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  1. Article ; Online: Natural anticoagulant discovery, the gift that keeps on giving: finding FV-Short.

    Dahlbäck, Björn

    Journal of thrombosis and haemostasis : JTH

    2023  Volume 21, Issue 4, Page(s) 716–727

    Abstract: The complex reactions of blood coagulation are balanced by several natural anticoagulants resulting in tuned hemostasis. During several decades, the knowledge base of the natural anticoagulants has greatly increased and we have also learned about ... ...

    Abstract The complex reactions of blood coagulation are balanced by several natural anticoagulants resulting in tuned hemostasis. During several decades, the knowledge base of the natural anticoagulants has greatly increased and we have also learned about antiinflammatory and cytoprotective activities expressed by antithrombin and activated protein C (APC). Some coagulation proteins have also been found to function as anticoagulants; e.g., thrombin when bound to thrombomodulin activates protein C. Another example is factor V (FV), which in addition to being a procofactor to FVa has emerged as an anticoagulant. The discovery of APC resistance, caused by FVLeiden, as a thrombosis risk factor resulted in the identification of FV as an APC cofactor working in synergy with protein S in the regulation of FVIIIa in the Xase complex. More recently, a natural anticoagulant FV splice isoform (FV-Short) was discovered when investigating the East Texas bleeding disorder. In FV-Short, the truncated B domain exposes a high-affinity binding site for tissue factor pathway inhibitor alpha (TFPIα), and together with protein S a high-affinity trimolecular complex is generated. The FXa-inhibitory activity of TFPIα is synergistically stimulated by FV-Short and protein S. The circulating FV-Short/protein S/TFPIα complex concentration is normally low (≈0.2 nM) but provides an anticoagulant threshold. In the East Texas bleeding, the concentration of the complex, and thus the threshold, is increased 10-fold, which results in bleeding manifestations. The anticoagulant properties of FV were discovered during investigations of individual patients and follow the great tradition of bed-to-bench and bench-to-bed research in the coagulation field.
    MeSH term(s) Humans ; Anticoagulants/chemistry ; Protein C/metabolism ; Factor V/metabolism ; Protein S/metabolism ; Blood Coagulation
    Chemical Substances Anticoagulants ; Protein C ; Factor V (9001-24-5) ; Protein S
    Language English
    Publishing date 2023-02-04
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2112661-6
    ISSN 1538-7836 ; 1538-7933
    ISSN (online) 1538-7836
    ISSN 1538-7933
    DOI 10.1016/j.jtha.2023.01.033
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  2. Article ; Online: Advances in Understanding Mechanisms of Thrombophilic Disorders.

    Dahlbäck, Björn

    Hamostaseologie

    2020  Volume 40, Issue 1, Page(s) 12–21

    Abstract: Venous thromboembolism constitutes a major medical problem afflicting millions of individuals worldwide each year. Its pathogenesis is multifactorial, involving both environmental and genetic risk factors. The most common genetic risk factor known to ... ...

    Abstract Venous thromboembolism constitutes a major medical problem afflicting millions of individuals worldwide each year. Its pathogenesis is multifactorial, involving both environmental and genetic risk factors. The most common genetic risk factor known to date is a mutation in the factor V (FV) gene (R506Q or FV Leiden), which impairs the normal regulation of FV by activated protein C (APC). APC is an important regulator of blood coagulation, cleaving and inactivating not only FV/FVa but also activated factor VIII (FVIIIa). In FVa, APC cleaves several sites, Arg506 (R506) being one of them. The R506Q mutation results in the APC resistance phenotype and a lifelong hypercoagulable state. A prothrombin gene mutation is another relatively frequent thrombosis risk factor, whereas deficiencies of the anticoagulant proteins antithrombin, protein C, or protein S are less common. As a result of the high prevalence of FV and prothrombin mutations in the general population, combinations of genetic defects are relatively common. Such individuals have highly increased risk of thrombosis.
    MeSH term(s) Humans ; Thrombophilia/genetics
    Language English
    Publishing date 2020-01-28
    Publishing country Germany
    Document type Journal Article ; Review
    ZDB-ID 801512-0
    ISSN 2567-5761 ; 0720-9355
    ISSN (online) 2567-5761
    ISSN 0720-9355
    DOI 10.1055/s-0040-1701612
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Article ; Online: Low FV beneficial in FVFVIII deficiency?

