bluuebunny/crossref_metadata_2025_split huggingface dataset:
Pivotal role of granulocyte colony-stimulating factor in the development of progenitors in the common myeloid pathway
Authors: Richards Michael K. , Liu Fulu , Iwasaki Hiromi , Akashi Koichi , Link Daniel C. 
Published: August 2003

AbstractGranulocyte colony-stimulating factor (G-CSF) is the principal cytokine regulating granulopoiesis. G-CSF receptor-deficient mice (G-CSFR-/-) are neutropenic but have only a modest reduction of committed myeloid progenitors. Since it is likely that compensatory mechanisms are induced by the severe neutropenia present in G-CSFR-/- mice, a competitive repopulation assay was performed. These data show that under basal conditions, G-CSF drives nearly all of granulopoiesis through multiple mechanisms. Most importantly, G-CSFR signals regulate the production and/or maintenance of committed-myeloid progenitors. Surprisingly, G-CSFR signals also play a significant role in the regulation of primitive multipotential progenitors in vivo. The contribution of G-CSFR-/- cells to the hematopoietic stem cell compartment is modestly reduced. Moreover, a marked decrease in the contribution of G-CSFR-/- cells to other progenitors in the myeloid pathway, including erythroid and megakaryocytic progenitors, is observed. In contrast, relative to the hematopoietic stem cell compartment, the contribution of G-CSFR-/- cells to the lymphoid lineages is increased. These data suggest that G-CSFR signals may play a role in directing the commitment of primitive hematopoietic progenitors to the common myeloid lineage. Thus, regulation of G-CSF levels may provide a mechanism for directing primitive hematopoietic progenitors into the common myeloid lineage in response to environmental stresses. (Blood. 2003; 102:3562-3568)
Lack of α2-antiplasmin promotes re-endothelialization via over-release of VEGF after vascular injury in mice
Authors: Matsuno Hiroyuki , Ishisaki Akira , Nakajima Keiichi , Okada Kiyotaka , Ueshima Shigeru , Matsuo Osamu , Kozawa Osamu 
Published: August 2003

AbstractWe here report that the arterial blood flow after endothelial injury in mice deficient in α2-antiplasmin (α2-AP-/- mice) was well maintained compared with that of wild-type mice. Moreover, the development of neointima 4 weeks after injury in α2-AP-/- mice was significantly decreased. Histologic observations showed a prompt recovery of endothelial cells with a much higher proliferating index in repaired endothelium in α2-AP-/- mice. The amount of secreted vascular endothelial growth factor (VEGF) by explanted vascular smooth muscle cells (SMCs) from α2-AP-/- mice was significantly increased. In separate experiments using a human endothelial cell (EC) line, we could demonstrate that plasminogen binds to ECs and that this binding can be prevented by α2-AP. Finally, an injection of either an anti-VEGF receptor-1 antibody or α2-AP reduced the prompt endothelial healing. α2-AP is the main inactivator of plasmin, which cleaves extracellular matrix-bound VEGF to release a diffusible proteolytic fragment. Lack of α2-AP, therefore, could lead to a local over-release of VEGF by the continuously active plasmin in the injured area, which could result in a prompt re-endothelialization after vascular injury. Our results provide new insight into the role of α2-AP and VEGF in the pathogenesis of re-endothelialization following vascular injury. (Blood. 2003;102: 3621-3628)
Primary endothelial cells isolated from the yolk sac and para-aortic splanchnopleura support the expansion of adult marrow stem cells in vitro
Authors: Li Weiming , Johnson Scott A. , Shelley William C. , Ferkowicz Michael , Morrison Paul , Li Yanjun , Yoder Mervin C. 
Published: August 2003

AbstractThe embryonic origin and development of hematopoietic and endothelial cells is highly interdependent. We hypothesized that primary endothelial cells from murine yolk sac and para-aortic splanchnopleura (P-Sp) may possess the capacity to expand hematopoietic stem cells (HSCs) and progenitor cells ex vivo. Using Tie2-GFP transgenic mice in combination with fluorochrome-conjugated monoclonal antibodies to vascular endothelial growth factor receptor-2 (Flk1) and CD41, we have successfully isolated pure populations of primary endothelial cells from 9.5-days after coitus (dpc) yolk sac and P-Sp. Adult murine bone marrow Sca-1+c-Kit+lin- cells were cocultured with yolk sac or P-Sp Tie2-GFP+Flk-1+CD41- endothelial cell monolayers for 7 days and the total number of nonadherent cells increased 47- and 295-fold, respectively, and hematopoietic progenitor counts increased 9.4- and 11.4-fold, respectively. Both the yolk sac and P-Sp endothelial cell cocultures facilitated long-term (&gt; 6 months) HSC competitive repopulating ability (2.8- to 9.8-fold increases, respectively). These data suggest that 9.5-dpc yolk sac- and P-Sp-derived primary Tie2-GFP+Flk-1+CD41- endothelial cells possess the capacity to expand adult bone marrow hematopoietic progenitor cell and HSC repopulating ability ex vivo. (Blood. 2003;102:4345-4353)
The proteasome inhibitor bortezomib interacts synergistically with histone deacetylase inhibitors to induce apoptosis in Bcr/Abl+ cells sensitive and resistant to STI571
Authors: Yu Chunrong , Rahmani Mohamed , Conrad Daniel , Subler Mark , Dent Paul , Grant Steven 
Published: August 2003

