bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enforced Expression of Spi-B Reverses T Lineage Commitment and Blocks β-Selection
Authors: Lefebvre Juliette M. , Haks Mariëlle C. , Carleton Michael O. , Rhodes Michele , Sinnathamby Gomathinayagam , Simon M. Celeste , Eisenlohr Laurence C. , Garrett-Sinha Lee Ann , Wiest David L. 
Published: April 2014

AbstractThe molecular changes that restrict multipotent murine thymocytes to the T cell lineage and render them responsive to Ag receptor signals remain poorly understood. In this study, we report our analysis of the role of the Ets transcription factor, Spi-B, in this process. Spi-B expression is acutely induced coincident with T cell lineage commitment at the CD4−CD8−CD44−CD25+ (DN3) stage of thymocyte development and is then down-regulated as thymocytes respond to pre-TCR signals and develop beyond the β-selection checkpoint to the CD4−CD8−CD44−CD25− (DN4) stage. We found that dysregulation of Spi-B expression in DN3 thymocytes resulted in a dose-dependent perturbation of thymocyte development. Indeed, DN3 thymocytes expressing approximately five times the endogenous level of Spi-B were arrested at the β-selection checkpoint, due to impaired induction of Egr proteins, which are important molecular effectors of the β-selection checkpoint. T lineage-committed DN3 thymocytes expressing even higher levels of Spi-B were diverted to the dendritic cell lineage. Thus, we demonstrate that the prescribed modulation of Spi-B expression is important for T lineage commitment and differentiation beyond the β-selection checkpoint; and we provide insight into the mechanism underlying perturbation of development when that expression pattern is disrupted.
Mechanisms of Dimethyl Sulfoxide Augmentation of IL-1β Production
Authors: Xing Liyu , Remick Daniel G. 
Published: April 2014

Abstract
Expression of the inflammatory cytokine IL-1β occurs in various inflammatory diseases, and IL-1β production is regulated at multiple levels. There are conflicting reports about the effects of antioxidants on IL-1β production. In this study, we investigated the regulatory role of the antioxidant DMSO on LPS-stimulated IL-1β gene expression in human PBMC and in vivo. This study demonstrated that 1% DMSO increased LPS-stimulated (50 ng/ml) IL-1β secretion in a dose- and time-dependent manner without altering TNF or IL-6. DMSO also elevated IL-1β secretion by PBMC in response to exogenous superoxide anions. Despite the increase in IL-1β, there was no augmentation of NF-κB with the addition of DMSO. The steady state mRNA coding for IL-1β following LPS stimulation was also increased. Cycloheximide studies demonstrated that the DMSO augmentation of IL-1β mRNA did not require de novo protein synthesis, and studies with actinomycin D showed that DMSO did not alter the half-life of IL-1β mRNA, suggesting that DMSO did not change the stability of IL-1β mRNA. Experiments using a reporter vector containing the 5′-flanking region of the human IL-1β gene revealed that DMSO augmented LPS-induced IL-1β reporter activity. In vivo, treatment of mice with DMSO significantly increased plasma levels of IL-1β after endotoxin challenge. These data indicate that DMSO directly increases LPS-stimulated IL-1β protein production through the mechanisms of augmenting promoter activity and increasing mRNA levels.
IFN-γ-Stimulated Transcriptional Activation by IFN-γ-Activated Transcriptional Element-Binding Factor 1 Occurs via an Inducible Interaction with CAAAT/Enhancer-Binding Protein-β
Authors: Meng Qingjun , Raha Abhijit , Roy Sanjit , Hu Junbo , Kalvakolanu Dhananjaya V. 
Published: April 2014

