bluuebunny/crossref_metadata_2025_split huggingface dataset:
Regulation of Human FcεRI α-Chain Gene Expression by Multiple Transcription Factors
Authors: Nishiyama Chiharu , Hasegawa Masanari , Nishiyama Makoto , Takahashi Kyoko , Akizawa Yushiro , Yokota Toyokazu , Okumura Ko , Ogawa Hideoki , Ra Chisei 
Published: April 2014

Abstract
Transcriptional regulation of the gene-encoding human FcεRI α-chain was analyzed in detail. EMSA revealed that either YY1 or PU.1 bound to the region close to that recognized by Elf-1. The α-chain promoter activity was up-regulated ∼2-fold by exogenously expressed YY1 or PU.1 and ∼7-fold by GATA-1, respectively, in KU812 cells. In contrast, coexpression of GATA-1 with either of PU.1 or YY1 dramatically activated the promoter ∼41- or ∼27-fold, respectively. Especially synergic activation by GATA-1 and PU.1 was surprising, because these transcription factors are known to inhibit the respective transactivating activities of each other. These up-regulating effects of PU.1 and YY1 with GATA-1 were inhibited by overexpression of Elf-1, indicating that Elf-1 serves as a repressor for the α-chain gene expression. Transcriptional regulation of the α-chain gene through four transcriptional factors is discussed.
Dominant Effects of Mutations in the Collagenous Domain of Mannose-Binding Protein
Authors: Wallis Russell 
Published: April 2014

Abstract
Individuals heterozygous for mutant alleles encoding serum mannose-binding protein (MBP, also known as mannose-binding lectin) show increased susceptibility to infections caused by a wide range of pathogenic microorganisms. To investigate the molecular defects associated with heterozygosity, wild-type rat serum MBP polypeptides (MBP-A: 56% identical in sequence to human MBP) and rat MBP polypeptides containing mutations associated with human immunodeficiency have been coexpressed using a well-characterized mammalian expression system. The resulting proteins are secreted almost exclusively as heterooligomers that are defective in activating the complement cascade. Functional defects are caused by structural changes to the N-terminal collagenous and cysteine-rich domains of MBP, disrupting interactions with associated serine proteases. The dominant effects of the mutations demonstrate how the presence of a single mutant allele gives rise to the molecular defects that lead to the disease phenotype in heterozygous individuals.
Signaling Pathways Involved in IL-8-Dependent Activation of Adhesion Through Mac-1
Authors: Takami Mimi , Terry Valeri , Petruzzelli Lilli 
Published: April 2014

Abstract
In human neutrophils, IL-8 induces chemotaxis, the respiratory burst, and granule release, and enhances cellular adhesion, a β2 integrin-dependent event. IL-8 stimulates neutrophil adhesion to purified fibrinogen in a Mac-1-dependent manner. Mitogen-activated protein kinase (MAPK) activation was detected in human neutrophil lysates after treatment with IL-8 and PMA, but not the activating mAb CBR LFA 1/2. IL-8-stimulated neutrophil adhesion to fibrinogen was blocked 50% by the MAPK/extracellular signal-related kinase-activating enzyme inhibitor PD098059. Adhesion was blocked ∼75% by inhibition of the phosphatidylinositol-3 kinase (PI3K) pathway with LY294002, supporting that activation of both MAPK and PI3K may play a role in IL-8-dependent inside-out signals that activate Mac-1. Activation of MAPK was inhibited in IL-8-stimulated cells in the presence of PI3K inhibitors LY294002 or wortmannin, supporting a model in which PI3K is upstream of MAPK. IL-8-stimulated neutrophil adhesion was inhibited 50% by bisindolylmaleimide-I, implicating protein kinase C (PKC) in the intracellular signaling from the IL-8R to Mac-1. A 74-kDa molecular mass species was detected by an activation-specific Ab to PKC when cells were stimulated with PMA or IL-8, but not a β2-activating Ab. Inhibition of either MAPK or PKC resulted in partial inhibition of IL-8-stimulated polymorphonuclear neutrophil adhesion, and treatment with both inhibitors simultaneously completely abolished IL-8-stimulated adhesion to ligand. Inhibition of PI3K blocked MAPK activation, but not PKC activation, suggesting a branch point that precedes PI3K activation. These data suggest that both MAPK and PKC are activated in response to IL-8 stimulation, and that these may represent independent pathways for β2 integrin activation in neutrophils.
Stat5B Shuttles Between Cytoplasm and Nucleus in a Cytokine-Dependent and -Independent Manner
Authors: Zeng Rong , Aoki Yutaka , Yoshida Minoru , Arai Ken-ichi , Watanabe Sumiko 
Published: April 2014