    Dahlbäck, Björn

    Blood

    2019  Volume 134, Issue 20, Page(s) 1686–1688

    MeSH term(s) Blood Coagulation Tests ; Disease Susceptibility ; Factor V ; Factor V Deficiency ; Factor VIII ; Humans
    Chemical Substances Factor V (9001-24-5) ; Factor VIII (9001-27-8)
    Language English
    Publishing date 2019-11-13
    Publishing country United States
    Document type Journal Article ; Comment
    ZDB-ID 80069-7
    ISSN 1528-0020 ; 0006-4971
    ISSN (online) 1528-0020
    ISSN 0006-4971
    DOI 10.1182/blood.2019003243
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  4. Article ; Online: Treating hemophilia by targeting protein S?

    Dahlbäck, Björn

    Blood

    2018  Volume 131, Issue 12, Page(s) 1271–1272

    MeSH term(s) Anticoagulants ; Hemophilia A ; Hemophilia B ; Hemostasis ; Humans ; Protein S
    Chemical Substances Anticoagulants ; Protein S
    Language English
    Publishing date 2018-03-22
    Publishing country United States
    Document type Journal Article ; Comment
    ZDB-ID 80069-7
    ISSN 1528-0020 ; 0006-4971
    ISSN (online) 1528-0020
    ISSN 0006-4971
    DOI 10.1182/blood-2018-01-828152
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Lean ApoM

    Dahlbäck, Björn

    Trends in endocrinology and metabolism: TEM

    2018  Volume 29, Issue 5, Page(s) 283–284

    Abstract: In Cell Reports, Christoffersen et al. [1] demonstrate that sphingosine 1-phosphate (S1P) bound to apolipoprotein M (apoM) regulates the activity and mass of brown adipose tissue (BAT). They found mice lacking apoM to have hyperactive BAT with high ... ...

    Abstract In Cell Reports, Christoffersen et al. [1] demonstrate that sphingosine 1-phosphate (S1P) bound to apolipoprotein M (apoM) regulates the activity and mass of brown adipose tissue (BAT). They found mice lacking apoM to have hyperactive BAT with high triglyceride (TG) utilization, resulting in low white adipose tissue (WAT) mass and low body weight.
    MeSH term(s) Adipose Tissue, Brown ; Animals ; Apolipoproteins ; Apolipoproteins M ; Lysophospholipids ; Mice ; Receptors, Lysosphingolipid ; Sphingosine/analogs & derivatives ; Triglycerides
    Chemical Substances ApoM protein, mouse ; Apolipoproteins ; Apolipoproteins M ; Lysophospholipids ; Receptors, Lysosphingolipid ; Triglycerides ; sphingosine 1-phosphate (26993-30-6) ; Sphingosine (NGZ37HRE42)
    Language English
    Publishing date 2018-03-13
    Publishing country United States
    Document type Journal Article ; Comment
    ZDB-ID 1042384-9
    ISSN 1879-3061 ; 1043-2760
    ISSN (online) 1879-3061
    ISSN 1043-2760
    DOI 10.1016/j.tem.2018.02.011
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  6. Article: Advances in Understanding Mechanisms of Thrombophilic Disorders

    Dahlbäck, Björn

    Hämostaseologie

    2020  Volume 40, Issue 01, Page(s) 12–21

    Abstract: Venous thromboembolism constitutes a major medical problem afflicting millions of individuals worldwide each year. Its pathogenesis is multifactorial, involving both environmental and genetic risk factors. The most common genetic risk factor known to ... ...

