bluuebunny/crossref_metadata_2025_split huggingface dataset:
The upstream stimulatory factor-2a inhibits plasminogen activator inhibitor-1 gene expression by binding to a promoter element adjacent to the hypoxia-inducible factor-1 binding site
Authors: Samoylenko Anatoly , Roth Ulrike , Jungermann Kurt , Kietzmann Thomas 
Published: July 2002

AbstractPlasminogen activator inhibitor-1 (PAI-1) expression is induced by hypoxia (8% O2) via the PAI-1 promoter region −175/−159 containing a hypoxia response element (HRE-2) binding the hypoxia-inducible factor-1 (HIF-1) and an adjacent response element (HRE-1) binding a so far unknown factor. The aim of the present study was to identify this factor and to investigate its role in the regulation of PAI-1 expression. It was found by supershift assays that the upstream stimulatory factor-2a (USF-2a) bound mainly to the HRE-1 of the PAI-1 promoter and to a lesser extent to HRE-2. Overexpression of USF-2a inhibited PAI-1 messenger RNA and protein expression and activated L-type pyruvate kinase expression in primary rat hepatocytes under normoxia and hypoxia. Luciferase (Luc) gene constructs driven by 766 and 276 base pairs of the 5′-flanking region of the PAI-1 gene were transfected into primary hepatocytes together with expression vectors encoding wild-type USF-2a and a USF-2a mutant lacking DNA binding and dimerization activity (ΔHU2a). Cotransfection of the wild-type USF-2a vector reduced Luc activity by about 8-fold, whereas cotransfection of ΔHU2a did not influence Luc activity. Mutation of the HRE-1 (−175/−168) in the PAI-1 promoter Luc constructs decreased USF-dependent inhibition of Luc activity. Mutation of the HRE-2 (−165/−158) was less effective. Cotransfection of a HIF-1α vector could compete for the binding of USF at HRE-2. These results indicated that the balance between 2 transcriptional factors, HIF-1 and USF-2a, which can bind adjacent HRE sites, appears to be involved in the regulation of PAI-1 expression in many clinical conditions.
Surgical and physical stress increases circulating blood dendritic cell counts independently of monocyte counts
Authors: Ho Christopher S. K. , López Jose Alejandro , Vuckovic Slavica , Pyke Christopher M. , Hockey Richard L. , Hart Derek N. J. 
Published: July 2002

Abstract
Dendritic cells (DCs) are specialized antigen-presenting cells that have the unique ability to initiate a primary immune response. The effect of physiologic stress on circulating blood DCs has thus far not been studied. In this study, we applied a recently developed method of counting blood DCs to test the hypothesis that significant stress to the body such as surgery and exercise might induce measurable changes in the DC numbers, subsets, phenotype, and function. Twenty-six patients scheduled for elective laparoscopic cholecystectomy, 4 for elective hysterectomy, 56 controls, and 5 volunteers who underwent a stress exercise test were enrolled in the study. Absolute DC counts increased acutely (71.7% ± 11% [SEM],P = .0001) in response to the stress of surgery and dropped below preoperative levels (−25% ± 14% [SEM],P = .05) on days 2-3. The perioperative DC subset balance remained constant. Interestingly, DC counts changed independently of monocyte counts. Exercise also induced a rise in DC counts but coincidentally with monocyte counts. Surprisingly, no phenotypic or functional activation of DCs was seen in either stress situations in vivo. DCs are rapidly mobilized into the circulation in response to surgical and exercise stress, which may serve to prepare the host's immune defenses against trauma. The independent regulation of the DC and monocyte counts reinforces the distinction between these 2 cell populations.
Platelet characteristics in patients with X-linked macrothrombocytopenia because of a novel GATA1mutation
Authors: Freson Kathleen , Devriendt Koen , Matthijs Gert , Van Hoof Achiel , De Vos Rita , Thys Chantal , Minner Kristien , Hoylaerts Marc F. , Vermylen Jos , Van Geet Chris 
Published: July 2002

