bluuebunny/crossref_metadata_2025_split huggingface dataset:
RGDS peptide induces caspase 8 and caspase 9 activation in human endothelial cells
Authors: Aguzzi Maria Simona , Giampietri Claudia , De Marchis Francesco , Padula Fabrizio , Gaeta Roberto , Ragone Gianluca , Capogrossi Maurizio C. , Facchiano Antonio 
Published: March 2004

AbstractPeptides containing the Arg-Gly-Asp (RGD) motif inhibit cell adhesion and exhibit a variety of other biologic effects including anticoagulant and antimetastatic activities. The aim of the present study was to examine the anchorage-independent effects of an RGD-containing peptide, Arg-Gly-Asp-Ser (RGDS), on human umbilical vein endothelial cells (HUVECs). Assays were performed on HUVECs seeded onto collagen IV; under these experimental conditions RGDS did not exert antiadhesive effects but significantly reduced FGF-2-dependent chemotaxis after 4 hours of treatment and reduced proliferation after 24 hours of treatment. Experiments carried out with caspase-specific inhibitors indicated that the observed antichemotactic effects required caspase 8 and caspase 9 activation. RGDS activated both caspase 8 and caspase 9 after 4 hours of treatment and caspase 3 after 24 hours of treatment, and markedly enhanced HUVEC apoptosis by transferase-mediated deoxyuridine triphosphate nick-end labeling (TUNEL)/Hoechst staining and fluorescence-activated cell sorting (FACS) analysis. Finally, confocal microscopy showed that RGDS localizes in the cytoplasm of live HUVECs within 4 hours and in vitro experiments showed that RGDS directly interacts with recombinant caspases 8 and 9 in a specific way. In summary, these results indicate that RGDS directly binds and activates caspases 8 and 9, inhibits chemotaxis, and induces apoptosis of HUVECs with a mechanism independent from its antiadhesive effect.
The VEGF receptor flt-1 (VEGFR-1) is a positive modulator of vascular sprout formation and branching morphogenesis
Authors: Kearney Joseph B. , Kappas Nicholas C. , Ellerstrom Catharina , DiPaola Frank W. , Bautch Victoria L. 
Published: March 2004

AbstractSprouting angiogenesis is critical to blood vessel formation, but the cellular and molecular controls of this process are poorly understood. We used time-lapse imaging of green fluorescent protein (GFP)-expressing vessels derived from stem cells to analyze dynamic aspects of vascular sprout formation and to determine how the vascular endothelial growth factor (VEGF) receptor flt-1 affects sprouting. Surprisingly, loss of flt-1 led to decreased sprout formation and migration, which resulted in reduced vascular branching. This phenotype was also seen in vivo, as flt-1-/- embryos had defective sprouting from the dorsal aorta. We previously showed that loss of flt-1 increases the rate of endothelial cell division. However, the timing of division versus morphogenetic effects suggested that these phenotypes were not causally linked, and in fact mitoses were prevalent in the sprout field of both wild-type and flt-1-/- mutant vessels. Rather, rescue of the branching defect by a soluble flt-1 (sflt-1) transgene supports a model whereby flt-1 normally positively regulates sprout formation by production of sflt-1, a soluble form of the receptor that antagonizes VEGF signaling. Thus precise levels of bioactive VEGF-A and perhaps spatial localization of the VEGF signal are likely modulated by flt-1 to ensure proper sprout formation during blood vessel formation. (Blood. 2004;103:4527-4535)
The Flt3 internal tandem duplication mutant inhibits the function of transcriptional repressors by blocking interactions with SMRT
Authors: Takahashi Shinichiro , McConnell Melanie J. , Harigae Hideo , Kaku Mitsuo , Sasaki Takeshi , Melnick Ari M. , Licht Jonathan D. 
Published: March 2004