Abstract
In response to cytokine stimuli, Stats are phosphorylated and translocated to the nucleus to activate target genes. Then, most are dephosphorylated and returned to the cytoplasm. Using Ba/F3 cells, we found that the nuclear export of Stat5B by cytokine depletion was inhibited by leptomycin B (LMB), a specific inhibitor of nuclear export receptor chromosome region maintenance 1. Interestingly, LMB treatment in the absence of cytokine led to the accumulation of Stat5B in the nucleus, suggesting that Stat5B shuttles between the nucleus and the cytoplasm as a monomer without cytokine stimulation. This notion is supported by the observation that LMB-induced accumulation of Stat5B in the nucleus was also observed with Stat5B having a mutated tyrosine 699, which is essential for dimer formation. Using a series of mutant Stat5Bs, we identified a part of the coiled coil domain to be a critical region for monomer nuclear import and a more N-terminal region to be critical for the cytokine stimulation dependent import of Stat5B. Taken together, we propose a model in which Stat5B shuttles between the nucleus and cytoplasm by two different mechanisms, one being a factor-independent constitutive shuttling by monomeric form, and the other, a factor stimulation-dependent one regulated by tyrosine phosphorylation and subsequent dimerization.
Recombinant Carp Parvalbumin, the Major Cross-Reactive Fish Allergen: A Tool for Diagnosis and Therapy of Fish Allergy
Authors: Swoboda Ines , Bugajska-Schretter Agnes , Verdino Petra , Keller Walter , Sperr Wolfgang R. , Valent Peter , Valenta Rudolf , Spitzauer Susanne 
Published: April 2014

Abstract
IgE-mediated reactions to fish allergens represent one of the most frequent causes of food allergy. We have constructed an expression cDNA library from carp (Cyprinus carpio) muscle in phage λgt11 and used serum IgE from a fish allergic patient to isolate 33 cDNA clones that coded for two parvalbumin isoforms (Cyp c 1.01 and Cyp c 1.02) with comparable IgE binding capacities. Both isoforms represented calcium-binding proteins that belonged to the β-lineage of parvalbumins. The Cyp c 1.01 cDNA was overexpressed in Escherichia coli, and rCyp c 1.01 was purified to homogeneity. Circular dichroism analysis and mass spectroscopy showed that rCyp c 1.01 represented a folded protein with mainly α-helical secondary structure and a molecular mass of 11,416 Da, respectively. rCyp c 1.01 reacted with IgE from all fish-allergic patients tested (n = 60), induced specific and dose-dependent basophil histamine release, and contained most of the IgE epitopes (70%) present in natural allergen extracts from cod, tuna, and salmon. Therefore, it may be used to identify patients suffering from IgE-mediated fish allergy. The therapeutic potential of rCyp c 1.01 is indicated by our findings that rabbit Abs raised against rCyp c 1.01 inhibited the binding of IgE (n = 25) in fish-allergic patients to rCyp c 1.01 between 35 and 97% (84% mean inhibition) and that depletion of calcium strongly reduced IgE recognition of rCyp c 1.01. The latter results suggest that it will be possible to develop strategies for immunotherapy for fish allergy that are based on calcium-free hypoallergenic rCyp c 1.01 derivatives.
Identification of the Streptococcal M Protein Binding Site on Membrane Cofactor Protein (CD46)
Authors: Giannakis Eleni , Jokiranta T. Sakari , Ormsby Rebecca J. , Duthy Thomas G. , Male Dean A. , Christiansen Dale , Fischetti Vince A. , Bagley Chris , Loveland Bruce E. , Gordon David L. 
Published: April 2014

Abstract
Adherence of group A streptococcus (GAS) to keratinocytes is mediated by an interaction between human CD46 (membrane cofactor protein) with streptococcal cell surface M protein. CD46 belongs to a family of proteins that contain structurally related short consensus repeat (SCR) domains and regulate the activation of the complement components C3b and/or C4b. CD46 possesses four SCR domains and the aim of this study was to characterize their interaction with M protein. Following confirmation of the M6 protein-dependent interaction between GAS and human keratinocytes, we demonstrated that M6 protein binds soluble recombinant CD46 protein and to a CD46 construct containing only SCRs 3 and 4. M6 protein did not bind to soluble recombinant CD46 chimeric proteins that had the third and/or fourth SCR domains replaced with the corresponding domains from another complement regulator, CD55 (decay-accelerating factor). Homology-based molecular modeling of CD46 SCRs 3 and 4 revealed a cluster of positively charged residues between the interface of these SCR domains similar to the verified M protein binding sites on the plasma complement regulators factor H and C4b-binding protein. The presence of excess M6 protein did not inhibit the cofactor activity of CD46 and the presence of excess C3b did not inhibit the ability of CD46 to bind M6 protein by ELISA. In conclusion, 1) adherence of M6 GAS to keratinocytes is M protein dependent and 2) a major M protein binding site is located within SCRs 3 and 4, probably at the interface of these two domains, at a site distinct from the C3b-binding and cofactor site of CD46.
Dual Role for Nitric Oxide in Paracoccidioidomycosis: Essential for Resistance, but Overproduction Associated with Susceptibility
Authors: Nascimento Flávia R. F. , Calich Vera L. G. , Rodríguez Dunia , Russo Momtchilo 
Published: April 2014

