bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cloning of human early B-cell factor and identification of target genes suggest a conserved role in B-cell development in man and mouse
Authors: Gisler Ramiro , Jacobsen Sten Erik W. , Sigvardsson Mikael 
Published: October 2019

AbstractEarly B-cell factor (EBF) is a helix–loop–helix transcription factor suggested to be essential for B-cell development in the mouse. Several genetic targets for EBF have been identified in mice, among these the surrogate light chain λ5 and the signal-transducing molecules Igα (mb-1) and Igβ (B29). This article reports cloning of the human homologue of EBF, hEBF. This protein has 93% sequence and 98.8% amino acid homology with mouse EBF. The encoded protein binds DNA and is expressed in cells of the B lineage, but not in cell populations representing T lymphocytes or myeloid cells. It is also shown that EBF-binding sites are functionally conserved in the humanmb-1 and B29 promoters because hEBF interacts with these in the electrophoretic mobility shift assay (EMSA) and have the ability to increase the activity of reporter constructs under the control of these promoters in nonlymphoid HeLa cells. A third genetic target for hEBF is the promoter of the human surrogate light chain14.1. This promoter contains 5 independent binding sites capable of interacting with hEBF in the EMSA, and the activity of the promoter was induced 24-fold in co-transfection experiments. These findings suggest that the human homologue of mouse EBF displays conserved biochemical features as well as genetic targets, indicating that this protein also has an important role in human B-cell development.
High incidence of chromosome 13 deletion in multiple myeloma detected by multiprobe interphase FISH
Authors: Shaughnessy John , Tian Erming , Sawyer Jeffrey , Bumm Klaus , Landes Reid , Badros Ashraf , Morris Christopher , Tricot Guido , Epstein Joshua , Barlogie Bart 
Published: October 2019

Abstract
Multiple myeloma (MM) is a hypoproliferative malignancy yielding informative karyotypes in no more than 30% of newly diagnosed cases. Although cytogenetic and molecular deletion of chromosome 13 is associated with poor prognosis, a MM tumor suppressor gene (TSG) has not been identified. To localize a minimal deleted region of chromosome 13, clonotypic plasma cells from 50 consecutive patients with MM were subjected to interphase fluorescence in situ hybridization (FISH) analysis using a panel of 11 probes spanning the entire long arm of chromosome 13. Whereas chromosome 13 abnormalities were absent in plasma cells from 25 normal donors, 86% of patients with MM demonstrated such aberrations. Heterogeneity, both in deletion frequency and extent, was confirmed by simultaneous FISH with 2 chromosome 13 probes. Deletion hot spots were noted at D13S272 (70%) and D13S31 (64%), 2 unlinked loci at 13q14. Homozygous deletions at these loci occurred in 12% (simultaneously in 8%) of the cases. Molecular deletions were found in all 14 patients with morphologic deletions, in 21 of 24 with uninformative karyotypes, and 8 of 12 patients with karyotype abnormalities lacking chromosome 13 deletion. Homozygous deletion of any marker was noted in 4% with low and in 36% with higher plasma cell labeling index greater than 0.4% (P = .01). The absence of increasing deletion incidence and extent with therapy duration suggests that the observed lesions are not induced by treatment. The high incidence and extent of chromosome 13 deletions require the correlation of specific deletion(s) with poor prognosis. These analyses will provide valuable guidance toward cloning of an MM-TSG.
Epolones induce erythropoietin expression via hypoxia-inducible factor-1α activation
Authors: Wanner Roger M. , Spielmann Patrick , Stroka Deborah M. , Camenisch Gieri , Camenisch Isabelle , Scheid Annette , Houck David R. , Bauer Christian , Gassmann Max , Wenger Roland H. 
Published: October 2019

