bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mice Overexpressing Histone Deacetylase 9 Display Abnormal B Cell Development and Proliferation.
Authors: Gil Veronica S. , Petrie Kevin , Chornet Manuel Boix , Howell Louise , Sebire Neil J. , Zelent Arthur 
Published: October 2019

Abstract
Histone acetylation plays a key role in regulating chromatin structure and gene expression. The activities of histone deacetylases (HDAC), enzymes that remove acetyl groups from lysines located at the amino-terminal tails of core histones, have been implicated in the pathogenesis of hematological malignancies. Consequently, inhibitors of these enzymes (HDACi) are considered an important new class of drugs for use in anti-cancer therapy and are now in various stages of development and clinical trials. For example, depsipeptide has now been granted a fast track designation by the FDA for development as a treatment for CTCL. To date, eleven HDACs have been identified and grouped on the basis of sequence homology to class I (HDACs 1–3 and 8), IIa (4, 5, 7 and 9) and IIb (6, 10 and 11). Depsipeptide and other currently used HDACi lack class and enzyme specificities. Additionally, the contribution of each HDAC to the pathogenesis of a given malignant disease is poorly understood. Improvements in HDACi specificities, together with advances in the understanding of the roles that individual HDACs play in normal hematopoiesis and distinct hematological neoplasms, are required for an effective use of these agents in anti-cancer therapies. We have previously identified and characterized HDAC9 as a class IIa enzyme that within the hematopoietic system is preferentially expressed in the lymphoid lineage. HDAC9 appears to be overexpressed in B lymphoid malignancies and associates at physiological levels with the BCL6 oncoprotein (Petrie et al, JBC278:16059–72, 2003), a transcriptional repressor implicated in the pathogenesis of non-Hodgkin’s lymphoma, suggesting a role for this chromatin modifying enzyme in B-cell transformation. In order to examine the function of HDAC9 in lymphoid development and cancer, we have generated transgenic mice that express the protein throughout the B lymphoid compartment under the control of the immunoglobulin heavy chain enhancer (Eμ). Initial data show that at an average of seven months these mice display splenomegaly and alterations to the splenic and bone marrow lymphoid populations. The presence of immature lymphocytes was also detected in peripheral blood. Consistent with these results and the above hypothesis, knockdown of HDAC9 results in strong inhibition of cell growth. These data indicate that aberrant expression of HDAC9 confers a proliferative advantage and leads to a phenotype resembling a pre-malignant condition.
Leukemogenic Cascade Induced by a Constitutively Active Neurotrophin Receptor, ΔTrkA.
Authors: Li Zhixiong , Meyer Johann , Rhein Mathias , Kustikova Olga , Rudolph Cornelia , Kamino Kenji , Neumann Thomas , Yang Min , Wahlers Anke , Fehse Boris , Reuther Gary W. , Schlegelberger Brigitte , Ganser Arnold , Baum Christopher 
Published: October 2019

Abstract
Various neurotrophins (NT) are expressed in the hematopoietic microenvironment to deliver their signals through TRK receptor tyrosine kinases. Although previous reports suggested a transforming potential of activated TRK signaling in hematopoiesis, the target cells and underlying mechanisms are largely unknown. In this study, we investigated in vivo leukemogenesis of ΔTrkA, a mutant of TRKA isolated from a patient with acute myeloid leukemia (AML). Retroviral expression of ΔTrkA in myeloid 32D cells induced AML at ~4 weeks after transplantation into syngeneic C3H/Hej mice (n=11). C57BL/6J mice (n=15) transplanted with ΔTrkA-transduced primary bone marrow cells developed myeloid and/or lymphoid leukemia with infiltration in multiple organs including bone marrow, spleen, liver, lung, and central nervous system. While activation of a tyrosine kinase generally is not sufficient to cause AML, surprisingly, 7 out of 15 C57BL/6J mice developed a polyclonal AML with a latency of <12 days. This strongly suggests that ΔTrkA is sufficient to block differentiation and promote proliferation of short-term repopulating myeloid progenitor cells. This simultaneous interference with two complementary leukemogenic pathways has not been reported for other oncogenic tyrosine kinases. However, as half of the mice survived this disorder, ΔTrkA does not seem to confer self-renewal properties to transformed blasts. Supporting this hypothesis, transplantation into lethally irradiated secondary recipients did not re-induce polyclonal AML, but rather gave rise to clonal acute lymphoblastic leukemia (ALL) after a latency of >78 days. This suggests that ΔTrkA can also transform long-term repopulating cells with a lymphoid potential. Retroviral insertion site analyses and spectral karyotyping revealed that induction of ALL by ΔTrkA required additional genetic lesions: Leukemic cells showed retroviral insertions in proto-oncogenes Bcl11a and Bcl11b, among others. Characterization of signal transduction demonstrated that PI3K and mTOR-raptor were crucial components of the transforming pathway induced by ΔTrkA. Phospholipase D was an important contributing factor, whereas STAT and MAP kinase pathways were not involved. In summary, our findings reveal potent transforming properties of altered NT receptor signaling in leukemia induction, which are in many respects distinct from other oncogenic tyrosine kinases. We would suggest to further evaluate the role of NT receptor signaling in leukemia pathogenesis, prognosis and treatment.
