scholarly journals Pathologic mechanisms of type 1 VWD mutations R1205H and Y1584C through in vitro and in vivo mouse models

Blood ◽  
2011 ◽  
Vol 117 (16) ◽  
pp. 4358-4366 ◽  
Author(s):  
Cynthia M. Pruss ◽  
Mia Golder ◽  
Andrea Bryant ◽  
Carol A. Hegadorn ◽  
Erin Burnett ◽  
...  
Keyword(s):  
Thrombus Formation ◽  
Wild Type ◽  
Injection Model ◽  
Injury Model ◽  
In Vitro Biosynthesis ◽  
Hydrodynamic Injections ◽  
Human And Mouse

Abstract Type 1 VWD is the mild to moderate reduction of VWF levels. This study examined the mechanisms underlying 2 common type 1 VWD mutations, the severe R1205H and more moderate Y1584C. In vitro biosynthesis was reduced for both mutations in human and mouse VWF, with the effect being more severe in R1205H. VWF knockout mice received hydrodynamic injections of mouse Vwf cDNA. Lower VWF antigen levels were demonstrated in both homozygous and heterozygous forms for both type 1 mutations from days 14-42. Recombinant protein infusions and hydrodynamic-expressed VWF propeptide to antigen ratios demonstrate that R1205H mouse VWF has an increased clearance rate, while Y1584C is normal. Recombinant ADAMTS13 digestions of Y1584C demonstrated enhanced cleavage of both human and mouse VWF115 substrates. Hydrodynamic-expressed VWF shows a loss of high molecular weight multimers for Y1584C compared with wild-type and R1205H. At normal physiologic levels of VWF, Y1584C showed reduced thrombus formation in a ferric chloride injury model while R1205H demonstrated similar thrombogenic activity to wild-type VWF. This study has elucidated several novel mechanisms for these mutations and highlights that the type 1 VWD phenotype can be recapitulated in the VWF knockout hydrodynamic injection model.

scholarly journals Construction of an Excisable Bacterial Artificial Chromosome Containing a Full-Length Infectious Clone of Herpes Simplex Virus Type 1: Viruses Reconstituted from the Clone Exhibit Wild-Type Properties In Vitro and In Vivo

2003 ◽  
Vol 77 (2) ◽  
pp. 1382-1391 ◽  
Author(s):  
Michiko Tanaka ◽  
Hiroyuki Kagawa ◽  
Yuji Yamanashi ◽  
Tetsutaro Sata ◽  
Yasushi Kawaguchi
Keyword(s):  
Vero Cells ◽  
Infectious Molecular Clone ◽  
Wild Type ◽  
Molecular Clone ◽  
Viral Genes ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT In recent years, several laboratories have reported on the cloning of herpes simplex virus type 1 (HSV-1) genomes as bacterial artificial chromosomes (BACs) in Escherichia coli and on procedures to manipulate these genomes by using the bacterial recombination machinery. However, the HSV-BACs reported so far are either replication incompetent or infectious, with a deletion of one or more viral genes due to the BAC vector insertion. For use as a multipurpose clone in research on HSV-1, we attempted to generate infectious HSV-BACs containing the full genome of HSV-1 without any loss of viral genes. Our results were as follows. (i) E. coli (YEbac102) harboring the full-length HSV-1 genome (pYEbac102) in which a BAC flanked by loxP sites was inserted into the intergenic region between UL3 and UL4 was constructed. (ii) pYEbac102 was an infectious molecular clone, given that its transfection into rabbit skin cells resulted in production of infectious virus (YK304). (iii) The BAC vector sequence was almost perfectly excisable from the genome of the reconstituted virus YK304 by coinfection of Vero cells with YK304 and a recombinant adenovirus, AxCANCre, expressing Cre recombinase. (iv) As far as was examined, the reconstituted viruses from pYEbac102 could not be phenotypically differentiated from wild-type viruses in vitro and in vivo. Thus, the viruses grew as well in Vero cells as did the wild-type virus and exhibited wild-type virulence in mice on intracerebral inoculation. (v) The infectious molecular clone pYEbac102 is in fact useful for mutagenesis of the HSV-1 genome by bacterial genetics, and a recombinant virus carrying amino acid substitutions in both copies of the α0 gene was generated. pYEbac102 will have multiple applications to the rapid generation of genetically engineered HSV-1 recombinants in basic research into HSV-1 and in the development of HSV vectors in human therapy.