AbstractA new mutation is described in the X-linked geneGATA1, resulting in macrothrombocytopenia and mild dyserythropoietic features but no marked anemia in a 4-generation family. The molecular basis for the observed phenotype is a substitution of glycine for aspartate in the strictly conserved codon 218 (D218G) of the amino-terminal zinc finger loop of the transcription factor GATA1. Zinc finger interaction studies demonstrated that this mutation results in a weak loss of affinity of GATA1 for its essential cofactor FOG1, whereas direct D218G-GATA1 binding to DNA was normal. The phenotypic effects of this mutation in the patients' platelets have been studied. Semiquantitative RNA analysis, normalized for β-actin messenger RNA, showed extremely low transcription of the GATA1 target genes GPIbβ and GPIXbut also a significantly lower expression of the nondirectly GATA1-regulated Gsα gene, suggestive of incomplete megakaryocyte maturation. In contrast, GPIIIa expression was close to normal in agreement with its early appearance during megakaryocyte differentiation. Flow cytometric analysis of patient platelets confirmed the existence of a platelet population with abnormal size distribution and reduced GPIb complex levels but with normal GPIIIa expression. It also showed the presence of very immature platelets lacking almost all membrane glycoproteins studied (GPIbα, GPIbβ, GPIIIa, GPIX, and GPV). Patients' platelets showed weak ristocetin-induced agglutination, compatible with the disturbed GPIb complex. Accordingly, electron microscopy of the patients' platelets revealed giant platelets with cytoplasmic clusters consisting of smooth endoplasmic reticulum and abnormal membrane complexes. In conclusion,GATA1 mutations can lead to isolated X-linked macrothrombocytopenia without anemia.
The acute promyelocytic leukemia–associated protein, promyelocytic leukemia zinc finger, regulates 1,25-dihydroxyvitamin D3–induced monocytic differentiation of U937 cells through a physical interaction with vitamin D3receptor
Authors: Ward Jeremy O. , McConnell Melanie J. , Carlile Graeme W. , Pandolfi Pier Paolo , Licht Jonathan D. , Freedman Leonard P. 
Published: July 2002

AbstractMonocyte differentiation induced by 1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is interrupted during the course of acute promyelocytic leukemia (APL). One form of APL is associated with the translocation t(11;17), which joins the promyelocytic leukemia zinc finger (PLZF) and retinoic acid receptor α (RARα) genes. Because PLZF is coexpressed in the myeloid lineage with the vitamin D3 receptor (VDR), the interplay between PLZF and VDR was examined. It was found that PLZF interacts directly with VDR. This occurred at least partly through contacts in the DNA-binding domain of VDR and the broad complex, tram-trak, bric-a-brac/pox virus zinc finger (BTB/POZ) domain of PLZF. Moreover, PLZF altered the mobility of VDR derived from nuclear extracts when bound to its cognate binding site, forming a slowly migrating DNA-protein complex. Overexpression of PLZF in a monocytic cell line abrogated 1,25(OH)2D3 activation from both a minimal VDR responsive reporter and the promoter of p21WAF1/CIP1, a target gene of VDR. Deletion of the BTB/POZ domain significantly relieved PLZF-mediated repression of 1,25(OH)2D3-dependent activation. In addition, stable, inducible expression of PLZF in U937 cells inhibited the ability of 1,25(OH)2D3 to induce surface expression of the monocytic marker CD14 and morphologic changes associated with differentiation. These results suggest that PLZF may play an important role in regulating the process by which 1,25(OH)2D3 induces monocytic differentiation in hematopoietic cells.
Combined genomic and antisense analysis reveals that the transcription factor Erg is implicated in endothelial cell differentiation
Authors: McLaughlin Fiona , Ludbrook Valerie J. , Cox Joanne , von Carlowitz Ira , Brown Suzy , Randi Anna M. 
Published: July 2002