    Abstract Venous thromboembolism constitutes a major medical problem afflicting millions of individuals worldwide each year. Its pathogenesis is multifactorial, involving both environmental and genetic risk factors. The most common genetic risk factor known to date is a mutation in the factor V (FV) gene (R506Q or FV Leiden), which impairs the normal regulation of FV by activated protein C (APC). APC is an important regulator of blood coagulation, cleaving and inactivating not only FV/FVa but also activated factor VIII (FVIIIa). In FVa, APC cleaves several sites, Arg506 (R506) being one of them. The R506Q mutation results in the APC resistance phenotype and a lifelong hypercoagulable state. A prothrombin gene mutation is another relatively frequent thrombosis risk factor, whereas deficiencies of the anticoagulant proteins antithrombin, protein C, or protein S are less common. As a result of the high prevalence of FV and prothrombin mutations in the general population, combinations of genetic defects are relatively common. Such individuals have highly increased risk of thrombosis.
    Keywords APC resistance ; FV Leiden ; TFPI
    Language English
    Publishing date 2020-01-28
    Publisher Georg Thieme Verlag KG
    Publishing place Stuttgart ; New York
    Document type Article
    ZDB-ID 801512-0
    ISSN 2567-5761 ; 0720-9355
    ISSN (online) 2567-5761
    ISSN 0720-9355
    DOI 10.1055/s-0040-1701612
    Database Thieme publisher's database

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  7. Article ; Online: A hydrophobic patch (PLVIVG; 1481-1486) in the B-domain of factor V-short is crucial for its synergistic TFPIα-cofactor activity with protein S and for the formation of the FXa-inhibitory complex comprising FV-short, TFPIα, and protein S.

    Dahlbäck, Björn / Tran, Sinh

    Journal of thrombosis and haemostasis : JTH

    2022  Volume 20, Issue 5, Page(s) 1146–1157

    Abstract: Background: Factor V-short (FV756-1458) is a natural splice variant functioning in synergy with protein S as tissue factor pathway inhibitor alpha (TFPIα)-cofactor in inhibition of factor Xa (FXa). An exposed acid region (AR2; 1493-1537) in the B domain ...

    Abstract Background: Factor V-short (FV756-1458) is a natural splice variant functioning in synergy with protein S as tissue factor pathway inhibitor alpha (TFPIα)-cofactor in inhibition of factor Xa (FXa). An exposed acid region (AR2; 1493-1537) in the B domain binds TFPIα. The preAR2 (1458-1492) is crucial for the synergistic TFPIα-cofactor activity between FV-short and protein S and for assembly of a trimolecular FXa-inhibitory complex among FV-short, protein S, and TFPIα.
    Objective: To identify which part of preAR2 is required for the synergistic TFPIα-cofactor activity between FV-short and protein S.
    Methods: A FXa-inhibition assay was used to test the synergistic TFPIα cofactor activity between protein S and new FV-short variants FV709-1476, FV712-1478, FV712-1481, FV712-1484, FV712-1487, and FV712-1490. A microtiter-based assay analyzed binding among FV-short variants, protein S, and TFPIα.
    Results: FV709-1476, FV712-1478, and FV712-1481 were fully active as synergistic TFPIα cofactors with protein S; FV712-1484 showed intermediate activity; and FV712-1487 and FV712-1490 were inactive. TFPIα interacted with all variants in the absence of protein S but FV712-1478 and FV712-1481 bound TFPIα with highest affinity. None of the FV-short variants bound directly to protein S in the absence of TFPIα. In the presence of TFPIα, efficient cooperative binding was demonstrated between protein S, TFPIα, and FV709-1476, FV712-1478, or FV712-1481. In contrast, no cooperativity among TFPIα, protein S, and FV712-1484, FV712-1487, or FV712-1490 was seen.
    Conclusion: A short hydrophobic patch in preAR2 (PLVIVG, 1481-1486) in FV-short is crucial for the synergistic TFPIα-cofactor activity between FV-short and protein S and for the assembly of a trimolecular FXa-inhibitory complex among FV-short, protein S, and TFPIα.
    MeSH term(s) Blood Coagulation ; Factor V/metabolism ; Factor Xa/metabolism ; Humans ; Hydrophobic and Hydrophilic Interactions ; Lipoproteins ; Protein S/metabolism ; Thrombin/metabolism
    Chemical Substances Lipoproteins ; Protein S ; lipoprotein-associated coagulation inhibitor ; Factor V (9001-24-5) ; Thrombin (EC 3.4.21.5) ; Factor Xa (EC 3.4.21.6)
    Language English
    Publishing date 2022-03-16
    Publishing country England
    Document type Journal Article
    ZDB-ID 2112661-6
    ISSN 1538-7836 ; 1538-7933
    ISSN (online) 1538-7836
    ISSN 1538-7933
    DOI 10.1111/jth.15690
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  8. Article ; Online: Vitamin K-Dependent Protein S: Beyond the Protein C Pathway.

