FVIII is synthesized as a single chain precursor of approximately 280 kD with the domain structure of A1-A2-B-A3-C1-C2 and it circulates as a series of metal ion-linked heterodimers that result from cleavages at B-A3 junction as well as additional cleavages within B domain. Factor VIII is converted to its active form, factor VIIIa, upon proteolytic cleavages by thrombin and is a heterotrimer composed of the A1, A2, and A3-C1-C2 subunits. A1 subunits of factor VIIIa terminates with 36 residue segment (Met337-Arg372) rich in acidic residues. This segment is removed after cleavages at Arg336 by activated protein C, which results in inactivation of the cofactor. In the present study, site-directed mutagenesis of FVIII at Arg336 to Gln336 was performed in order to produce an inactivation resistant mutant rFVIII (rFVIIIm) with an extended physiological stability. A recombinant mutant heavy chain of FVIII (rFVIII-Hm; Arg336 to Gln336) and wild-type light chain of FVIII (rFVIII-L) were expressed in Baculovirus-insect cell (Sf9) system, and a biologically active recombinant mutant FVIII (rFVIIIm) was reconstituted from rFVIII-Hm and rFVIII-L in the FVIII-depleted human plasma containing 40 mM CaCl2. The rFVIIIm exhibited cofactor activity of FVIIIa (2.85 x 10(-2) units/mg protein) that sustained the high level activity during in vitro incubation at 37 degrees C for 24 h, while the cofactor activity of normal plasma was declined steadily for the period. These results indicate that rFVIIIm (Arg336 to Gln336) expressed in Baculovirus-insect cell system is inactivation resistant in the plasma coagulation milieu and may be useful for the treatment of hemophilia A.
Animal ; Baculoviridae/genetics ; Blotting, Western ; Cell Line ; Factor VIII/metabolism* ; Factor VIII/genetics ; Factor VIII/chemistry ; Factor VIII/biosynthesis ; Genetic Vectors ; Human ; Mutagenesis, Site-Directed ; Recombinant Proteins/metabolism ; Recombinant Proteins/genetics ; Recombinant Proteins/chemistry ; Recombinant Proteins/biosynthesis ; Spodoptera

OBJECTIVETo construct a recombinant lentiviral vector (pXZ208-BDDhFVIII) mediating B-domain-deleted human coagulation factor VIII (BDDhFVIII) gene and investigate its expression in HLF, Chang-Liver and MSC cells.

METHODSBDDhFVIII gene fragment was separated by endonuclease digestion and was cloned into the multiple cloning sites of pXZ208 to construct a recombinant lentiviral vector pXZ208-BDDhFVIII. Viral particles were prepared by means of three-plasmid cotransfection of 293T package cells by calcium phosphate precipitation. After infection, the coagulant activity of human FVIII in the culture medium of 293T, HLF, Chang-Liver and MSC cells was assayed by one-stage method. The gene transduction efficiency was assayed by flow cytometry (FCM). Furthermore, PCR was performed to test the integration of BDDhFVIII.

RESULTSThe infection rates of HLF, Chang-Liver and MSC were (74.52 +/- 7.57)%, (27.24 +/- 6.53)% and (42.34 +/- 5.84)% respectively. The activities of FVIII in supernatants of HLF, Chang-Liver and MSC were (54.1 +/- 5.6)%, (22.5 +/- 2.9)% and (12.5 +/- 2.7)% respectively. BDDhFVIII gene integration was detected in all the infected cells.

CONCLUSIONThe recombinant lentiviral vector pXZ208-BDDhFVIII was successfully constructed and efficiently integrated into target cells to express human FVIII activity in vitro.

