bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulatory CD4+CD25+ T Cells Modulated the Immune Response of a Mild Hemophilia A Subject to an Immunodominant FVIII Epitope within a Distinct Time Window.
Authors: James Eddie A. , Kwok William W. , Thompson Arthur R. , Pratt Kathleen P. 
Published: April 2020

Abstract
A mild hemophilia A subject with a missense mutation, A2201P, developed high titer neutralizing antibodies against infused factor VIII (FVIII) following post−operative FVIII administration. This missense mutation is in the C2 domain of FVIII. His baseline clotting activity fell from 10% to 3% of normal; FVIII infusions were discontinued, and his factor VIII clotting activity improved to its baseline within 2 mo. His inhibitor titer to FVIII declined over the ensuing year during which 12 samples were studied for T−cell epitopes, antibody titer, or both. His HLA haplotype was DR0101/DR1503, allowing use of fluorescent−labeled MHC Class II tetramers specific for DR0101. These were loaded with synthetic 20−mer peptides spanning the FVIII C2 domain to identify specific T cells responding to epitopes on FVIII by FACS. Proliferation assays were also carried out stimulating T cells with FVIII, the recombinant wild−type FVIII C2 domain, the C2 domain with mutation A2201P, and peptides. Tetramer staining and proliferation assays of total CD4+ and CD4+CD25− fractions indicated that CD4+CD25+ regulatory T cells modulated his immune response to FVIII between 10 and 19 weeks following the initial bleed. Peptides containing the wild type A2201, but not P2201, elicited strong T−cell responses. Markedly decreased staining of the total CD4 fractions compared to CD4+CD25− fractions in response to a peptide containing A2201 was observed between weeks 10 and 19 (see Figure showing staining at week 10). T−cell proliferation assays were carried out for cloned, expanded T cells that were selected using the tetramers. These T cell clones proliferated in response to FVIII, wild−type C2 protein, and peptides with the native A2201 sequence, whereas a peptide containing the mutation A2201P abrogated tetramer binding and proliferation. The T−cell epitope corresponded to a predicted MHC Class II binding motif for DR0101, underscoring the importance of studying T−cell responses within the context of each individual’s HLA haplotype. The epitope also overlapped a B−cell epitope identified by peptide mapping of the subject’s anti−FVIII C2 domain IgG fraction. Tetramer−guided T−cell epitope mapping provides greater sensitivity and specificity and markedly less ambiguous information than traditional mapping methods based on proliferation in response to peptides. FACS sorting of stained T cells allowed cloning of single T cells that retained the original specificity for the factor VIII peptides comprising this immunodominant T−cell epitope.
Response to peptide 2194-2213 10 weeks after inhibitor first appeared Response to peptide 2194-2213 10 weeks after inhibitor first appeared
Randomized, Prospective Clinical Trial of rFVIIa for Secondary Prophylaxis in Hemophilia Patients with Inhibitors.
Authors: Konkle Barbara A. , Ebbesen Liselotte S. , Friedrich Ute , Bianco Raul P. , Lissitchkov Toshko , Rusen Luminita , Serban Margit A. 
Published: April 2020

Abstract
Introduction: Hemophilia patients with inhibitors experience frequent bleeds and reduced quality of life (QoL). This trial evaluated whether once−daily prophylaxis therapy with activated recombinant factor VII (rFVIIa; 90 or 270 μg/kg) for 3 months can effectively reduce bleed frequency compared with on−demand therapy, without compromising safety.
Methods: Thirty−eight hemophilia inhibitor patients with frequent bleeds entered a 3−month observation period where on−demand therapy was continued according to local practice. Twenty−two patients with a stable bleed frequency (≥4 bleeds/month) were randomized 1:1 to once−daily dosing with 90 or 270 μg/kg rFVIIa in a double−blind, parallel−group design. To maintain blinding, the same volume was administered in both groups. Patients then entered a 3−month post−treatment observation period, where on−demand therapy was resumed.
Results: The number of bleeds per month was significantly reduced by 45% and 59% with 90 or 270 μg/kg rFVIIa prophylaxis, respectively, compared with the observation period (Fig.). Similar reductions were seen for all bleeds, irrespective of site or cause. The majority of this reduced bleeding frequency was maintained in the 3 month post−treatment period (27% and 50% reductions, respectively). There were no treatment− or dose−dependent patterns in the number or type of adverse events. No thromboembolic events or withdrawals due to adverse events or ineffective treatment were reported. The benefits of reducing bleeding frequency in this trial translated into improvements in QoL.
Conclusions: These results support the concept of secondary rFVIIa prophylaxis in inhibitor patients with frequent bleeds. Clinically relevant reductions in number of bleeds and improvements in quality of life were observed during prophylaxis compared with conventional on−demand therapy without raising any safety concerns.
Figure Figure
Proteolysis of MLL Family Proteins Is Essential for Taspase1−Orchestrated Cell Cycle Progression.
Authors: Hsieh James J. , Takeda Shugaku , Chen David Y. , Westergard Todd D. , Fisher Jill K. , Rubens Jeffrey A. , Sasagawa Satoru , Kan Jason T. , Korsmeyer Stanley J. , Cheng Emily H. 
Published: April 2020

