OBJECTIVE: To investigate whether co-transfection of wild-type VWFpp with VWF mutant in D1 region is able to correct VWF defects in biosynthesis and secretion. METHODS: Four VWF mutant plasmids were single transfected into HEK 293 cells, or co-transfected into HEK 293 cells with the wild type VWFpp plasmids. The VWF in supernatant and lysate of transfected cells were analyzed by ELISA, vertical VWF multimer electrophoresis. The retention of VWF in endoplasmic reticulum of transfected cells were detected by immunofluorescence confocal microscope. RESULTS: In the vertical VWF multimer analysis, with co-expressing VWF mutant and VWFpp, the VWF multimer bands disappeared, and the VWF antigen in both supernatant and lysate of cells decreased, compared with the single expression of VWF mutant. Although the intracellular levels of VWF antigens decreased after co-expression, the retention rate of VWF mutant decreased in endoplasmic reticulum. CONCLUSION VWFpp can reduce the retention of VWF in endoplasmic reticulum, assists the transport of VWF between subcellular organelles. However, VWFpp inhibits the biosynthesis and secretion of VWF about the mutant in D1 domain.
HEK293 Cells ; Humans ; von Willebrand Diseases ; von Willebrand Factor/metabolism*

Humans ; Isoantibodies ; von Willebrand Factor ; metabolism

OBJECTIVE: To develop monoclonal antibodies that can specifically recognize human von Willebrand factor (VWF) propeptide (VWFpp) in plasma, and establish a rapid and reliable method for the detection of VWFpp antigen in plasma by using the double-antibody sandwich ELISA with the obtained anti-VWFpp monoclonal antibody. METHODS: The recombinant human VWFpp (D1 and D2 regions) protein expressed in eukaryotic cells was used as immunogen to immunize BALB/c mice with routine method, so as to obtain clones of fusion cells. After screening and identification, hybridoma cell lines secreting monoclonal antibodies against VWFpp were selected, and then double-antibody sandwich ELISA assay was used to construct VWFpp antigen detection kit for the determination of VWFpp in human plasma. The levels of VWFpp antigen in plasma of 12 leukemia patients who underwent bone marrow transplantation were dynamically detected. RESULTS: Two hybridoma cell lines that can be subcultured continuously and secrete monoclonal antibodies against VWFpp were obtained and named SZ175 and SZ176 respectively. Identified by ELISA and Western blot, the antibodies could both specifically recognize VWFpp but couldn't recognize mature VWF (without propeptide). Based on the principle of double-antibody sandwich ELISA, monoclonal antibodies SZ175 and SZ176 were successfully made into a kit for detecting VWFpp antigen. The plasma VWFpp levels of leukemia patients before and after bone marrow transplantation were dynamically detected. The results showed that the plasma VWFpp levels of the patients after transplantation were significantly higher than those before transplantation. CONCLUSION Two monoclonal antibodies against VWFpp were successfully prepared, and a double-antibody sandwich ELISA detection kit for VWFpp antigen was constructed, which provides a powerful tool for further study on the biological function of VWFpp, the clinical diagnosis and classification of von Willebrand disease (VWD), and the prognostic monitoring of endothelial injury-related diseases.
Animals ; Mice ; Humans ; von Willebrand Factor ; Antibodies, Monoclonal ; Protein Precursors/metabolism* ; von Willebrand Diseases/diagnosis* ; Prognosis

OBJECTIVETo study the influence of C-terminal domain of ADAMTS13 on its cleaving activity.

METHODSThe full-length wild-type (WT) and C-terminal domain truncated type (TT, TSP8 + CUB domains were deleted) of human ADAMTS13 recombinant protein were transfected into and permanent expressed on Hela cells. Western blot and R-CBA were used to directly detect the activities of the two recombinant proteins under the static and stressed condition respectively. ELISA was used to compare the binding abilities of the two proteins by coating with vWF.

RESULTSThe recombinant proteins were identified by Western blot with anti-his-tag or anti-ADAMTS13 antibodies. With pretreatment of 1.5 M urea, the enzyme activity of TT was significantly higher than that of WT, and so did in binding ability with vWF While, only WT could cleave vWF under high stress.

CONCLUSIONThe distal carboxyl-terminal TSP8 together with CUB domains of ADAMTS13 may affect the enzyme activity by regulating the binding of ADAMTS13 to vWF in different conditions, and they are very important for the enzyme activity under high stress force condition.