AbstractInteractions between the proteasome inhibitor bortezomib and histone deacetylase inhibitors (HDIs) have been examined in Bcr/Abl+ human leukemia cells (K562 and LAMA 84). Coexposure of cells (24-48 hours) to minimally toxic concentrations of bortezomib + either suberoylanilide hydroxamic acid (SAHA) or sodium butyrate (SB) resulted in a striking increase in mitochondrial injury, caspase activation, and apoptosis, reflected by caspases-3 and -8 cleavage and poly(adenosine diphosphate-ribose) polymerase (PARP) degradation. These events were accompanied by down-regulation of the Raf-1/mitogen-induced extracellular kinase (MEK)/extracellular signal-related kinase (ERK) pathway as well as diminished expression of Bcr/Abl and cyclin D1, cleavage of p21CIP1 and phosphorylation of the retinoblastoma protein (pRb), and induction of the stress-related kinases Jun kinase (JNK) and p38 mitogen-activated protein kinase (MAPK). Transient transfection of cells with a constitutively active MEK construct significantly protected them from bortezomib/SAHA-mediated lethality. Coadministration of bortezomib and SAHA resulted in increased reactive oxygen species (ROS) generation and diminished nuclear factor κB (NF-κB) activation; moreover, the free radical scavenger L-N-acetylcyteine (LNAC) blocked bortezomib/SAHA-related ROS generation, induction of JNK and p21CIP1, and apoptosis. Lastly, this regimen potently induced apoptosis in STI571 (imatinib mesylate)-resistant K562 cells and CD34+ mononuclear cells obtained from a patient with STI571-resistant disease, as well as in Bcr/Abl- leukemia cells (eg, HL-60, U937, Jurkat). Together, these findings raise the possibility that combined proteasome/histone deacetylase inhibition may represent a novel strategy in leukemia, including apoptosis-resistant Bcr/Abl+ hematologic malignancies. (Blood. 2003;102:3765-3774)
Circadian clock genes oscillate in human peripheral blood mononuclear cells
Authors: Boivin Diane B. , James Francine O. , Wu Aibin , Cho-Park Park F. , Xiong Huabao , Sun Zhong S. 
Published: August 2003

AbstractIn mammals, it is well documented that observable circadian rhythms are controlled by a central oscillator that is organized in transcriptional and translational feedback loops involving several clock genes. Although recent studies have demonstrated that clock genes oscillate in many peripheral tissues, their characteristics in the human immune system remain unknown. The present study investigates whether circadian clock genes function in human peripheral blood mononuclear cells. On the basis of studies derived from 3 human subjects under controlled conditions, circadian clock genes hPer1, hPer2, hPer3, and hDec1 are expressed in a circadian manner in human peripheral blood mononuclear cells (PBMCs), with the peak level occurring during the habitual time of activity. The demonstration of functional circadian machinery in human PBMCs suggests that peripheral blood cells may be useful for the investigation of human circadian rhythms and their associated disorders. (Blood. 2003;102:4143-4145)
Clonal dominance of chronic myelogenous leukemia is associated with diminished sensitivity to the antiproliferative effects of neutrophil elastase
Authors: Ouriaghli Frank El , Sloand Elaine , Mainwaring Lori , Fujiwara Hiroshi , Keyvanfar Keyvan , Melenhorst J. Joseph , Rezvani Katayoun , Sconocchia Giuseppe , Solomon Scott , Hensel Nancy , Barrett A. John 
Published: August 2003

