scholarly journals Characterization of des-(741–1668)-factor VIII, a single-chain factor VIII variant with a fusion site susceptible to proteolysis by thrombin and factor Xa

1995 ◽  
Vol 312 (1) ◽  
pp. 49-55 ◽  
Author(s):  
M J S H Donath ◽  
R T M de Laaf ◽  
P T M Biessels ◽  
P J Lenting ◽  
J W van de Loo ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Heavy Chain ◽  
Light Chain ◽  
Factor Xa ◽  
Single Chain ◽  
Factor Ixa ◽  
Fusion Site ◽  
Von Willebrand ◽  
Willebrand Factor

A factor VIII variant has been characterized in which the heavy chain is directly fused to the light chain. Des-(741-1668)-factor VIII lacks the processing site at Arg1648, as Arg740 of the heavy chain is fused to Ser1669 of the light chain. The sequence of the fusion site is similar to that of other cleavage sites in factor VIII. The fusion site of des-(741-1668)-factor VIII was readily cleaved by both thrombin and factor Xa, and the same result was obtained for heavy chain cleavage. In contrast, des-(741-1668)-factor VIII cleavage by thrombin at position Arg1689 proceeded at a lower rate than the analogous cleavage by factor Xa, which presumably takes place at position Arg1721. The rate of cleavage at position Arg1689 by thrombin was also lower than that at the other processing sites. When des-(741-1668)-factor VIII was activated by thrombin, initial rates of factor Xa formation were similar to the rates obtained when plasma-derived factor VIII was activated by thrombin or factor Xa. Remarkably, activation of des-(741-1668)-factor VIII proceeded at a higher rate by factor Xa than by thrombin. These results indicate that factor VIII activation is strongly associated with cleavage at position Arg1689 or Arg1721. For the interaction between des-(741-1668)-factor VIII and von Willebrand factor, a Kd value of (0.8 +/- 0.3) x 10(-10) M was determined, which is similar to that of heterodimeric factor VIII. The affinity of single-chain des-(741-1668)-factor VIII for factor IXa was found to be 27 +/- 6 nM. The in vivo recovery and half-life of des-(741-1668)-factor VIII were assessed in guinea pigs. Upon infusion of des-(741-1668)-factor VIII at a dosage of 50 units/kg body weight, a rise of 1.0 +/- 0.3 unit/ml in factor VIII activity was obtained. The same recovery was determined for wild-type factor VIII. The half-life of des-(741-1668)-factor VIII was found to be 3 +/- 1 h, compared with 4 +/- 2 h for heterodimeric recombinant factor VIII. In conclusion, des-(741-1668)-factor VIII displays normal activity, is readily cleaved by thrombin and factor Xa at its fusion site, binds with high affinity to von Willebrand factor and factor IXa, and behaves like heterodimeric recombinant factor VIII in guinea pigs. By virtue of these properties, des-(741-1668)-factor VIII may prove useful for the treatment of bleeding episodes in patients with haemophilia A.

THE INTERACTION BETWEEN FACTOR VIII AND VON WILLEBRAND FACTOR

1987 ◽  
Author(s):  
Joost A Koedam ◽  
Rob J Hamer ◽  
Nel H Beeser-Visser ◽  
Etienne Jap Tjoen San ◽  
Kees Schippers ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Heavy Chain ◽  
Light Chain ◽  
Disulfide Bonds ◽  
Factor Xa ◽  
Exchange Chromatography ◽  
Solid Matrix ◽  
Von Willebrand ◽  
Willebrand Factor

