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Suzuki A, Suzuki N, Kanematsu T, Okamoto S, Tamura S, Kikuchi R, Katsumi A, Kiyoi H, Kojima T, Matsushita T. Impact of variation in reagent combinations for one-stage clotting assay on assay discrepancy in nonsevere haemophilia A. Int J Lab Hematol 2020; 43:131-138. [PMID: 32915508 DOI: 10.1111/ijlh.13335] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2020] [Revised: 08/01/2020] [Accepted: 08/17/2020] [Indexed: 11/29/2022]
Abstract
INTRODUCTION Factor VIII activity (FVIII:C) is measured by one-stage clotting assay (OSA) or chromogenic substrate assay (CSA). Significant differences in FVIII:C between OSA (FVIII:C1st ) and CSA (FVIII:CChr ) are described as assay discrepancy in nonsevere haemophilia A (HA). A large number of reagent combinations (APTT reagent and FVIII-deficient plasma) are used for OSA, but the impact of variations in reagent combinations on assay discrepancy has not been fully characterized. AIM To clarify the variations in FVIII:C1st /FVIII:CChr ratios according to OSA reagent combination in HA subjects with/without assay discrepancy. METHODS Thirty-nine patients previously diagnosed with nonsevere HA were enrolled, and their FVIII genes were investigated and FVIII:C levels were assessed by a single CSA reagent and 11 OSA reagent combinations. Receiver operating characteristic (ROC) curve analysis was used to predict possible cut-off values of the FVIII:C1st /FVIII:CChr ratio to define FVIII assay discrepancy for each reagent combination. RESULTS Patients were categorized into nondiscrepant (n = 25), discrepant (n = 5) and unclassified (n = 9) groups according to their genotypes and information in the database. The FVIII:C1st /FVIII:CChr ratio in nondiscrepant HA varied widely, depending on the APTT reagents and FVIII-deficient plasma used. The ratio in discrepant HA patients differed with respect to their genotype and the reagent combination used. ROC curve analyses revealed that cut-off values to distinguish the assay discrepancy differed depending on the reagents used, but revealed two novel genotype variants, p.Cys573Gly and p.Gly582Arg, associated with FVIII assay discrepancy. CONCLUSION Our findings showed that the FVIII:C1st /FVIII:CChr ratio is dependent on the reagent combination used for OSA.
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Affiliation(s)
- Atsuo Suzuki
- Department of Medical Technique, Nagoya University Hospital, Nagoya, Japan
| | - Nobuaki Suzuki
- Department of Transfusion Medicine, Nagoya University Hospital, Nagoya, Japan
| | - Takeshi Kanematsu
- Department of Clinical Laboratory, Nagoya University Hospital, Nagoya, Japan
| | - Shuichi Okamoto
- Department of Haematology-Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Shogo Tamura
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Ryosuke Kikuchi
- Department of Medical Technique, Nagoya University Hospital, Nagoya, Japan
| | - Akira Katsumi
- Department of Haematology, National Centre for Geriatrics and Gerontology, Obu, Japan
| | - Hitoshi Kiyoi
- Department of Haematology-Oncology, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tetsuhito Kojima
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tadashi Matsushita
- Department of Transfusion Medicine, Nagoya University Hospital, Nagoya, Japan.,Department of Clinical Laboratory, Nagoya University Hospital, Nagoya, Japan
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Takagi Y, Murata M, Kozuka T, Nakata Y, Hasebe R, Tamura S, Takagi A, Matsushita T, Saito H, Kojima T. Missense mutations in the gene encoding prothrombin corresponding to Arg596 cause antithrombin resistance and thrombomodulin resistance. Thromb Haemost 2018; 116:1022-1031. [DOI: 10.1160/th16-03-0223] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2016] [Accepted: 08/15/2016] [Indexed: 11/05/2022]
Abstract
SummaryAntithrombin (AT) and thrombomodulin (TM) play important roles in the process of natural anticoagulation in vivo. Recently, we reported that the prothrombin Yukuhashi mutation (p.Arg596Leu) was associated with AT and TM resistance-related thrombophilia. To assess the AT and TM resistances associated with other missense mutations by single base substitution in the Arg596 codon, we generated recombinant variants (596Gln, 596Trp, 596Gly, and 596Pro) and investigated the effects on AT and TM anticoagulant functions. All variants except 596Pro were secreted in amounts comparable to that of the wild-type but exhibited variable procoagulant activities. After a 30-minute inactivation by AT, the relative residual activity of wild-type thrombin decreased to 15 ± 4.0%, in contrast to values of all variants were maintained at above 80%. The thrombin–AT complex formation, as determined by enzyme-linked immunosorbent assay, was reduced with all tested variants in the presence and absence of heparin. In the presence of soluble TM (sTM), the relative fibrinogen clotting activity of wild-type thrombin decreased to 16 ± 0.12%, whereas that of tested variants was 37%–56%. In a surface plasmon resonance assay, missense Arg596 mutations reduced thrombin–TM affinity to an extent similar to the reduction of fibrinogen clotting inhibition. In the presence of sTM or cultured endothelial-like cells, APC generation was enhanced differently by variant thrombins in a thrombin–TM affinity- dependent manner. These data indicate that prothrombin Arg596 missense mutations lead to AT and TM resistance in the variant thrombins and suggest that prothrombin Arg596 is important for AT- and TM- mediated anticoagulation.