Egr-1 Functions as a Tumor Suppressor for Leukemias Caused by Different Oncogenes.
Authors: Gibbs John D. , Liebermann Dan A. , Hoffman Barbara 
Published: October 2019

Abstract
Deregulated expression of the proto-oncogenes c-myc, E2F-1 and c-myb in M1 myeloid leukemic cells rendered these cells incapable of undergoing myeloid terminal differentiation and its associated growth arrest, and prevented the loss in leukemogenicity normally observed when M1 cells are induced to differentiate. We recently showed that expressing Egr-1 in M1myc cells abrogated the c-myc-mediated block in terminal myeloid differentiation, with the cells undergoing macrophage maturation in the absence of growth arrest. Importantly, Egr-1 also abrogated c-myc-driven leukemogenicity. In this study, we asked if Egr-1 functions as a tumor suppressor by abrogating the block in differentiation caused by other oncogenes. It was shown that expressing Egr-1 in M1E2F-1 cells completely overrode the block in terminal myeloid cell differentiation, with the cells undergoing macrophage maturation, and unlike in myc/Egr-1 expressing cells, also becoming growth arrested. In contrast, expression of Egr-1 in M1myb cells promoted progression of the differentiation program to an intermediate stage of differentiation, but the cells became neither fully matured nor growth arrested, continuing to proliferate indefinitely. As seen for expression of Egr-1 in M1myc cells, Egr-1 expression in M1E2F-1 cells also abrogated E2F-1 driven leukemogenicity. In contrast, Egr-1 co-expression with c-myb in M1myb cells did not abrogate myb driven leukemia. Taken together, it can be concluded that Egr-1 is dominant to both E2F-1 and c-myc with regard to terminal morphological differentiation and the ability to suppress leukemias, whereas the proto-oncogene c-myb is dominant to Egr-1. These findings indicate that the tumor suppressor Egr-1 provides important tools for differentiation therapy of multiple leukemic phenotypes, dependent on the molecular nature of the activated oncogene.
Microparticles Are a Major Determinant of Thrombin Generation Measured by Technothrombin®TGA.
Authors: Kaufmann Viktoria , Mager Jutta , Eichinger Sabine , Binder Bernd R. 