scholarly journals Accumulation of Tissue Factor into Developing Thrombi In Vivo Is Dependent upon Microparticle P-Selectin Glycoprotein Ligand 1 and Platelet P-Selectin

2003 ◽  
Vol 197 (11) ◽  
pp. 1585-1598 ◽  
Author(s):  
Shahrokh Falati ◽  
Qingde Liu ◽  
Peter Gross ◽  
Glenn Merrill-Skoloff ◽  
Janet Chou ◽  
...  
Keyword(s):  
Tissue Factor ◽  
Blood Coagulation ◽  
Thrombus Formation ◽  
Recipient Mouse ◽  
Wild Type ◽  
Activated Platelets ◽  
Injury Model ◽  
Platelet Thrombus ◽  
Flowing Blood

Using a laser-induced endothelial injury model, we examined thrombus formation in the microcirculation of wild-type and genetically altered mice by real-time in vivo microscopy to analyze this complex physiologic process in a system that includes the vessel wall, the presence of flowing blood, and the absence of anticoagulants. We observe P-selectin expression, tissue factor accumulation, and fibrin generation after platelet localization in the developing thrombus in arterioles of wild-type mice. However, mice lacking P-selectin glycoprotein ligand 1 (PSGL-1) or P-selectin, or wild-type mice infused with blocking P-selectin antibodies, developed platelet thrombi containing minimal tissue factor and fibrin. To explore the delivery of tissue factor into a developing thrombus, we identified monocyte-derived microparticles in human platelet–poor plasma that express tissue factor, PSGL-1, and CD14. Fluorescently labeled mouse microparticles infused into a recipient mouse localized within the developing thrombus, indicating that one pathway for the initiation of blood coagulation in vivo involves the accumulation of tissue factor– and PSGL-1–containing microparticles in the platelet thrombus expressing P-selectin. These monocyte-derived microparticles bind to activated platelets in an interaction mediated by platelet P-selectin and microparticle PSGL-1. We propose that PSGL-1 plays a role in blood coagulation in addition to its known role in leukocyte trafficking.

Macrovascular thrombosis is driven by tissue factor derived primarily from the blood vessel wall

Blood ◽  
2005 ◽  
Vol 105 (1) ◽  
pp. 192-198 ◽  
Author(s):  
Sharlene M. Day ◽  
Jennifer L. Reeve ◽  
Brian Pedersen ◽  
Diana M Farris ◽  
Daniel D. Myers ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Tissue Factor ◽  
Vessel Wall ◽  
Thrombus Formation ◽  
Vena Cava ◽  
Vascular Wall ◽  
Blood Vessel Wall ◽  
Wild Type

Abstract Leukocytes and leukocyte-derived microparticles contain low levels of tissue factor (TF) and incorporate into forming thrombi. Although this circulating pool of TF has been proposed to play a key role in thrombosis, its functional significance relative to that of vascular wall TF is poorly defined. We tested the hypothesis that leukocyte-derived TF contributes to thrombus formation in vivo. Compared to wild-type mice, mice with severe TF deficiency (ie, TF–/–, hTF-Tg+, or “low-TF”) demonstrated markedly impaired thrombus formation after carotid artery injury or inferior vena cava ligation. A bone marrow transplantation strategy was used to modulate levels of leukocyte-derived TF. Transplantation of low-TF marrow into wild-type mice did not suppress arterial or venous thrombus formation. Similarly, transplantation of wild-type marrow into low-TF mice did not accelerate thrombosis. In vitro analyses revealed that TF activity in the blood was very low and was markedly exceeded by that present in the vessel wall. Therefore, our results suggest that thrombus formation in the arterial and venous macrovasculature is driven primarily by TF derived from the blood vessel wall as opposed to leukocytes.