Factor VIII (FVIII) circulates in plasma as a non-covalent complex with von Willebrand factor (VWF), a large multimeric adhesive glycoprotein. VWF serves as a carrier for FVIII and is thought to stabilize FVIII. The interaction between the two proteins was studied by binding purified human 125I-FVIII to VWF which was coated on a solid matrix. Experiments employing isolated heavy and light chains of FVIII and monoclonal antibodies indicated that binding occurred through the carboxyterminal 80kDa light chain of factor VIII. Treatment of VWF-bound 125I-FVIII with thrombin resulted in the release of a light chain-derived 70kDa fragment and a heavy chain-derived 50kDa fragment. A 42kDa heavy chain-derived fragment was found in the fraction which remained bound to VWF. Treatment with factor Xa (FXa) resulted in the release of 63, 50, 45, and 42kDa fragments. No phospholipids were required for proteolysis of FVIII by either of these enzymes. In solution, the activation of FVIII by FXa, but not by thrombin, was inhibited by VWF. Neither activation, nor cleavage or release from VWF were observed when FVIII was incubated with factor IXa. Activation of FVIII was parallelled by its release from VWF. We conclude that the thrombin-activated form of FVIII consists of a complex between the 70kDa and 50kDa fragments. Inactivation of FVIII by activated protein C (APC) was inhibited when FVIII was complexed to VWF. This protective effect of VWF was abolished upon activation of FVIII and its subsequent release from VWF.In order to locate the binding site for FVIII on the VWF molecule, we digested VWF with Staphylococcal V8 protease (Sp). Digestion products were isolated with Mono Q ion-exchange chromatography and identified as Spl (39 kDa), SpII dimers (220 kDa) and Spill dimers (a triplet ranging from 210-280 kDa) by their molecular weight and chromatographic behaviour (J.-P. Girma et al.. Biochemistry 1986, 25:3156-3163). Purified VWF or digestion products were spotted on nitrocellulose paper, followed by blocking with an albumin solution. Binding of FVIII was studied by incubating the filters with 125I-FVIII, followed by autoradiography. Fifty ng of VWF was sufficient in order to detect FVIII binding. No binding was observed to partially reduced dimeric undigested VWF. Of the isolated digestion products, only the SpIII dimer was able to bind 125I-FVIII. After Western blotting of VWF-fragments from SDS-polyacrylamide gels, 125I-FVIII bound only to the bands which represented SpIII. Therefore, the domain on VWF responsible for the binding of FVIII seems to be located on its aminoterminal SpIII fragment. The integrity of internal disulfide bonds and dimerisation of VWF are required for FVIII binding.

scholarly journals Differential proteolytic activation of factor VIII-von Willebrand factor complex by thrombin

1989 ◽  
Vol 86 (17) ◽  
pp. 6508-6512 ◽  
Author(s):  
D C Hill-Eubanks ◽  
C G Parker ◽  
P Lollar
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Heavy Chain ◽  
Light Chain ◽  
Coagulation Factor ◽  
Stable Form ◽  
Proteolytic Activation ◽  
Chain Cleavage ◽  
Von Willebrand ◽  
Willebrand Factor

Blood coagulation factor VIII (fVIII) is a plasma protein that is decreased or absent in hemophilia A. It is isolated as a mixture of heterodimers that contain a variably sized heavy chain and a common light chain. Thrombin catalyzes the activation of fVIII in a reaction that is associated with cleavages in both types of chain. We isolated a serine protease from Bothrops jararacussu snake venom that catalyzes thrombin-like heavy-chain cleavage but not light-chain cleavage in porcine fVIII as judged by NaDodSO4/PAGE and N-terminal sequence analysis. Using a plasma-free assay of the ability of activated fVIII to function as a cofactor in the activation of factor X by factor IXa, we found that fVIII is activated by the venom enzyme. The venom enzyme-activated fVIII was isolated in stable form by cation-exchange HPLC. von Willebrand factor inhibited venom enzyme-activated fVIII but not thrombin-activated fVIII. These results suggest that the binding of fVIII to von Willebrand factor depends on the presence of an intact light chain and that activated fVIII must dissociate from von Willebrand factor to exert its cofactor effect. Thus, proteolytic activation of fVIII-von Willebrand factor complex appears to be differentially regulated by light-chain cleavage to dissociate the complex and heavy-chain cleavage to activate the cofactor function.

A Factor VIII Neutralizing Monoclonal Antibody and a Human Inhibitor Alloantibody Recognizing Epitopes in the C2 Domain Inhibit Factor VIII Binding to von Willebrand Factor and to Phosphatidylserine

1993 ◽  
Vol 69 (03) ◽  
pp. 240-246 ◽  
Author(s):  
Midori Shima ◽  
Dorothea Scandella ◽  
Akira Yoshioka ◽  
Hiroaki Nakai ◽  
Ichiro Tanaka ◽  
...  
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Factor Viii ◽  
Von Willebrand Factor ◽  
Light Chain ◽  
Amino Acid Residues ◽  
Amino Terminal ◽  
Neutralizing Monoclonal Antibody ◽  
Von Willebrand ◽  
Willebrand Factor

