bluuebunny/crossref_metadata_2025_split huggingface dataset:
Identification of a novel 14-3-3ζ binding site within the cytoplasmic tail of platelet glycoprotein Ibα
Authors: Mangin Pierre , David Tovo , Lavaud Vincent , Cranmer Susan L. , Pikovski Inna , Jackson Shaun P. , Berndt Michael C. , Cazenave Jean-Pierre , Gachet Christian , Lanza François 
Published: April 2004

AbstractThe glycoprotein Ib-V-IX (GPIb-V-IX) complex interacts with subendothelial von Willebrand factor (VWF) to ensure recruitment of platelets at sites of vascular injury, a process that culminates in integrin αIIbβ3-dependent stable adhesion and spreading. Interaction of the 14-3-3ζ adaptor protein with the C-terminal 606-610 phosphoserine motif of the GPIbα subunit has been implicated in the control of αIIbβ3 activation and cell spreading. In this study, we have examined potentially novel 14-3-3ζ binding sites by expressing mutant forms of GPIbα in Chinese-hamster-ovary (CHO) cells. Analysis of a series of neighboring 11-12 residue deletions identified a critical role for the 580-LVAGRRPSALS-590 sequence in promoting GPIbα-14-3-3ζ interaction. Development of a phosphospecific antibody demonstrated high levels of phosphorylation of the Ser587 and Ser590 residues in resting platelets (which became dephosphorylated during platelet spreading on VWF), and peptides containing these phosphorylated residues effectively displaced 14-3-3ζ from GPIbα. Analysis of single and double alanine substitutions of Ser587 and Ser590 demonstrated a major role for these residues in promoting GPIbα-14-3-3ζ binding. Moreover, these cell lines exhibited a defect in cell spreading on immobilized VWF. These studies demonstrate the existence of a second major 14-3-3ζ binding site within the cytoplasmic tail of GPIbα that has an important functional role in regulating integrin-dependent cell spreading. (Blood. 2004;104:420-427)
Caspase-12: a developmental link between G-protein–coupled receptors and integrin αIIbβ3 activation
Authors: Kerrigan Steven W. , Gaur Meenakshi , Murphy Ronan P. , Shattil Sanford J. , Leavitt Andrew D. 
Published: April 2004

Abstract
Fibrinogen binding by integrin αIIbβ3 is promoted by platelet agonists that increase the affinity and avidity of αIIbβ3 for fibrinogen through a process called “inside-out” signaling. Having previously demonstrated that inside-out activation of αIIbβ3 is defective in murine megakaryocytes that lack the transcription factor NF-E2, we screened for NF-E2–regulated genes that affect αIIbβ3 activation. Caspase-12 is the most down-regulated gene we identified in NF-E2–/– megakaryocytes. Therefore, the role of this protein in αIIbβ3 activation was determined using platelets from caspase-12–/– mice. Despite wild-type levels of αIIbβ3, caspase-12–/– platelets exhibit reduced fibrinogen binding to αIIbβ3 following stimulation by adenosine diphosphate (ADP) or protease-activated receptor 4 (PAR4) receptor-activating peptide. The defect in αIIbβ3 activation is associated with decreased cytosolic free calcium and inositol triphosphate levels, and with reduced aggregation, despite wild-type phospholipase Cβ expression levels. In contrast, agonist-induced surface expression of P-selectin, suppression of cAMP levels following ADP stimulation, and spreading on immobilized fibrinogen are unimpaired. Moreover, although caspase-12 is highly expressed in mature megakaryocytes, it is undetectable in platelets. Taken together, these studies establish that caspase-12 expression in murine megakaryocytes is regulated, directly or indirectly, by NF-E2, and suggest that caspase-12 participates in the development of fully functional signaling pathways linking some G-protein–coupled receptors to αIIbβ3 activation.
Role of the CXCR4/SDF-1 chemokine axis in circulating neutrophil homeostasis
Authors: Suratt Benjamin T. , Petty Joseph M. , Young Scott K. , Malcolm Kenneth C. , Lieber Jonathan G. , Nick Jerry A. , Gonzalo Jose-Angel , Henson Peter M. , Worthen G. Scott 
Published: April 2004