Abstract
IFN-γ-activated transcriptional element (GATE)-binding factor 1 (GBF1) was identified as a transactivator that induces gene expression through GATE, a novel IFN-inducible element. Although it can induce gene expression, it is an extremely weak DNA-binding protein on its own. GATE also binds another transcription factor, C/EBP-β. Therefore, we explored whether GBF1 physically interacts with C/EBP-β to induce IFN-γ-regulated transcription. In response to IFN-γ, C/EBP-β undergoes phosphorylation at a critical ERK1/2 phosphorylation motif. Mutational inactivation of this motif and/or interference with the ERK1/2 activation prevented the IFN-γ-induced interactions between GBF1 and C/EBP-β. A 37-aa long peptide derived from the GBF1 protein can associate with C/EBP-β in an IFN-inducible manner. These results identify a converging point for two transactivators that exert their effects through a single response element. Together, our studies identify a novel regulatory mechanism that controls IFN-induced transcription.
Electroporation as a “Prime/Boost” Strategy for Naked DNA Vaccination against a Tumor Antigen
Authors: Buchan Sarah , Grønevik Eirik , Mathiesen Iacob , King Catherine A. , Stevenson Freda K. , Rice Jason 
Published: April 2014

AbstractWe have developed novel DNA fusion vaccines encoding tumor Ags fused to pathogen-derived sequences. This strategy activates linked T cell help and, using fragment C of tetnus toxin, amplification of anti-tumor Ab, CD4+, and CD8+ T cell responses is achievable in mice. However, there is concern that simple DNA vaccine injection may produce inadequate responses in larger humans. To overcome this, we tested electroporation as a method to increase the transfection efficiency and immune responses by these tumor vaccines in vivo in mice. Using a DNA vaccine expressing the CTL epitope AH1 from colon carcinoma CT26, we confirmed that effective priming and tumor protection in mice are highly dependent on vaccine dose and volume. However, suboptimal vaccination was rendered effective by electroporation, priming higher levels of AH1-specific CD8+ T cells able to protect mice from tumor growth. Electroporation during priming with our optimal vaccination protocol did not improve CD8+ T cell responses. In contrast, electroporation during boosting strikingly improved vaccine performance. The prime/boost strategy was also effective if electroporation was used at both priming and boosting. For Ab induction, DNA vaccination is generally less effective than protein. However, prime/boost with naked DNA followed by electroporation dramatically increased Ab levels. Thus, the priming qualities of DNA fusion vaccines, integrated with the improved Ag expression offered by electroporation, can be combined in a novel homologous prime/boost approach, to generate superior antitumor immune responses. Therefore, boosting may not require viral vectors, but simply a physical change in delivery, facilitating application to the cancer clinic.
Binding of the Complement Inhibitor C4bp to Serogroup BNeisseria meningitidis
Authors: Jarva Hanna , Ram Sanjay , Vogel Ulrich , Blom Anna M. , Meri Seppo 
Published: April 2014

AbstractNeisseria meningitidis (meningococcus) is an important cause of meningitis and sepsis. Currently, there is no effective vaccine against serogroup B meningococcal infection. Host defense against neisseriae requires the complement system (C) as indicated by the fact that individuals deficient in properdin or late C components (C6-9) have an increased susceptibility to recurrent neisserial infections. Because the classical pathway (CP) is required to initiate efficient complement activation on neisseriae, meningococci should be able to evade it to cause disease. To test this hypothesis, we studied the interactions of meningococci with the major CP inhibitor C4b-binding protein (C4bp). We tested C4bp binding to wild-type group B meningococcus strain (H44/76) and to 11 isogenic mutants thereof that differed in capsule expression, lipo-oligosaccharide sialylation, and/or expression of either porin (Por) A or PorB3. All strains expressing PorA bound radiolabeled C4bp, whereas the strains lacking PorA bound significantly less C4bp. Increased binding was observed under hypotonic conditions. Deleting PorB3 did not influence C4bp binding, but the presence of polysialic acid capsule reduced C4bp binding by 50%. Bound C4bp remained functionally active in that it promoted the inactivation of C4b by factor I. PorA-expressing strains were also more resistant to C lysis than PorA-negative strains in a serum bactericidal assay. Binding of C4bp thus helps Neisseria meningitidis to escape CP complement activation.
Exchanging ESAT6 with TB10.4 in an Ag85B Fusion Molecule-Based Tuberculosis Subunit Vaccine: Efficient Protection and ESAT6-Based Sensitive Monitoring of Vaccine Efficacy
Authors: Dietrich Jes , Aagaard Claus , Leah Robert , Olsen Anja W. , Stryhn Anette , Doherty T. Mark , Andersen Peter 
Published: April 2014