AbstractClinical observations suggest that in chronic myelogenous leukemia (CML), the Philadelphia chromosome (Ph+) clone has a growth advantage over normal hematopoiesis. Patients with CML have high levels of neutrophil elastase, which has recently been shown to antagonize the action of granulocyte-colony-stimulating factor (G-CSF) and other growth factors. We therefore compared the effect of elastase on the growth of normal and CML progenitor cells. In 10-day suspension cultures of normal or CML CD34+ cells supplemented with G-CSF, stem cell factor (SCF), and granulocyte macrophage-colony-stimulating factor (GM-CSF), CML cells had diminished sensitivity to the growth inhibitory effect of elastase. When equal numbers of CML and normal CD34+ cells were cocultured for 10 days, there was no change in the relative proportions of normal and leukemic cells (measured by fluorescence in situ hybridization [FISH] or flow cytometry). However, when elastase was added, CML cells predominated at the end of the culture period (78% vs 22% with 1 μg/mL and 80% vs 20% with 5 μg/mL elastase). CML neutrophils substituted effectively for elastase in suppressing the proliferation of normal CD34+ cells, but this effect was abrogated by serine protease inhibitors. These results suggest that elastase overproduction by the leukemic clone can change the growth environment by digesting growth factors, thereby giving advantage to Ph+ hematopoiesis. (Blood. 2003; 102:3786-3792)
Cathepsin-B-dependent apoptosis triggered by antithymocyte globulins: a novel mechanism of T-cell depletion
Authors: Michallet Marie-Cécile , Saltel Frederic , Preville Xavier , Flacher Monique , Revillard Jean-Pierre , Genestier Laurent 
Published: August 2003

AbstractAntithymocyte globulins (ATGs), the immunoglobulin G (IgG) fraction of sera from rabbits or horses immunized with human thymocytes or T-cell lines, are used in conditioning regimens for bone marrow transplantation, in the treatment of acute graft-versus-host disease, in the prevention or treatment of acute rejection in organ transplantation, and in severe bone marrow aplasia. In nonhuman primates, ATGs induce rapid, dose-dependent, T-cell depletion in peripheral lymphoid tissues, where apoptotic cells can be demonstrated in T-cell zones. We show here that increasing ATG concentrations in vitro resulted in reduced lymphocyte proliferative responses, associated with a rapid increase in the percentage of apoptotic cells. Apoptosis did not require prior exposure to interleukin-2, nor did it result in CD178/CD95 or tumor necrosis factor/tumor necrosis factor receptor (TNF/TNF-R) interactions; it was therefore clearly different from activation-induced cell death. Cytochrome c release, caspase-9, and caspase-3 activation were not implicated, excluding a direct involvement of the intrinsic mitochondrial pathway. The cysteine protease inhibitor E64d and cathepsin-B-specific inhibitors conferred significant protection, whereas apoptosis was associated with the release of active cathepsin B into the cytosol. These data demonstrate a role for cathepsin B in T-cell apoptosis induced by ATGs at concentrations achieved during clinical use. (Blood. 2003; 102:3719-3726)
Identification and characterization of 2 types of erythroid progenitors that express GATA-1 at distinct levels
Authors: Suzuki Norio , Suwabe Naruyoshi , Ohneda Osamu , Obara Naoshi , Imagawa Shigehiko , Pan Xiaoqing , Motohashi Hozumi , Yamamoto Masayuki 
Published: August 2003

AbstractTranscription factor GATA-1 is essential for the development of the erythroid lineage. To ascertain whether strict control of GATA-1 expression level is necessary for achieving proper erythropoiesis, we established transgenic mouse lines expressing green fluorescent protein (GFP) under the control of the GATA-1 gene hematopoietic regulatory domain. We examined the GATA-1 expression level by exploiting the transgenic mice and found 2 GFP-positive hematopoietic progenitor fractions in the bone marrow. One is the GFPhigh fraction containing mainly CFU-E and proerythroblasts, which coexpress transferrin receptor, while the other is the GFPlow/transferrin receptor-negative fraction containing BFU-E. Since the intensity of green fluorescence correlates well with the expression level of GATA-1, these results indicate that GATA-1 is highly expressed in erythroid colony-forming unit (CFU-E) but low in erythroid burst-forming unit (BFU-E), suggesting that the incremental expression of GATA-1 is required for the formation of erythroid progenitors. We also examined GFP-positive fractions in the transgenic mouse spleen and fetal liver and identified fractions containing BFU-E and CFU-E, respectively. This study also presents an efficient method for enriching the CFU-E and BFU-E from mouse hematopoietic tissues. (Blood. 2003;102:3575-3583)
Functional defects of dendritic cells in patients with CD40 deficiency
Authors: Fontana Stefania , Moratto Daniele , Mangal Surinder , De Francesco Maria , Vermi William , Ferrari Simona , Facchetti Fabio , Kutukculer Necil , Fiorini Claudia , Duse Marzia , Das Pranab K. , Notarangelo Luigi D. , Plebani Alessandro , Badolato Raffaele 
Published: August 2003