AbstractThe bone marrow is the primary site for neutrophil production and release into the circulation. Because the CXC chemokine receptor-4/stromal derived factor-1 (CXCR4/SDF-1) axis plays a central role in the interactions of hematopoietic stem cells, lymphocytes, and developing neutrophils in the marrow, we investigated whether reciprocal CXCR4-dependent mechanisms might be involved in neutrophil release and subsequent return to the marrow following circulation. Neutralizing antibody to CXCR4 reduced marrow retention of infused neutrophils (45.7% ± 0.5% to 6.9% ± 0.5%) and was found to mobilize neutrophils from marrow (34.4% ± 4.4%). Neutrophil CXCR4 expression and SDF-1-induced calcium flux decreased with maturation and activation of the cells, corresponding to the decreased marrow homing associated with these characteristics in vivo. Infusion of the inflammatory mediator and CXCR2 ligand KC led to mobilization of neutrophils from marrow by itself and was augmented 3-fold by low doses of CXCR4-blocking antibody that otherwise had no mobilizing effect. Examination of KC and SDF-1 calcium signaling demonstrated that the effect of KC may, in part, be due to heterologous desensitization to SDF-1. These results suggest that the CXCR4/SDF-1 axis is critical in circulating neutrophil homeostasis and that it may participate in the rapid release of neutrophils from the marrow during inflammation through a novel interaction with inflammatory CXC chemokines. (Blood. 2004;104:565-571)
Age-related phenotypic and oncogenic differences in T-cell acute lymphoblastic leukemias may reflect thymic atrophy
Authors: Asnafi Vahid , Beldjord Kheira , Libura Marta , Villarese Patrick , Millien Corrine , Ballerini Paola , Kuhlein Emilienne , Lafage-Pochitaloff Marina , Delabesse Eric , Bernard Olivier , Macintyre Elizabeth 
Published: April 2004

AbstractPostnatal thymic involution occurs progressively throughout the first 3 decades of life. It predominantly affects T-cell receptor (TCR) αβ-lineage precursors, with a consequent proportional increase in multipotent thymic precursors. We show that T-acute lymphoblastic leukemias (T-ALLs) demonstrate a similar shift with age from predominantly TCR expressing to an immature (IM0/δ/γ) stage of maturation arrest. Half demonstrate HOX11, HOX11L2, SIL-TAL1, or CALM-AF10 deregulation, with each being associated with a specific, age-independent stage of maturation arrest. HOX11 and SIL-TAL represent αβ-lineage oncogenes, whereas HOX11L2 expression identifies an intermediate αβ/γδ-lineage stage of maturation arrest. In keeping with preferential αβ-lineage involution, the incidence of SIL-TAL1 and HOX11L2 deregulation decreased with age. In contrast, HOX11 deregulation became more frequent, suggesting longer latency. TAL1/LMO1 deregulation is more frequent in αβ-lineage T-ALL, when it is predominantly due to SIL-TAL1 rearrangements in children but to currently unknown mechanisms in adolescents and adults. LMO2 was more frequently coexpressed with LYL1, predominantly in IM0/δ/γ adult cases, than with TAL1. These age-related changes in phenotype and oncogenic pathways probably reflect progressive changes in the thymic population at risk of malignant transformation.
T-cell receptor–induced phosphorylation of the ζ chain is efficiently promoted by ZAP-70 but not Syk
Authors: Steinberg Marcos , Adjali Oumeya , Swainson Louise , Merida Peggy , Bartolo Vincenzo Di , Pelletier Ludivine , Taylor Naomi , Noraz Nelly 
Published: April 2004

