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D Ginsburg

Publications and source records attributed to D Ginsburg.

At least 19 recordsLinked to original sources
PubMed2006

Genetic regulation of plasma von Willebrand factor levels: quantitative trait loci analysis in a mouse model.

BACKGROUND: The genetic factors responsible for the wide variation in plasma von Willebrand factor (VWF) levels observed among individuals are largely unknown, although these genes are also likely to contribute to variability in the severity of von Willebrand disease (VWD) and other bleeding and thrombotic disorders. We have previously mapped two genes contributing to the regulation of plasma VWF levels in mice (Mvwf1 on chromosome 11 and Mvwf2 on chromosome 6). OBJECTIVE: To identify additional quantitative trait loci (QTL) contributing to the genetic regulation of murine plasma VWF levels. METHODS: To map genetic loci contributing to the > 7-fold difference in plasma VWF levels between two mouse strains (A/J and CASA/RkJ), high-density individual genotyping and R/qtl analyses were applied to a previously generated set of approximately 200 F2 mice obtained from an intercross of these two inbred lines. RESULTS: Genomic loci for two additional candidate VWF modifier genes were identified: Mvwf3 on chromosome 4 and Mvwf4 on chromosome 13. These loci demonstrate primarily epistatic effects when co-inherited with two CASA/RkJ Vwf alleles, although Mvwf4 may also exert a small, independent, additive effect. CONCLUSIONS: Mvwf3 and Mvwf4, combined with the effect of Mvwf2, explain approximately 45% of the genetic variation in plasma VWF level among the A/J and CASA/RkJ strains. Mvwf3 and Mvwf4 exhibit homology of synteny to three human chromosomal segments (on chromosomes 1, 5 and 6) previously reported by the Genetic Analysis of Idiopathic Thrombophilia (GAIT) study, suggesting that orthologs of Mvwf3 and Mvwf4 may also encode important VWF modifier genes in humans.

Animals↗
PubMed2005

Combined factor V and factor VIII deficiency in a Thai patient: a case report of genotype and phenotype characteristics.

A Thai woman, with no family history of bleeding disorders, presented with excessive bleeding after minor trauma and tooth extraction. The screening coagulogram revealed prolonged activated partial thromboplastin time and prothrombin time. The specific-factor assay confirmed the diagnosis of combined factor V and factor VIII deficiency (F5F8D). Her plasma levels of factor V and factor VIII were 10% and 12.5% respectively. The medications and blood product treatment to prevent bleeding from invasive procedure included 1-deamino-8-d-arginine vasopressin, cryoprecipitate, factor VIII concentrate, fresh frozen plasma and antifibrinolytic agent. Gene analysis of the proband identified two LMAN1 gene mutations; one of which is 823-1 G --> C, a novel splice acceptor site mutation that is inherited from her father, the other is 1366 C --> T, a nonsense mutation that is inherited from her mother. Thus, the compound heterozygote of these two mutations in LMAN1 cause combined F5F8D.

Adult↗
PubMed2005

Identifying novel genetic determinants of hemostatic balance.

Incomplete penetrance and variable expressivity confound the diagnosis and therapy of most inherited thrombotic and hemorrhagic disorders. For many of these diseases, some or most of this variability is determined by genetic modifiers distinct from the primary disease gene itself. Clues toward identifying such modifier genes may come from studying rare Mendelian disorders of hemostasis. Examples include identification of the cause of combined factor V and VIII deficiency as mutations in the ER Golgi intermediate compartment proteins LMAN1 and MCFD2. These proteins form a cargo receptor that facilitates the transport of factors V and VIII, and presumably other proteins, from the ER to the Golgi. A similar positional cloning approach identified ADAMTS-13 as the gene responsible for familial TTP. Along with the work of many other groups, these findings identified VWF proteolysis by ADAMTS-13 as a key regulatory pathway for hemostasis. Recent advances in mouse genetics also provide powerful tools for the identification of novel genes contributing to hemostatic balance. Genetic studies of inbred mouse lines with unusually high and unusually low plasma VWF levels identified polymorphic variation in the expression of a glycosyltransferase gene, Galgt2, as an important determinant of plasma VWF levels in the mouse. Ongoing studies in mice genetically engineered to carry the factor V Leiden mutation may similarly identify novel genes contributing to thrombosis risk in humans.

ADAM Proteins↗
PubMed2004

Familial multiple coagulation factor deficiencies: new biologic insight from rare genetic bleeding disorders.