Published: October 2019

Abstract
We have recently shown that a thrombin generation assay using low concentrations of phospholipids (3,2 mM; 20% PS) can discriminate patients with an increased risk for recurrent venous thromboembolism after cessation of anticoagulant therapy from those with a lower risk (Hron et al JAMA 2006). Patients with peak thrombin of ≥400nM had a ~3-fold higher relative risk of recurrence than those with peak thrombin <400nM. This difference was not explained by a larger proportion of patients with clotting factor abnormalities among those with high peak thrombin. We therefore investigated which other factors might influence peak thrombin generation. For this purpose 35 healthy male plasma donors were analyzed. Thrombin generation was measured in standard platelet poor plasma and in plasma made microparticle (MP) free by centrifugation for 120 minutes at 35,250 x g using low (3,2μM) and high (32μM ) phospholipids concentrations at the same tissue factor concentration (71,6 pM). For control purposes, peak thrombin was measured under similar conditions in 12 individuals each having either heterozygous FVLeiden mutation, being on vitamin K-antagonist therapy (VKA; mean INR=3.2) or having a lupus anticoagulant. In healthy plasma donors peak thrombin as generated by tissue factor and low phospholipids (RCL) in platelet poor plasma was 110±40 nM and increased to 306±99 nM in the presence of high phospholipids (RCH). When MP free plasma was used, however, peak thrombin dropped to 23±13 nM (RCL) and 109±43 nM thrombin (RCH), respectively. When MPs were re-added to MP-free plasma samples, a dose dependent increase in peak thrombin was found both for RCL and RCH reagents. At a MP concentration of 25,000 added per 1 ml MP free plasma, peak thrombin was 381±24 nM for RCL and 399±63 nM for RCH. The effects of MPs on peak thrombin using RCL were much more pronounced than the differences in peak thrombin seen between plasmas from individuals with FVLeiden, during anticoagulant therapy or with lupus anticoagulant as compared to controls (FVLeiden : 161±50 nM; VKA: 50±12 nM; lupus: 37±23 nM; controls: 110±40 nM). These results indicate that MPs contained in platelet poor plasma are a major determinant of peak thrombin in thrombin generation assays when low phospholipids are used and might cause increased peak thrombin levels found in patients with recurrent venous thromboembolism.
High Affinity Autoantibodies to ADAMTS13 in the Antiphospholipid Syndrome.
Authors: Austin Steven K. , Starke Richard D. , Purdy Gordon , Lawrie Andrew S. , Machin Samuel J. , Mackie Ian J. 
Published: October 2019

Abstract
Autoantibodies to ADAMTS13 are well known to play an important role in the development of microthrombosis and organ ischaemia in thrombotic thrombocytopenic purpura (TTP). Antiphospholipid syndrome (APS) is an autoimmune disorder associated with thrombosis and pregnancy failure, but in severe cases of APS, microvascular thrombosis can occur similar to that seen in TTP - suggesting possible mutual pathogenic factors. The role of ADAMTS13 in APS patients is unknown and we hypothesize that ADAMTS13 may play a role in the development of thrombosis in the APS population. We evaluated ADAMTS13 in 68 patients: 52 with APS (as defined by the revised Sapporo Criteria), and 16 with anti-phospholipid antibodies (aPL) only. Of the 68 patients, 38 (56%) had IgG antibody to ADAMTS13 (median 13.2 ug/ml, range 9.8 – 28.3 ug/ml, NR< 9.6 ug/ml) by ELISA (Imubind ELISA, American Diagnostica Inc). 25/68 patients (37%) demonstrated low ADAMTS13 activity by our in-house collagen binding assay (median 33.2%, range 0–64%, NR 66–126%), with 12 of the 25 patients demonstrating detectable antibody to ADAMTS13. Low activity was not associated with elevated VWF:Ag levels suggesting that high VWF turnover did not account for the low ADAMTS Activity. In addition, ADAMTS13 Antigen levels (Imubind ELISA, American Diagnostica Inc) were elevated in 45/68 (66%) (median 850 ng/ml, range 890–1379 ng/ml, NR350-730ng/ml) indicating discordance with the observed low ADAMTS13 activity levels. The increased ADAMTS13 antigen may reflect a compensatory response to the presence of autoantibodies to ADAMTS13 in APS. The abnormal ADAMTS13 findings were not associated with the presence of anticardiolipin antibody, anti-β2glycoprotein1 or lupus anticoagulant. Similarly, no association was seen in analysis of clinical subgroups (arterial or venous thrombosis, recurrent miscarriage). We subsequently purified IgG from plasma of 3 of the APS patients with detectable anti-ADAMTS13 autoantibody and observed strong binding to ADAMTS13 via ELISA. Furthermore using the purified IgG, increasing NaCl concentrations did not prevent antibody binding to ADAMTS suggesting that these antibodies are high affinity. These findings suggest that ADAMTS13 autoantibodies may have a role in other autoimmune thrombotic conditions aside from TTP. In APS, the prevalence of these high affinity antibodies may well be a pathogenic feature integral to shifting the haemostatic balance in favour of thrombosis.
Myeloproliferative Disease in the Pathogenesis and Survival of Budd-Chiari Syndrome.
Authors: Smalberg Jasper H. , Murad Sarwa D. , Braakman Eric , Valk Peter , Kappers-Klunne Mies C. , Janssen Harry L. , Leebeek Frank W.G. 