AbstractEngagement of the T-cell receptor (TCR) results in the activation of Lck/Fyn and ZAP-70/Syk tyrosine kinases. Lck-mediated tyrosine phosphorylation of signaling motifs (ITAMs) in the CD3-ζ subunits of the TCR is an initial step in the transduction of signaling cascades. However, ζ phosphorylation is also promoted by ZAP-70, as TCR-induced ζ phosphorylation is defective in ZAP-70–deficient T cells. We show that this defect is corrected by stable expression of ZAP-70, but not Syk, in primary and transformed T cells. Indeed, these proteins are differentially coupled to the TCR with a 5- to 10-fold higher association of ZAP-70 with ζ as compared to Syk. Low-level Syk-ζ binding is associated with significantly less Lck coupled to the TCR. Moreover, diminished coupling of Lck to ζ correlates with a poor phosphorylation of the positive regulatory tyr352 residue of Syk. Thus, recruitment of Lck into the TCR complex with subsequent ζ chain phosphorylation is promoted by ZAP-70 but not Syk. Importantly, the presence of ZAP-70 positively regulates the TCR-induced tyrosine phosphorylation of Syk. The interplay between Syk and ZAP-70 in thymocytes, certain T cells, and B-chronic lymphocytic leukemia cells, in which they are coexpressed, will therefore modulate the amplitude of antigen-mediated receptor signaling.
HIV-1–specific cytotoxicity is preferentially mediated by a subset of CD8+ T cells producing both interferon-γ and tumor necrosis factor–α
Authors: Lichterfeld Mathias , Yu Xu G. , Waring Michael T. , Mui Stanley K. , Johnston Mary N. , Cohen Daniel , Addo Marylyn M. , Zaunders John , Alter Galit , Pae Eunice , Strick Daryld , Allen Todd M. , Rosenberg Eric S. , Walker Bruce D. , Altfeld Marcus 
Published: April 2004

AbstractCD8+ T cells play a crucial role in the control of viral infections by direct elimination of infected cells and secretion of a number of soluble factors. Recent data suggest that HIV-1-specific CD8+ T cell subsets may differ in their ability to exert these effector functions. Here, we directly compared the cytokine secretion patterns and cytotoxic capacity of HIV-1-specific CD8+ T cells, using a flow-cytometric cytotoxicity assay based on caspase-3 activation in dying target cells. These experiments revealed considerable intraindividual and interindividual differences among epitope-specific T-cell effector functions: while the frequency of HIV-1-specific CD8+ T cells secreting interferon-γ but no tumor necrosis factor-α (TNF-α) following antigenic stimulation was only weakly correlated to their cytotoxic activity (R = 0.05, P = .57), a subset of CD8+ T cells secreting both inter-feron-γ and TNF-α was substantially more strongly associated with cytotoxicity (R = 0.67, P &lt; .001). This subset of CD8+ T cells also exhibited stronger intracellular perforin expression and more pronounced direct ex vivo HIV-1-specific cytoxicity than CD8+ T cells secreting solely interferon-γ following sorting of these subpopulations according to their cytokine profile. These results suggest that HIV-1-specific cytotoxicity of CD8+ T cells is preferentially mediated by a subset of CD8+ T cells secreting both interferon-γ and TNF-α. (Blood. 2004;104:487-494)
Positive and negative regulatory roles of the WW-like domain in TEL-PDGFβR transformation
Authors: Chen Jing , Williams Ifor R. , Kutok Jeffery L. , Duclos Nicole , Anastasiadou Ema , Masters Shane C. , Fu Haian , Gilliland D. Gary 
Published: April 2004

AbstractTEL-platelet-derived growth factor-β receptor (TEL-PDGFβR) is expressed in chronic myelomonocytic leukemias associated with t(5;12)(q33;p13), and the fusion tyrosine kinase retains a conserved WW-like domain in the PDGFβR autoinhibitory juxtamembrane region. Here we report that mutation of the 2 conserved tryptophan residues of the WW-like domain has opposing effects on TELPDGFβR kinase activation. Alanine substitution of W593, essential for protein-protein interaction in the context of other WW domains, impaired TEL-PDGFβR-mediated transformation of hematopoietic cells due to inhibition of TEL-PDGFβR kinase activity. In contrast, alanine substitution of W566, essential for structural integrity of WW domain in other contexts, had no effect on TEL-PDGFβR activation and oncogenic activity. Surprisingly, however, the W566A mutation suppressed the W593A phenotype. Double mutant W566A/W593A was indistinguishable from the wild-type fusion protein with regard to kinase activity, ability to confer factor-independent growth to Ba/F3 cells, or ability to induce a myeloproliferative disease in mice. Additional mutational analysis identified other substitutions within the WW-like domain in addition to W566A that could also suppress the W593A phenotype, including mutations predicted to diminish the autoinhibitory function of the juxtamembrane region. Therefore, the WW-like domain in the context of TELPDGFβR may have both positive and negative regulatory roles in kinase activation. (Blood. 2004;104:535-542)
Proteomics applied to the clinical follow-up of patients after allogeneic hematopoietic stem cell transplantation
Authors: Kaiser Thorsten , Kamal Haytham , Rank Andreas , Kolb Hans-Jochem , Holler Ernst , Ganser Arnold , Hertenstein Bernd , Mischak Harald , Weissinger Eva Maria 
Published: April 2004