Endothelium but Not Platelet-Derived Protein Disulfide Isomerase Is Required for Fibrin Generation during Thrombus Formation in Vivo.

Blood ◽  
2008 ◽  
Vol 112 (11) ◽  
pp. 691-691 ◽  
Author(s):  
Reema Jasuja ◽  
Jaehyung Cho ◽  
Bruce Furie ◽  
Barbara Furie
Keyword(s):  
Endothelial Cells ◽  
Protein Disulfide Isomerase ◽  
Thrombus Formation ◽  
Fibrin Deposition ◽  
Wild Type ◽  
Disulfide Isomerase ◽  
Laser Injury ◽  
Injury Model ◽  
Protein Disulfide

Abstract We have previously reported that protein disulfide isomerase is required in wild-type mice for platelet thrombus formation and fibrin generation in an in vivo laser injury model of thrombosis (Cho et al. J. Clin. Invest., 2008; 118:1123–31). Fibrin deposition after laser injury to the vessel wall in Par4−/− mice, lacking the G protein-coupled platelet thrombin receptor, is independent of platelets or requires minimal platelet activation or accumulation (Vandendries et al. Proc. Natl. Acad. Sci., 2007; 104:288–92). However, protein disulfide isomerase inhibitors have a dramatic effect on fibrin accumulation in Par4− mice, suggesting that these inhibitors may function by a platelet independent mechanism. Here, we compare the contributions of endothelium and platelet-derived protein disulfide isomerase to fibrin generation in the mouse laser injury model of thrombosis. In vitro studies using cultured human umbilical vein endothelial cells and human aortic endothelial cells show that protein disulfide isomerase can be secreted rapidly into the culture medium from these cells upon thrombin stimulation. Using intravital microscopy, we observe that protein disulfide isomerase is not detectable on the vessel wall prior to laser injury but can be detected on the injured cremaster arteriolar wall and in the developing thrombus very rapidly after laser induced injury in the live mouse. The median integrated fluorescence intensity for protein disulfide isomerase in wild-type mice was compared to wild-type mice injected with 10ug/g mouse of Integrilin, an inhibitor of platelet activation and platelet thrombus formation, and thus, an inhibitor of the contribution of platelet derived protein disulfide isomerase to thrombus formation. Protein disulfide isomerase expression was similar in both treated and untreated animals upto 30 seconds post-laser injury. After 30 seconds, the expression of protein disulfide isomerase in integrilin treated mice was significantly decreased compared to that in untreated mice, indicating that the initial protein disulfide isomerase was derived from the endothelium and later additional protein disulfide isomerase was derived from the platelets following their accumulation in the developing thrombus. Fibrin deposition, a measure of thrombin generation was comparable in wild-type mice that had been treated with Integrilin or treated with a control buffer, suggesting that endothelial-derived protein disulfide isomerase was sufficient for fibrin generation. The rate and amount of fibrin generation was indistinguishable in both groups. Furthermore, inhibition of the protein disulfide isomerase with the function blocking monoclonal antibody RL-90 (3ug/g mouse) eliminated any fibrin deposition in wild-type mice that had been treated with Integrilin. Taken together, these data indicate that endothelium-derived protein disulfide isomerase is necessary to support fibrin deposition in vivo in our laser injury model of thrombus formation. The initial protein disulfide isomerase expressed at the site of injury is derived from endothelial cells but platelets activated at the site of thrombus formation contribute, amplify and sustain protein disulfide isomerase expression.