Published: October 2019

Abstract
Budd-Chiari syndrome (BCS) is a rare disorder caused by obstruction of the hepatic veins or the suprahepatic inferior vena cava. Myeloproliferative diseases (MPD) are the most important aetiological factor in BCS. The aim of this study was to evaluate multifactorial aetiology in BCS patients with MPD, to assess potential added value of the recently discovered JAK2 mutation in the diagnostics of MPD in BCS, and to determine the survival of MPD patients in BCS. All patients referred to our university hospital with primary, non-malignant BCS between January 1980 and January 2006 were included in this study (n=40). Median age was 28.4 years (18.4–53.3), 26 patients (65%) were female and in nine patients (23%) additional portal vein thrombosis (PVT) was present. Overall mean follow-up was 7.1 ± 6.9 years. Only two patients were lost to follow-up, of which one MPD patient. In addition to standard MPD work-up according to WHO criteria, JAK2 mutation analysis was performed in 17 patients. MPD was present in 33% of the patients: Polycythemia Vera (n=6), Essential Thrombocythemia (ET) (n=6) and unclassifiable MPD (n=1). JAK2 mutation was identified in seven out of the 17 tested BCS patients (41%). In two patients suspect for ET, but who failed to meet WHO criteria, JAK2 mutation analysis led to the diagnosis of MPD. In 38% of patients with MPD additional pro-thrombotic factors were present. Survival rates in patients with MPD at 1, 5, and 10 years remained constant at 92% (95% CI, 78%–100%). Survival rates in patients without MPD at 1, 5, and 10 years were 89% (95% CI, 77%–100%), 64% (95% CI, 44%–85%) and 53% (95% CI, 28%–79%), respectively. There was no significant difference in survival between the two (P=0.18). Additional PVT was only present in patients without MPD in our population, which may account for the slightly lowered survival of these patients, since more extensive thrombosis in the splanchnic area is associated with poorer survival. In addition, three patients with and one patients without MPD underwent liver transplantation, which may have affected survival rate in favour of MPD patients. In conclusion, we report MPD in 33% of our BCS patients. In 38% of the patients with MPD, additional pro-thrombotic factors were present. These results enforce the necessity of extensive screening for additional pro-thrombotic conditions. Our study clearly confirms the importance of JAK2 mutation analysis in patients with BCS. Long term follow-up did not show a significant difference in survival between patients with and without MPD.
Methionine-Loading and Random Homocysteine Tests Have No Added Value in Risk Assessment for Venous and Arterial Thrombosis.
Authors: Lijfering Willem M. , Veeger Nic J.G.M. , Brouwer Jan-Leendert P. , van de Poel Marlene H.W. , van der Meer Jan 
Published: October 2019

Abstract
Hyperhomocysteinemia is a risk factor for venous and arterial thrombosis. Different diagnostic strategies are used to identify subjects at risk of thrombosis, related to hyperhomocysteinemia. Measurements of fasting and methionine-loading levels are usually recommended. Alternatively, random homocysteine measurements may simplify the procedure. Random levels < 10 and > 20 μmol/l are considered to indicate normohomocysteinemia and hyperhomocysteinemia, respectively, while consecutive fasting and methionine-loading tests are required at levels 10–20 μmol/l. We performed a study to assess the most suitable strategy in a large cohort of families with hereditary (index) deficiencies of protein S, protein C or antithrombin. Random, fasting and methionine-loading homocysteine samples were measured in 713 relatives. According to predefined cut-off levels hyperhomocysteinemic and normohomocysteinemic relatives were identified and their absolute risks of thrombosis were compared. Relatives with random homocysteine levels > 20 μmol/l were not at risk of venous or arterial thrombosis compared to relatives with levels < 10 μmol/l (relative risks 0.9 [95% CI, 0.4–2.3] and 1.7 [0.5–5.7], respectively). Fasting hyperhomocysteinemia (homocysteine levels > 18.5 μmol/l) was associated with an increased risk of venous and arterial thrombosis (relative risks 2.6 [1.3–4.8] and 3.7 [1.5–8.4)], respectively) (Table). Relatives with normal fasting homocysteine levels, but methionine-loading hyperhomocysteinemia (homocysteine levels > 58.8 μmol/l) were not at risk; relative risk 0.8 (0.2–1.9) for venous thrombosis and 1.1 (0.2–3.9) for arterial thrombosis. Exclusion of relatives with an index deficiency did not alter the risk estimates, while annual incidences of normohomocysteinemic relatives decreased to 0.19% per year (0.12–0.29), which is comparable with the annual incidence in the normal population. As only fasting homocysteine identified subjects at risk of thrombosis, random homocysteine and methionine-loading tests can be omitted in clinical practice.