AbstractInduction of erythropoietin (Epo) expression under hypoxic conditions is mediated by the heterodimeric hypoxia-inducible factor (HIF)-1. Following binding to the 3′ hypoxia-response element (HRE) of the Epo gene, HIF-1 markedly enhances Epo transcription. To facilitate the search for HIF-1 (ant)agonists, a hypoxia-reporter cell line (termed HRCHO5) was constructed containing a stably integrated luciferase gene under the control of triplicated heterologous HREs. Among various agents tested, we identified a class of substances called epolones, which induced HRE-dependent reporter gene activity in HRCHO5 cells. Epolones are fungal products known to induce Epo expression in hepatoma cells. We found that epolones (optimal concentration 4-8 μmol/L) potently induce HIF-1α protein accumulation and nuclear translocation as well as HIF-1 DNA binding and reporter gene transactivation. Interestingly, the activity of a compound related to the fungal epolones, ciclopirox olamine (CPX), was blocked after addition of ferrous iron. This suggests that CPX might interfere with the putative heme oxygen sensor, as has been proposed for the iron chelator deferoxamine mesylate (DFX). However, about 10-fold higher concentrations of DFX (50-100 μmol/L) than CPX were required to maximally induce reporter gene activity in HRCHO5 cells. Moreover, structural, functional, and spectrophotometric data imply a chelator:iron stoichiometry of 1:1 for DFX but 3:1 for CPX. Because the iron concentration in the cell culture medium was determined to be 16 μmol/L, DFX but not CPX function can be explained by complete chelation of medium iron. These results suggest that the lipophilic epolones might induce HIF-1α by intracellular iron chelation.
Hydroxyurea-induced marked oscillations of platelet counts in patients with polycythemia vera
Authors: Tefferi Ayalew , Elliott Michelle A. , Kao Pai Chih , Yoon Sooyoung , El-Hemaidi Ihab , Pearson Thomas C. 
Published: October 2019

Abstract
Two prospectively studied patients with polycythemia vera (PV) whose platelet counts showed marked periodic fluctuation during treatment with hydroxyurea (HU) are reported. Cycle lengths in both were approximately 28 to 30 days. In one patient, the cyclic process was no longer evident when treatment with HU was withheld, and it reappeared on treatment rechallenge. Circulating thrombopoietin (TPO) levels fluctuated out of phase with the platelet count despite markedly reduced TPO-receptor (c-Mpl) expression in bone marrow megakaryocytes. These observations suggest that the cyclic phenomenon may be related to both a transient state of HU-induced depletion of megakaryocytes and a concentration-dependent mitigation by TPO of the HU effect on megakaryocytes and their precursors. It is conceivable that the affected patients harbor a megakaryocyte progenitor pool whose apoptotic activity is differently modulated by either HU or high concentrations of TPO.
Polarized expression of bone morphogenetic protein-4 in the human aorta-gonad-mesonephros region
Authors: Marshall Caroline J. , Kinnon Christine , Thrasher Adrian J. 
Published: October 2019

AbstractIn the mammal, definitive hematopoietic stem cells (HSCs) are first derived from mesodermal cells within a region of the embryonic para-aortic splanchnopleura known as the aorta-gonad-mesonephros (AGM). Within this region, HSCs are thought to arise from hemangioblast precursors located in the ventral wall of the dorsal aorta. However, the factors that regulate HSC development in vivo are still largely unknown. Bone morphogenetic protein (BMP)-4, a member of the transforming growth factor beta (TGF-β) superfamily of growth factors, is a potent ventralizing factor and has been implicated in the commitment of embryonic mesodermal cells to a hematopoietic fate in a number of systems. In the human AGM, we find that BMP-4 is expressed at high levels, and with striking polarity, in a region of densely packed cells underlying intra-aortic hematopoietic clusters. In contrast, TGF-β1 is expressed predominantly by hematopoietic cells within the clusters. These findings implicate both BMP-4 and TGF-β1 in the initiation and regulation of hematopoiesis in the human AGM. Furthermore, the distribution of BMP-4 expression is highly suggestive of a direct role in the specification of human hematopoietic cells from embryonic mesoderm in vivo.
Identification of novel circulating human embryonic blood stem cells
Authors: Gallacher Lisa , Murdoch Barbara , Wu Dongmei , Karanu Francis , Fellows Fraser , Bhatia Mickie 
Published: October 2019