Platelet JNK1 is involved in secretion and thrombus formation

Blood ◽  
2010 ◽  
Vol 115 (20) ◽  
pp. 4083-4092 ◽  
Author(s):  
Frédéric Adam ◽  
Alexandre Kauskot ◽  
Paquita Nurden ◽  
Eric Sulpice ◽  
Marc F. Hoylaerts ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Thrombus Formation ◽  
Blood Perfusion ◽  
Collagen Matrix ◽  
In Vivo Model ◽  
Wild Type ◽  
Platelet Secretion

Abstract The role of c-Jun NH2-terminal kinase 1 (JNK1) in hemostasis and thrombosis remains unclear. We show here, with JNK1-deficient (JNK1−/−) mice, that JNK1 plays an important role in platelet biology and thrombus formation. In tail-bleeding assays, JNK1−/− mice exhibited longer bleeding times than wild-type mice (396 ± 39 seconds vs 245 ± 32 seconds). We also carried out in vitro whole-blood perfusion assays on a collagen matrix under arterial shear conditions. Thrombus formation was significantly reduced for JNK1−/− platelets (51%). In an in vivo model of thrombosis induced by photochemical injury to cecum vessels, occlusion times were 4.3 times longer in JNK1−/− arterioles than in wild-type arterioles. Moreover, in vitro studies carried out in platelet aggregation conditions demonstrated that, at low doses of agonists, platelet secretion was impaired in JNK1−/− platelets, leading to altered integrin αIIbβ3 activation and reduced platelet aggregation, via a mechanism involving protein kinase C. JNK1 thus appears to be essential for platelet secretion in vitro, consistent with its role in thrombus growth in vivo. Finally, we showed that ERK2 and another isoform of JNK affect platelet aggregation through 2 pathways, one dependent and another independent of JNK1.

scholarly journals Regions of the Herpes Simplex Virus Type 1 Latency-Associated Transcript That Protect Cells from Apoptosis In Vitro and Protect Neuronal Cells In Vivo

2002 ◽  
Vol 76 (2) ◽  
pp. 717-729 ◽  
Author(s):  
Maryam Ahmed ◽  
Martin Lock ◽  
Cathie G. Miller ◽  
Nigel W. Fraser
Keyword(s):  
Herpes Simplex ◽  
Trigeminal Ganglia ◽  
Wild Type ◽  
Exon 1 ◽  
Induced Apoptosis ◽  
Simplex Virus ◽  
In Cells

ABSTRACT Recent studies have suggested that the latency-associated transcript (LAT) region of herpes simplex virus type 1 (HSV-1) is effective at blocking virus-induced apoptosis both in vitro and in the trigeminal ganglia of acutely infected rabbits (Inman et al., J. Virol. 75:3636–3646, 2001; Perng et al., Science 287:1500–1503, 2000). By transfecting cells with a construct expressing the Pst-Mlu segment of the LAT, encompassing the LAT exon 1, the stable 2.0-kb intron, and 5′ part of exon 2, we confirmed that this region was able to diminish the onset of programmed cell death initiated by anti-Fas and camptothecin treatment. In addition, caspase 8-induced apoptosis was specifically inhibited in cells expressing the Pst-Mlu LAT fragment. To further delineate the minimal region of LAT that is necessary for this antiapoptotic function, LAT mutants were used in our cotransfection assays. In HeLa cells, the plasmids lacking exon sequences were the least effective at blocking apoptosis. However, similar to previous work (Inman et al., op. cit.), our data also indicated that the 5′ end of the stable 2.0-kb LAT intron appeared to contribute to the promotion of cell survival. Furthermore, cells productively infected with the 17N/H LAT mutant virus, a virus deleted in the LAT promoter, exon 1, and about half of the intron, exhibited a greater degree of DNA fragmentation than cells infected with wild-type HSV-1. These data support the finding that the exon 1 and 2.0-kb intron region of the LAT transcription unit display an antiapoptotic function both in transfected cells and in the context of the virus infection in vitro. In trigeminal ganglia of mice acutely infected with the wild-type virus, 17, and 17ΔSty, a virus lacking most of exon 1, apoptosis was not detected in cells that were positive for virus particles. However, dual staining was observed in cells from mice infected with 17N/H virus, indicating that the LAT antiapoptotic function demonstrated in cells transfected by LAT-expressing constructs may also play a role in protecting cells from virus-induced apoptosis during acute viral infection in vivo.