Galium ; Humans ; Recombinant Proteins ; metabolism ; Transfection ; von Willebrand Factor ; genetics

OBJECTIVETo investigate the susceptibility of von Willebrand factor (VWF) type 2A mutant A1500E to proteolysis by metalloprotease ADAMTS13 and to provide the direct supports for the pathogenesis of VWF mutation A1500E responsible for von Willebrand disease (VWD) type 2A.

METHODSRecombinant wild-type VWF (WT-VWF) and A1500E mutant VWF transiently expressed on transfected HeLa cell lines. Expression media were collected and concentrated, then cleaved directly by recombinant ADAMTS13 (rADAMTS13). Compared with WT-VWF, the susceptibility of A1500E mutant VWF to proteolysis by ADAMTS13 was analyzed using SDS-agarose gel VWF multimers analysis.

RESULTSIn vitro the expression of VWF:Ag in the supernatants of WT-VWF and A1500E mutant VWF were 1.10 U/ml and 0.78 U/ml, respectively, while VWF:Ag in cells lysates of A1500E mutant VWF was 90.6% of that of WT-VWF. The SDS-agarose gel VWF multimers analysis showed that there were no differences between WT-VWF and A1500E mutant VWF. The A1500E mutant VWF could be efficiently cleaved by ADAMTS13 under static condition without denaturants such as urea and guanidine HCl. VWF multimeric analysis showed that high and intermediate molecular weight multimers dramatically decreased while low molecular weight multimers obviously increased. Conversely, WT-VWF could not be cleaved by ADAMTS13 under the same condition.

CONCLUSIONThe A1500E mutation resulted in VWF more susceptible to ADAMTS13-dependent proteolysis, which belonged to VWD type 2A group 2 mutation.

ADAM Proteins ; genetics ; metabolism ; ADAMTS13 Protein ; Genotype ; HeLa Cells ; Humans ; Hydrolysis ; Mutation ; Recombinant Proteins ; genetics ; metabolism ; von Willebrand Disease, Type 2 ; genetics ; metabolism ; von Willebrand Factor ; genetics

OBJECTIVETo analyze phenotype and genotype of three Chinese pedigrees with von Willebrand disease (vWD), and explore the molecular mechanism.

METHODSBleeding time (BT), activated partial thromboplastin time (APTT), ristocetin-induced platelet aggregation (RIPA), von Willebrand factor (vWF): ristocetin cofactor (RCof) (vWF:RCof), vWF antigen (vWF:Ag), vWF activity (vWF:A) test, vWF collagen binding assay (vWF:CB), vWF and Factor VIII (FVIII) binding assay (vWF:FVIII:B) and multimer analysis were used for phenotype diagnosis. Genomic DNA was extracted from the peripheral blood (PB). All the 52 exons and flanking sequences of the probands' vWF gene were amplified by PCR and analyzed by direct sequencing.

RESULTSAPTT were prolonged in all three probands, while BT were normal excepting for proband 3. Plasma RIPA, vWF:RCo, vWF:Ag, vWF:A and vWF:CB were decreased in different extents. In multimer analysis, proband 3 lost the large and intermediate molecular weight multimers, while proband 1 and 2 were normal. Gene analysis in the three probands revealed three heterozygous missense mutations of 144067 G→A (R2287Q) in exon 39, 110374G→A (R1374H) and 110770C→T (S1506L) in exon 28 and heterozygous polymorphism 110667G→A (D1472H) in exon 28, respectively.

CONCLUSIONThe three heterozygous mutations (R2287Q, R1374H and S1506L) and an heterozygous polymorphism (D1472H) are genetic defects of the hereditary vWD of the three pedigrees respectively. R2287Q is a novel mutation reported for the first time in the literature.