Abstract
Taspase1 was identified as the threonine endopeptidase that cleaves MLL for proper Hox gene expression in vitro. To investigate its functions in vivo, we generated Taspase1−/− mice. Taspase1 deficiency results in non−cleavage (nc) of MLL and MLL2 and homeotic transformations. Remarkably, our in vivo studies uncover an unexpected role of Taspase1 in cell cycle. Taspase1−/− animals are smaller in size. Taspase1−/− MEFs exhibit impaired proliferation and acute deletion of Taspase1 leads to a marked reduction of thymocytes. Taspase1 deficiency incurs down−regulation of Cyclin Es, As, and Bs and up−regulation of p16Ink4a. We show that MLL and MLL2 directly target E2Fs for Cyclin expression. The un−cleaved precursor MLL displays a reduced histone H3 methyl transferase activity in vitro. Accordingly, CHIP assays demonstrate a markedly decreased histone H3 K4 tri−methylation at Cyclin E1 and E2 genes in Taspase1−/− cells. Furthermore, MLLnc/nc;2nc/nc MEFs are also impaired in proliferation. Our data are consistent with a model in which precursor MLLs, activated by Taspase1, target to Cyclins through E2Fs to methylate histone H3 at K4, leading to activation. Lastly, Taspase1−/− cells are resistant to oncogenic transformation and Taspase1 is over−expressed in many cancer cell lines. Thus, Taspase1 may serve as a target for cancer therapeutics.
Notch1 Expression Is Regulated at Translational Level by 3′UTR Region in Hematopoietic Stem Cell Development.
Authors: Mizuno Shin-ichi , Ozawa Hidetoshi , Shigematsu Hirokazu , Arinobu Yojiro , Yong Chong , Iino Tadafumi , Akashi Koichi 
Published: April 2020

Abstract
In hematopoietic stem cell development, the expression of critical genes is precisely regulated in a stage specific manner, which supports normal hematopoietic development through adequately regulating timing of cell division, self-renewal, and lineage commitment of hematopoietic stem cells. Regulation of gene expression is known to take place at transcriptional level. In addition to the transcriptional regulation, there are growing evidences that translational control of critical genes may play a role, especially in embryogenic development, suggesting an interesting possibility that translational control may also play a role in hematopoiesis. Here, we provide the evidence that the expression of a key transcription factor in lymphoid development, Notch1, is controlled at translational level in hematopoietic stem cell. To examine whether translation of mRNAs of hematopoietic major factors can be regulated at each stage of hematopoietic development, we established a retrovirus sensor vector, in which 3′UTR (untranslated region) of target genes is placed between the GFP coding region and the retrovirus 3′LTR. Since the transcribed mRNA from this vector is a fusion mRNA of GFP and 3′UTR from the gene of interest, this vector allows us to visualize the effect of 3′UTR on translational control of particular genes by GFP as a reporter. We cloned 3′UTR fragments from PU.1, GATA-1, GATA-2, C/EBPα and Notch1 genes into the sensor vector. Then, we introduced these retrovirus vectors into prospectively-purified hematopoietic stem and progenitor cells, including HSC, CMP and GMP, and their GFP intensities were monitored by a flowcytometer. We found that induction of the sensor vector with the 3′UTR sequence from Notch1 showed marked suppression of the GFP intensity at the HSC stage. The 3′UTR sequences from the other 4 transcription factors did not show such intensive inhibitory effect. Suppression of Notch1 transcription by its 3′UTR was further confirmed by using a retrovirus vector which has two distinct markers of YFP and GFP-3′UTR fusion genes under bi-directional EF1α promoter. These data suggest that the expression of Notch1 should be regulated at translational level by its 3′UTR at the HSC stage as well as at transcriptional level. Our data provide the first evidence that the stage-specific translational regulation can play an important role in organization of hematopoietic development.
Hemolysis in Sickle Cell Mice Causes Pulmonary Hypertension Due to Global Impairment in Nitric Oxide Bioavailability.
Authors: Hsu Lewis L. , Champion Hunter C. , Campbell-Lee Sally A. , Bivalacqua Trinity J. , Manci Elizabeth A. , Diwan Bhalchandra A. , Schimel Daniel M. , Cochard Audrey E. , Wang Xunde , Schechter Alan N. , Noguchi Constance Tom , Gladwin Mark T. 
Published: April 2020

