Disease relevance of F8

• Haemophilia A is a classic X-linked disease which affects 1 in 5-10,000 males in all populations and is caused by defects in coagulation factor VIII [1].
• The live-born rates of normal and FVIII-deficient animals injected in utero with adenovirus murine FVIII (3.3 x 10(5) plaque-forming units) was 87% [2].
• However, tolerant mice immunized with tetanus toxoid (TT) developed high anti-TT antibody, demonstrating that tolerance is fVIII specific [3].
• We showed a successful way to generate domain specific anti-FVIII antibodies by using a series of Escherichia coli expressed FVIII fusion peptides [4].
• Role of coagulation FVIII in septic peritonitis assessed in hemophilic mice [5].

High impact information on F8

• In spite of the lack of FVIII in the plasma of 2bF8trans mice, the bleeding phenotype of FVIIInull mice was corrected [6].
• The FVIII transgene product was stored in platelets and released at the site of platelet activation [6].
• Expression of beta-galactosidase and Factor VIII (a marker for endothelial cells) was determined by immunohistochemical staining of tumor sections [7].
• Normal, carrier (X(H)X), and FVIII-deficient (X(H)Y and X(H)X(H)) fetuses injected with adenoviral vectors carrying luciferase or beta-galactosidase reporter genes showed high-level gene expression with 91% fetal survival [2].
• Previous clinical trials have suffered from transient, subtherapeutic expression of human fVIII transgenes [8].

Chemical compound and disease context of F8

• A factor VIII-deficient knockout mouse was used as a model for severe hemophilia A to characterize the immune response to recombinant human factor VIII (fVIII) and to study new approaches for induction of immune tolerance to fVIII [3].
• To apply this system to hemophilia A inhibitor formation, we created retroviral vectors expressing fVIII amino acids S2173-Y2332 (C2 domain) and S373-R740 (A2 domain) in frame with an IgG heavy chain backbone [9].
• Factor VIII (fVIII) is the procoagulant plasma glycoprotein that is missing or decreased in hemophilia A [10].
• Here, we transplanted bone marrow cells transduced with an optimized MSCV-based FVIII oncoretroviral vector into immunocompetent hemophilia A mice that had been conditioned with a potentially lethal dose of irradiation (800 cGy), a sublethal dose of irradiation (550 cGy), or a nonmyeloablative preparative regimen involving busulfan [11].
• Cells from Lewis lung carcinoma (primary and metastasis), Ehrlich carcinoma ascites and JW sarcoma ascites were able to shorten markedly the recalcification time of normal, Factor VIII- and Factor VII-deficient but not of Factor X-deficient human plasma [12].

Biological context of F8

• Pulse-field linkage of the P3, G6pd and Cf-8 genes on the mouse X chromosome: demonstration of synteny at the physical level [13].
• Achievement of high-level (10%-100% of normal) FVIII expression and phenotypic correction required co-injection of an SB transposase-expressing plasmid to facilitate transgene integration in immunotolerized animals [14].
• We used the Sleeping Beauty (SB) transposon, delivered as naked plasmid DNA by tail-vein injection, to integrate B-domain-deleted FVIII genes into the chromosomes of hemophilia A mice and correct the phenotype [14].
• Since FVIII protein is a neoantigen to these mice, sustaining therapeutic plasma FVIII levels was problematic due to inhibitory antibody production [14].
• In the present study, we examined FVIII gene expression in different tissues on a quantitative basis [15].

Anatomical context of F8

• This observation suggests a role for cells other than hepatocytes in fVIII biosynthesis during FHF [16].
• These activated T cells can be specific for either FVIII or third-party antigens [17].
• We used a murine model of anti-factor VIII (FVIII) antibody responses in hemophilia A to study the requirements for the restimulation of FVIII-specific memory B cells and their differentiation into anti-FVIII antibody-producing cells [17].
• As expected, the production of anti-FVIII antibodies by plasma cells is not dependent on any of the costimulatory interactions tested [17].
• Taken together, these results suggest that besides hepatocytes, non-parenchymal cells (e.g. sinusoidal endothelial cells) contribute to FVIII synthesis [15].

Associations of F8 with chemical compounds

• We have attempted to identify nonhepatocytic sites of fVIII biosynthesis by inducing FHF in mice using acetaminophen overdose, a common cause of human FHF [16].
• CONCLUSIONS: Despite a higher plasma total cholesterol concentration compared with E degrees mice, E degrees/FVIII degrees mice developed dramatically less early-stage atherosclerotic lesions [18].
• Receptor-mediated clearance of FVIII is facilitated by heparan sulfate proteoglycans of extracellular matrix, which provide the initial binding of FVIII to the cell surface [19].
• In vivo neutralization of a C2 domain-specific human anti-Factor VIII inhibitor by an anti-idiotypic antibody [20].
• We stably expressed in mammalian cells nine active B-domainless human fVIII molecules containing single alanine substitutions at these sites [21].

Physical interactions of F8

• Identification of coagulation factor VIII A2 domain residues forming the binding epitope for low-density lipoprotein receptor-related protein [22].

Other interactions of F8

• The three genes, P3, G6pd and Cf-8 all lie within 400 Kb of DNA [13].
• The growth of tumor cells and blood vessels was examined histologically and by immunohistochemical localization of von Willibrand Factor VIII (vWF) [23].
• METHODS AND RESULTS: Apolipoprotein E and FVIII double-deficient mice (E degrees/FVIII degrees) were generated [18].
• Immunostaining for Factor VIII revealed that tumors transduced with IL-17 had significantly higher vascular density when compared with controls [24].
• Retinoic acid-treated, but not untreated, cells lost expression of vimentin and fibronectin, gained the ability to incorporate acetylated low density lipoprotein, and expressed Factor VIII-related antigen [25].

Analytical, diagnostic and therapeutic context of F8

• Hemophilia A is a lead candidate for treatment by gene therapy because small increments in the missing secreted protein product, coagulation factor VIII (FVIII), would result in substantial clinical amelioration [14].
• At 150 days after treatment, 12 of 22 anti-CD40L-treated mice remained tolerant to fVIII (anti-fVIII antibody titers less than 1 microg/mL) [3].
• In situ hybridization analysis confirmed that liver and kidney were rich in FVIII mRNA [15].
• An enzyme-linked immunosorbant assay (ELISA) using D2 or E6 was designed to detect plasma FVIII [4].
• IgG antibodies from rabbit anti-F8 serum were coupled to Sepharose, and used to obtain the specific antigen by affinity chromatography [26].

References