AbstractIt has recently been shown that the transcription factor Erg, an Ets family member, drives constitutive expression of the intercellular adhesion molecule 2 (ICAM-2) in human umbilical vein endothelial cells (HUVECs) and that its expression is down-regulated by the pleiotropic cytokine tumor necrosis factor α (TNF-α). To identify other Erg target genes and to define its function in the endothelium, a combined approach of antisense oligonucleotides (GeneBloc) and differential gene expression was used. Treatment of HUVECs with Erg-specific GeneBloc for 24, 48, and 72 hours suppressed Erg mRNA and protein levels at all time points. Total RNA extracted from HUVECs treated withErg-specific or control GeneBloc was analyzed for differences in gene expression using high-density, sequence-verified cDNA arrays containing 482 relevant genes. Inhibition ofErg expression resulted in decreased expression ofICAM-2, as predicted. Four more genes decreased in Erg-deficient HUVECs were the extracellular matrix proteinsSPARC and thrombospondin, the adhesive glycoprotein von Willebrand factor, and the small GTPaseRhoA. Each of these molecules has been directly or indirectly linked to angiogenesis because of its role in vascular remodeling, adhesion, or shape change. Therefore, the role of Erg in vascular remodeling was tested in an in vitro model, and the results showed that HUVECs treated with Erg GeneBloc had a decreased ability to form tubulelike structures when grown on Matrigel. These results suggest that Erg may be a mediator of the TNF-α effects on angiogenesis in vivo.
Genomic and proteomic analysis of the myeloid differentiation program
Authors: Lian Zheng , Wang Le , Yamaga Shigeru , Bonds Wesley , Beazer-Barclay Y. , Kluger Yuval , Gerstein Mark , Newburger Peter E. , Berliner Nancy , Weissman Sherman M. 
Published: July 2002

AbstractAlthough the mature neutrophil is one of the better characterized mammalian cell types, the mechanisms of myeloid differentiation are incompletely understood at the molecular level. A mouse promyelocytic cell line (MPRO), derived from murine bone marrow cells and arrested developmentally by a dominant-negative retinoic acid receptor, morphologically differentiates to mature neutrophils in the presence of 10 μM retinoic acid. An extensive catalog was prepared of the gene expression changes that occur during morphologic maturation. To do this, 3′-end differential display, oligonucleotide chip array hybridization, and 2-dimensional protein electrophoresis were used. A large number of genes whose mRNA levels are modulated during differentiation of MPRO cells were identified. The results suggest the involvement of several transcription regulatory factors not previously implicated in this process, but they also emphasize the importance of events other than the production of new transcription factors. Furthermore, gene expression patterns were compared at the level of mRNA and protein, and the correlation between 2 parameters was studied.
The Hox cofactor and proto-oncogene Pbx1 is required for maintenance of definitive hematopoiesis in the fetal liver
Authors: DiMartino Jorge F. , Selleri Licia , Traver David , Firpo Meri T. , Rhee Joon , Warnke Roger , O'Gorman Stephen , Weissman Irving L. , Cleary Michael L. 
Published: July 2002