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Tamura S, Murata-Kawakami M, Takagi Y, Suzuki S, Katsumi A, Takagi A, Kojima T. In vitro exploration of latent prothrombin mutants conveying antithrombin resistance. Thromb Res 2017; 159:33-38. [PMID: 28961453 DOI: 10.1016/j.thromres.2017.09.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2017] [Revised: 09/05/2017] [Accepted: 09/19/2017] [Indexed: 11/30/2022]
Abstract
INTRODUCTION Antithrombin resistance (ATR) prothrombinemia is an inherited thrombophilic disorder caused by missense mutations in prothrombin gene (F2) at Arg596 of the sodium-binding region. Previously, prothrombin mutants Yukuhashi (Arg596Leu), Belgrade (Arg596Gln), and Padua 2 (Arg596Trp) were reported as ATR-prothrombins possessing a risk of familial venous thrombosis. To identify additional F2 mutations causing the ATR-phenotype, we investigated the coagulant properties of recombinant prothrombins mutated at amino acid residues within the sodium-binding region by single nucleotide substitutions (Thr540, Arg541, Glu592, and Lys599). MATERIALS AND METHODS We constructed expression vectors of prothrombin mutants, established stably transfected HEK293 cells, and isolated the recombinant prothrombin proteins. We evaluated procoagulant activity and ATR-phenotypes of those mutants in reconstituted plasma by mixing with prothrombin deficient plasma. RESULTS The secreted quantity of all prothrombin mutants was the same as that of the wild-type prothrombin. Procoagulant activity of each mutant varied from 1.7% to 79.5% in a one-stage clotting assay and from 2.0% to 104.5% in a two-stage chromogenic assay. Most prothrombin mutants tested presented with a severe ATR-phenotype. To estimate the thrombosis risk of these mutations, we determined the residual clotting activity (RCA) after 30min inactivation with antithrombin. RCA scores, normalized to the wild-type, revealed that prothrombin mutants Lys599Arg (5.35) and Glu592Gln (4.71) had high scores, which were comparable with prothrombins Yukuhashi (4.36) and Belgrade (5.19). CONCLUSIONS Mutation of prothrombin at the sodium-binding site caused ATR-phenotypes. Of those tested, Lys599Arg and Glu592Gln may possess a thrombosis risk as large as the known pathogenic prothrombins Yukuhashi and Belgrade.
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Affiliation(s)
- Shogo Tamura
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Moe Murata-Kawakami
- Department of Transfusion Medicine, Nagoya University Hospital, Nagoya, Japan
| | - Yuki Takagi
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan; Japan Society for the Promotion of Science, Tokyo, Japan
| | - Sachiko Suzuki
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Akira Katsumi
- Department of Transfusion Medicine, National Center for Geriatrics and Gerontology, Obu, Japan
| | - Akira Takagi
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
| | - Tetsuhito Kojima
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan.
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Mallet C, Lamribet K, Giraud S, Dupuis-Girod S, Feige JJ, Bailly S, Tillet E. Functional analysis of endoglin mutations from hereditary hemorrhagic telangiectasia type 1 patients reveals different mechanisms for endoglin loss of function. Hum Mol Genet 2014; 24:1142-54. [PMID: 25312062 DOI: 10.1093/hmg/ddu531] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Hereditary hemorrhagic telangiectasia (HHT) is an autosomal dominant inheritable vascular dysplasia caused by mutations in genes encoding either endoglin or activin receptor-like kinase-1 (ALK1). Functional significance of endoglin missense mutations remains largely unknown leading to a difficult discrimination between polymorphisms and pathogenic mutations. In order to study the functional significance of endoglin mutations and to help HHT1 diagnosis, we developed a cellular assay based on the ability of endoglin to enhance ALK1 response to bone morphogenetic protein 9 (BMP9). We generated and characterized 31 distinct ENG mutants reproducing human HHT1 missense mutations identified in patients of the Molecular Genetics Department in Lyon. We found that 16 mutants behaved like wild-type (WT) endoglin, and thus corresponded to benign rare variants. The 15 other variants showed defects in BMP9 response and were identified as pathogenic mutations. Interestingly, two mutants (S278P and F282V) had lost their ability to bind BMP9, identifying two crucial amino acids for BMP9 binding to endoglin. For all the others, the functional defect was correlated with a defective trafficking to the cell surface associated with retention in the endoplasmic reticulum. Further, we demonstrated that some intracellular mutants dimerized with WT endoglin and impaired its cell-surface expression thus acting as dominant-negatives. Taken together, we show that endoglin loss-of-function can result from different mechanisms in HHT1 patients. We also provide a diagnostic tool helping geneticists in screening for novel or conflicting ENG mutations.