Abstract
Using a murine model of susceptibility and resistance to paracoccidioidomycosis, we have previously demonstrated that immunosuppression occurs in susceptible (B10.A), but not in resistant (A/Sn), mouse strains. Accumulating evidence shows that NO is involved in the induction of T cell immunosuppression during infection as well as in the killing of Paracoccidioides brasiliensis. In the present work, we focused on NO and other macrophage products that could be associated with resistance or susceptibility to paracoccidioidomycosis. A striking difference was related to NO and TNF production. Macrophages from B10.A mice produced high and persistent NO levels, while in A/Sn animals, TNF production predominated. In in vitro cultures, P. brasiliensis-infected macrophages from A/Sn mice also produced large amounts of TNF, while B10.A macrophages only produced NO. TNF production by B10.A macrophages appeared to be suppressed by NO, because the addition of aminoguanidine sulfate, an inducible NO synthase (NOS2) inhibitor, resulted in TNF production. These results suggested that enhanced TNF or NO production is associated with resistance and susceptibility, respectively. However, regardless of the mouse strain, NOS2-deficient or aminoguanidine sulfate-treated mice presented extensive tissue lesions with increased fungal load in lungs and liver compared with their controls. We conclude that NOS2-derived NO is essential for resistance to paracoccidioidomycosis, but overproduction is associated with susceptibility.
Divergence of Apoptosis-Inducing and Preventing Signals in Bacteria-Faced Macrophages Through Myeloid Differentiation Factor 88 and IL-1 Receptor-Associated Kinase Members
Authors: Ruckdeschel Klaus , Mannel Oliver , Schröttner Percy 
Published: April 2014

Abstract
The induction of apoptosis in host cells is a common strategy by which pathogenic bacteria interfere with the host immune response. The Yersinia enterocolitica outer protein P (YopP) inhibits activation of transcription factor NF-κB in macrophages, which suppresses NF-κB-dependent antiapoptotic activities. The simultaneous initiation of proapoptotic signaling by yersiniae infection or LPS treatment results in macrophage apoptosis. In this study, we used YopP as a tool to dissect survival- and death-inducing pathways in bacteria-faced macrophages. We cotransfected J774A.1 macrophages with expression plasmids for YopP and dominant-negative mutants of signal transmitters of the NF-κB cascade downstream from the LPS receptor complex. Dominant-negative myeloid differentiation factor 88 (MyD88) or IL-1R-associated kinase (IRAK) 2 diminished LPS-induced apoptosis in YopP-transfected macrophages, suggesting implication of MyD88 and IRAK2 in signaling cell death. In contrast, dominant-negative IRAK1 and TNFR-associated factor 6 (TRAF6) did not provide protection, but augmented LPS-mediated apoptosis in the absence of YopP, which indicates roles of IRAK1 and TRAF6 in the antiapoptotic signal relay of the NF-κB cascade. The distinct functions of IRAK members in macrophage survival were reflected by opposing effects of dominant-negative IRAK1 and IRAK2 on Y. enterocolitica-mediated apoptosis. Yersiniae- and LPS-dependent cell death were substantially attenuated by a specific caspase-8 inhibitory peptide or by dominant negative Fas-associated death domain protein (FADD). This suggests, that Yersinia-induced apoptosis involves a proapoptotic signal relay through MyD88 and IRAK2, which potentially targets the Fas-associated death domain protein/caspase-8 apoptotic pathway, whereas IRAK1 and TRAF6 counteract the bacteria-induced cytotoxic response by signaling macrophage survival.
Enlargement of Secretory Vesicles by Protein Tyrosine Phosphatase PTP-MEG2 in Rat Basophilic Leukemia Mast Cells and Jurkat T Cells
Authors: Wang Xiaodong , Huynh Huong , Gjörloff-Wingren Anette , Monosov Edvard , Stridsberg Mats , Fukuda Minoru , Mustelin Tomas 
Published: April 2014