Abstract
Pbx1 is the product of a proto-oncogene originally discovered at the site of chromosomal translocations in acute leukemias. It binds DNA as a complex with a broad subset of homeodomain proteins, but its contributions to hematopoiesis have not been established. This paper reports that Pbx1 is expressed in hematopoietic progenitors during murine embryonic development and that its absence results in severe anemia and embryonic lethality at embryonic day 15 (E15) or E16. Definitive myeloerythroid lineages are present inPbx1−/−fetal livers, but the total numbers of colony-forming cells are substantially reduced. Fetal liver hypoplasia reflects quantitative as well as qualitative defects in the most primitive multilineage progenitors and their lineage-restricted progeny. Hematopoietic stem cells from Pbx1−/−embryos have reduced colony-forming activity and are unable to establish multilineage hematopoiesis in competitive reconstitution experiments. Common myeloid progenitors (CMPs), the earliest known myeloerythroid-restricted progenitors, are markedly depleted inPbx1−/−embryos at E14 and display clonogenic defects in erythroid colony formation. Comparative cell-cycle indexes suggest that these defects result largely from insufficient proliferation. Megakaryocyte- and erythrocyte-committed progenitors are also reduced in number and show decreased erythroid colony-forming potential. Taken together, these data indicate that Pbx1 is essential for the function of hematopoietic progenitors with erythropoietic potential and that its loss creates a proliferative constriction at the level of the CMP. Thus, Pbx1 is required for the maintenance, but not the initiation, of definitive hematopoiesis and contributes to the mitotic amplifications of progenitor subsets through which mature erythrocytes are generated.
Myelopoiesis in the zebrafish, Danio rerio
Authors: Bennett Carolyn M. , Kanki John P. , Rhodes Jennifer , Liu Ting X. , Paw Barry H. , Kieran Mark W. , Langenau David M. , Delahaye-Brown Anne , Zon Leonard I. , Fleming Mark D. , Look A. Thomas 
Published: July 2002

AbstractGenome-wide chemical mutagenesis screens in the zebrafish(Danio rerio) have led to the identification of novel genes affecting vertebrate erythropoiesis. In determining if this approach could also be used to clarify the molecular genetics of myelopoiesis, it was found that the developmental hierarchy of myeloid precursors in the zebrafish kidney is similar to that in human bone marrow. Zebrafish neutrophils resembled human neutrophils, possessing segmented nuclei and myeloperoxidase-positive cytoplasmic granules. The zebrafish homologue of the human myeloperoxidase (MPO) gene, which is specific to cells of the neutrophil lineage, was cloned and used to synthesize antisense RNA probes for in situ hybridization analyses of zebrafish embryos. Granulocytic cells expressing zebrafishmpo were first evident at 18 hours after fertilization (hpf) in the posterior intermediate cell mass (ICM) and on the anterior yolk sac by 20 hpf. By 24 hpf, mpo-expressing cells were observed along the ICM and within the developing vascular system. Thus, the mpo gene should provide a useful molecular probe for identifying zebrafish mutants with defects in granulopoiesis. The expression of zebrafish homologues was also examined in 2 other mammalian hematopoietic genes, Pu.1, which appears to initiate a commitment step in normal mammalian myeloid development, andL-Plastin, a gene expressed by human monocytes and macrophages. The results demonstrate a high level of conservation of the spatio-temporal expression patterns of these genes between zebrafish and mammals. The morphologic and molecular genetic evidence presented here supports the zebrafish as an informative model system for the study of normal and aberrant human myelopoiesis.
Ascorbic acid enhances arsenic trioxide–induced cytotoxicity in multiple myeloma cells
Authors: Grad Jennifer M. , Bahlis Nizar J. , Reis Isildinha , Oshiro Marc M. , Dalton William S. , Boise Lawrence H. 
Published: July 2002