    Dahlbäck, Björn

    Seminars in thrombosis and hemostasis

    2017  Volume 44, Issue 2, Page(s) 176–184

    Abstract: Protein S is a vitamin K-dependent plasma glycoprotein circulating in plasma at a concentration of around 350 nM. Approximately 60% of protein S in human plasma is bound to the complement regulatory protein C4b-binding protein (C4BP) in a high-affinity, ... ...

    Abstract Protein S is a vitamin K-dependent plasma glycoprotein circulating in plasma at a concentration of around 350 nM. Approximately 60% of protein S in human plasma is bound to the complement regulatory protein C4b-binding protein (C4BP) in a high-affinity, high-molecular-weight complex. Protein S in plasma has multiple anticoagulant properties and heterozygous protein S deficiency is associated with increased risk of venous thrombosis. Homozygous deficiency in man and mice is associated with severe thrombosis in fetal life, defects in the vascular system development, and not compatible with life. Protein S has additional functions beyond being an anticoagulant. It affects the complement regulatory properties of C4BP, and moreover, protein S interacts with tyrosine kinase receptors of the TAM family, which comprises Tyro3, Axl, and Mer. The TAM receptor interaction is important for the ability of protein S to stimulate phagocytosis of apoptotic cells. This review will discuss the multiple functions of protein S, describing its role as cofactor to activated protein C with a subsequent focus on the other functions of protein S.
    MeSH term(s) Blood Coagulation/physiology ; Blood Coagulation Tests/methods ; Humans ; Protein S/metabolism
    Chemical Substances Protein S
    Language English
    Publishing date 2017-09-13
    Publishing country United States
    Document type Journal Article ; Review
    ZDB-ID 196901-8
    ISSN 1098-9064 ; 0094-6176
    ISSN (online) 1098-9064
    ISSN 0094-6176
    DOI 10.1055/s-0037-1604092
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: The preAR2 region (1458-1492) in factor V-Short is crucial for the synergistic TFPIα-cofactor activity with protein S and the assembly of a trimolecular factor Xa-inhibitory complex comprising FV-Short, protein S, and TFPIα.

    Dahlbäck, Björn / Tran, Sinh

    Journal of thrombosis and haemostasis : JTH

    2021  Volume 20, Issue 1, Page(s) 58–68

    Abstract: Background: Factor V-Short (FV756-1458) is a natural splice variant in which 702 residues are deleted from the B domain. It exposes an acid region (AR2; 1493-1537) that binds tissue factor pathway inhibitor alpha (TFPIα). Protein S also interacts with ... ...