Abstract
Previously we have shown that Ag85B-ESAT-6 is a highly efficient vaccine against tuberculosis. However, because the ESAT-6 Ag is also an extremely valuable diagnostic reagent, finding a vaccine as effective as Ag85B-ESAT-6 that does not contain ESAT-6 is a high priority. Recently, we identified a novel protein expressed by Mycobacterium tuberculosis designated TB10.4. In most infected humans, TB10.4 is strongly recognized, raising interest in TB10.4 as a potential vaccine candidate and substitute for ESAT-6. We have now examined the vaccine potential of this protein and found that vaccination with TB10.4 induced a significant protection against tuberculosis. Fusing Ag85B to TB10.4 produced an even more effective vaccine, which induced protection against tuberculosis comparable to bacillus Calmette-Guérin vaccination and superior to the individual Ag components. Thus, Ag85B-TB10 represents a new promising vaccine candidate against tuberculosis. Furthermore, having now exchanged ESAT-6 for TB10.4, we show that ESAT-6, apart from being an excellent diagnostic reagent, can also be used as a reagent for monitoring vaccine efficacy. This may open a new way for monitoring vaccine efficacy in clinical trials.
Cyclic AMP Response Element-Binding Protein Positively Regulates Production of IFN-γ by T Cells in Response to a Microbial Pathogen
Authors: Samten Buka , Howard Susan T. , Weis Steven E. , Wu Shiping , Shams Homayoun , Townsend James C. , Safi Hassan , Barnes Peter F. 
Published: April 2014

AbstractIFN-γ is essential for resistance to many intracellular pathogens, including Mycobacterium tuberculosis. Transcription of the IFN-γ gene in activated T cells is controlled by the proximal promoter element (−73 to −48 bp). CREB binds to the IFN-γ proximal promoter, and binding is enhanced by phosphorylation of CREB. Studies in human T cell lines and in transgenic mice have yielded conflicting results about whether CREB is a positive or a negative regulator of IFN-γ transcription. To determine the role of CREB in mediating IFN-γ production in response to a microbial pathogen, we evaluated the peripheral blood T cell response to M. tuberculosis in healthy tuberculin reactors. EMSAs, chromatin immunoprecipitation, and Western blotting demonstrated that stimulation of PBMC with M. tuberculosis induced phosphorylation and enhanced binding of CREB to the IFN-γ proximal promoter. Neutralization of CREB with intracellular Abs or down-regulation of CREB levels with small interfering RNA decreased M. tuberculosis-induced production of IFN-γ and IFN-γ mRNA expression. In addition, M. tuberculosis-stimulated T cells from tuberculosis patients, who have ineffective immunity, showed diminished IFN-γ production, reduced amounts of CREB binding to the IFN-γ proximal promoter, and absence of phosphorylated CREB. These findings demonstrate that CREB positively regulates IFN-γ production by human T cells that respond to M. tuberculosis.
Estradiol Is Required for a Proper Immune Response to Bacterial and Viral Pathogens in the Female Brain
Authors: Soucy Geneviève , Boivin Guy , Labrie Fernand , Rivest Serge 
Published: April 2014