Abstract
A phase 1 diagnostic study was performed to evaluate a novel technology for clinical proteom research based on capillary electrophoresis and mass spectrometry. Urine from 40 patients after hematopoietic stem cell transplantation (HSCT; 35 allogeneic, 5 autologous) and 5 patients with sepsis was collected for a period of 100 days and analyzed. More than 1000 different polypeptides could be detected in individual samples. Polypeptide patterns excreted in the urine of patients were significantly different from those of healthy volunteers. No significant differences were detected comparing different conditioning regimens. The aim of this study was to identify polypeptide patterns functioning as early indicators of graft-versus-host disease (GVHD). Eighteen patients developed GVHD after allogeneic HSCT. Sixteen differentially excreted polypeptides formed a pattern of early GVHD markers, allowing discrimination of GVHD from patients without complications with 82% specificity and 100% sensitivity, cross-validated. Inclusion of 13 sepsis-specific polypeptides allowed us to distinguish sepsis from GVHD with a specificity of 97% and a sensitivity of 100%. Sequencing 2 prominent GVHD-indicative polypeptides led to the identification of a peptide from leukotriene A4 hydrolase and a peptide from serum albumin. The data reveal that capillary electrophoresis and mass spectrometry allow identification of biomarkers for a variety of diseases or related complications. (Blood. 2004;104:340-349)
Apoptosis of human primary B lymphocytes is inhibited by N-acetyl-L-cysteine
Authors: Rosati Emanuela , Sabatini Rita , Ayroldi Emira , Tabilio Antonio , Bartoli Andrea , Bruscoli Stefano , Simoncelli Costantino , Rossi Ruggero , Marconi Pierfrancesco 
Published: April 2004

AbstractThiols are important molecules to control apoptosis. This study examined the effect of N-acetyl-L-cysteine (NAC) on in vitro spontaneous apoptosis of human tonsillar B lymphocytes (TBL). Results show that NAC inhibits TBL apoptosis and maintains their survival in vitro. The antiapoptotic action of NAC is progressively reduced when its addition to culture is delayed, is reversible, and is not blocked by cycloheximide. The antiapoptotic activity of NAC is associated with its ability to inhibit caspase-3 and -7 proteolytic processing, DNA-fragmentation factor 45 cleavage, and DNA fragmentation. Furthermore, NAC inhibits BID cleavage and cytochrome c release from mitochondria and increases the expression of Bcl-2 and BclXL survival proteins. However, it has no effect on caspase-9 cleavage and increases that of caspase-8 and poly(adenosine 5′-diphosphate-ribose)polymerase. We conclude that NAC-induced inhibition of TBL apoptosis is associated with inhibition of caspase-3 and -7 processing and is accompanied by changes in several regulatory components of the apoptotic process. These results pose the question of whether microenvironment thiols may in part contribute to in vivo B cell survival.
FcγRIIa expression with FcγRI results in C-reactive protein- and IgG-mediated phagocytosis
Authors: Bodman-Smith Katherine B , Gregory Rachel E , Harrison Patrick T , Raynes John G 
Published: April 2004