    Abstract Background: Factor V-Short (FV756-1458) is a natural splice variant in which 702 residues are deleted from the B domain. It exposes an acid region (AR2; 1493-1537) that binds tissue factor pathway inhibitor alpha (TFPIα). Protein S also interacts with TFPIα and serves as TFPIα-cofactor in factor Xa (FXa) inhibition. FV-Short and protein S function as synergistic TFPIα-cofactors in inhibition of FXa. FV810-1492 is an artificial FV-Short variant that cannot synergize with protein S as TFPIα cofactor even though it contains AR2 and binds TFPIα.
    Objective: To elucidate the mechanisms for the synergism between FV756-1458 and protein S as TFPIα cofactors.
    Methods: Four FV-Short variants were created, FV756-1458 and FV712-1458 contained the preAR2 region (1458-1492), whereas FV810-1492 and FV713-1492 lacked this region. The synergistic TFPIα cofactor activity between FV-Short variants and protein S was analyzed by FXa-inhibition. A microtiter-based assay tested binding between FV-Short variants, protein S, and TFPIα.
    Results: The two preAR2-containing FV-Short variants were active as synergistic TFPIα cofactors, whereas the other two were inactive. All variants bound to TFPIα. None of the FV-Short variants bound directly to protein S. The combination of TFPIα and preAR2-containing FV-Short variants bound protein S, whereas TFPIα together with the preAR2-minus variants did not. Protein S potentiated TFPIα-binding to the preAR2-containing variants and binding between TFPIα and protein S was stimulated only by the preAR2-containing variants.
    Conclusion: The preAR2 region is demonstrated to be crucial for the synergistic TFPIα-cofactor activity between FV-Short and protein S and for the assembly of a trimolecular FXa-inhibitory complex comprising FV-Short, protein S, and TFPIα.
    MeSH term(s) Blood Coagulation ; Factor V/metabolism ; Factor Xa/metabolism ; Humans ; Lipoproteins ; Protein S/metabolism ; Thrombin/metabolism
    Chemical Substances Lipoproteins ; Protein S ; lipoprotein-associated coagulation inhibitor ; Factor V (9001-24-5) ; Thrombin (EC 3.4.21.5) ; Factor Xa (EC 3.4.21.6)
    Language English
    Publishing date 2021-10-19
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2112661-6
    ISSN 1538-7836 ; 1538-7933
    ISSN (online) 1538-7836
    ISSN 1538-7933
    DOI 10.1111/jth.15547
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  10. Article ; Online: Pro- and anticoagulant properties of factor V in pathogenesis of thrombosis and bleeding disorders.

    Dahlbäck, Björn

    International journal of laboratory hematology

    2016  Volume 38 Suppl 1, Page(s) 4–11

    Abstract: Factor V (FV) serves an important role in the regulation of blood coagulation, having both pro- and anticoagulant properties. The circulating high molecular weight single-chain FV molecule undergoes a series of proteolytic cleavages during both ... ...

    Abstract Factor V (FV) serves an important role in the regulation of blood coagulation, having both pro- and anticoagulant properties. The circulating high molecular weight single-chain FV molecule undergoes a series of proteolytic cleavages during both activation of coagulation and during anticoagulant regulation of coagulation by activated protein C (APC). It is noteworthy that mutations in the factor V gene (F5) either cause thrombosis or bleeding. New insights into the importance and complexity of FV functions have been generated from elucidation of the pathogenic mechanisms of two familial mutations in the F5 gene. The first mutation was identified as a result of the discovery of APC resistance as the most common risk factor for venous thrombosis. The mutation (FV Leiden) predicts the Arg(506) Gln replacement, which impairs the normal regulation of FVa by APC, as the Arg506 site is an important APC cleavage site. In addition, elucidation of APC resistance resulted in the discovery of the anticoagulant APC cofactor activity of FV. The second FV mutation (FV(A2440G) ), identified in a family with an autosomal dominant bleeding disorder, has led to the discovery of an alternative splicing generating a previously unidentified FV isoform (FV-Short), which inhibits coagulation via an unexpected and intriguing mechanism involving the coagulation inhibitor TFPI-α. These are naturally occurring mutations in the F5 gene that have generated new knowledge on the role of FV in regulation of coagulation and the importance of genetic risk factors for thrombosis and bleeding.
    MeSH term(s) Activated Protein C Resistance ; Blood Coagulation/genetics ; Blood Coagulation Disorders/blood ; Blood Coagulation Disorders/etiology ; Blood Coagulation Disorders/genetics ; Factor V/genetics ; Factor V/physiology ; Humans ; Lipoproteins ; Mutation ; Thrombosis/blood ; Thrombosis/etiology ; Thrombosis/genetics
    Chemical Substances Lipoproteins ; lipoprotein-associated coagulation inhibitor ; Factor V (9001-24-5)
    Language English
    Publishing date 2016-05
    Publishing country England
    Document type Journal Article ; Review
    ZDB-ID 2268590-X
    ISSN 1751-553X ; 1751-5521 ; 0141-9854
    ISSN (online) 1751-553X
    ISSN 1751-5521 ; 0141-9854
    DOI 10.1111/ijlh.12508
    Database MEDical Literature Analysis and Retrieval System OnLINE

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