AbstractFms-like tyrosine kinase 3 (Flt3) is a type III receptor tyrosine kinase (RTK). Between 20% and 30% of acute myeloid leukemia (AML) patients have either an internal tandem duplication (ITD) of the juxtamembrane region or a point mutation of the Flt3 receptor leading to the constitutive activation of downstream signaling pathways and aberrant cell growth. The silencing mediator of retinoic and thyroid hormone receptors (SMRT) corepressor mediates transcriptional repression by interacting with transcription factors such as the promyelocytic leukemia zinc finger (PLZF) protein. Previous reports indicate that SMRT interaction with transcription factors can be disrupted by phosphorylation through activation of RTK pathways. We report here that the Flt3-ITD interferes with the transcriptional and biologic action of the PLZF transcriptional repressor. In the presence of Flt3-ITD, PLZF-SMRT interaction was reduced, transcriptional repression by PLZF was inhibited, and PLZF-mediated growth suppression of leukemia cells was partially blocked. Furthermore, overexpression of Flt3-ITD led to a partial relocalization of SMRT protein from the nucleus to the cytoplasm. Nuclear export was dependent on the SMRT receptor interaction domain (RID), and Flt3-ITD enhances the binding of nuclear-cytoplasm shuttling protein nuclear factor-κB-p65 (NFκB-p65) to this region. These data suggest that activating mutations of Flt3 may disrupt transcriptional repressor function resulting in aberrant gene regulation and abnormal leukemia cell growth. (Blood. 2004;103:4650-4658)
Modulating erythrocyte chimerism in a mouse model of pyruvate kinase deficiency
Authors: Richard Robert E. , Weinreich Michael , Chang Kai-Hsin , Ieremia Jessica , Stevenson Mary M. , Blau C. Anthony 
Published: March 2004

Abstract
In vivo selection may provide a means to increase the relative number of cells of donor origin in recipients with hemopoietic chimerism. We have tested whether in vivo selection using chemical inducers of dimerization (CIDs) can direct the expansion of transduced normal donor erythrocytes in recipients with chimerism using a mouse model of pyruvate kinase deficiency. Marrow cells from normal CBA/N mice were transduced with a vector (F36VmplGFP) that promotes cell growth in the presence of CIDs. Transduced cells were then transplanted into minimally conditioned, pyruvate kinase-deficient recipients (CBA-Pk-1slc/Pk-1slc) to establish stable chimerism. CID administration resulted in expansion of normal donor erythrocytes and improvement of the anemia. The preferential expansion of normal erythrocytes also resulted in a decrease in erythropoietin levels, reducing the drive for production of pyruvate kinase-deficient red blood cells. CID-mediated expansion of genetically modified erythrocytes could prove a useful adjunct to transplantation methods that achieve erythroid chimerism. (Blood. 2004;103:4432-4439)
Identification of Flk-1 target genes in vasculogenesis: Pim-1 is required for endothelial and mural cell differentiation in vitro
Authors: Zippo Alessio , De Robertis Alessandra , Bardelli Monia , Galvagni Federico , Oliviero Salvatore 
Published: March 2004

AbstractThe tyrosine kinase receptor fetal liver kinase 1 (Flk-1) plays a crucial role in vasculogenesis and angiogenesis, but its target genes remain elusive. Comparing Flk-1+/+ with Flk-1-/- embryonic stem (ES) cells, we identified transcripts regulated by the vascular endothelial growth factor A (VEGF-A)/Flk-1 pathway at an early stage of their differentiation to endothelial and mural precursors. Further analysis of a number of these genes (Nm23-M1, Nm23-M2, Slug, Set, pp32, Cbp, Ship-1, Btk, and Pim-1) showed that their products were transiently up-regulated in vivo in endothelial cells (ECs) during angiogenesis of the ovary, and their mRNA was rapidly induced in vitro by VEGF-A in human umbilical cord vein endothelial cells (HUVECs). Functional analysis by RNA interference (RNAi) in ES cells induced to differentiate demonstrated that Pim-1 is required for their differentiation into ECs and smooth muscle cells (SMCs). In HUVECs, RNAi showed that Pim-1 is required in ECs for VEGF-A-dependent proliferation and migration. The identification of Flk-1 target genes should help in elucidating the molecular pathways that govern the vasculogenesis and angiogenesis processes. (Blood. 2004;103:4536-4544)
Familial eosinophilia: a benign disorder?
Authors: Klion Amy D. , Law Melissa A. , Riemenschneider William , McMaster Mary Lou , Brown Margaret R. , Horne McDonald , Karp Barbara , Robinson Michael , Sachdev Vandana , Tucker Eben , Turner Maria , Nutman Thomas B. 
Published: March 2004