scholarly journals Virus Particle Core Defects Caused by Mutations in the Human Immunodeficiency Virus Capsid N-Terminal Domain

2005 ◽  
Vol 79 (3) ◽  
pp. 1470-1479 ◽  
Author(s):  
Isabel Scholz ◽  
Brian Arvidson ◽  
Doug Huseby ◽  
Eric Barklis
Keyword(s):  
Human Immunodeficiency Virus ◽  
Wild Type ◽  
Immunodeficiency Virus ◽  
Order Structures ◽  
Binding Loop ◽  
Hiv 1 ◽  
Cypa Binding

ABSTRACT The N-terminal domains (NTDs) of the human immunodeficiency virus type 1 (HIV-1) capsid (CA) protein have been modeled to form hexamer rings in the mature cores of virions. In vitro, hexamer ring units organize into either tubes or spheres, in a pH-dependent fashion. To probe factors which might govern hexamer assembly preferences in vivo, we examined the effects of mutations at CA histidine residue 84 (H84), modeled at the outer edges of NTD hexamers, as well as a nearby histidine (H87) in the cyclophilin A (CypA) binding loop. Although mutations at H87 yielded infectious virions, mutations at H84 produced assembly-competent but poorly infectious virions. The H84 mutant viruses incorporated wild-type levels of CypA and viral RNAs and showed nearly normal signals in virus entry assays. However, mutant CA proteins assembled aberrant virus cores, and mutant core fractions retained abnormally high levels of CA but reduced reverse transcriptase activities. Our results suggest that HIV-1 CA residue 84 contributes to a structure which helps control either NTD hexamer assembly or the organization of hexamers into higher-order structures.

Abstract 456: Antiphospholipid Antibodies Promote Platelet Activation and Thrombosis by Inhibition of Platelet eNOS

Circulation ◽  
2007 ◽  
Vol 116 (suppl_16) ◽  
Author(s):  
Craig Morrell ◽  
AnneMarie Swaim ◽  
Tanika Martin ◽  
Guillermina Girardi ◽  
Jane E Salmon ◽  
...  
Keyword(s):  
Platelet Activation ◽  
Antiphospholipid Antibodies ◽  
Thrombus Formation ◽  
Ldl Receptor ◽  
Wild Type ◽  
Human Igg ◽  
Increased Risk ◽  
Receptor Family

The antiphospholipid syndrome (APS) is an autoimmune systemic disorder characterized by the persistent presence of antiphospholipid antibodies (aPL Ab) and increased risk of thrombosis, coronary artery disease and myocardial infarction. Although platelets are known direct targets of aPL Ab action, the molecular basis of aPL Ab actions on platelets remains unclear. Platelet endothelial NO synthase (eNOS) is a key regulator of platelet function, with NO causing blunted activation. We therefore determined whether aPL Ab modulate platelet eNOS. Normal human IgG (NH IgG) and human IgG containing polyclonal aPL Ab were obtained from healthy individuals and APS patients, respectively, and purified using protein G-Sepharose chromatography. Using both human and mouse platelets, we found that aPL Ab increased agonist-induced platelet activation whereas NH IgG did not. In contrast to the enhanced activation by aPL Ab in platelets from wild-type mice, aPL Ab had no effect on platelets isolated from eNOS null mice. Pre-treatment of platelets with aPL Ab also inhibited insulin-mediated eNOS stimulation as evidenced by diminished cGMP production and DAF2 fluorescence. Receptor associated protein (RAP), an antagonist of ligand binding to members of the LDL receptor family, blocked aPL Ab-induced increases in platelet activation. RAP also prevented aPL Ab-mediated antagonism of platelet eNOS, indicating that aPL Ab signal through the platelet ApoER2â ϵ™ (LRP8) to attenuate eNOS activity. Furthermore, using intravital microscopy of the mouse mesenteric circulation, we demonstrated that platelets from wild-type mice treated with aPL Ab have increased rolling on a stimulated endothelium and a decreased time to thrombus formation in vivo versus platelets treated with NH IgG. In contrast, aPL Ab did not alter the in vivo function of platelets from eNOS null mice. These cumulative in vitro and in vivo findings demonstrate that aPL Ab antagonism of platelet eNOS through LDL receptor family member binding underlies aPL Ab-mediated thrombosis.