SummaryA neutralizing monoclonal antibody, NMC-VIII/5, recognizing the 72 kDa thrombin-proteolytic fragment of factor VIII light chain was obtained. Binding of the antibody to immobilized factor VIII (FVIII) was completely blocked by a light chain-specific human alloantibody, TK, which inhibits FVIII activity. Immunoblotting analysis with a panel of recombinant protein fragments of the C2 domain deleted from the amino-terminal or the carboxy-terminal ends demonstrated binding of NMC-VIII/5 to an epitope located between amino acid residues 2170 and 2327. On the other hand, the epitope of the inhibitor alloantibody, TK, was localized to 64 amino acid residues from 2248 to 2312 using the same recombinant fragments. NMC-VIII/5 and TK inhibited FVIII binding to immobilized von Willebrand factor (vWF). The IC50 of NMC-VIII/5 for the inhibition of binding to vWF was 0.23 μg/ml for IgG and 0.2 μg/ml for F(ab)'2. This concentration was 100-fold lower than that of a monoclonal antibody NMC-VIII/10 which recognizes the amino acid residues 1675 to 1684 within the amino-terminal portion of the light chain. The IC50 of TK was 11 μg/ml by IgG and 6.3 μg/ml by F(ab)'2. Furthermore, NMC-VIII/5 and TK also inhibited FVIII binding to immobilized phosphatidylserine. The IC50 for inhibition of phospholipid binding of NMC-VIII/5 and TK (anti-FVIII inhibitor titer of 300 Bethesda units/mg of IgG) was 10 μg/ml.

scholarly journals A monoclonal antibody to factor VIII inhibits von Willebrand factor binding and thrombin cleavage

Blood ◽  
1991 ◽  
Vol 77 (9) ◽  
pp. 1929-1936 ◽  
Author(s):  
JW Precup ◽  
BC Kline ◽  
DN Fass
Keyword(s):  
Monoclonal Antibody ◽  
Amino Acid ◽  
Factor Viii ◽  
Von Willebrand Factor ◽  
Light Chain ◽  
Amino Acid Residues ◽  
Protein Fragments ◽  
Thrombin Cleavage ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract To study the interaction of human factor VIII (FVIII) with its various ligands, select regions of cDNA encoding FVIII light chain were cloned into the plasmid expression vector pET3B to overproduce FVIII protein fragments in the bacterium Escherichia coli. Partially purified FVIII protein fragments were used to produce monoclonal antibodies. One monoclonal antibody, 60-B, bound both an FVIII protein fragment (amino acid residues 1563 through 1909) and recombinant human FVIII, but not porcine FVIII. This antibody prevented FVIII-vWF binding and acted as an inhibitor in both the activated partial thromboplastin time (APTT) assay and a chromogenic substrate assay that measured factor Xa generation. The ability of the antibody to inhibit FVIII activity was diminished in a dose-dependent fashion by von Willebrand factor. This anti-FVIII monoclonal antibody bound to a synthetic peptide, K E D F D I Y D E D E, equivalent to FVIII amino acid residues 1674 through 1684. The 60-B antibody did not react with a peptide in which the aspartic acid residue at 1681 (underlined) was changed to a glycine, which is the amino acid present at this position in porcine FVIII. Gel electrophoretic analysis of thrombin cleavage patterns of human FVIII showed that the 60-B antibody prevented thrombin cleavage at light chain residue 1689. The coagulant inhibitory activity of the 60-B antibody may be due, in part, to the prevention of thrombin activation of FVIII light chain.

scholarly journals Light Chain of Factor VIII Is Sufficient for Accelerating Cleavage of von Willebrand Factor by ADAMTS13 Metalloprotease

2012 ◽  
Vol 287 (39) ◽  
pp. 32459-32466 ◽  
Author(s):  
Wenjing Cao ◽  
Denise E. Sabatino ◽  
Ekaterina Altynova ◽  
Amy M. Lange ◽  
Veronica C. Casina ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Light Chain ◽  
Von Willebrand ◽  
Willebrand Factor

von Willebrand Factor Protects Ca2+-Dependent Structure of the Factor VIII Light Chain.

Blood ◽  
2005 ◽  
Vol 106 (11) ◽  
pp. 1008-1008 ◽  
Author(s):  
Masahiro Takeyama ◽  
Midori Shima ◽  
Keiji Nogami ◽  
Masahiro Okuda ◽  
Yoshihiko Sakurai ◽  
...  
Keyword(s):  
Factor Viii ◽  
Von Willebrand Factor ◽  
Divalent Cation ◽  
Light Chain ◽  
Metal Ion ◽  
Exchange Resin ◽  
Cation Exchange Resin ◽  
The Other ◽  
Von Willebrand ◽  
Willebrand Factor

