as inactive procofactors and how specific bond cleavage facilitates the conversion to the active cofactor state is only starting to become known. These molecular processes undoubtedly play critical regulatory roles, evolved to maintain normal hemostasis since factor Va and factor VIIIa have a tremendous influence on thrombin generation. This review will detail our current understanding of the molecular process of procofactor activation and highlight structural features that play a major role in factor V and factor VIII activation.
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Affiliation(s)
- Mettine H.A. Bos
- Department of Pediatrics, Division of Hematology, The Children's Hospital of Philadelphia
| | - Rodney M. Camire
- Department of Pediatrics, Division of Hematology, The Children's Hospital of Philadelphia
- The University of Pennsylvania, School of Medicine, Philadelphia, PA, USA
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18
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Abstract
Activation of precursor proteins by specific and limited proteolysis is a hallmark of the hemostatic process. The homologous coagulation factors (F)V and FVIII circulate in an inactive, quiescent state in blood. In this so-called procofactor state, these proteins have little, if any procoagulant activity and do not participate to any significant degree in their respective macromolecular enzymatic complexes. Thrombin is considered a key physiological activator, cleaving select peptide bonds in FV and FVIII which ultimately leads to appropriate structural changes that impart cofactor function. As the active cofactors (FVa and FVIIIa) have an enormous impact on thrombin and FXa generation, maintaining FV and FVIII as inactive procofactors undoubtedly plays an important regulatory role that has likely evolved to maintain normal hemostasis. Over the past three decades there has been widespread interest in studying the proteolytic events that lead to the activation of these proteins. While a great deal has been learned, mechanistic explanations as to how bond cleavage facilitates conversion to the active cofactor species remain incompletely understood. However, recent advances have been made detailing how thrombin recognizes FV and FVIII and also how the FV B-domain plays a dominant role in maintaining the procofactor state. Here we review our current understanding of the molecular process of procofactor activation with a particular emphasis on FV.
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Affiliation(s)
- R M Camire
- Department of Pediatrics, Division of Hematology, The Children's Hospital of Philadelphia and The University of Pennsylvania, School of Medicine, Philadelphia, PA, USA.
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19
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Markoff A, Gerke V, Bogdanova N. Combined homology modelling and evolutionary significance evaluation of missense mutations in blood clotting factor VIII to highlight aspects of structure and function. Haemophilia 2009; 15:932-41. [PMID: 19473423 DOI: 10.1111/j.1365-2516.2009.02009.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Most small lesions in the factor VIII (FVIII) gene that cause haemophilia A (HA) are single nucleotide substitutions resulting in amino acid replacing (missense) mutations and leading to various phenotypes, ranging from mild to severe. We took a combined approach of homology modelling and quantitative evaluation of evolutionary significance of amino acid replacing alterations using the Grantham Matrix Score (GMS) to assess their structural effects and significance of pathological expression. Comparative homology models of all amino acid substitutions summarized in the FVIII mutations database plus these identified and reported lately by us or by our collaborators were evaluated. Altogether 640 amino acid replacing mutations were scored for potential distant or local conformation changes, influence on the molecular stability and predicted contact residues, using available FVIII domain models. The average propensity to substitute amino acid residues by mutation was found comparable to the overall probability of de novo mutations. Missense changes reported with various HA phenotypes were all confirmed significant using GMS. The fraction of these, comprising residues apparently involved in intermolecular interactions, exceeds the average proportion of such residues for FVIII. Predicted contact residues changed through mutation were visualized on the surface of FVIII domains and their possible functional implications were verified from the literature and are discussed considering available structural information. Our predictive modelling adds on the current view of domain interface molecular contacts. This structural insight could aid in part to the design of engineered FVIII constructs for therapy, to possibly enhance their stability and prolong circulating lifetime.
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Affiliation(s)
- A Markoff
- Institut für Medizinische Biochemie, ZMBE, WWU Münster, Von Esmarch Str. 56, Münster 48149, Germany.