In Vitro and In Vivo Characterization of a Murine Model of Suppressed Intrinsic Pathway Using a FX Variant: FXRoma.

Blood ◽  
2007 ◽  
Vol 110 (11) ◽  
pp. 2697-2697
Author(s):  
Elise Roy ◽  
Paris Margaritis ◽  
Harre D. Downey ◽  
Katherine A. High
Keyword(s):  
Mouse Model ◽  
Thrombus Formation ◽  
Bleeding Tendency ◽  
Factor X ◽  
Wild Type ◽  
Intrinsic Pathway ◽  
Vessel Occlusion ◽  
Tail Clip

Abstract The complex and dynamic interplay between the intrinsic and extrinsic pathways of blood coagulation is incompletely understood. The mediator of prothrombin cleavage, Factor X (FX), plays a pivotal role as part of both the extrinsic and intrinsic tenase complexes. Moreover, the existence of naturally occurring Factor X mutations that can be asymmetrically activated through one but not both of these pathways affords one strategy for analyzing the relationship of the two pathways. The Factor X Roma (FXRoma) variant, originally described in a patient with mild bleeding tendency (severe following trauma, De Stefano et al., 1988), is due to a missense mutation (Thr318←Met) in exon 8. Coagulation testing revealed markedly decreased activity (1–3% wild-type) in the intrinsic pathway as measured by aPTT, but substantially higher activity (30–50% wild-type) in the extrinsic pathway as measured by PT. We chose to generate a mouse model of FX asymmetric activation to further probe the extrinsic-intrinsic pathway physiological relationship in hemostasis and thrombosis. For this, we used both an in vitro and an in vivo approach. We first constructed and purified the mouse homolog of FXRoma (mFXRoma) as well as wild-type mFX. Using a clotting-based assay, mFXRoma exhibited intrinsic and extrinsic activity comparable to that reported for the human mutation (5% and 18%, respectively). The reduced intrinsic and extrinsic activity of mFXRoma was not due to a secretion defect, based on Western blot analysis of supernatant and cell extracts from mFXRoma and mFX stably-transfected human embryonic kidney (HEK-293) cell lines. Mice homozygous for the analogous mutation (Thr315←Met) in exon 8 of the murine FX gene were generated by using a plug-and-socket approach. This resulted in the endogenous mFX exon 8 sequence being replaced with the mutated one, thus affording gene expression under the endogenous promoter. Analysis of mFXRoma homozygous mice showed a 6.4% and 19.2% intrinsic and extrinsic activity relative to wild-type littermates, respectively, confirming our in vitro data. The reduced activity in these mice resulted in a slight reduction in levels of the thrombin-antithrombin (TAT) complex. To determine any physiological defect of this mutation on the two pathways of coagulation, we performed two hemostatic challenges of the macrocirculation (tail clip and FeCl3-induced thrombus formation). In the tail-clip assay, blood loss showed no statistical difference between wild-type (n=5) and mFXRoma (n=6) mice. In contrast, following FeCl3-induced injury on the carotid artery (larger vessel diameter that in the tail), mFXRoma mice (3/3) failed to result in vessel occlusion (up to 30 min of observation), whereas wild-type littermates showed stable vessel occlusion (3/4) within ∼6 min of FeCl3 application. Although the type of injury was different, these data suggest that an impeded intrinsic activity of FX does not appear to affect hemostasis of the macrocirculation at relatively small diameter vessels but is essential for thrombus formation in large diameter vessels, and a relatively normal extrinsic activity does not compensate for this defect. This mouse model will aid in determining the safety and efficacy of therapeutic approaches based on impeding the intrinsic pathway of coagulation.

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