AbstractUsing murine models, primitive hematopoietic cells capable of repopulation have been shown to reside in various anatomic locations, including the aortic gonad mesonephros, fetal liver, and bone marrow. These sites are thought to be seeded by stem cells migrating through fetal circulation and would serve as ideal targets for in utero cellular therapy. In humans, however, it is unknown whether similar stem cells exist. Here, we identify circulating hematopoeitic cells present during human in utero development that are capable of multilineage repopulation in immunodeficient NOD/SCID (nonobese diabetic/severe combined immunodeficient) mice. Using limiting dilution analysis, the frequency of these fetal stem cells was found to be 1 in 3.2 × 105, illustrating a 3- and 22-fold enrichment compared with full-term human cord blood and circulating adult mobilized–peripheral blood, respectively. Comparison of in vivo differentiation and proliferative capacity demonstrated that circulating fetal stem cells are intrinsically distinct from hematopoietic stem cells found later in human development and those derived from the fetal liver or fetal bone marrow compartment at equivalent gestation. Taken together, these studies demonstrate the existence of unique circulating stem cells in early human embryonic development that provide a novel and previously unexplored source of pluripotent stem cell targets for cellular and gene-based fetal therapies.
Interleukin-3 supports expansion of long-term multilineage repopulating activity after multiple stem cell divisions in vitro
Authors: Bryder David , Jacobsen Sten E. W. 
Published: October 2019

Abstract
Although long-term repopulating hematopoietic stem cells (HSC) can self-renew and expand extensively in vivo, most efforts at expanding HSC in vitro have proved unsuccessful and have frequently resulted in compromised rather than improved HSC grafts. This has triggered the search for the optimal combination of cytokines for HSC expansion. Through such studies, c-kit ligand (KL), flt3 ligand (FL), thrombopoietin, and IL-11 have emerged as likely positive regulators of HSC self-renewal. In contrast, numerous studies have implicated a unique and potent negative regulatory role of IL-3, suggesting perhaps distinct regulation of HSC fate by different cytokines. However, the interpretations of these findings are complicated by the fact that different cytokines might target distinct subpopulations within the HSC compartment and by the lack of evidence for HSC undergoing self-renewal. Here, in the presence of KL+FL+megakaryocyte growth and development factor (MGDF), which recruits virtually all Lin−Sca-1+kit+ bone marrow cells into proliferation and promotes their self-renewal under serum-free conditions, IL-3 and IL-11 revealed an indistinguishable ability to further enhance proliferation. Surprisingly, and similar to IL-11, IL-3 supported KL+FL+MGDF-induced expansion of multilineage, long-term reconstituting activity in primary and secondary recipients. Furthermore, high-resolution cell division tracking demonstrated that all HSC underwent a minimum of 5 cell divisions, suggesting that long-term repopulating HSC are not compromised by IL-3 stimulation after multiple cell divisions. In striking contrast, the ex vivo expansion of murine HSC in fetal calf serum-containing medium resulted in extensive loss of reconstituting activity, an effect further facilitated by the presence of IL-3.
Egr-1 gene is induced by the systemic administration of the vascular endothelial growth factor and the epidermal growth factor
Authors: Liu Lixin , Tsai Jo C. , Aird William C. 
Published: October 2019