AbstractC-reactive protein (CRP) is a pattern-recognition molecule, which can bind to phosphorylcholine and certain phosphorylated carbohydrates found on the surface of a number of microorganisms. CRP has been shown recently to bind human Fc receptor for immunoglobulin G (IgG; FcγR)I and mediate phagocytosis and signaling through the γ-chain. To date, binding of monomeric CRP to FcγRII has been contentious. We demonstrate that erythrocytes opsonized with CRP bind FcγRIIa-transfected COS-7 cells. In addition, we demonstrate that FcγRI can use FcγRIIa R131 and H131 to phagocytose erythrocytes coated with IgG or purified or recombinant CRP in the absence of the γ-chain. COS-7 cells expressing FcγRIIa or FcγRI alone did not phagocytose opsonized erythrocytes. Such phagocytosis required the cytoplasmic domain of FcγRIIa, as mutation of tyrosine at position 205 and truncation of the cytoplasmic domain from the end of the transmembrane region (position 206), resulting in the loss of the immunoreceptor tyrosine activatory motif, abrogated phagocytosis. FcγRIIa R131 was more efficient than FcγRIIa H131 at mediating CRP-dependent phagocytosis.
Membrane receptor-mediated apoptosis and caspase activation in the differentiated EoL-1 eosinophilic cell line
Authors: Al-Rabia Mohammed W , Blaylock Morgan G , Sexton Darren W , Walsh Garry M 
Published: April 2004

AbstractCaspases are key molecules in the control of apoptosis, but relatively little is known about their contribution to eosinophil apoptosis. We examined caspase-3, -8, and -9 activities in receptor ligation-dependent apoptosis induction in the differentiated human eosinophilic cell line EoL-1. Differentiated EoL-1 exhibited bi-lobed nuclei, eosinophil-associated membrane receptors, and basic granule proteins. Annexin-V fluorescein isothiocyanate binding to EoL-1 revealed significant (P&lt;0.01) apoptosis induction in cells cultured for 20 h with monoclonal antibodies (mAb) specific for CD45 (71%±4.3), CD45RA (58%±2.3), CD45RB (68%±2.4), CD95 (47%±2.6), and CD69 (52%±2.1) compared with control (23%±1.6) or CD45RO mAb (27%±3.9). The pan-caspase inhibitor Z-Val-Ala-Asp-fluoromethylketone (fmk) and inhibitors of caspase-8 (Z-Ile-Glu-Thr-Asp-fmk) and caspase-9 (Z-Leu-Glu-His-Asp-fmk) significantly inhibited mAb-induced apoptosis of EoL-1 but had no effect on constitutive (baseline) apoptosis at 16 and 20 h. Caspase activity was analyzed using the novel CaspaTag™ technique and flow cytometry. EoL-1 treated with pan-CD45, CD45RA, CD45RB, and CD95 mAb exhibited caspase-3 and -9 activation at 12 h post-treatment, which increased at 16 and 20 h. Activated caspase-8 was detected 12 and 16 h after ligation with CD45, CD45RA, CD45RB, and CD95 mAb followed by a trend toward basal levels at 20 h. CD69 ligation resulted in caspase-3 activation, a modest but significant activation of caspase-8, and a loss in mitochondrial transmembrane potential but had no significant effect on activation of caspase-9. Thus, the intrinsic and extrinsic caspase pathways are involved in controlling receptor ligation-mediated apoptosis induction in human eosinophils, findings that may aid the development of a more targeted, anti-inflammatory therapy for asthma.
Mechanism of apoptosis induced by S100A8/A9 in colon cancer cell lines: the role of ROS and the effect of metal ions
Authors: Ghavami Saeid , Kerkhoff Claus , Los Marek , Hashemi Mohammad , Sorg Clemens , Karami-Tehrani Fatemeh 
Published: April 2004