Abstract
Multiple myeloma (MM) is a clonal B-cell malignancy characterized by slow-growing plasma cells in the bone marrow (BM). Patients with MM typically respond to initial chemotherapies; however, essentially all progress to a chemoresistant state. Factors that contribute to the chemorefractory phenotype include modulation of free radical scavenging, increased expression of drug efflux pumps, and changes in gene expression that allow escape from apoptotic signaling. Recent data indicate that arsenic trioxide (As2O3) induces remission of refractory acute promyelocytic leukemia and apoptosis of cell lines overexpressing Bcl-2 family members; therefore, it was hypothesized that chemorefractory MM cells would be sensitive to As2O3. As2O3 induced apoptosis in 4 human MM cell lines: 8226/S, 8226/Dox40, U266, and U266/Bcl-xL. The addition of interleukin-6 had no effect on cell death. Glutathione (GSH) has been implicated as an inhibitor of As2O3-induced cell death either through conjugating As2O3 or by sequestering reactive oxygen induced by As2O3. Consistent with this possibility, increasing GSH levels with N-acetylcysteine attenuated As2O3 cytotoxicity. Decreases in GSH have been associated with ascorbic acid (AA) metabolism. Clinically relevant doses of AA decreased GSH levels and potentiated As2O3-mediated cell death of all 4 MM cell lines. Similar results were obtained in freshly isolated human MM cells. In contrast, normal BM cells displayed little sensitivity to As2O3 alone or in combination with AA. Together, these data suggest that As2O3 and AA may be effective antineoplastic agents in refractory MM and that AA might be a useful adjuvant in GSH-sensitive therapies.
Specific von Willebrand factor–cleaving protease in thrombotic microangiopathies: a study of 111 cases
Authors: Veyradier Agnès , Obert Bernadette , Houllier Anne , Meyer Dominique , Girma Jean-Pierre 
Published: July 2002

AbstractRetrospective studies of patients with thrombotic microangiopathies (TMAs) have shown that a deficient activity of von Willebrand factor (vWF)–cleaving protease is involved in thrombotic thrombocytopenic purpura (TTP) but not in the hemolytic-uremic syndrome (HUS). To further analyze the relevance of this enzymatic activity in TMA diagnosis, a 20-month multicenter study of vWF-cleaving protease activity was conducted in adult patients prospectively enrolled in the acute phase of TMA. Patients with sporadic (n = 85), intermittent (n = 21), or familial recurrent (n = 5) forms of TMA (66 manifesting as TTP and 45 as HUS) were included. TMA was either idiopathic (n = 42) or secondary to an identified clinical context (n = 69). vWF-cleaving protease activity was normal in 46 cases (7 TTP and 39 HUS) and decreased in 65 cases (59 TTP and 6 HUS). A protease inhibitor was detected in 31 cases and was observed only in patients manifesting TTP with a total absence of protease activity. Among the 111 patients, mean vWF antigen levels were increased and the multimeric distribution of vWF was very heterogeneous, showing either a defect of the high-molecular-weight forms (n = 40), a normal pattern (n = 21), or the presence of unusually large multimers (n = 50). Statistical analysis showed that vWF-protease deficiency was associated with the severity of thrombocytopenia (P &lt; .01). This study emphasizes that vWF-cleaving protease deficiency specifically concerns a subgroup of TMA corresponding to the TTP entity.
Bifurcation of osteoclasts and dendritic cells from common progenitors
Authors: Miyamoto Takeshi , Ohneda Osamu , Arai Fumio , Iwamoto Katsuya , Okada Seiji , Takagi Katsumasa , Anderson Dirk M. , Suda Toshio 
Published: July 2002

AbstractOsteoclasts and dendritic cells are derived from monocyte/macrophage precursor cells; however, how their lineage commitment is regulated is unknown. This study investigated the differentiation pathways of osteoclasts and dendritic cells from common precursor cells at the single-cell level. Osteoclastogenesis induced by macrophage colony-stimulating factor (M-CSF) and receptor activator of nuclear factor–κB ligand (RANKL) or tumor necrosis factor-α (TNF-α) is completely inhibited by addition of granulocyte-macrophage colony-stimulating factor (GM-CSF) or interleukin-3 at early stages of differentiation. GM-CSF–treated cells express both c-Fms and RANK and also low levels of CD11c and DEC205, which are detected on dendritic cells. Addition of GM-CSF also reduces expression of both c-Fos and Fra-1, which is an important event for inhibition of osteoclastogenesis. Overexpression of c-Fos by retroviral infection or induction in transgenic mice can rescue a failure in osteoclast differentiation even in the presence of GM-CSF. By contrast, differentiation into dendritic cells is inhibited by M-CSF, indicating that M-CSF and GM-CSF reciprocally regulate the differentiation of both lineages. Dendritic cell maturation is also inhibited when c-Fos is expressed at an early stage of differentiation. Taken together, these findings suggest that c-Fos is a key mediator of the lineage commitment between osteoclasts and dendritic cells. The lineage determination of osteoclast progenitors seen following GM-CSF treatment functions through the regulation of c-Fos expression.
Increased and prolonged inflammation and angiogenesis in delayed-type hypersensitivity reactions elicited in the skin of thrombospondin-2–deficient mice
Authors: Lange-Asschenfeldt Bernhard , Weninger Wolfgang , Velasco Paula , Kyriakides Themis R. , von Andrian Ulrich H. , Bornstein Paul , Detmar Michael 
Published: July 2002