Abstract
Pulmonary hypertension is a highly prevalent complication of sickle cell disease and is a strong risk factor for early mortality. However, the pathophysiological mechanisms by which sickle hemoglobin leads to pulmonary vasculopathy remain unclear. Transgenic mice provide opportunities for mechanistic studies of vascular pathophysiology in an animal model of severe sickle cell disease. Using micro-cardiac catheterization we found that all mice expressing exclusively human sickle hemoglobin develop pulmonary hypertension. Recognizing that the NO pathways can have complex abnormalities in other conditions of pulmonary hypertension, the NO axis in sickle mice was assessed by multiple methods. From a mechanistic standpoint the mice exhibit profound pulmonary and systemic endothelial dysfunction and vascular instability characterized by diminished responses to authentic nitric oxide (NO), NO donors and endothelium-dependent pulmonary vasodilators, and enhanced responses to vaso-constrictors. However, endothelium-independent vasodilation in the sickle mice was normal. Mechanisms of vasculopathy in sickle mice involve global dysregulation of the NO-axis: impaired constitutive nitric oxide synthase activity with loss of eNOS coupling (dimerization), increased NO scavenging by plasma hemoglobin and superoxide, increased arginase activity, and depleted intravascular nitrite reserves. Consistent with a functional rather than structural defect, light microscopy and computed tomography of the lungs revealed no plexogenic arterial remodeling, thrombi/emboli, or inflammation. Transplanting sickle marrow into wild-type mice conferred the same phenotype. Similar pathobiology was observed in a non-sickle mouse model of acute alloimmune hemolysis, supporting a major role of hemolysis as a mechanism for this dysregulation of NO and vasculopathy. In this study, alloimmune hemolytic mice were chosen for comparison in order to generalize beyond hemoglobinopathies. Future analogous studies with thalassemic mice may be useful to model pulmonary hypertension in human thalassemia intermedia. In conclusion, this animal model extends the evidence for global impairment in NO responsiveness and NO production in sickle cell disease, and suggests that hemolytic anemia is associated with endothelial dysfunction and pulmonary hypertension.
Regular Blood Transfusion Does Not Prevent Progression of Cerebral Lesions Evidenced by Magnetic Resonance Imaging in Children with Sickle Cell Disease (SCD).
Authors: Brousse Valentine , Hertz-Pannier Lucie , Bresson Jean-Louis , De Montalembert Mariane 
Published: April 2020

Abstract
Purpose: The effects of chronic transfusion on the cerebral vessel abnormalities in SCD patients are unknown. Chronic transfusion has been reported to be effective in preventing recurrence of overt strokes, and occurrence of a first stroke in children with abnormal transcranial Doppler ultrasonography (TCD). However, cerebrovascular events may occur despite adequate prevention, suggesting that transfusion therapy does not cure nor even stabilize vessels disease. We conducted a single center retrospective study to determine the evolution of cerebral lesions in SCD children on regular transfusion therapy using magnetic resonance imaging.
Material and methods: Children with homozygous sickle cell anemia chronically transfused for first or secondary prevention of stroke were included in the study. All patients had been started in a program of monthly transfusions, maintaining constantly hemoglobin S level below 30%, in the month following the stroke or the abnormal TCD. They underwent cerebral magnetic resonance imaging (MRI) and magnetic resonance angiography (MRA) every one to two years. An expert neuroradiologist unaware of the date of the imaging and unaware of the identity of the patients reviewed resulting images. Standard MRI criteria were used to identify lacunae, cerebral atrophy, infarcts and leucoencephalopathy, with progressive grading. Standard MRA criteria were used to identify arterial tortuosity, stenosis/occlusion and moya-moya with progressive grading. All MRI and MRA were scored, and these scores were compared longitudinally in each patient using a Paired Rank test.
Results: 18 children (9 males, 9 females) were enrolled. Chronic transfusion therapy was prescribed and initiated for 10 patients with initial strokes (mean age at the stroke 6,8 +/− 2,5 yrs) and 8 patients with abnormal TCD (mean age at the TCD 7,2 +/− 2,9 yrs). Mean follow-up was 6,8 +/− 4,1 yrs in the stroke group, 1,7 +/− 1,0 yrs in the abnormal TCD group. A total of 45 MR images were reviewed (median MR/patient: 3 [2–4]). Initial scores were lower in the abnormal TCD group than in the stroke group (mean score respectively 1 [0–7] versus 12 [2–26]). Comparison of longitudinal scores in the group of patients with initial stroke evidenced progression of lesions (p=0,008). The longitudinal scores were not significantly different in the abnormal TCD group, but this may be explained by the shorter follow-up.
Conclusion: Blood transfusion maintaining permanently HbS level &lt;30% does not prevent progression of cerebral micro or macro vascular lesions in SCD children having had a 1st stroke. A lengthier follow-up is needed to reach a conclusion in the case of children with abnormal TCD. Our results support the case that early bone marrow transplant therapy should be applied to prevent progression of cerebral vasculopathy in SCD children at risk.
Aberrant Expression of the Homeobox Gene CDX2 in Acute Myeloid Leukemia.
Authors: Scholl Claudia , Bansal Dimple , Dohner Konstanze , Eiwen Karina , Lee Benjamin H. , Rucker Frank G. , Schlenk Richard F. , Bullinger Lars , Dohner Hartmut , Gilliland D. Gary , Frohling Stefan 
Published: April 2020