Abstract
Stimulus-induced secretion of bioactive polypeptides is a fundamental aspect of the immune system. Secretory proteins are synthesized in the endoplasmic reticulum and are transported through the Golgi apparatus to the trans-Golgi network, where they are sorted into transport vesicles that bud off and fuse into condensing vacuoles, which subsequently undergo an editing and concentration process to become mature secretory vesicles. In this study, we report that the PTP-MEG2 protein tyrosine phosphatase is located on these vesicles in mast cells. Expression of PTP-MEG2 caused a striking enlargement of these vesicles in both rat basophilic leukemia mast cells and Jurkat T leukemia cells into giant vesicles with diameters of up to several micrometers. The fused vesicles did not acquire markers for other compartments and were adjacent to the trans-Golgi network, contained carboxypeptidase E, chromogranin C, and IL-2, and had an electron-dense core typical of secretory vesicles. Expression of PTP-MEG2 also caused a reduction in the secretion of IL-2 from stimulated Jurkat cells. The effects of PTP-MEG2 on secretory vesicles required the catalytic activity of PTP-MEG2 and was rapidly reversed by pervanadate. We propose that PTP-MEG2 represents a novel connection between tyrosine dephosphorylation and the regulation of secretory vesicles in hematopoietic cells.
TNF Regulates Chemokine Induction Essential for Cell Recruitment, Granuloma Formation, and Clearance of Mycobacterial Infection
Authors: Roach Daniel R. , Bean Andrew G. D. , Demangel Caroline , France Malcolm P. , Briscoe Helen , Britton Warwick J. 
Published: April 2014

Abstract
Host immunity to mycobacterial infection is dependent on the activation of T lymphocytes and their recruitment with monocytes to form granulomas. These discrete foci of activated macrophages and lymphocytes provide a microenvironment for containing the infection. The cytokine, TNF, is essential for the formation and maintenance of granulomas, but the mechanisms by which TNF regulates these processes are unclear. We have compared the responses of TNF-deficient (TNF−/−) and wild-type C57BL/6 mice to infection with Mycobacterium smegmatis, a potent inducer of TNF, and virulent Mycobacterium tuberculosis to delineate the TNF-dependent and -independent components of the process. The initial clearance of M. smegmatis was TNF independent, but TNF was required for the early expression of mRNA encoding C-C and C-X-C chemokines and the initial recruitment of CD11b+ macrophages and CD4+ T cells to the liver during the second week of infection. Late chemokine expression and cell recruitment developed in TNF−/− mice associated with enhanced Th1-like T cell responses and mycobacterial clearance, but recruited leukocytes did not form tight granulomas. Infection of TNF−/− mice with M. tuberculosis also resulted in an initial delay in chemokine induction and cellular recruitment to the liver. Subsequently, increased mRNA expression was evident in TNF−/− mice, but the loosely associated lymphocytes and macrophages failed to form granulomas and prevent progressive infection. Therefore, TNF orchestrates early induction of chemokines and initial leukocyte recruitment, but has an additional role in the aggregation of leukocytes into functional granulomas capable of controlling virulent mycobacterial infection.
Rapid IL-4 Production by Leishmania Homolog of Mammalian RACK1-Reactive CD4+ T Cells in Resistant Mice Treated Once with Anti-IL-12 or -IFN-γ Antibodies at the Onset of Infection with Leishmania major Instructs Th2 Cell Development, Resulting in Nonhealing Lesions
Authors: Launois Pascal , Gumy Alain , Himmelrich Hayo , Locksley Richard M. , Röcken Martin , Louis Jacques A. 
Published: April 2014

Abstract
Rapid production of IL-4 by Leishmania homolog of mammalian RACK1 (LACK)-reactive CD4+ T cells expressing the Vβ4-Vα8 TCR chains has been shown to drive aberrant Th2 cell development and susceptibility to Leishmania major in BALB/c mice. In contrast, mice from resistant strains fail to express this early IL-4 response. However, administration of either anti-IL-12 or -IFN-γ at the initiation of infection allows the expression of this early IL-4 response in resistant mice. In this work we show that Leishmania homolog of mammalian RACK1-reactive CD4+ T cells also expressing the Vβ4-Vα8 TCR chains are the source of the early IL-4 response to L. major in resistant mice given anti-IL-12 or -IFN-γ Abs only at the onset of infection. Strikingly, these cells were found to be required for the reversal of the natural resistance of C57BL/6 mice following a single administration of anti-IL-12 or -IFN-γ Abs. Together these results suggest that a deficiency in mechanisms capable of down-regulating the early IL-4 response to L. major contributes to the exquisite susceptibility of BALB/c mice to L. major.
Mycobacterium tuberculosisInduces Differential Cytokine Production from Dendritic Cells and Macrophages with Divergent Effects on Naive T Cell Polarization
Authors: Hickman Somia Perdow , Chan John , Salgame Padmini 
Published: April 2014