AbstractEgr-1 is a transcription factor that couples short-term changes in the extracellular milieu to long-term changes in gene expression. In cultured endothelial cells, the Egr-1 gene has been shown to respond to a variety of extracellular signals. However, the physiological relevance of these findings remains unclear. To address this question, the growth factor-mediated response of the Egr-1 gene under in vivo conditions was analyzed. To that end, either vascular endothelial growth factor (VEGF) or epidermal growth factor (EGF) was injected into the intraperitoneal cavity of mice. Growth factors were delivered to all tissues examined, as evidenced by the widespread distribution of I125-labeled growth factors and the phosphorylation of their respective receptors. In Western blot analyses of whole-tissue extracts, Egr-1 protein levels were shown to be induced in the heart, brain, liver, and spleen of VEGF-treated mice, and in the heart, lung, brain, liver and skeletal muscle of EGF-treated animals. Changes in Egr-1 levels did not correlate with changes in receptor phosphorylation or ERK1/2 phosphorylation. In Northern blot analyses, VEGF induced Egr-1 mRNA levels in all tissues examined except lung and kidney, whereas EGF led to increased transcripts in all tissues except kidney. In immunofluorescence studies, VEGF induced Egr-1 in microvascular endothelial cells of the heart and liver, and EGF induced Egr-1 in the microvascular bed of skeletal muscle. Taken together, these results suggest that the Egr-1 gene is differentially regulated in response to systemically administered VEGF and EGF.
Mature dendritic cells pulsed with freeze–thaw cell lysates define an effective in vitro vaccine designed to elicit EBV-specific CD4+ and CD8+ T lymphocyte responses
Authors: Herr Wolfgang , Ranieri Elena , Olson Walter , Zarour Hassane , Gesualdo Loreto , Storkus Walter J. 
Published: October 2019

AbstractImmunotherapy trials targeting the induction of tumor-reactive T-cell responses in cancer patients appear to hold significant promise. Because nonmutated lineage-specific antigens and mutated idiotypic antigens may be coexpressed by tumor cells, the use of autologous tumor material to promote the broadest range of antitumor T-cell specificities has significant clinical potential in cancer vaccination trials. As a model for vaccination in the cancer setting, we chose to analyze the promotion of T-cell responses against Epstein-Barr virus (EBV)-transformed B-lymphoblastoid cell line (B-LCL)–derived antigens in vitro. A series of bulk antigenic formats (freeze–thaw lysate, trifluoroacetic acid lysate, extracted membranes, affinity-purified MHC class I– and class II–presented peptides, acid-eluted peptides) prepared from EBV B-LCLs were tested for their ability to stimulate EBV B-LCL–reactive CD4+ and CD8+ T lymphocytes in vitro when pulsed onto autologous dendritic cells (DCs). DC presentation of freeze–thaw lysate material derived from (either autologous or allogeneic) EBV B-LCLs with an Mr of 10 kd or larger stimulated optimal anti-EBV B-LCL responsiveness from freshly isolated CD4+ and CD8+ peripheral blood T cells. These in vivo “memory” T-cell responses were observed only in EBV-seropositive donors. CD4+ T-cell responses to lysate-pulsed DCs were Th1 type (ie, strong interferon-γ and weak interleukin-5 responses). While CD8+ T-cell responses were also observed in interferon-γ Elispot assays and in cytotoxicity assays, these responses were of low frequency unless the DC stimulators were induced to “mature” after being fed with tumor lysates. Optimal-length, naturally processed, and MHC class I– or class II–presented tumor peptides were comparatively poorly immunogenic in this model system.
Heparin and heparan sulfate bind interleukin-10 and modulate its activity
Authors: Salek-Ardakani Shahram , Arrand John R. , Shaw David , Mackett Mike 
Published: October 2019