Abstract
Although the neuroprotective effects of estrogens are well recognized, the exact mechanisms involved in the ability of these sex steroids to protect the cerebral tissue still remain unclear. We tested in our study the hypothesis that estradiol (E2) modulates the innate immune response and expression of genes encoding proteins that a provide survival signal to neurons during infection. Mice received a single systemic or cerebral injection of LPS to trigger a robust but transient inflammatory reaction in the brain. The endotoxin increased transcriptional activation of genes encoding TLR2, TNF-α, and IL-12 in microglial cells. Expression of these transcripts was largely inhibited in the brain of ovariectomized mice at time 24 h postchallenge. E2 replacement therapy totally rescued the ability of the endotoxin to trigger microglial cells and these permissive effects of E2 are mediated via the estrogen receptor (ER)α. Indeed, ERα-deficient mice exhibited an inappropriate reaction to LPS when compared with ERβ-deficient and wild-type mice. This defective innate immune response was also associated with a widespread viral replication and neurodegeneration in ovariectomized mice inoculated intranasally with HSV-2. These data provide evidence that interaction of E2 with their nuclear ERα plays a critical role in the control of cytokines involved in the transfer from the innate to adaptive immunity. This transfer is deviant in mice lacking E2, which allows pathogens to hide from immune surveillance and exacerbates neuronal damages during viral encephalitis.
Neutrophil-Derived Heparin-Binding Protein (HBP/CAP37) Deposited on Endothelium Enhances Monocyte Arrest under Flow Conditions
Authors: Soehnlein Oliver , Xie Xun , Ulbrich Holger , Kenne Ellinor , Rotzius Pierre , Flodgaard Hans , Eriksson Einar E. , Lindbom Lennart 
Published: April 2014

AbstractIn acute inflammation, infiltration of neutrophils often precedes a second phase of monocyte invasion, and data in the literature suggest that neutrophils may directly stimulate mobilization of monocytes via neutrophil granule proteins. In this study, we present a role for neutrophil-derived heparin-binding protein (HBP) in monocyte arrest on endothelium. Adhesion of neutrophils to bovine aorta endothelial cells (ECs) or HUVEC-triggered secretion of HBP and binding of the protein to the EC surface. Blockade of neutrophil adhesion by treatment with a mAb to CD18 greatly reduced accumulation of HBP. In a flow chamber model, immobilized recombinant HBP induced arrest of human monocytes or monocytic Mono Mac 6 (MM6) cells to activated EC or plates coated with recombinant adhesion molecules (E-selectin, P-selectin, VCAM-1). However, immobilized recombinant HBP did not influence arrest of neutrophils or lymphocytes. Treatment of MM6 cells with recombinant HBP evoked a rapid and clear-cut increase in cytosolic free Ca2+ that was found to be critical for the HBP-induced monocyte arrest inasmuch as pretreatment with the intracellular calcium chelating agent BAPTA-AM abolished the evoked increase in adhesion. Thus, secretion of a neutrophil granule protein, accumulating on the EC surface and promoting arrest of monocytes, could contribute to the recruitment of monocytes at inflammatory loci.
Junctional Adhesion Molecule-C Regulates the Early Influx of Leukocytes into Tissues during Inflammation
Authors: Aurrand-Lions Michel , Lamagna Chrystelle , Dangerfield John P. , Wang Shijun , Herrera Pedro , Nourshargh Sussan , Imhof Beat A. 
Published: April 2014

AbstractLeukocyte recruitment from blood to inflammatory sites occurs in a multistep process that involves discrete molecular interactions between circulating and endothelial cells. Junctional adhesion molecule (JAM)-C is expressed at different levels on endothelial cells of lymphoid organs and peripheral tissues and has been proposed to regulate neutrophil migration by its interaction with the leukocyte integrin Mac-1. In the present study, we show that the accumulation of leukocytes in alveoli during acute pulmonary inflammation in mice is partially blocked using neutralizing Abs against JAM-C. To confirm the function of JAM-C in regulating leukocyte migration in vivo, we then generated a strain of transgenic mice overexpressing JAM-C under the control of the endothelial specific promotor Tie2. The transgenic animals accumulate more leukocytes to inflammatory sites compared with littermate control mice. Intravital microscopy shows that this is the result of increased leukocyte adhesion and transmigration, whereas rolling of leukocytes is not significantly affected in transgenic mice compared with littermates. Thus, JAM-C participates in the later steps of the leukoendothelial adhesion cascade.
Questioning Current Concepts in Acute Pancreatitis: Endotoxin Contamination of Porcine Pancreatic Elastase Is Responsible for Experimental Pancreatitis-Associated Distant Organ Failure
Authors: Geisler Fabian , Algül Hana , Riemann Marc , Schmid Roland M. 
Published: April 2014