Cell Line ; Factor VIII ; biosynthesis ; genetics ; metabolism ; Gene Expression ; Genetic Vectors ; Humans ; Lentivirus ; genetics ; Plasmids ; Transfection

The study was purposed to prepare the recombinant lentiviral vector pTK161 and pTK162 carrying B-domain-deleted canine factor (BDDcFVIII) gene, and to investigate whether the canine FVIII (cVIII) can be expressed in vitro. The BDDcFVIII gene was ligated behind PUB and 2OH1 promotors to create lentiviral vectors pTK161 and pTK162. Meantime lentiviral vectors pTK161' and pTK161' were produced by cloning a green fluorescent protein (GFP) into pTK151 and pTK152, which was driven by PUB and 2OH1 promotors respectively. Vector supernatant were prepared by using transfer calcium phosphate mediated-cotransfection of 293T cells. The virus vector, DeltaNRF packaging-plasmid, and VSV-G envelope-plasmid was assayed by titers and cFVIII activity in cell culture supernatant after infection into 293T cells. pTK161, pTK162, pTK161' and pTK161' were identified by restriction enzyme analyzing. The results showed that the lentiviral vectors pTK161, pTK162, pTK161' and pTK161' were successfully constructed, and the titers of pTK161' and pTK161' reached to 1.54 x 10(6) U/ml and 2.83 x 10(6) U/ml; the activity of cFVIII could be detected at 24 hours after infection of 293T cells by pTK161 and pTK162, and achieved the highest level at 72 hours later. The higher level of cFVIII activity was achieved by transfected with pTK162 than that of pTK161 (p < 0.05), which closed to the cFVIII activity in normal dog plasma. 1/4 of the highest level could be detected 6 weeks later. It is concluded that the prepared HIV1-based lentiviral vectors can infect 293T cells to express cFVIII effectively. The results provide the basis for further studying HIV-1-based lentiviral vector gene therapy for hemophilia A.
Animals ; Dogs ; Factor VIII ; biosynthesis ; genetics ; Genetic Vectors ; genetics ; HIV-1 ; genetics ; metabolism ; Recombinant Proteins ; biosynthesis ; genetics

OBJECTIVETo develop a monoclonal antibody (mAb) directed to FVIII C2 domain and investigate its effect on FVIII activity.

METHODSFVIII C2 protein was expressed in E. coli and purified. A murine antihuman FVIII C2 domain mAb SZ-132 was developed by standard hybridoma technology and characterized. In coagulation assays, different concentrations of SZ-132 were incubated with freshly collected pooled human plasma and the residual activity of FVIII and activated partial thromboplastin time (APTT) were determined. The effects of SZ-132 on rhFVIII binding to purified human vWF, phosphatidylserine (PS) and platelets were assessed by enzyme linked immunosorbent assays (ELISA).

RESULTSSZ-132 could inhibit FVIII procoagulant activity in a dose-dependent manner within the concentrations of 0-25 microg/ml and the FVIII activity was completely inhibited on above 25 microg/ml. It could also prevent rhFVIII from binding to vWF, PS and platelets.

CONCLUSIONSSZ-132 is a neutralizing mAb against FVIII C2 domain and can inhibit FVIII procoagulant activity by preventing FVIII from binding to vWF and PS.

Animals ; Antibodies, Monoclonal ; biosynthesis ; immunology ; Antibodies, Neutralizing ; biosynthesis ; immunology ; Factor VIII ; immunology ; metabolism ; Humans ; Male ; Mice ; Mice, Inbred BALB C

OBJECTIVETo get stable cell line expressing B domain-deleted human FVIII (BDDhFVIII) by constructing the eukaryotic expression plasmid.

METHODSEukaryotic expression plasmid containing BDDhFVIII was constructed and transfected into HepG2 cells via electroporation. The expression and purification of the target protein was detected by Western blot.

RESULTSResults of enzyme digestion and sequence analysis demonstrated that the gene of BDDhFVIII was correctly inserted into the eukaryotic expression vector pcDNA4/v5-his. Western blot confirmed the successful expression of BDDhFVIII at the protein levels in HepG2 cells.

CONCLUSIONThe constructed eukaryotic expression vector was able to generate high level expression of human FVIII in HepG2 cells, thus could construct human blood coagulation FVIII stable cell line successfully.