AbstractAngiogenesis and enhanced microvascular permeability are hallmarks of a large number of inflammatory diseases. Although up-regulation of proangiogenic factors such as vascular endothelial growth factor and interleukin-8 have been previously reported in inflamed tissue, the biologic role of endogenous inhibitors of angiogenesis in inflammation has remained unclear. To investigate the biologic role of the potent angiogenesis inhibitor thrombospondin-2 (TSP-2) in the control of cutaneous inflammation, delayed-type hypersensitivity reactions were elicited in the ear skin of wild-type and TSP-2–deficient mice by topical sensitization and challenge with oxazolone. Cutaneous TSP-2 expression was up-regulated in the inflamed skin of wild-type mice, predominantly in dermal fibroblasts and microvessels. Lack of TSP-2 resulted in a significantly enhanced inflammatory response with increased angiogenesis, edema formation, and inflammatory infiltration. Ear swelling and inflammation persisted for more than 2 weeks in TSP-2–deficient mice, as compared with 1 week in wild-type mice. Although baseline vascular permeability was unchanged, significantly enhanced microvascular leakage was found in the inflamed skin of TSP-2–deficient mice. Moreover, the fraction of rolling leukocytes was significantly increased in the untreated skin of TSP-2–deficient mice. These results reveal an important role of TSP-2 in limiting the extent and the duration of edema formation, angiogenesis, and inflammatory cell infiltration during acute and chronic inflammation.
The mechanism of tumor cell clearance by rituximab in vivo in patients with B-cell chronic lymphocytic leukemia: evidence of caspase activation and apoptosis induction
Authors: Byrd John C. , Kitada Shinichi , Flinn Ian W. , Aron Jennifer L. , Pearson Michael , Lucas David , Reed John C. 
Published: July 2002

AbstractRituximab is a chimeric monoclonal antibody directed at CD20 with significant activity in non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL). A variety of pathways of tumor cytotoxicity different from cytotoxic chemotherapy have been proposed for this therapeutic antibody including antibody-dependent cellular cytotoxicity and complement-mediated cell lysis. This report describes that a proportion of patients with CLL receiving rituximab treatment have in vivo activation of caspase-9, caspase-3, and poly(ADP-ribose) polymerase (PARP) cleavage in blood leukemia cells immediately following infusion of rituximab. This suggests that apoptosis using a pathway similar to fludarabine and other chemotherapeutic agents is intricately involved in the blood elimination of tumor cells after rituximab treatment. Patients having caspase-3 activation and PARP cleavage in vivo had a significantly lower blood leukemia cell count after treatment as compared to those without caspase activation. Significant down-modulation of the antiapoptotic proteins XIAP and Mcl-1 was also noted, possibly explaining in part how rituximab sensitizes CLL cells to the cytotoxic effect of chemotherapy in vivo. These findings suggest that the therapeutic benefit of antibody-based therapy in vivo for patients with CLL depends in part on induction of apoptosis and provides another area of focus for studying mechanisms of antibody-resistance in neoplastic cells.