Venous Thrombosis Observation Relatives Incidence/year (%) Relative Risk years with event (95% CI) (95% CI) * Methionine-loading performed in relatives with no fasting hyperhomocysteinemia Fasting Homocysteine No hyperhomocysteinemia 10408 55 0.53 (0.40–0.69) Reference Hyperhomocysteinemia 804 11 1.37 (0.68–2.45) 2.6(1.3–4.8) Methionine-loading test* No hyperhomocysteinemia 9341 50 0.54 (0.40–0.71) Reference Hyperhomocysteinemia 986 4 0.41 (0.11–1.04) 0.8(0.2–1.9) Arterial Thrombosis Fasting Homocysteine No hyperhomocysteinemia 11096 21 0.19 (0.12–0.29) Reference Hyperhomocysteinemia 1004 7 0.70 (0.28–1.44) 3.7(1.5–8.4) Methionine-loading test* No hyperhomocysteinemia10008 10008 19 0.19 (0.11–0.30) Reference Hyperhomocysteinemia 1000 2 0.20 (0.02–0.72) 1.1(0.2–3.9)
Fibronectin Is Not the Only Important Molecule Required for Fibrinogen/VWF-Independent Platelet Aggregation: Study of Thrombosis in a New Strain of Triple Deficient Mice.
Authors: Reheman Adili , Hong Yang , Spring Christopher M. , Chen Pingguo , Wagner Denisa D. , Fassler Reinhard , Freedman John , Ni Heyu 
Published: October 2019

Abstract
Fibrinogen (Fg) has been considered essential for platelet aggregation. We demonstrated, however, that thrombi do form in Fg-deficient mice and in mice doubly deficient for both fibrinogen and von Willebrand factor (Fg/VWF−/−). We further reported that β3 integrin and thrombin are critical for this Fg/VWF-independent platelet aggregation. In Fg−/− or Fg/VWF−/− mice, platelet fibronectin (Fn) content is increased 3–5 fold. Furthermore, thrombus growth and stability are impaired in plasma Fn conditional deficient (M×-Cre, Fnflox/flox) mice. These data are consistent with the most recent studies of Fn assembly and suggest that Fn may support platelet thrombus formation. To examine whether Fn is the alternative key molecule which mediates platelet aggregation and thrombus formation in Fg/VWF−/− mice, we developed a novel strain of triple knockout (TKO) mice by breeding Fg/VWF−/− mice with M×-Cre+/− Fnflox/flox conditional knockout mice. Cre- littermates delivered from the same parents were used as a control. Fn depletion was induced by i.p. injections of polyinonic-polycytidylic acid. We found that TKO mice are viable with dramatically decreased levels of Fn in both the plasma (<2% of control) and platelets (<20% of control) as determined by immunoblot. No significant difference was found in peripheral blood cell counts or platelet surface adhesion proteins (GPIbα, P-selectin, β3 and β1 integrins) as compared with control mice. Unexpectedly, TKO platelet aggregation induced by thrombin and thrombin receptor activation peptide (TRAP) was enhanced in both platelet rich plasma and PIPES buffer (P<0.05). This phenomenon was also observed in a parallel-plate flow chamber. Significantly more TKO aggregates formed when fluorescently labelled whole blood was perfused over a collagen surface at 500s−1 (P<0.001). We also studied thrombus formation in TKO and Cre- control mice using intravital microscopy. Our preliminary data showed no obvious decrease in thrombus formation in TKO mice and injured arterioles occluded in one of two experimental mice. Our data suggest that Fn is not the only important molecule required for platelet aggregation and thrombus formation in Fg/VWF−/− mice. Further investigation of how Fn may inhibit Fg/VWF-independent platelet aggregation and the identification of what ligand(s) support this novel aggregation pathway may unveil an alternative haemostatic pathway in the absence of Fg and VWF.