Abstract
The caudal-type homeobox transcription factor 2 (CDX2) plays an important role in embryonic development and regulates the proliferation and differentiation of intestinal epithelial cells in the adult. Ectopic expression of CDX2 in the hematopoietic compartment was previously identified as the key pathogenetic event in a single patient with acute myeloid leukemia (AML) and t(12;13)(p13;q12). Using real-time quantitative PCR, we detected aberrant CDX2 expression in 153 (90%) of 170 patients with AML, in patients with high-risk myelodysplastic syndrome or advanced-stage chronic myeloid leukemia, and in several AML cell lines, but not in bone marrow derived from normal individuals. Expression of CDX2 was monoallelic in the majority of cases with informative single-nucleotide polymorphisms in the CDX2 coding region, but was not related to mutations in the CDX2 coding region or in the predicted CDX2 promoter sequence, gene-specific hypomethylation of the CDX2 promoter, or increased CDX2 gene copy numbers. Stable knockdown of CDX2 expression by lentivirus-mediated RNA interference inhibited the proliferation of various human AML cell lines exhibiting CDX2 transcript levels that were in the range of those observed in most primary AML samples, and strongly reduced their clonogenic potential in vitro. Primary murine hematopoietic progenitor cells transduced with Cdx2 acquired serial replating activity in vitro, could be continuously propagated in liquid culture, generated a fully penetrant and transplantable AML in vivo, and displayed dysregulated expression of Hox family members. Together, these results (i) demonstrate that aberrant expression of CDX2 is a frequent event in myeloid leukemogenesis, (ii) suggest a role for CDX2 as part of a common effector pathway that increases the proliferative capacity and promotes the self-renewal potential of hematopoietic progenitors, and (iii) support the unifying hypothesis that CDX2 is responsible, at least in part, for abnormalities in HOX gene expression in AML.
Inhibition of the NPM-ALK Fusion Tyrosine Kinase in Hematopoietic Neoplasia by the Small Molecule Tyrosine Kinase Antagonist TAE684.
Authors: Sternberg David W. , Ray Arghya , Lee Benjamin H. , Adelsperger Jennifer , Duclos Nicole , McDowell Elizabeth , Haq Naznin , Imbach Patricia , Ohmori Osamu , Honda Toshiyuki , Warmuth Markus , Fabbro Doriano , Griffin James D. , Roesel Johannes 
Published: April 2020