Abstract Factor VIII (FVIII) cofactor function is dependent on the presence of divalent cation, since its active form is metal-linked heterotrimer as well as factor V (FV). The activity of FVIII (FVIII:C) and FV in normal plasma were completely and selectively inactivated by the treatment with divalent cation exchange resin, imidinoacetate. However, FVIII antigen (FVIII:Ag) was preserved, suggesting that deprivation of FVIII:C by the resin was not due to absorption of FVIII but due to inactivation. Both FVIII:Ag and FVIII:C of recombinant FVIII were decreased by treatment with the resin. However, FVIII:Ag but not FVIII:C, was preserved in FVIII and von Willebrand factor complex (FVIII/VWF). Sandwich ELISA using anti-A3 and anti-A2 monoclonal antibodies revealed that association with heavy and the light chains were impaired in the resin-treated FVIII. These results suggested that FVIII was inactivated by deprivation of the metal ion by the resin and that VWF protected cation-dependent FVIII structure. Therefore, we tested if the resin deprives the metal ion such as Ca2+ from FVIII or FVIII/VWF. [Ca2+] in FVIII preparation was decreased from 1.30 to 0.07 mM by the resin. Furthermore, [Ca2+] was decreased from 0.39 to 0.01 mM in FVIII/VWF preparation. [Ca2+] was recovered completely by elution with 1 N HCl from the resins used in both preparations. FVIII:C of the resin-treated FVIII/VWF was partially recovered by addition of Ca2+, whilst FVIII:C of the resin-treated FVIII was not recovered. When FVIII was treated with the resin after addition of [Ca2+], the inactivation of FVIII was dose-dependently inhibited by ~20 % (at [Ca2+]: ~75 mM). On the other hand, the inactivation of FVIII was inhibited by ~60 % (at [Ca2+]: ~25 mM) in FVIII/VWF preparation. Present results demonstrated that FVIII was selectively inactivated by the cation exchange resin due to deprivation of Ca2+. Kinetic experiments by surface plasmon resonance using BIAcore demonstrated that the resin-treated FVIII as well as treated C2 didn’t interact with phospholipid and VWF. Furthermore, immunoblot analysis using the resin-treated FVIII revealed that anti-A2 monoclonal antibody reacted with the heavy chain, whilst anti-A3 and anti-C2 antibodies failed to react with the light chain. On the other hand, these antibodies reacted with the light chain in the experiment using FVIII/VWF, indicating that VWF protects antigenic conformation of the FVIII light chain. Present findings suggest another protection mechanism of VWF on FVIII through stabilization of Ca2+-dependent structure of the FVIII light chain.

SYNTHESIS. PROCESSING AND SECRETION OF HUMAN FACTOR VIII IN MAMMALIAN CELLS: REQUIREMENT FOR VON WILLEBRAND FACTOR

1987 ◽  
Author(s):  
Louise C Wasley ◽  
Andrew J Dorner ◽  
Randal C Kaufman
Keyword(s):  
Factor Viii ◽  
Cell Lines ◽  
Von Willebrand Factor ◽  
Light Chain ◽  
Human Factor ◽  
Conditioned Media ◽  
Mammalian Cell Lines ◽  
Human Factor Viii ◽  
Von Willebrand ◽  
Willebrand Factor

In the plasma factor VIII exists as a complex with von Willebrand factor (vWF). The cloning of the cDNA for factor VIII has provided the ability to develop mammalian cell lines which express high levels of factor VIII by using appropriatate expression plasmids and DNA cotransformation with selectable markers. We have studied the synthesis, processing, and secretion of factor VIII expressed in baby hamster kidney cells and in Chinese hamster ovary cells by 35S-methionine pulse and chase labeling and analysis by immunoprecipitation with specific antibodies which recognize the light and heavy chains of factor VIII. In both mammalian cell lines, factor VIII is synthesized as a primary translation product of 230 kDa. A significant amount remains within the endoplasmic reticulum in a stable complex with a glucose regulated protein of 78 kDa. The remainder traverses into the Golgi compartment where it is cleaved to the heavy and light chain forms. Very shortly thereafter the mature factor VIII appears in the conditioned media as the mature heavy and light chain species. Very little single chain factor VIII is secreted into the conditioned media. The accumulation of factor VIII in the conditioned media requires the presence of vWF factor. In the absence of vWF, the factor VIII appears as unassociated heavy and light chains which are rapidly degraded. Bovine, porcine, or human 3WF all effectively stabilize human factor VIII expressed in these rodent cell lines. These results suggest the presence of vWF promotes factor VIII chain association which stabilizes the factor VIII to proteolysis.

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