Electroporation ; Factor VIII ; genetics ; Gene Expression ; Genetic Vectors ; biosynthesis ; Hemophilia A ; genetics ; Hep G2 Cells ; Humans ; Plasmids ; biosynthesis ; Recombination, Genetic

In an earlier study, a site directed mutant rFVIII (rFVIII(m), Arg(336) -> Gln(336)) expressed in baculovirus-insect cell (Sf9) system was found to sustain high level activity during incubation at 37 for 24 h while the cofactor activity of normal plasma was declined steadily. In this study, a mutant B-domain deleted rFVIII(m), Arg(336) -> Gln(336) expressed in baculovirus-insect cell (Sf9) system was characterized for its enzymatic and chemical properties. The expressed rFVIII(m) and plasma FVIII (pFVIII) were purified by immunoaffinity column chromatography and identified by Western blot analysis. The partially purified rFVIII(m) exhibited cofactor specific activity of 2.01 X 10(3)units/mg protein. The molecular weight of rFVIII(m) ranged between 40 to 150 kDa with a major band at 150 kDa. Treatment of both rFVIII(m) and pFVIII with thrombin increased their cofactor activity in a similar pattern. Treatment of both the activated rFVIII(m) and native FVIII with APC decreased their cofactor activities, however, the former exhibited a slower decrease than the latter, although no significant difference was present. rFVIII(m) formed a complex with vWF, resulting in a stabilized form, and the lag period of thrombin-mediated activating was extended by vWF association. These results implicated that rFVIII(m) expressed in baculovirus-insect cell system had a comparable capacity as FVIII cofactor activity and might be a good candidate for the FVIII replacement therapy for hemophilia A patients.
Animals ; Baculoviridae/genetics ; Cell Line ; Factor VIII/biosynthesis/*genetics/isolation & purification/*metabolism ; Insects ; Macromolecular Systems ; Mutation/*genetics ; Protein C/pharmacology ; Recombinant Proteins/biosynthesis/*genetics/isolation & purification/*metabolism ; Thrombin/pharmacology ; von Willebrand Factor/metabolism

Abdominal lymphangiomas are uncommon angiomatous tumor occurring mainly in childhood. This is a retrospective clinicopathologic study of 17 cases of abdominal lymphangioma. The patients included are five children and 12 adults, with a mean age at initial presentation of 30.7 years (age ranges 3-63). The locations of the tumors were mesentery (5), retroperitoneum (4), colon (3), omentum (3), mesocolon (1) and gallbladder (1). Infiltrative growth was more common pattern than entirely circumscribed pattern. Masses were mostly multilocular cysts and contained chyle or serous fluid. On immunohistochemical staining, 16 cases were reactive for either CD31 or factor VIII-related antigen. These fact would suggest that intra-abdominal lymphangiomas simulate the immunohistochemical features of collecting lymphatics. Follow up was possible in 12 cases for 3-50 months (mean 19 months) and only one patient showed local recurrence. Although abdominal lymphangiomas are rare in adulthood and correct preoperative diagnosis is difficult, awareness of such a possibility in adulthood will contribute to make a correct preoperative diagnosis.
Abdominal Neoplasms/physiopathology ; Abdominal Neoplasms/pathology* ; Abdominal Neoplasms/metabolism ; Adult ; Antigens, CD31/biosynthesis ; Child ; Child, Preschool ; Factor VIII/biosynthesis ; Female ; Human ; Lymphangioma/physiopathology ; Lymphangioma/pathology* ; Lymphangioma/metabolism ; Male ; Middle Age ; Retrospective Studies

OBJECTIVETo accomplish a kind of therapeutic gene for hemophilia A, and observe the expression of human factor VIII (hF VIII) in vivo.

METHODSHuman clotting factor VIII cDNA with B-domain deleted (Delta760aa approximately 1639aa) was inserted into vector pRC/RSV to form pRC/RSV-hF VIII BD, which conjugated with in vivo liposome transfection reagent (DOTAP-Cholesterol) to accomplish a kind of therapeutic gene, pRC/RSV-hF VIII BD-DOTAP-Cholesterol. Mice were injected with pRC/RSV-hF VIII BD-DOTAP-Cholesterol i.m. and sacrificed 48 hours, 10 days, 20 days, 30 days, 40 days and 50 days later, respectively. Tissues such as heart, liver, spleen, lung, kidney and muscle were harvested, the distribution and transcription as well as expression of hF VIII BD cDNA were detected by means of PCR, RT-PCR and immunohistochemistry techniques. In addition, the antigen and antibody of hF VIII in plasma were measured.