Abstract
Anaplastic large cell lymphoma (ALCL) constitutes approximately 10–30 percent of childhood lymphomas and 3 percent of non-Hodgkin lymphomas in adults. Approximately 50–60 percent of ALCL patients express the ALK tyrosine kinase fused to a variety of partner proteins as a result of chromosomal translocation. The activated ALK fusion kinase drives proliferative and survival signaling in lymphoma cells that carry these translocations, and the native ALK protein is overexpressed in a variety of other hematologic and non-hematologic malignancies. Given the known functional role of NPM-ALK in the pathogenesis of some lymphomas, we developed the small molecule ALK antagonist TAE684 that targets the kinase catalytic domain. In Ba/F3 murine hematopoietic cells and human ALCL cells that require NPM-ALK for growth, TAE684 was selectively cytotoxic and rapidly triggered apoptotic cell death. We have extended these findings to animal models of hematopoietic neoplasia driven by the expression of NPM-ALK. In a murine NPM-ALK-Ba/F3 allograft model, oral administration of TAE684 prolonged the survival to 83 days, compared to 51 days for the control placebo-treated group (p=0.0028). Moreover, we used a murine retroviral bone marrow transplant model of NPM-ALK-driven hematopoietic neoplasia to assess the efficacy of TAE684 treatment. The median survival in the placebo-treated group was 18 days (range 11–18 days), whereas all but one mouse treated with TAE684 oral gavage survived to the study endpoint (range 23–25 days). The prolongation in survival was highly significant (p&lt;0.0001) and was associated with a reduction in peripheral blood leukocytosis, decreased splenomegaly, and resolution of tissue infiltration with atypical granulocytic, B-lymphoid, and histiocytic/macrophage cells. Thus, in two rapidly progressive models of hematopoietic neoplasia, oral administration of the TAE684 compound was able to produce marked control of disease in most recipient mice. The prolonged survival of mice treated with TAE684 can be attributed to the ablation of aggressive hematopoietic malignancy that is driven by expression of the NPM-ALK fusion kinase. We anticipate that TAE684 will be effective in the management of lymphomas that express ALK fusion kinases and in non-hematologic malignancies associated with aberrant expression of the native ALK protein.
Heat Shock Protein 90 (HSP90) Is a Rational Therapeutic Target in Diffuse Large B-Cell Lymphoma.
Authors: Abramson Jeremy S. , Chen Wen , Takahashi Hidenobu , Juszczynski Przemyslaw , Kutok Jeffery L. , Shipp Margaret A. 
Published: April 2020

Abstract
Diffuse large B-cell lymphoma (DLBCL) is a heterogeneous disease that is currently treated with a homogeneous approach based on empiric combination chemotherapy. To elucidate molecular differences in DLBCL subsets and identify more rational treatment targets, coordinate transcriptional profiling was used to define three groups of DLBCLs: “Oxidative Phosphorylation” (OxPhos), “B-cell Receptor/Proliferation” (BCR), and “Host Response” (HR). Of interest, the HSP90 α and β isoforms were differentially expressed in the DLBCL subsets; the stress-induced α isoform was more abundant in OxPhos tumors (p &lt; .0001) whereas the constitutively expressed β isoform was increased in BCR DLBCLs (p &lt; .0001). HSP90 α and β differ in the length of their N-termini but share a common ATP binding domain, the target site for recently developed HSP90 inhibitors, such as IPI-504 (Infinity Pharmaceuticals, Cambridge, MA). Although differential HSP90 isoform expression likely reflects underlying biological differences in the DLBCL subsets, the shared ATP binding domain suggests that both isoforms, and the majority of DLBCLs, may be effectively targeted with HSP90 inhibitors. For these reasons, we determined the IC50 and cytotoxic potential of IPI-504 in an extensive series of DLBCL cell lines. IPI-504 inhibited the proliferation of DLBCL cell lines at IC50s ranging from 0.04 μM in the most sensitive line to 12.67 μM in the most resistant line. Annexin V/PI staining revealed that IPI-504 was cytotoxic to most DLBCL cell lines at low micromolar doses; even cell lines that were relatively resistant to IPI-504 at lower doses (2 μM) underwent apoptosis with prolonged exposure to increased IPI-504 doses (72 hrs. and 8 μM). Cell lines that were most sensitive to IPI-504 expressed high levels of a major HSP90 client protein, pAKT, and exhibited a dose-dependent decrease in pAKT levels following IPI-504 treatment. For these reasons, we assessed the efficacy of IPI-504 in association with a PI3K/AKT pathway inhibitor, LY24009, in the DLBCL panel. Combined treatment with the HSP90 and PI3K inhibitors was highly synergistic (Method of Chou and Talalay; Calcusyn software, Biosoft, Ferguson, MO), inhibiting cellular proliferation by over 95% in evaluated DLBCL cell lines. In contrast, the combination of concurrent IPI-504 and an empiric chemotherapeutic agent, doxorubicin, was antagonistic, underscoring the importance of rational combination therapy. We conclude that: 1) HSP90 isoforms are differentially expressed in primary DLBCL subsets; and 2) inhibition of HSP90, via the conserved ATP binding domain, leads to dose-dependent apoptosis that is associated with depletion of pAKT in DLBCL cell lines. The HSP90 inhibitor IPI-504 possesses both single-agent efficacy as well as synergy when combined with PI3K inhibitors, suggesting that this rational targeted approach warrants further clinical investigation.