AbstractThe systemic inflammatory response syndrome is responsible for pancreatitis-associated mortality. Recent in vitro and in vivo studies have suggested that pancreatic elastase is one missing link between the localized inflammatory process in the pancreas and distant organ dysfunction and failure. It has been shown that pancreatic elastase activates transcription factors, including NF-κB, and induces TNF-α secretion in myeloid cells via TLRs. In this study we demonstrate that a highly purified low endotoxin pancreatic elastase preparation (El-UP) failed both to activate NF-κB and to induce TNF-α release in RAW 264.7 cells and bone marrow-derived macrophages. In contrast, a less purified elastase preparation (El-IV) caused activation of NF-κB and was able to induce TNF-α release at very low concentrations. These effects were sensitive to pretreatment of the cells with polymyxin B and were resistant to heat inactivation. Endotoxin activity as determined by the Limulus amebocyte lysate assay was &gt;3 orders of magnitude lower in the low endotoxin elastase preparation (El-UP) compared with less purified elastase preparations (El-IV). In contrast to contaminated elastase or LPS, elastase free of contamination (El-UP) failed to induce elevated serum TNF-α levels or pulmonary neutrophil infiltration after i.p. application in mice and did not induce lethality when coinjected with d-galactosamine. Failure of low endotoxin elastase (El-UP) to induce proinflammatory effects in vivo and in vitro was not due to functional inactivity of the elastase preparation, as determined by elastase activity assay. These results question current concepts of direct proinflammatory effects attributed to pancreatic elastase.
Human Lymphoid and Myeloid Cell Development in NOD/LtSz-scid IL2Rγnull Mice Engrafted with Mobilized Human Hemopoietic Stem Cells
Authors: Shultz Leonard D. , Lyons Bonnie L. , Burzenski Lisa M. , Gott Bruce , Chen Xiaohua , Chaleff Stanley , Kotb Malak , Gillies Stephen D. , King Marie , Mangada Julie , Greiner Dale L. , Handgretinger Rupert 
Published: April 2014

Abstract
Ethical considerations constrain the in vivo study of human hemopoietic stem cells (HSC). To overcome this limitation, small animal models of human HSC engraftment have been used. We report the development and characterization of a new genetic stock of IL-2R common γ-chain deficient NOD/LtSz-scid (NOD-scid IL2Rγnull) mice and document their ability to support human mobilized blood HSC engraftment and multilineage differentiation. NOD-scid IL2Rγnull mice are deficient in mature lymphocytes and NK cells, survive beyond 16 mo of age, and even after sublethal irradiation resist lymphoma development. Engraftment of NOD-scid IL2Rγnull mice with human HSC generate 6-fold higher percentages of human CD45+ cells in host bone marrow than with similarly treated NOD-scid mice. These human cells include B cells, NK cells, myeloid cells, plasmacytoid dendritic cells, and HSC. Spleens from engrafted NOD-scid IL2Rγnull mice contain human Ig+ B cells and lower numbers of human CD3+ T cells. Coadministration of human Fc-IL7 fusion protein results in high percentages of human CD4+CD8+ thymocytes as well human CD4+CD8− and CD4−CD8+ peripheral blood and splenic T cells. De novo human T cell development in NOD-scid IL2Rγnull mice was validated by 1) high levels of TCR excision circles, 2) complex TCRβ repertoire diversity, and 3) proliferative responses to PHA and streptococcal superantigen, streptococcal pyrogenic exotoxin. Thus, NOD-scid IL2Rγnull mice engrafted with human mobilized blood stem cells provide a new in vivo long-lived model of robust multilineage human HSC engraftment.
Activation of Discoidin Domain Receptor 1 on CD14-Positive Bronchoalveolar Lavage Fluid Cells Induces Chemokine Production in Idiopathic Pulmonary Fibrosis
Authors: Matsuyama Wataru , Watanabe Masaki , Shirahama Yuko , Oonakahara Ken-ichi , Higashimoto Ikkou , Yoshimura Teizo , Osame Mitsuhiro , Arimura Kimiyoshi 
Published: April 2014