AbstractGlycosaminoglycans (GAG) are a group of negatively charged molecules that have been shown to bind and directly regulate the bioactivity of growth factors and cytokines such as basic fibroblast growth factor, transforming growth factor-β, IL-7, and interferon-γ. The ability of GAG to interact with human IL-10 (hIL-10) and the effect of these interactions on its biologic activity were analyzed. It was demonstrated by affinity chromatography that hIL-10 binds strongly to heparin–agarose at physiological pH. Biosensor-based binding kinetic analysis indicated an equilibrium dissociation constant, Kd, of 54 nmol/L for this interaction. Human IL-10 stimulated CD16 and CD64 expression on the monocyte/macrophage population within peripheral blood mononuclear cells, with optimal concentrations between 1 and 10 ng/mL. Soluble heparin, heparan sulfate, chondroitin sulfate, and dermatan sulfate were shown to inhibit the hIL-10–induced expression of CD16 and CD64 in a concentration-dependent manner. Heparin and heparan sulfate were most effective with IC50 values of 100 to 500 μg/mL. Considerably higher concentrations of dermatan sulfate and chondroitin 4-sulfate were required with an IC50 of 2000 to 5000 μg/mL, whereas chondroitin 6-sulfate was essentially inactive. The antagonistic effect of heparin on hIL-10 activity was shown to be dependent on N-sulfation, inasmuch as de-N-sulfated heparin had little or no inhibitory effect on the IL-10– induced expression of CD16, whereas the effect of de-O-sulfated heparin was comparable to that of unmodified heparin. Furthermore, the inhibition of cell-bound proteoglycan sulfation reduced the hIL-10–mediated expression of CD16 molecules on monocytes/macrophages. Taken together, these findings support the hypothesis that soluble and cell-surface GAG and, in particular, their sulfate groups are important in binding and modulation of hIL-10 activity.
Natural killer cell dysfunction and apoptosis induced by chronic myelogenous leukemia cells: role of reactive oxygen species and regulation by histamine
Authors: Mellqvist Ulf-Henrik , Hansson Markus , Brune Mats , Dahlgren Claes , Hermodsson Svante , Hellstrand Kristoffer 
Published: October 2019

AbstractNatural killer (NK) cells are deficient in patients with chronic myelogenous leukemia (CML), but the mechanisms responsible for the dysfunction are not completely understood. This study reports that CML cells effectively inhibit the baseline and interleukin-2 (IL-2)-induced NK cell cytotoxicity against a CML cell-derived line (K562). A sizable fraction of NK cells subsequently acquired features characteristic of programmed cell death/apoptosis. The CML cell-mediated inhibition of NK cells required triggering of reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase-mediated formation of reactive oxygen species (ROS) and was prevented by catalase, a scavenger of ROS, and by histamine, acting via H2-receptor–mediated inhibition of ROS production in CML cells. In contrast, nonmalignant neutrophilic granulocytes inhibited NK cells via ROS production without the requirement of exogenous NADPH oxidase-triggering stimuli. We propose that paracrine production of ROS may contribute to the dysfunction of NK cells in CML and that histamine may serve as an autocrine inhibitor of ROS formation in leukemic granulocytes.
Red cells from glutathione peroxidase-1–deficient mice have nearly normal defenses against exogenous peroxides
Authors: Johnson Robert M. , Goyette Gerard , Ravindranath Yaddanapudi , Ho Ye-Shih 
Published: October 2019

AbstractThe role of glutathione peroxidase in red cell anti-oxidant defense was examined using erythrocytes from mice with a genetically engineered disruption of the glutathione peroxidase-1 (GSHPx-1) gene. Because GSHPx-1 is the sole glutathione peroxidase in the erythrocyte, all red cell GSH peroxidase activity was eliminated. Oxidation of hemoglobin and membrane lipids, using the cis-parinaric acid assay, was determined during oxidant challenge from cumene hydroperoxide and H2O2. No difference was detected between wild-type red cells and GSHPx-1–deficient cells, even at high H2O2 exposures. Thus, GSHPx-1 appears to play little or no role in the defense of the erythrocyte against exposure to peroxide. Simultaneous exposure to an H2O2 flux and the catalase inhibitor 3-amino-1,2,4-triazole supported this conclusion. Hemoglobin oxidation occurred only when catalase was depleted. Circulating erythrocytes from the GSHPx-1–deficient mice exhibited a slight reduction in membrane thiols, indicating that high exposure to peroxides might occur naturally in the circulation.
Bone morphogenetic protein-2 induces apoptosis in human myeloma cells with modulation of STAT3
Authors: Kawamura Chiharu , Kizaki Masahiro , Yamato Kenji , Uchida Hideo , Fukuchi Yumi , Hattori Yutaka , Koseki Takeyoshi , Nishihara Tatsuji , Ikeda Yasuo 
Published: October 2019