Combined deficiency of factor (F)V and FVIII (F5F8D) and combined deficiency of vitamin K-dependent clotting factors (VKCFD) comprise the vast majority of reported cases of familial multiple coagulation factor deficiencies. Recently, significant progress has been made in understanding the molecular mechanisms underlying these disorders. F5F8D is caused by mutations in two different genes (LMAN1 and MCFD2) that encode components of a stable protein complex. This complex is localized to the secretory pathway of the cell and likely functions in transporting newly synthesized FV and FVIII, and perhaps other proteins, from the ER to the Golgi. VKCFD is either caused by mutations in the gamma-carboxylase gene or in a recently identified gene encoding the vitamin K epoxide reductase. These two proteins are essential components of the vitamin K dependent carboxylation reaction. Deficiency in either protein leads to under-carboxylation and reduced activities of all the vitamin K-dependent coagulation factors, as well as several other proteins. The multiple coagulation factor deficiencies provide a notable example of important basic biological insight gained through the study of rare human diseases.

Carbon-Carbon Ligases↗
PubMed2003

LMAN1 is a molecular chaperone for the secretion of coagulation factor VIII.

Combined deficiency of both coagulation factors (F)V and VIII is a rare autosomal recessive bleeding disorder caused by null expression of LMAN1 (previously termed ERGIC-53) in a majority of affected individuals. Previously, a requirement for a functional LMAN1 cycling pathway between the ER and Golgi was demonstrated for efficient secretion of FV and FVIII (Moussalli et al. J Biol Chem 1999; 274: 32569), however, the molecular nature of the interaction between LMAN1 and its cargo was not characterized. Using coimmunoprecipitation of LMAN1 and FVIII from transfected HeLa and COS-1 cells, we demonstrate an interaction between LMAN1 and FVIII in vivo. The interaction was mediated via high mannose-containing asparagine-linked oligosaccharides that are densely situated within the B domain of FVIII, as well as protein-protein interactions. These results are interpreted based on the recent determination of the crystal structure of the carbohydrate recognition domain of LMAN1.

Factor V Deficiency↗
PubMed2001

Mutations in a member of the ADAMTS gene family cause thrombotic thrombocytopenic purpura.

Thrombotic thrombocytopenic purpura (TTP) is a life-threatening systemic illness of abrupt onset and unknown cause. Proteolysis of the blood-clotting protein von Willebrand factor (VWF) observed in normal plasma is decreased in TTP patients. However, the identity of the responsible protease and its role in the pathophysiology of TTP remain unknown. We performed genome-wide linkage analysis in four pedigrees of humans with congenital TTP and mapped the responsible genetic locus to chromosome 9q34. A predicted gene in the identified interval corresponds to a segment of a much larger transcript, identifying a new member of the ADAMTS family of zinc metalloproteinase genes (ADAMTS13). Analysis of patients' genomic DNA identified 12 mutations in the ADAMTS13 gene, accounting for 14 of the 15 disease alleles studied. We show that deficiency of ADAMTS13 is the molecular mechanism responsible for TTP, and suggest that physiologic proteolysis of VWF and/or other ADAMTS13 substrates is required for normal vascular homeostasis.

Chromosome Mapping↗
PubMed2001

Plasminogen activator inhibitor-1 regulates tumor growth and angiogenesis.

Elevated expression of plasminogen activator inhibitor-1 (PAI-1) in tumors is associated with a poor prognosis in many cancers. Reduced tumor growth and angiogenesis have also been reported in mice deficient in PAI-1. These results suggest that PAI-1 may be required for efficient angiogenesis and tumor growth. In the present study, we demonstrate that PAI-1 can both enhance and inhibit the growth of M21 human melanoma tumors in nude mice and that this appears to be due to PAI-1 regulation of angiogenesis. Quantitative analysis of angiogenesis in a Matrigel implant assay indicated that in PAI-1 null mice angiogenesis was reduced approximately 60% compared with wild-type mice, while in mice overexpressing PAI-1, angiogenesis was increased nearly 3-fold. Furthermore, addition of PAI-1 to implants in wild-type mice enhanced angiogenesis up to 3-fold at low concentrations but inhibited angiogenesis nearly completely at high concentrations. Together, these data demonstrate that PAI-1 is a potent regulator of angiogenesis and hence of tumor growth and suggest that understanding the mechanism of this activity may lead to the development of important new therapeutic agents for controlling pathologic angiogenesis.

Animals↗
PubMed2001

Synthesis of selenium-derivatized nucleosides and oligonucleotides for X-ray crystallography.

We report here the synthesis of nucleoside and oligonucleotide analogs containing selenium, which serves as an anomalous scattering center to enable MAD phase determination in nucleotide X-ray crystallography. We have developed a phase transfer approach to introduce the selenium functionality in A, C, G, T, and U nucleosides at 5'-positions. In the incorporation of the selenium functionality, the leaving groups (bromide, mesyl, and tosyl) were readily displaced by sodium selenide, sodium diselenide, and sodium methyl selenide with yields higher than 90%. Selenium-derivatized oligonucleotides have been synthesized via phosphoramidite chemistry.