RESULTSThere was high expression of hF VIII in plasma and tissues at the 48(th) hour after injection. On day 10, antigen level of hF VIII in plasma reached its peak, 17.55 ng/ml, and gradually reduced later. The antibody of hF VIII in plasma emerged on day 10 after injection, and increased and gradually reached 37.06 U/ml on day 50 after injection. PCR, RT-PCR and immunohistochemistry showed that hF VIII BD cDNA and its transcription as well as expression existed in all kinds of tissues, and lasted longer in spleen, lungs and kidneys than in heart, liver and muscle.

CONCLUSIONTherapeutic gene, pRC/RSV-hF VIII BD-DOTAP-Cholesterol, produced by combination of pRC/RSV-hF VIII BD and DOTAP-Cholesterol liposome can express human F VIII successfully in vivo, which lays an experimental foundation for curing hemophilia A by gene-drug in clinic.

Animals ; DNA, Complementary ; Disease Models, Animal ; Factor VIII ; biosynthesis ; genetics ; therapeutic use ; Gene Expression ; Genetic Therapy ; Genetic Vectors ; Hemophilia A ; therapy ; Humans ; Liposomes ; Mice ; Mice, Inbred BALB C ; Tissue Distribution ; Transfection

OBJECTIVE: To explore the differentiation potential of QY1 bone marrow mesenchymal stem cell (MSCs) line cells into cardiacmyocytes and vascular endothelial cells in vitro, to optimize the suitable conditions of MSCs differentiating into cardiomyocytes in vitro, and to examine the potentials of MSCs differentiating into cardiomyogenesis and vasculogenesis. METHODS: Specifically committed differentiation inductive medium was employed, including 5-azacytidine for cardiomyogenesis and vascular endothelial growth factor for vasculogenesis in culture respectively in vitro. The differentiated cells were identified by immunohistochemistry and molecular biology. RESULTS: MSCs line cells had been cultured in the normal culture medium for 72 hours, then the differentiation inductive medium including 10 micromol/L 5-azacytidine was added into the normal culture dishes for 24 hours only. After that the culture medium was changed back to the normal culture medium. Normal culture medium was changed every 7 days. The second induction was performed after 14 days. The differentiated cells treated with 5-azacytidine could beat spontaneously and formed myotube structures in the optimal induction conditions, and the differentiation rate was (39.47+/-0.56)%. The differentiated cells expressed specific cardiomyocytic proteins identified by the positive immunohistochemistry staining with anti-alpha-sarcomeric antibody and anti-Cx-43 antibody, and also expressed the alpha-myosin heavy chain examined by RT-PCR. The differentiated cells began to appear as the lined up vascular endothelial cells after 48 hour treatment with vascular endothelial growth factor. Some of the differentiated cells connected each other to form vascular endothelial web-like structure after 7 day treatment with vascular endothelial growth factor. On 14 d after treating with vascular endothelial growth factor, the differentiated cells were identified by immunohistochemistry staining. The expressions of both specific surface antibody CD31 and factor VIII for vascular endothelial cells were positive. CONCLUSION The cells of QY1 bone marrow mesenchymal stem cell line may differentiate into cardiomyocytes or vascular endothelial cells in vitro under specific condition.
Azacitidine ; pharmacology ; Bone Marrow Cells ; cytology ; Cell Differentiation ; drug effects ; physiology ; Cell Line ; Dose-Response Relationship, Drug ; Endothelial Cells ; cytology ; metabolism ; Factor VIII ; biosynthesis ; Humans ; Immunohistochemistry ; Mesenchymal Stem Cells ; cytology ; Multipotent Stem Cells ; cytology ; Myocytes, Cardiac ; cytology ; Platelet Endothelial Cell Adhesion Molecule-1 ; biosynthesis