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Affiliation(s)
- Christine Mallet
- Inserm, U1036, Grenoble F-38000, France, CEA, DSV, iRTSV, Laboratoire Biologie du Cancer et de L'Infection, Grenoble F-38000, France, University Grenoble-Alpes, Grenoble F-38000, France
| | - Khadija Lamribet
- Inserm, U1036, Grenoble F-38000, France, CEA, DSV, iRTSV, Laboratoire Biologie du Cancer et de L'Infection, Grenoble F-38000, France, University Grenoble-Alpes, Grenoble F-38000, France
| | - Sophie Giraud
- Hôpital Edouard Herriot Service de Génétique Moléculaire et Clinique, Lyon, France and
| | - Sophie Dupuis-Girod
- Hospices Civils de Lyon, Hôpital Louis Pradel, Genetic Department and National Reference Center for Rendu-Osler Disease, France
| | - Jean-Jacques Feige
- Inserm, U1036, Grenoble F-38000, France, CEA, DSV, iRTSV, Laboratoire Biologie du Cancer et de L'Infection, Grenoble F-38000, France, University Grenoble-Alpes, Grenoble F-38000, France
| | - Sabine Bailly
- Inserm, U1036, Grenoble F-38000, France, CEA, DSV, iRTSV, Laboratoire Biologie du Cancer et de L'Infection, Grenoble F-38000, France, University Grenoble-Alpes, Grenoble F-38000, France
| | - Emmanuelle Tillet
- Inserm, U1036, Grenoble F-38000, France, CEA, DSV, iRTSV, Laboratoire Biologie du Cancer et de L'Infection, Grenoble F-38000, France, University Grenoble-Alpes, Grenoble F-38000, France,
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Okuyama E, Suzuki A, Murata M, Ando Y, Kato I, Takagi Y, Takagi A, Murate T, Saito H, Kojima T. Molecular mechanisms of syndecan-4 upregulation by TNF-α in the endothelium-like EAhy926 cells. J Biochem 2013; 154:41-50. [PMID: 23576453 DOI: 10.1093/jb/mvt024] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Syndecan-4, a cell-surface heparan sulfate proteoglycan, can participate in inflammation and wound healing as a host defense molecule. Tumour necrosis factor (TNF)-α, one of the most potent proinflammatory cytokines, is known to upregulate syndecan-4 expression, but the precise mechanisms are unclear. To elucidate these mechanisms in detail, we examined syndecan-4 upregulation by TNF-α in the endothelium-like EAhy926 cell. Of the two putative nuclear factor kappa-B (NF-κB) binding sites in the syndecan-4 gene (SDC4) promoter, deletion or mutation of one or both sites significantly diminished the effects of TNF-α. Electrophoretic mobility shift assays showed that p65 and c-Rel, but not p50, bound to these NF-κB binding sites, whereas pull-down assays showed binding of all three NF-κB components. Chromatin immunoprecipitation assays clearly showed that p65 and phosphorylated p65, but not p50 or c-Rel, bound to the SDC4 promoter. An NF-κB inhibitor, p65 knockdown and a transcriptional elongation inhibitor completely blocked the effect of TNF-α on SDC4 promoter activity and significantly, but not completely, blocked that on SDC4 mRNA expression. These data suggest that NF-κB p65 could be a key mediator of syndecan-4 upregulation by TNF-α through two binding sites in the SDC4 promoter, but other NF-κB-p65 independent pathways might also be involved through transcriptional elongation.
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Affiliation(s)
- Eriko Okuyama
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya 461-8673, Japan
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Miyawaki Y, Suzuki A, Fujita J, Maki A, Okuyama E, Murata M, Takagi A, Murate T, Kunishima S, Sakai M, Okamoto K, Matsushita T, Naoe T, Saito H, Kojima T. Thrombosis from a prothrombin mutation conveying antithrombin resistance. N Engl J Med 2012; 366:2390-6. [PMID: 22716977 DOI: 10.1056/nejmoa1201994] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We identified a novel mechanism of hereditary thrombosis associated with antithrombin resistance, with a substitution of arginine for leucine at position 596 (p.Arg596Leu) in the gene encoding prothrombin (called prothrombin Yukuhashi). The mutant prothrombin had moderately lower activity than wild-type prothrombin in clotting assays, but the formation of thrombin-antithrombin complex was substantially impaired. A thrombin-generation assay revealed that the peak activity of the mutant prothrombin was fairly low, but its inactivation was extremely slow in reconstituted plasma. The Leu596 substitution caused a gain-of-function mutation in the prothrombin gene, resulting in resistance to antithrombin and susceptibility to thrombosis.
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Affiliation(s)
- Yuhri Miyawaki
- Department of Pathophysiological Laboratory Sciences, Nagoya University Graduate School of Medicine, Nagoya, Japan
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