Crystallography, X-Ray↗
PubMed2001

A standard nomenclature for von Willebrand factor gene mutations and polymorphisms. On behalf of the ISTH SSC Subcommittee on von Willebrand factor.

Examination of the entire von Willebrand factor (VWF) gene for mutations, particularly in types 1 and 3 von Willebrand disease (VWD) is becoming more widely practised. The sequence of the entire VWF gene will soon be compiled as a single sequence. For these reasons, a clearly defined nomenclature to use for numbering the VWF nucleotide and amino acid sequence is required. The following recommendations are made for VWF numbering. VWF cDNA nucleotide sequence should be numbered from the A of the initiator ATG as the +1 position. Genomic DNA should be prefixed with a "g" and also numbered from this position. Amino acid (aa) numbering should be from the initiator methionine as the +1 position with sequential numbering of aa throughout VWF. To avoid confusion with previously used numbering schemes for mature VWF, which started from serine 764 of pre-pro VWF, the use of the single letter amino acid code is recommended.

Humans↗
PubMed2001

Getting at the variable expressivity of von Willebrand disease.

Von Willebrand disease (VWD) is a heterogeneous bleeding disorder caused by abnormalities of von Willebrand factor (VWF). VWF levels vary widely in the general population, and this variation is likely to be a major factor accounting for the incomplete penetrance and variable expressivity of VWD. In addition, variation in VWF level may play an important role in determining the risk of venous thrombosis. A large component of the variation in VWF level in the general population has been shown to be attributable to genetic factors. This review will focus on the current understanding of the genetic causes for variation in VWF level, and will highlight future directions for getting at the variable expressivity of von Willebrand disease.

ABO Blood-Group System↗
PubMed2000

Plasminogen activator inhibitor-1 deficiency protects against atherosclerosis progression in the mouse carotid artery.

Dissolution of the fibrin blood clot is regulated in large part by plasminogen activator inhibitor-1 (PAI-1). Elevated levels of plasma PAI-1 may be an important risk factor for atherosclerotic vascular disease and are associated with premature myocardial infarction. The role of the endogenous plasminogen activation system in limiting thrombus formation following atherosclerotic plaque disruption is unknown. This study found that genetic deficiency for PAI-1, the primary physiologic regulator of tissue-type plasminogen activator (tPA), prolonged the time to occlusive thrombosis following photochemical injury to carotid atherosclerotic plaque in apolipoprotein E-deficient (apoE(-/-)) mice. However, anatomic analysis revealed a striking difference in the extent of atherosclerosis at the carotid artery bifurcation between apoE(-/-) mice and mice doubly deficient for apoE and PAI-1 (PAI-1(-/-)/apoE(-/-)). Consistent with a previous report, PAI-1(+/+)/apoE(-/-)and PAI-1(-/-)/apoE(-/-) mice developed similar atherosclerosis in the aortic arch. The marked protection from atherosclerosis progression at the carotid bifurcation conferred by PAI-1 deficiency suggests a critical role for PAI-1 in the pathogenesis of atherosclerosis at sites of turbulent flow, potentially through the inhibition of fibrin clearance. Consistent with this hypothesis, intense fibrinogen/fibrin staining was observed in atherosclerotic lesions at the carotid bifurcation compared to the aortic arch. These observations identify significant differences in the pathogenesis of atherosclerosis at varying sites in the vascular tree and suggest a previously unappreciated role for the plasminogen activation system in atherosclerosis progression at sites of turbulent flow. (Blood. 2000;96:4212-4215)

Animals↗
PubMed2000

Spontaneous thrombosis in mice carrying the factor V Leiden mutation.

A polymorphism in coagulation factor V, factor V Leiden (FVL), is the major known genetic risk factor for thrombosis in humans. Approximately 10% of mutation carriers experience clinically significant thrombosis in their lifetime. In a small subset of patients, thrombosis is associated with coinheritance of other prothrombotic gene mutations. However, the potential contribution of additional genetic risk factors in the majority of patients remains unknown. To gain insight into the molecular basis for the variable expressivity of FVL, mice were generated carrying the homologous mutation (R504Q [single-letter amino acid codes]) inserted into the endogenous murine Fv gene. Adult heterozygous (FvQ/+) and homozygous (FvQ/Q) mice are viable and fertile and exhibit normal survival. Compared with wild-type mice, adult FvQ/Q mice demonstrate a marked increase in spontaneous tissue fibrin deposition. No differences in fetal development or survival are observed among FvQ/Q, FvQ/+ or control littermates on the C57BL/6J genetic background. In contrast, on a mixed 129Sv-C57BL/6J genetic background, FvQ/Q mice develop disseminated intravascular thrombosis in the perinatal period, resulting in significant mortality shortly after birth. These results may explain the high degree of conservation of the R504/R506 activated protein C cleavage site within FV among mammalian species and suggest an important contribution of other genetic factors to the thrombosis associated with FVL in humans. (Blood. 2000;96:4222-4226)

Activated Protein C Resistance↗
PubMed2000

Prothrombotic phenotype of protein Z deficiency.