AbstractFamilial eosinophilia (FE) is an autosomal dominant disorder characterized by marked eosinophilia and progression to end organ damage in some, but not all, affected family members. To better define the pathogenesis of FE, 13 affected and 11 unaffected family members (NLs) underwent a detailed clinical evaluation at the National Institutes of Health (NIH). No clinical abnormalities were more frequent in the family members with FE compared with the NLs. There was, however, a decreased prevalence of asthma in family members with FE compared with unaffected family members. Eosinophil morphology as assessed by either light or transmission electron microscopy was normal in family members with and without FE. Although levels of eosinophil-derived neurotoxin (EDN) and major basic protein (MBP) were elevated in patients with FE compared with NL, levels of both granule proteins were lower than in nonfamilial hypereosinophilic syndrome (HES). Similarly, increased surface expression of the activation markers CD69, CD25, and HLA-DR was detected by flow cytometry on eosinophils from patients with FE compared with NL, albeit less than that seen in HES. These data suggest that, despite prolonged marked eosinophilia, FE can be distinguished from HES by a more benign clinical course that may be related to a relative lack of eosinophil activation.
Familial acquired thrombotic thrombocytopenic purpura: ADAMTS13 inhibitory autoantibodies in identical twins
Authors: Studt Jan-Dirk , Hovinga Johanna A. Kremer , Radonic Radovan , Gasparovic Vladimir , Ivanovic Dragutin , Merkler Marijan , Wirthmueller Urs , Dahinden Clemens , Furlan Miha , Lämmle Bernhard 
Published: March 2004

Abstract
Thrombotic thrombocytopenic purpura (TTP) either occurs in a congenital form caused by ADAMTS13 gene mutations or it is acquired and most often due to ADAMTS13 inhibitory autoantibodies. In congenital TTP siblings are often affected, while acquired TTP occurs sporadically and familial clustering has not been described so far. We report identical twin sisters suffering from acquired TTP due to immunoglobulin G (IgG) autoantibodies inactivating ADAMTS13, suggesting an important role of hitherto unidentified genetic determinants of ADAMTS13 inhibitor formation. These cases also demonstrate that familial clustering is not sufficient for unambiguously diagnosing hereditary ADAMTS13 deficiency and congenital TTP. (Blood. 2004;103:4195-4197)
Analysis of T-cell repertoire in hepatitis-associated aplastic anemia
Authors: Lu Jun , Basu Atanu , Melenhorst J. Joseph , Young Neal S. , Brown Kevin E. 
Published: March 2004

AbstractHepatitis-associated aplastic anemia (HAA) is a syndrome of bone marrow failure following an acute attack of seronegative hepatitis. Clinical features and liver histology suggest a central role for an immune-mediated mechanism. To characterize the immune response, we investigated the T-cell repertoire (T-cell receptor [TCR] Vβ chain subfamily) of intrahepatic lymphocytes in HAA patients by TCR spectratyping. In 6 of 7 HAA liver samples, a broad skewing pattern in the 21 Vβ subfamilies tested was observed. In total, 62% ± 18% of HAA spectratypes showed a skewed pattern, similar to 68% ± 18% skewed spectratype patterns in 3 of 4 patients with confirmed viral hepatitis. Additionally, the T-cell repertoire had similarly low levels of complexity. In the peripheral blood lymphocytes (PBLs) of a separate group of HAA patients prior to treatment, 60% ± 15% skewed spectratypes were detected, compared with only 18% ± 8% skewed spectratypes in healthy controls. After successful immunosuppressive treatment, an apparent reversion to a normal T-cell repertoire with a corresponding significant increase in T-cell repertoire complexity was observed in the HAA samples. In conclusion, our data suggest an antigen-driven T-cell expansion in HAA and achievement of a normal T-cell repertoire during recovery from HAA. (Blood. 2004;103:4588-4593)
ABC transporter activities of murine hematopoietic stem cells vary according to their developmental and activation status
Authors: Uchida Naoyuki , Dykstra Brad , Lyons Kristin , Leung Frank , Kristiansen Merete , Eaves Connie 
Published: March 2004

AbstractPrimitive hematopoietic cells from several species are known to efflux both Hoechst 33342 and Rhodamine-123. We now show that murine hematopoietic stem cells (HSCs) defined by long-term multilineage repopulation assays efflux both dyes variably according to their developmental or activation status. In day 14.5 murine fetal liver, very few HSCs efflux Hoechst 33342 efficiently, and they are thus not detected as “side population” (SP) cells. HSCs in mouse fetal liver also fail to efflux Rhodamine-123. Both of these features are retained by most of the HSCs present until 4 weeks after birth but are reversed by 8 weeks of age or after a new HSC population is regenerated in adult mice that receive transplants with murine fetal liver cells. Activation of adult HSCs in vivo following 5-fluorouracil treatment, or in vitro with cytokines, induces variable losses in Rhodamine-123 and Hoechst 33342 efflux activities, and HSCs from mdr-1a/1b-/- mice show a dramatic decrease in Rhodamine-123 efflux ability. Thus, the Rhodamine-123 and Hoechst 33342 efflux properties of murine HSCs fluctuate in the same fashion as a number of other HSC markers, suggesting these are regulated by a common control mechanism that operates independently of that regulating the regenerative function of HSCs. (Blood. 2004;103:4487-4495)
The biology of CML blast crisis
Authors: Calabretta Bruno , Perrotti Danilo 
Published: March 2004