AbstractBone morphogenetic proteins (BMPs), members of the transforming growth factor (TGF)–β superfamily, are a group of related proteins that are capable of inducing the formation of cartilage and bone but are now regarded as multifunctional cytokines. We show in this report a novel function of BMPs in hematopoietic cells: BMP-2 induces apoptosis not only in human myeloma cell lines (U266, RPMI 8226, HS-Sultan, IM-9, OPM-2, and KMS-12 cells), but also in primary samples from patients with multiple myeloma. The mechanism of BMP-2–induced apoptosis was investigated with the use of U266 cells, which are dependent on the interleukin-6 autocrine loop. We showed that BMP-2 caused cell-cycle arrest in the G1 phase and the subsequent apoptosis of myeloma cells. BMP-2 up-regulated the expression of cyclin-dependent kinase inhibitors (p21CIP1/WAF1 and p27KIP1) and caused hypophosphorylation of retinoblastoma (Rb) protein. In studies of apoptosis-associated proteins, BMP-2 was seen to down-regulate the expression of Bcl-xL; however, BMP-2 had no effects on the expression of Bcl-2, Bax, or Bad. Therefore, BMP-2 induces apoptosis in various human myeloma cells by means of the down-regulation of Bcl-xL and by cell-cycle arrest through the up-regulation of p21CIP1/WAF1 and p27KIP1 and by the hypophosphorylation of Rb. Further analysis showed that the signal transducer and activator of transcription 3 (STAT3) was inactivated immediately after BMP-2 treatment. We conclude that BMP-2 would be useful as a novel therapeutic agent in the treatment of multiple myeloma both by means of its antitumor effect of inducing apoptotis and through its original bone-inducing activity, because bone lesions are frequently seen in myeloma patients.
Stat5a/b contribute to interleukin 7–induced B-cell precursor expansion, but abl- andbcr/abl-induced transformation are independent of Stat5
Authors: Sexl Veronika , Piekorz Roland , Moriggl Richard , Rohrer Juerg , Brown Michael P. , Bunting Kevin D. , Rothammer Kristen , Roussel Martine F. , Ihle James N. 
Published: October 2019

AbstractThe cytokines interleukin 7 (IL-7) and interleukin 4 (IL-4) regulate lymphoid differentiation and function and activate the transcription factor Stat5. Using mice deficient for the 2 highly related transcription factors, Stat5a and Stat5b (Stat5a/b−/−), we investigated the role of Stat5 for B-cell differentiation, expansion, and function. Peripheral blood B cells of Stat5-deficient mice are significantly reduced, but no proliferation defects in response to various mitogenic stimuli are found. Also, IgM and IgG1 antibody production and immunoglobulin class switching are not affected. Pre- and pro-B cells of Stat5-deficient animals were found to have reduced responses to IL-7. Pro- and pre-B cells are the target cells of the abloncogene and numerous studies have suggested that Stat5a/b is essential for transformation by derivatives of the Abelson(abl) gene. To assess the role of Stat5a/b in transformation, we have evaluated the ability of variousabl derivatives to transform cells from Stat5a/b-deficient mice in vitro or in vivo. We demonstrate that the absence of Stat5a/b is not essential for the induction of lymphoid or myeloid tumors in vivo or on the ability to transform bone marrow cells in vitro.