AbstractWe have recently identified 2 patients with a rare autosomal recessive form of hyper IgM disease, known as HIGM3, caused by mutations in the CD40 gene. These patients had opportunistic infections observed on X-linked hyper IgM syndrome (HIGM), suggesting that the CD40-CD40 ligand interaction is important for promoting T-cell-mediated immunity. To evaluate whether innate immunity signals may substitute CD154 for inducing the maturation of dendritic cells (DCs), we analyzed monocyte-derived DCs in these patients. Monocyte-derived DCs of HIGM3 subjects on ex vivo stimulation with tumor necrosis factor-α (TNF-α) or lipopolysaccharide (LPS) combined with interferon-γ (IFN-γ) normally express all the markers of mature DCs, such as CD83 and DC-LAMP. However, cell surface levels of HLA-DR in mature DCs are reduced, as is costimulatory activity of these cells for allogeneic naive T cells. In addition, CD40-deficient DCs secrete lower amounts of interleukin-12 (IL-12) but larger quantities of IL-10 than control subjects. Finally, analysis of circulating plasmacytoid DCs demonstrates a normal percentage of this subset in CD40-deficient cells, but IFN-α secretion in response to herpes simplex virus 1 (HSV-1) infection is severely reduced in patients. These observations suggest that the severe impairment of DC maturation may contribute to the defect of T-cell-mediated immunity observed in HIGM3 patients. (Blood. 2003;102:
Human CD8+CD25+ thymocytes share phenotypic and functional features with CD4+CD25+ regulatory thymocytes
Authors: Cosmi Lorenzo , Liotta Francesco , Lazzeri Elena , Francalanci Michela , Angeli Roberta , Mazzinghi Benedetta , Santarlasci Veronica , Manetti Roberto , Vanini Vittorio , Romagnani Paola , Maggi Enrico , Romagnani Sergio , Annunziato Francesco 
Published: August 2003

AbstractCD8+CD25+ cells, which expressed high levels of Foxp3, glucocorticoid-induced tumor necrosis factor receptor (GITR), CCR8, tumor necrosis factor receptor 2 (TNFR2), and cytotoxic T-lymphocyte-associated antigen 4 (CTLA-4) mRNAs, were identified in the fibrous septa and medullary areas of human thymus. Activated CD8+CD25+ thymocytes did not produce cytokines, but most of them expressed surface CTLA-4 and transforming growth factor β1 (TGF-β1). Like CD4+CD25+, CD8+CD25+ thymocytes suppressed the proliferation of autologous CD25-T cells via a contact-dependent mechanism. The suppressive activity of CD8+CD25+ thymocytes was abrogated by a mixture of anti-CTLA-4 and anti-TGF-β1 antibodies and it was mediated by their ability to inhibit the expression of the interleukin 2 receptor α chain on target T cells. These results demonstrate the existence of a subset of human CD8+CD25+ thymocytes sharing phenotype, functional features, and mechanism of action with CD4+CD25+ T regulatory cells. (Blood. 2003;102:4107-4114)
The contributions of the α2β1 integrin to vascular thrombosis in vivo
Authors: He Li , Pappan Loretta K. , Grenache David G. , Li Zhengzhi , Tollefsen Douglas M. , Santoro Samuel A. , Zutter Mary M. 
Published: August 2003

AbstractThe α2β1 integrin serves as a receptor for collagens, laminin, and several other nonmatrix ligands. Many studies have suggested that the α2β1 integrin is a critical mediator of platelet adhesion to collagen within the vessel wall after vascular injury and that the interactions of the platelet α2β1 integrin with subendothelial collagen after vascular injury are required for proper hemostasis. We have used the α2β1 integrin-deficient mouse to evaluate the contributions of the α2β1 integrin in 2 in vivo models of thrombosis. Studies using a model of endothelial injury to the carotid artery reveal that the α2β1 integrin plays a critical role in vascular thrombosis at the blood-vessel wall interface under flow conditions. In contrast, the α2β1 integrin is not required for the formation of thrombi and pulmonary emboli following intravascular injection of collagen. Our results are the first to document a critical in vivo role for the α2β1 integrin in thrombus formation at the vessel wall under conditions of shear following vascular injury. (Blood. 2003;102:3652-3657)
NK-cell purging of leukemia: superior antitumor effects of NK cells H2 allogeneic to the tumor and augmentation with inhibitory receptor blockade
Authors: Koh Crystal Y. , Ortaldo John R. , Blazar Bruce R. , Bennett Michael , Murphy William J. 
Published: August 2003