AbstractChronic myelogenous leukemia (CML) evolves from a chronic phase characterized by the Philadelphia chromosome as the sole genetic abnormality into blast crisis, which is often associated with additional chromosomal and molecular secondary changes. Although the pathogenic effects of most CML blast crisis secondary changes are still poorly understood, ample evidence suggests that the phenotype of CML blast crisis cells (enhanced proliferation and survival, differentiation arrest) depends on cooperation of BCR/ABL with genes dysregulated during disease progression. Most genetic abnormalities of CML blast crisis have a direct or indirect effect on p53 or Rb (or both) gene activity, which are primarily required for cell proliferation and survival, but not differentiation. Thus, the differentiation arrest of CML blast crisis cells is a secondary consequence of these abnormalities or is caused by dysregulation of differentiation-regulatory genes (ie, C/EBPα). Validation of the critical role of certain secondary changes (ie, loss of p53 or C/EBPα function) in murine models of CML blast crisis and in in vitro assays of BCR/ABL transformation of human hematopoietic progenitors might lead to the development of novel therapies based on targeting BCR/ABL and inhibiting or restoring the gene activity gained or lost during disease progression (ie, p53 or C/EBPα).
Telomere length correlates with histopathogenesis according to the germinal center in mature B-cell lymphoproliferative disorders
Authors: Ladetto Marco , Compagno Mara , Ricca Irene , Pagano Marco , Rocci Alberto , Astolfi Monica , Drandi Daniela , di Celle Paola Francia , Dell'Aquila Maria , Mantoan Barbara , Vallet Sonia , Pagliano Gloria , De Marco Federica , Francese Roberto , Santo Loredana , Cuttica Alessandra , Marinone Carlo , Boccadoro Mario , Tarella Corrado 
Published: March 2004

AbstractIn this study we investigated telomere restriction fragment (TRF) length in a panel of mature B-cell lymphoproliferative disorders (MBCLDs) and correlated this parameter with histology and histopathogenesis in relation to the germinal center (GC). We assessed 123 MBCLD samples containing 80% or more tumor cells. TRF length was evaluated by Southern blot analysis using a chemiluminescence-based assay. GC status was assessed through screening for stable and ongoing somatic mutations within the immunoglobulin heavy-chain genes. Median TRF length was 6170 bp (range, 1896-11 200 bp) and did not correlate with patient age or sex. TRF length was greater in diffuse large cell lymphoma, Burkitt lymphoma, and follicular lymphoma (medians: 7789 bp, 9471 bp, and 7383 bp, respectively) than in mantle cell lymphoma and chronic lymphocytic leukemia (medians: 3582 bp and 4346 bp, respectively). GC-derived MBCLDs had the longest telomeres, whereas those arising from GC-inexperienced cells had the shortest (P &lt; 10-9). We conclude that (1) TRF length in MBCLD is highly heterogeneous; (2) GC-derived tumors have long telomeres, suggesting that minimal telomere erosion occurs during GC-derived lymphomagenesis; and (3) the short TRF lengths of GC-inexperienced MBCLDs indicates that these neoplasms are good candidates for treatment with telomerase inhibitors, a class of molecules currently the subject of extensive preclinical evaluation. (Blood. 2004;103:4644-4649)
Genetic abnormalities and juvenile hemochromatosis: mutations of the HJV gene encoding hemojuvelin
Authors: Lee Pauline L. , Beutler Ernest , Rao Sreenivas V. , Barton James C. 
Published: March 2004

AbstractJuvenile hemochromatosis is an early-onset form of iron storage disease characterized by hypogonadotrophic hypogonadism and cardiomyopathy. Recently, the putative causative gene (LOC148738) encoding a protein designated hemojuvelin was cloned. The previously proposed designation of this gene as HFE2 is contrary to established convention, because it is not a member of the HFE family. We suggest that it be designated HJV. We sequenced this gene in members of 2 previously reported kinships that manifest typical juvenile hemochromatosis. In one kinship, 2 previously undescribed mutations of HJV were identified, c.238T&gt;C (C80R) and c.302T&gt;C (L101P). In the second kinship, 2 previously identified mutations, G320V and I222N, were found. These studies confirm that mutations in HJV cause juvenile hemochromatosis. (Blood. 2004;103:4669-4671)
Complete protection from relapsing experimental autoimmune encephalomyelitis induced by syngeneic B cells expressing the autoantigen
Authors: Chen Chiann-Chyi , Rivera Amariliz , Dougherty Joseph P. , Ron Yacov 
Published: March 2004