Adult ; Child ; DNA Mutational Analysis ; Female ; Genotype ; Heterozygote ; Humans ; Male ; Pedigree ; Phenotype ; von Willebrand Diseases ; diagnosis ; genetics ; von Willebrand Factor ; genetics ; metabolism

This study was to acquire recombinant protein of von Willebrand factor cleaving protease (ADAMTS13, a disintegrin and metalloprotease with a thromboSpondin type 1 motifs 13), for further studies on its biological function in thrombosis and hemostasis. We transfected the Hela cells with the plasmid pSecTag-ADAMTS13 by lipofectamine. A positive cell cloning was selected by hygromycin-B. The recombinant protein was purified with Ni-NTA agarose column by gradient imidazole. The purity and immune activity of purified products were identified with SDS-PAGE and Western blotting respectively. We also measured the enzymatic activity of recombinant protein (rADAMTS13) by GST-His two-site ELISA assay. The results showed that we successfully constructed Hela cells ADAMTS2-4 which expressed high level of rADAMTS13. We received about 5.8 mg recombinant protein in culture supernantants per liter purified with Ni-NTA column. The protein formed a main lane at the position of 190 kDa with SDS-PAGE and reacted with polyclonal antibody against ADAMTS13 by Western blotting. The amount of rADAMTS13 activity was 6.4 U/mL, according to the normal plasma defined as 1 U/mL. In conclusion, rADAMTS13 protein had high purity, immune activity and good enzymatic activity, which could establish the experimental foundation for further research on biological function and mechanism of this unique metalloprotease.
ADAM Proteins ; biosynthesis ; genetics ; metabolism ; ADAMTS13 Protein ; HeLa Cells ; Humans ; Recombinant Proteins ; biosynthesis ; genetics ; metabolism ; Transfection ; von Willebrand Factor ; metabolism

OBJECTIVETo study effect of von Willebrand factor (vWF) on the proliferation, adhesion and migration of human colorectal cancer cells.

METHODSHuman colorectal cancer cell line SW480 was cultured in vitro, and the expression of vWF in SW480 cells was detected by immunocytochemistry. SW480 cells were treated with vWF antibody (vWFAb), and the morphological change was examined by inverted microscope. Cell proliferation and ability to adhere extracellular matrix IIII( collagen were detected with MTT. Migration ability of SW480 cells was assayed by Transwell.

RESULTSThe human colorectal cancer cell line SW480 expressed vWF which was mainly in nucleus and slightly in cytoplasm. vWFAb significantly inhibited the proliferation ability of SW480 cells in dose- and time-dependent manner (P<0.05). After vWFAb treatment, SW480 cells adhesion decreased significantly (P<0.05), and transmembrane migration of cells significantly decreased (54.60+/-11.01 vs 97.27+/-10.01, P<0.01).

CONCLUSIONSHuman colorectal cancer cells can express vWF. vWF in human colorectal cancer cells plays an important role in promoting proliferation, adhesion, and migration.

Apoptosis ; Cell Adhesion ; Cell Line, Tumor ; Cell Movement ; Colorectal Neoplasms ; metabolism ; pathology ; Humans ; Neoplasm Metastasis ; von Willebrand Factor ; metabolism

A disintegrin-metalloproteinase 28 (ADAM28) is one of important members of ADAM family, that is involved in various biological events including cell adhesion, proteolysis, growth and metastasis of solid tumors and hematological malignancies. Studies have shown that ADAM28 is highly expressed in several human tumors, such as lung, breast and bladder cancers, and chronic lymphocytic leukemia, and its tissue expression levels correlate with cancer metastasis. ADAM28-mediated cancer cell metastasis may be related with the cleavage of von Willebrand's factor (vWF), insulin-like growth factor binding protein-3 (IGFBP-3) and connective tissue growth factor (CTGF), as well as the promoting PSGL-1/P-selectin-mediated cell adhesion. This review summarizes the basic and translational aspects of ADAM28 biology that might stimulate the interest in ADAM28 research and discovery of novel ADAM28 targets, providing potential novel therapies for metastatic cancers.
ADAM Proteins ; metabolism ; Cell Adhesion ; Connective Tissue Growth Factor ; metabolism ; Humans ; Insulin-Like Growth Factor Binding Protein 3 ; metabolism ; Neoplasm Metastasis ; Neoplasms ; pathology ; von Willebrand Factor ; metabolism

Antigens, CD34 ; metabolism ; Hemangioendothelioma, Epithelioid ; metabolism ; pathology ; surgery ; Hepatectomy ; methods ; Humans ; Liver Neoplasms ; metabolism ; pathology ; surgery ; Male ; Middle Aged ; Vascular Endothelial Growth Factor A ; metabolism ; von Willebrand Factor ; metabolism