AbstractNatural killer (NK) cells are composed of subsets characterized by the expression of inhibitory or activating receptors, or both, specific for different major histocompatibility complex (MHC) class I determinants. We have previously shown that inhibitory receptor blockade of syngeneic NK cells was an effective means of ex vivo purging of leukemia-contaminated bone marrow and that the transplantation of mice with the purged bone marrow cells (BMCs) resulted in long-term, relapse-free survival. We have extended the investigation to assess the antitumor effects mediated by NK cells H2-allogeneic to tumor cells. We demonstrate that various tumor cell lines are more susceptible to lysis by H2-allogeneic NK cells than by syngeneic NK cells in vitro even though comparable percentages of Ly49 NK cells were present. Using allogeneic NK cells to purge leukemia-contaminating BMCs before transplantation resulted in a higher proportion of mice with long-term survival than using syngeneic NK cells. Allogeneic NK cells did not suppress hematopoietic reconstitution as measured by granulocyte/monocyte-colony-forming unit (CFU-GM), complete blood count (CBC), and donor chimerism at various days after transplantation. Inhibitory receptor blockade of allogeneic NK cells also significantly increased these antitumor effects at lower NK/tumor ratios compared with those of syngeneic NK cells. These results demonstrate that H2-allogeneic NK cells mediate more potent antitumor effects than syngeneic NK cells without adverse hematologic effects and thus may be useful in cancer therapy. (Blood. 2003;102:4067-4075)
Multiple integrin-ligand interactions synergize in shear-resistant platelet adhesion at sites of arterial injury in vivo
Authors: Grüner Sabine , Prostredna Miroslava , Schulte Valerie , Krieg Thomas , Eckes Beate , Brakebusch Cord , Nieswandt Bernhard 
Published: August 2003

Abstract
Damage to the integrity of the vessel wall results in exposure of the subendothelial extracellular matrix (ECM), which triggers integrin-dependent adhesion and aggregation of platelets. The role of platelet β1 integrins in these processes remains mostly undefined. Here, we demonstrate by intravital fluorescence microscopy that platelet adhesion and thrombus growth on the exposed ECM of the injured carotid artery is not significantly altered in α2-null mice and even in mice with a Cre/loxP-mediated loss of all β1 integrins on their platelets. In contrast, inhibition of αIIbβ3 integrin on platelets in wild-type mice blocked aggregate formation and reduced platelet adhesion by 60.0%. Strikingly, αIIbβ3 inhibition had a comparable effect in α2-null mice, demonstrating that other receptors mediate shear-resistant adhesion in the absence of functional α2β1 and αIIbβ3. These were identified to be α5β1 and/or α6β1 as αIIbβ3 inhibition abrogated platelet adhesion in β1-null mice. We conclude that shear-resistant platelet adhesion on the injured vessel wall in vivo is a highly integrated process involving multiple integrin-ligand interactions, none of which by itself is essential. (Blood. 2003;102:4021-4027)
Defective RNA ribose synthesis in fibroblasts from patients with thiamine-responsive megaloblastic anemia (TRMA)
Authors: Boros László G. , Steinkamp Mara P. , Fleming Judith C. , Lee Wai-Nang Paul , Cascante Marta , Neufeld Ellis J. 
Published: August 2003

AbstractFibroblasts from patients with thiamine-responsive megaloblastic anemia (TRMA) syndrome with diabetes and deafness undergo apoptotic cell death in the absence of supplemental thiamine in their cultures. The basis of megaloblastosis in these patients has not been determined. Here we use the stable [1,2-13C2]glucose isotope-based dynamic metabolic profiling technique to demonstrate that defective high-affinity thiamine transport primarily affects the synthesis of nucleic acid ribose via the nonoxidative branch of the pentose cycle. RNA ribose isolated from TRMA fibroblasts in thiamine-depleted cultures shows a time-dependent decrease in the fraction of ribose derived via transketolase, a thiamine-dependent enzyme in the pentose cycle. The fractional rate of de novo ribose synthesis from glucose is decreased several fold 2 to 4 days after removal of thiamine from the culture medium. No such metabolic changes are observed in wild-type fibroblasts or in TRMA mutant cells in thiamine-containing medium. Fluxes through glycolysis are similar in TRMA versus control fibroblasts in the pentose and TCA cycles. We conclude that reduced nucleic acid production through impaired transketolase catalysis is the underlying biochemical disturbance that likely induces cell cycle arrest or apoptosis in bone marrow cells and leads to the TRMA syndrome in patients with defective high-affinity thiamine transport. (Blood. 2003;102: 3556-3561)