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20
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Newell JL, Fay PJ. Cleavage at Arg-1689 influences heavy chain cleavages during thrombin-catalyzed activation of factor VIII. J Biol Chem 2009; 284:11080-9. [PMID: 19240027 DOI: 10.1074/jbc.m900234200] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The procofactor, factor VIII, is activated by thrombin or factor Xa-catalyzed cleavage at three P1 residues: Arg-372, Arg-740, and Arg-1689. The catalytic efficiency for thrombin cleavage at Arg-740 is greater than at either Arg-1689 or Arg-372 and influences reaction rates at these sites. Because cleavage at Arg-372 appears rate-limiting and dependent upon initial cleavage at Arg-740, we investigated whether cleavage at Arg-1689 influences catalysis at this step. Recombinant B-domainless factor VIII mutants, R1689H and R1689Q were prepared and stably expressed to slow and eliminate cleavage, respectively. Specific activity values for the His and Gln mutations were approximately 50 and approximately 10%, respectively, that of wild type. Thrombin activation of the R1689H variant showed an approximately 340-fold reduction in the rate of Arg-1689 cleavage, whereas the R1689Q variant was resistant to thrombin cleavage at this site. Examination of heavy chain cleavages showed approximately 4- and 11-fold reductions in A2 subunit generation and approximately 3- and 7-fold reductions in A1 subunit generation for the R1689H and R1689Q mutants, respectively. These results suggest a linkage between light chain cleavage and cleavages in heavy chain. Results obtained evaluating proteolysis of the factor VIII mutants by factor Xa revealed modest rate reductions (<5-fold) in generating A2 and A1 subunits and in cleaving light chain at Arg-1721 from either variant, suggesting little dependence upon prior cleavage at residue 1689 as compared with thrombin. Overall, these results are consistent with a competition between heavy and light chains for thrombin exosite binding and subsequent proteolysis with binding of the former chain preferred.
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Affiliation(s)
- Jennifer L Newell
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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21
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Nogami K, Saenko EL, Takeyama M, Giddings JC, Yoshioka A, Shima M. Identification of a thrombin-interactive site within the FVIII A2 domain that is responsible for the cleavage at Arg372. Br J Haematol 2007; 140:433-43. [PMID: 18081893 DOI: 10.1111/j.1365-2141.2007.06935.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
FVIII is activated by cleavage at Arg(372), Arg(740), and Arg(1689) by thrombin. This study showed that an anti-A2 monoclonal antibody, with a specific epitope for residues 484-509, and anti-FVIII inhibitor alloantibodies with similar A2 epitopes, inhibited thrombin-catalyzed FVIII activation. Sodium dodecyl sulphate polyacrylamide gel electrophoresis analysis showed that cleavage at Arg(372) but not at Arg(740) occurred at approximately fourfold decreased rate in the presence of anti-A2 antibody. Peptide 484-509 also inhibited co-factor activation, consistent with inhibition of cleavage at Arg(372). Direct binding studies using active-site modified thrombin showed that a 484-509 peptide as well as the anti-A2 antibodies blocked the A2-thrombin binding. Furthermore, covalent cross-linking was observed between the 484-509 peptide and thrombin following reaction with 1-ethyl-3-(3-dimethylaminopropyl)-carbodiimide. Mutant A2 molecules in which the clustered basic residues in this sequence were converted to alanine were used to assess the binding reactions in a surface plasmon resonance-based assay. Mutants R484A, R489A, R490A, H497A and K499A possessed two to fivefold lower affinity than wild-type A2. These findings demonstrate that clustered basic residues within the 484-509 region of the A2 domain play a part of key role in thrombin-binding, which is responsible for thrombin-catalyzed FVIII activation by cleavage at Arg(372).
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Affiliation(s)
- Keiji Nogami
- Department of Paediatrics, Nara Medical University, Kashihara, Nara, Japan.
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22
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Varfaj F, Wakabayashi H, Fay PJ. Residues Surrounding Arg336 and Arg562 Contribute to the Disparate Rates of Proteolysis of Factor VIIIa Catalyzed by Activated Protein C. J Biol Chem 2007; 282:20264-72. [PMID: 17519239 DOI: 10.1074/jbc.m701327200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Activated Protein C (APC) inactivates factor VIIIa by cleavage at Arg(336) and Arg(562) within the A1 and A2 subunits, respectively, with reaction at the former site occurring at a rate approximately 25-fold faster than the latter. Recombinant factor VIII variants possessing mutations within the P4-P3' sequences were used to determine the contributions of these residues to the disparate cleavage rates at the two P1 sites. Specific activity values for 336(P4-P3')562, 336(P4-P2)562, and 336(P1'-P3')562 mutants, where indicated residues surrounding the Arg(336) site were replaced with those surrounding Arg(562), were similar to wild type (WT) factor VIII; whereas 562(P4-P3')336 and 562(P4-P2)336 mutants showed specific activity values <1% the WT value. Inactivation rates for the 336 site mutants were reduced approximately 6-11-fold compared with WT factor VIIIa, and approached values attributed to cleavage at Arg(562). Cleavage rates at Arg(336) were reduced approximately 100-fold for 336(P4-P3')562, and approximately 9-16-fold for 336(P4-P2)562 and 336(P1'-P3')562 mutants. Inhibition kinetics revealed similar affinities of APC for WT factor VIIIa and 336(P4-P3')562 variant. Alternatively, the 562(P4-P3')336 variant showed a modest increase in cleavage rate ( approximately 4-fold) at Arg(562) compared with WT, whereas these rates were increased by approximately 27- and 6-fold for 562(P4-P3')336 and 562(P4-P2)336, respectively, using the factor VIII procofactor form as substrate. Thus the P4-P3' residues surrounding Arg(336) and Arg(562) make significant contributions to proteolysis rates at each site, apparently independent of binding affinity. Efficient cleavage at Arg(336) by APC is attributed to favorable P4-P3' residues at this site, whereas cleavage at Arg(562) can be accelerated following replacement with more optimal P4-P3' residues.