AbstractExperimental autoimmune encephalomyelitis (EAE), an animal model for human multiple sclerosis (MS), is a typical CD4+ T-cell-mediated autoimmune disease of the central nervous system (CNS) characterized by perivascular inflammation culminating in focal demyelinations. Like MS, EAE induced by proteolipid protein (PLP) usually follows the form of a relapsing-remitting disease. We have previously described an immunotherapy model in which infusion of autologous B cells expressing the PLP encephalitogenic determinant induced PLP-specific unresponsiveness and protected mice from induction of EAE. Here we show that the same treatment when initiated after disease onset, which resembles the clinical situation presented in MS, completely protects all treated animals from further relapses. We also show that protected animals were unresponsive to PLP as measured by delayed-type hypersensitivity (DTH). This represents a novel immunotherapeutic approach that can be exploited to develop treatments for human MS and other T-cell-mediated autoimmune diseases. (Blood. 2004;103:4616-4618)
Fcγ receptor signaling in primary human microglia: differential roles of PI-3K and Ras/ERK MAPK pathways in phagocytosis and chemokine induction
Authors: Song Xianyuan , Tanaka Sakae , Cox Dianne , Lee Sunhee C 
Published: March 2004

AbstractCryptococcus neoformans monoclonal antibody immune complex (IC) induces β-chemokines and phagocytosis in primary human microglia via activation of Fc receptor for immunoglobulin G (FcγR). In this report, we investigated microglial FcγR signal-transduction pathways by using adenoviral-mediated gene transfer and specific inhibitors of cell-signaling pathways. We found that Src inhibitor PP2 and Syk inhibitor piceatannol inhibited phagocytosis, macrophage-inflammatory protein-1α (MIP-1α) release, as well as phosphorylation of extracellular-regulated kinase (ERK) and Akt, consistent with Src/Syk involvement early in FcγR signaling. Constitutively active mitogen-activated protein kinase kinase (MEK) induced MIP-1α, and Ras dominant-negative (DN) inhibited IC-induced ERK phosphorylation and MIP-1α production. These results suggest that the Ras/MEK/ERK pathway is necessary and sufficient in IC-induced MIP-1α expression. Neither Ras DN nor the MEK inhibitor U0126 inhibited phagocytosis. In contrast, phosphatidylinositol-3 kinase (PI-3K) inhibitors Wortmannin and LY294002 inhibited phagocytosis without affecting ERK phosphorylation or MIP-1α production. Conversely, Ras DN or U0126 did not affect Akt phosphorylation. Together, these results demonstrate distinct roles played by the PI-3K and Ras/MEK/ERK pathways in phagocytosis and MIP-1α induction, respectively. Our results demonstrating activation of functionally distinct pathways following microglial FcγR engagement may have implications for human central nervous system diseases.
Defective macrophage function in neonates and its impact on unresponsiveness of neonates to polysaccharide antigens
Authors: Chelvarajan R L , Collins S M , Doubinskaia I E , Goes S , Van Willigen J , Flanagan D , de Villiers W J S , Bryson J S , Bondada S 
Published: March 2004

AbstractNeonates do not respond to thymus-independent (TI) antigens (Ag), making them vulnerable to infection with encapsulated bacteria. The antibody (Ab) response of adult and neonatal B cells to TI Ag requires certain cytokines, which are provided by T cells or macrophages (MΦ). Lipopolysaccharide (LPS) failed to induce neonatal MΦ to produce interleukin (IL)-1β and tumor necrosis factor α (TNF-α) mRNA and to secrete IL-1β, IL-12, and TNF-α. However, LPS induced neonates to secrete some IL-6 and three- to fivefold more IL-10 than adults. Accordingly, adding adult but not neonatal MΦ could restore the response of purified adult B cells to trinitrophenol (TNP)–LPS, a TI Ag. Increased IL-10 is causally related to decreased IL-1β and IL-6 production, as IL-10−/− neonatal MΦ responded to LPS by secreting more IL-1β and IL-6 than wild-type (WT) neonatal MΦ. When cultures were supplemented with a neutralizing Ab to IL-10, WT neonatal MΦ secreted increased amounts of IL-6 and allowed neonatal MΦ to promote adult B cells to mount an Ab response against TNP–LPS. Thus, neonates do not respond to TI Ag as a result of the inability of neonatal MΦ to secrete cytokines, such as IL-1β and IL-6, probably as a result of an excess production of IL-10. This dysregulated cytokine secretion by neonatal MΦ may be a result of a reduction in expression of Toll-like receptor-2 (TLR-2) and TLR-4 and CD14.