AbstractDiscoidin domain receptor 1 (DDR1) is a receptor tyrosine kinase activated by collagen. We previously reported the functional expression of DDR1 on human monocyte-derived macrophages in vitro; however, information regarding its role in diseases is limited. Idiopathic pulmonary fibrosis (IPF) is a chronic lung disease, and the lesions contain an abundance of collagen. In this study, we examined DDR1 expression on bronchoalveolar lavage fluid (BALF) cells and investigated its functionality using samples obtained from 28 IPF patients, 13 chronic obstructive pulmonary disease patients, and 14 healthy volunteers. The DDR1 expression level in CD14-positive BALF cells was higher in IPF patients than in chronic obstructive pulmonary disease patients or healthy volunteers. The predominant isoform was DDR1b in the IPF group, while DDR1a was predominant in the other two groups. Using immunohistochemical analysis, we also detected DDR1 expression on infiltrating inflammatory cells in the IPF lesion. In IPF patients, DDR1 activation induced the production of MCP-1, IL-8, MIP-1 α, and matrix metalloproteinase-9 (MMP-9) from CD14-positive BALF cells in a p38 MAPK-dependent manner. In contrast, DDR1 activation of CD14-positive BALF cells in the other groups did not induce the production of these chemokines or MMP-9. These chemokines and MMP-9 contribute to the development of IPF and, therefore, we suggest that DDR1 might be associated with the pathogenesis of IPF in the tissue microenvironment.
Absence of Recipient CCR5 Promotes Early and Increased Allospecific Antibody Responses to Cardiac Allografts
Authors: Amano Hiroyuki , Bickerstaff Alice , Orosz Charles G. , Novick Andrew C. , Toma Hiroshi , Fairchild Robert L. 
Published: April 2014

AbstractAcute rejection is mediated by T cell infiltration of allografts, but mechanisms mediating the delayed rejection of allografts in chemokine receptor-deficient recipients remain unclear. The rejection of vascularized, MHC-mismatched cardiac allografts by CCR5−/− recipients was investigated. Heart grafts from A/J (H-2a) donors were rejected by wild-type C57BL/6 (H-2b) recipients on day 8–10 posttransplant vs day 8–11 by CCR5−/− recipients. When compared with grafts from wild-type recipients, however, significant decreases in CD4+ and CD8+ T cells and macrophages were observed in rejecting allografts from CCR5-deficient recipients. These decreases were accompanied by significantly lower numbers of alloreactive T cells developing to IFN-γ-, but not IL-4-producing cells in the CCR5−/− recipients, suggesting suboptimal priming of T cells in the knockout recipients. CCR5 was more prominently expressed on activated CD4+ than CD8+ T cells in the spleens of allograft wild-type recipients and on CD4+ T cells infiltrating the cardiac allografts. Rejecting cardiac allografts from wild-type recipients had low level deposition of C3d that was restricted to the graft vessels. Rejecting allografts from CCR5−/− recipients had intense C3d deposition in the vessels as well as on capillaries throughout the graft parenchyma similar to that observed during rejection in donor-sensitized recipients. Titers of donor-reactive Abs in the serum of CCR5−/− recipients were almost 20-fold higher than those induced in wild-type recipients, and the high titers appeared as early as day 6 posttransplant. These results suggest dysregulation of alloreactive Ab responses and Ab-mediated cardiac allograft rejection in the absence of recipient CCR5.