AbstractThe protein complex S100A8/A9, abundant in the cytosol of neutrophils, is secreted from the cells upon cellular activation and induces apoptosis in tumor cell lines and normal fibroblasts in a zinc-reversible manner. In the present study, we present evidence that the S100A8/A9 also exerts its apoptotic effect by a zinc-independent mechanism. Treatment of the colon carcinoma cells with different concentrations of human S100A8/A9 or the metal ion chelator diethylenetriaminepentacetic acid (DTPA) resulted in a significant increase of cell death. Annexin V/phosphatidylinositol and Hoechst 33258 staining revealed that cell death was mainly of the apoptotic type. A significant increase in the activity of caspase-3 and -9 was observed in both cell lines after treatment. Caspase-8 activation was negligible in both cell lines. The cytotoxicity/apoptotic effect of human S100A8/A9 and DTPA was inhibited significantly (P&lt;0.05) by Zn+2 and Cu+2, more effectively than by Ca2+ and Mg2+. The antioxidant N-acetyl-L-cysteine inhibited the cytotoxicity/apoptotic effect of S100A8/A9 and DTPA. However, as a result of the different time-courses of both agents and that the S100A8/A9-induced apoptosis was not completely reversed, we conclude that S100A8/A9 exerts its apoptotic effect on two colon carcinoma cell lines through a dual mechanism: one via zinc exclusion from the target cells and the other through a yet-undefined mechanism, probably relaying on the cell-surface receptor(s).
Leishmania major-mediated prevention of programmed cell death induction in infected macrophages is associated with the repression of mitochondrial release of cytochrome c
Authors: Akarid Khadija , Arnoult Damien , Micic-Polianski Juliette , Sif Jamila , Estaquier Jérôme , Ameisen Jean Claude 
Published: April 2004

AbstractLeishmania are obligate, intracellular parasites of macrophages in their vertebrate hosts, including humans, in which they cause disease. Here, we report that in vitro infection with Leishmania major protects murine bone marrow-derived macrophages against programmed cell death (PCD) induced by deprival of macrophage-colony stimulating factor and delays PCD caused by treatment with staurosporine, a broad inducer of PCD. This preventive effect was observed in macrophages from L. major-susceptible BALB/c and L. major-resistant C57BL/6 mice, indicating that repression of PCD did not depend on genetic background-specific regulation of T helper cell type 1 (Th1)/Th2 cytokine secretion. Prevention of effector caspase activation and PCD was associated with a repression of mitochondrial release of cytochrome c and did not involve the nuclear factor-κB pathway. The capacity of L. major to delay PCD induction in the infected macrophages may have implications for Leishmania pathogenesis by favoring the invasion of its host and the persistence of the parasite in the infected cells.
A new role for monoamine oxidases in the modulation of macrophage-inducible nitric oxide synthase gene expression
Authors: Vega Antonio , Chacón Pedro , Monteseirín Javier , El Bekay Rajaa , Álvarez Moisés , Alba Gonzalo , Conde José , Martín-Nieto José , Bedoya Francisco J , Pintado Elizabeth , Sobrino Francisco 
Published: April 2004

AbstractThis report focuses on the modulatory role of endogenous H2O2 on lipopolysaccharide (LPS)/interferon-γ (IFN-γ)-induced inducible nitric oxide synthase (NOS2) gene expression in rat peritoneal macrophages. Exogenously added H2O2 was initially found to inhibit the synthesis of NOS2, which prompted us to assess the effect of the activity of monoamine oxidase (MAO) and semicarbazide-sensitive amine oxidase (SSAO) as H2O2-forming enzymes on NOS2 gene expression. In the presence of their substrates, tyramine for MAO and benzylamine for SSAO, intracellular synthesis of H2O2 took place with concomitant inhibition of LPS/IFN-γ-induced NOS2 protein synthesis, as detected by Western blotting, flow cytometry, and immunofluorescence microscopy analyses. Pargyline and semicarbazide, specific inhibitors of MAO and SSAO, respectively, canceled this negative effect of MAO substrates on NOS2 expression. In the presence of Fe2+ and Cu2+ ions, inhibition of NOS2 expression was enhanced, suggesting the participation in this regulation of species derived from Fenton chemistry. In addition, the negative effect of H2O2, generated by MAOs, was found to be exerted on NOS2 mRNA levels. These data offer a new insight in the control of NOS2 expression through the intracellular levels of H2O2 and other reactive oxygen species (ROS). The hypothesis can be raised that the inhibition of NOS by H2O2 could constitute a protective mechanism against the cytotoxic consequences of the activation of ROS-generating enzymes, thus providing a new, singular role for the MAO family of proteins.