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Affiliation(s)
- Fatbardha Varfaj
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14642, USA
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23
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Newell JL, Fay PJ. Proteolysis at Arg740 facilitates subsequent bond cleavages during thrombin-catalyzed activation of factor VIII. J Biol Chem 2007; 282:25367-75. [PMID: 17595160 DOI: 10.1074/jbc.m703433200] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Thrombin activates factor VIII by proteolysis at three P1 residues: Arg372, Arg740, and Arg1689. Cleavage at Arg372 and Arg1689 are essential for procofactor activation; however cleavage at Arg740 has not been rigorously studied. To evaluate the role for cleavage at Arg740, we prepared and stably expressed two recombinant B-domainless factor VIII mutants, R740H and R740Q to slow and eliminate, respectively, cleavage at this site. Specific activity values for the variants were approximately 50 and 20%, respectively, that of wild-type factor VIII. Activation of factor VIII R740H by thrombin showed an approximately 40-fold reduction in the rate of A2 subunit generation, which reflected an approximately 20-fold reduction in cleavage rate at Arg372. Similarly, a approximately 40-fold rate reduction in cleavage at Arg1689 and consequent generation of the A3-C1-C2 subunit were observed. Rate values for A2 and A3-C1-C2 subunit generation were reduced by >700-fold and approximately 140-fold, respectively, in the R740Q variant. These results suggest that initial cleavage at Arg740 affects cleavage at both Arg372 and Arg1689 sites. Results obtained evaluating proteolysis of the factor VIII mutants by factor Xa revealed more modest rate reductions (<10-fold) in generating A2 and A3-C1-C2 subunits from either variant, suggesting that factor Xa-catalyzed activation of factor VIII was significantly less dependent upon prior cleavage at residue 740 than thrombin. Overall, these results support a model whereby cleavage of factor VIII by thrombin is an ordered pathway with cleavage at Arg740 facilitating cleavages at Arg372 and Arg1689, which result in procofactor activation.
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Affiliation(s)
- Jennifer L Newell
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, Rochester, New York 14642, USA
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24
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Varfaj F, Neuberg J, Jenkins P, Wakabayashi H, Fay P. Role of P1 residues Arg336 and Arg562 in the activated-Protein-C-catalysed inactivation of Factor VIIIa. Biochem J 2006; 396:355-62. [PMID: 16503879 PMCID: PMC1462720 DOI: 10.1042/bj20060117] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
APC (activated Protein C) inactivates human Factor VIIIa following cleavage at residues Arg336 and Arg562 within the A1 and A2 subunits respectively. The role of the P1 arginine in APC-catalysed inactivation of Factor VIIIa was examined by employing recombinant Factor VIIIa molecules where residues 336 and 562 were replaced with alanine and/or glutamine. Stably expressed Factor VIII proteins were activated by thrombin and resultant Factor VIIIa was reacted at high concentration with APC to minimize cofactor inactivation due to A2 subunit dissociation. APC cleaved wild-type Factor VIIIa at the A1 site with a rate approximately 25-fold greater than that for the A2 site. A1 mutants R336A and R336Q were inactivated approximately 9-fold slower than wild-type Factor VIIIa, whereas the A2 mutant R562A was inactivated approximately 2-fold slower. No cleavage at the mutated sites was observed. Taken together, these results suggested that cleavage at the A1 site was the dominant mechanism for Factor VIIIa inactivation catalysed by the proteinase. On the basis of cleavage at Arg336, a K(m) value for wild-type Factor VIIIa of 102 nM was determined, and this value was significantly greater than K(i) values (approximately 9-18 nM) obtained for an R336Q/R562Q Factor VIIIa. Furthermore, evaluation of a series of cluster mutants in the C-terminal region of the A1 subunit revealed a role for acidic residues in segment 341-345 in the APC-catalysed proteolysis of Arg336. Thus, while P1 residues contribute to catalytic efficiency, residues removed from these sites make a primary contribution to the overall binding of APC to Factor VIIIa.
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Affiliation(s)
- Fatbardha Varfaj
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14642, U.S.A
| | - Julie Neuberg
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14642, U.S.A
| | - P. Vincent Jenkins
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14642, U.S.A
| | - Hironao Wakabayashi
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14642, U.S.A
| | - Philip J. Fay
- Department of Biochemistry and Biophysics, University of Rochester School of Medicine, 601 Elmwood Avenue, Rochester, NY 14642, U.S.A
- To whom correspondence should be addressed (email )
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