Protein Z (PZ) is a vitamin K-dependent plasma protein whose function has been uncertain. The structure of PZ is very similar to that of the coagulation-related factors VII, IX, and X and PC, but PZ differs from these other proteins in that it is not the zymogen of a serine protease. We have shown recently that PZ forms a calcium ion-dependent complex with activated factor X at phospholipid surfaces and that this interaction leads to the inhibition of activated factor X activity through, in part, the action of a previously unidentified plasma protein named PZ-dependent protease inhibitor. Herein, we report that the presence of PZ dampens the coagulation response in human plasma and that concomitant PZ deficiency dramatically increases the severity of the prothrombotic phenotype of factor V(Leiden) mice. The results indicate that PZ plays a physiologically important role in the regulation of coagulation.

Animals↗
PubMed2000

Partitioning of serpin-proteinase reactions between stable inhibition and substrate cleavage is regulated by the rate of serpin reactive center loop insertion into beta-sheet A.

The serpin family of serine proteinase inhibitors is a mechanistically unique class of naturally occurring proteinase inhibitors that trap target enzymes as stable covalent acyl-enzyme complexes. This mechanism appears to require both cleavage of the serpin reactive center loop (RCL) by the proteinase and a significant conformational change in the serpin structure involving rapid insertion of the RCL into the center of an existing beta-sheet, serpin beta-sheet A. The present study demonstrates that partitioning between inhibitor and substrate modes of reaction can be altered by varying either the rates of RCL insertion or deacylation using a library of serpin RCL mutants substituted in the critical P(14) hinge residue and three different proteinases. We further correlate the changes in partitioning with the actual rates of RCL insertion for several of the variants upon reaction with the different proteinases as determined by fluorescence spectroscopy of specific RCL-labeled inhibitor mutants. These data demonstrate that the serpin mechanism follows a branched pathway, and that the formation of a stable inhibited complex is dependent upon both the rate of the RCL conformational change and the rate of enzyme deacylation.

Amino Acids↗
PubMed2000

Plasminogen activator inhibitor-1 and vitronectin promote vascular thrombosis in mice.

Occlusive thrombosis depends on the net balance between platelets, coagulation, and fibrinolytic factors. Epidemiologic information suggests that plasminogen activator inhibitor-1 (PAI-1), a central regulator of the fibrinolytic system, plays an important role in determining the overall risk for clinically significant vascular thrombosis. Vitronectin (VN), an abundant plasma and matrix glycoprotein, binds PAI-1 and stabilizes its active conformation. This study assessed the role of PAI-1 and VN expression in the formation of occlusive vascular thrombosis following arterial or venous injury. The common carotid arteries of 17 wild-type (WT) mice and 8 mice deficient in PAI-1 were injured photochemically while blood flow was continuously monitored. WT mice developed occlusive thrombi at 52.0 +/- 3.8 minutes (mean +/- SEM) following injury; mice deficient in PAI-1 developed occlusive thrombosis at 127 +/- 15 minutes (P <.0001). Mice deficient in VN (n = 12) developed vascular occlusion 77 +/- 11 minutes after injury, intermediate between the values observed for WT mice (P <.03) and mice deficient in PAI-1 (P <.01). PAI-1 and VN also affected the time to occlusion after injury to the jugular vein. Three WT mice developed occlusive venous thrombosis an average of 39.7 +/- 1 minutes following the onset of injury, whereas the jugular veins of 4 mice deficient in PAI-1 and 4 deficient in VN occluded 56.7 +/- 5 and 58.7 +/- 2 minutes, respectively, following injury (P <.04 and P <.01 compared to WT mice). These results suggest that endogenous fibrinolysis and its regulation by PAI-1 and VN have important roles in the development of occlusive vascular thrombosis after vascular injury. (Blood. 2000;95:577-580)

Animals↗
PubMed2000

Successful bone marrow transplantation in a patient with Schimke immuno-osseous dysplasia.

Early death in Schimke immuno-osseous dysplasia often results from renal failure and/or cell-mediated immunodeficiency. Kidney transplants have improved renal function, but effective therapy for the immunodeficiency has not yet been reported. We describe markedly improved marrow function 2 years after bone marrow transplantation in a boy with Schimke immunoosseous dysplasia.

Antigens, CD↗