AbstractTh1-mediated cellular responses are important for protection in tuberculosis. However, the mechanisms and APC types responsible for initiating Th1 responses are not well understood. These studies show that macrophages and dendritic cells, albeit both being APC, respond differently following Mycobacterium tuberculosis infection and thereby have different consequences for the development of naive T cells. We report that M. tuberculosis-infected dendritic cells bias the polarization of OVA peptide-specific naive transgenic T cells to the Th1 phenotype, and, in contrast, in the presence of infected macrophages naive T cells do not develop a Th1 phenotype. Comparison of the cytokine profile expressed by the infected dendritic cells and macrophages revealed several differences, the most striking being that infected macrophages did not express the Th1-promoting cytokine IL-12. These studies also show that IL-10 is responsible for the failure of IL-12 production by M. tuberculosis-infected macrophages, and that the effects of IL-10 can be overcome by IFN-γ priming. We speculate that the observed difference in response of the two APC types to M. tuberculosis infection may be a reflection of their respective roles in immune initiation and granuloma regulation.
Impaired Th2 Development and Increased Mortality DuringSchistosoma mansoniInfection in the Absence of CD40/CD154 Interaction
Authors: MacDonald Andrew S. , Patton Elisabeth A. , La Flamme Anne C. , Araujo Maria I. , Huxtable Clive R. , Bauman Beverley , Pearce Edward J. 
Published: April 2014

AbstractThe role of CD40/CD154 interaction during infection has primarily focused on pathogens that drive inflammatory Th1 responses. In this study, we show that CD40/CD154 interaction is a fundamental requirement for Th2 response development to the parasitic helminth Schistosoma mansoni. Compared with infected wild-type mice, greatly reduced levels of Th2-associated cytokines were measured both in vitro and in vivo, and no IgE or IgG1 was detected in infected CD154−/− mice. In the absence of an overt Th2 response, no exaggerated Th1 response was mounted by CD154−/− mice. Infected CD154−/− mice suffered severe morbidity and mortality, even though parasitemias in wild-type and CD154−/− mice did not differ significantly. These data indicate that CD40/CD154 interaction is required to allow development of a Th2-dominated immune response to S. mansoni and support the view that failure to develop such a response can have fatal consequences.
Profound Differences in Leukocyte-Endothelial Cell Responses to Lipopolysaccharide Versus Lipoteichoic Acid
Authors: Yipp Bryan G. , Andonegui Graciela , Howlett Christopher J. , Robbins Stephen M. , Hartung Thomas , Ho May , Kubes Paul 
Published: April 2014

AbstractWe have investigated the effects of LPS from Escherichia coli, lipoteichoic acid (LTA), and peptidoglycan (PepG) from Staphylococcus aureus, and live S. aureus on leukocyte-endothelial interactions in vivo using intravital microscopy to visualize muscle microvasculature. Systemic vs local administration of LPS induced very different responses. Local administration of LPS into muscle induced significant leukocyte rolling, adhesion, and emigration in postcapillary venules at the site of injection. LPS given systemically dramatically dropped circulating leukocyte counts and increased neutrophils in the lung. However, the drop in circulating leukocytes was not associated with leukocyte sequestration to the site of injection (peritoneum) nor to peripheral microvessels in muscles. Unlike LPS, various preparations of LTA had no systemic and very minor local effect on leukocyte-endothelial interactions, even at high doses and for prolonged duration. LPS, but not LTA, potently activated human endothelium to recruit leukocytes under flow conditions in vitro. Endothelial adhesion molecule expression was also increased extensively with LPS, but not LTA. Interestingly, systemic administration of live S. aureus induced leukocyte-endothelial cell responses similar to LPS. PepG was able to induce leukocyte-endothelial interactions in muscle and peritoneum, but had no effect systemically (no increase in neutrophils in lungs and no decrease in circulating neutrophil counts). These results demonstrate that: 1) LPS has potent, but divergent local and systemic effects on leukocyte-endothelial interactions; 2) S. aureus can induce a systemic response similar to LPS, but this response is unlikely to be due to LTA, but more likely to be mediated in part by PepG.