bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cyclic Adenosine 5′-Monophosphate Response Element Modulator Is Responsible for the Decreased Expression of c-fos and Activator Protein-1 Binding in T Cells from Patients with Systemic Lupus Erythematosus
Authors: Kyttaris Vasileios C. , Juang Yuang-Taung , Tenbrock Klaus , Weinstein Arthur , Tsokos George C. 
Published: April 2014

Abstract
T cells from patients with systemic lupus erythematosus express increased levels of the cAMP response element modulator (CREM) that has been shown to bind to the IL-2 promoter and suppress its activity. In this study, we demonstrate that CREM binds to the proximal promoter of the c-fos proto-oncogene in live systemic lupus erythematosus T cells and represses its expression following stimulation in vitro. Decreased levels of c-fos protein result in decreased AP-1 activity, as determined in shift assays. Blockade of the translation of CREM mRNA with an antisense CREM vector increases the expression of c-fos and the AP-1 activity. The levels of c-fos mRNA vary with disease activity. We conclude that CREM represses the expression of c-fos and limits the activity of the enhancer AP-1. Thus, CREM is involved indirectly in the modulation of transcriptional regulation of multiple genes including IL-2.
Cutting Edge: Direct Interaction of TLR4 with NAD(P)H Oxidase 4 Isozyme Is Essential for Lipopolysaccharide-Induced Production of Reactive Oxygen Species and Activation of NF-κB
Authors: Park Hye Sun , Jung Hye Young , Park Eun Young , Kim Jaesang , Lee Won Jae , Bae Yun Soo 
Published: April 2014

AbstractLPS, the primary constituent of the outer membrane of Gram-negative bacteria, is recognized by TLR4. Binding of TLR4 to LPS triggers various cell signaling pathways including NF-κB activation and reactive oxygen species (ROS) production. In this study, we present the data that LPS-induced ROS generation and NF-κB activation are mediated by a direct interaction of TLR4 with (NAD(P)H oxidase 4 (Nox) 4), a protein related to gp91phox (Nox2) of phagocytic cells, in HEK293T cells. Yeast two hybrid and GST pull-down assays indicated that the COOH-terminal region of Nox4 interacted with the cytoplasmic tail of TLR4. Knockdown of Nox4 by transfection of small interference RNA specific to the Nox4 isozyme in HEK293T cells expressing TLR4 along with MD2 and CD14 resulted in inhibition of LPS-induced ROS generation and NF-κB activation. Taken together, these results indicate that direct interaction of TLR4 with Nox4 is involved in LPS-mediated ROS generation and NF-κB activation.
Adoptive Transfer of Paternal Antigen-Hyporesponsive T Cells Induces Maternal Tolerance to the Allogeneic Fetus in Abortion-Prone Matings
Authors: Jin Li-Ping , Li Da-Jin , Zhang Jin-Ping , Wang Ming-Yan , Zhu Xiao-Yong , Zhu Ying , Meng Yi , Yuan Min-Min 
Published: April 2014

AbstractThe embryo expresses paternal Ags foreign to the mother and therefore has been viewed as an allograft. It has been shown that anergic T cells generated by blocking of the CD28/B7 costimulatory pathway with anti B7-1 and anti B7-2 mAbs can be transferred as suppresser cells to prevent allograft rejection. Little is known, however, about the in vivo function of anti-B7-treated T cells after their transfer into abortion-prone mice in the maintenance of materno-fetal tolerance. In the present study, abortion-prone CBA/J females mated with DBA/2 males were administered anti-B7-1 and anti-B7-2 mAbs on day 4 of gestation (murine implantation window). The anti-B7-treated T cells subsequently were adoptively transferred into abortion-prone CBA/J mice. We demonstrated that costimulation blockade with anti-B7 mAbs at the time of implantation resulted in altered allogeneic T cell response and overcame increased maternal rejection to the fetus in the CBA/J×DBA/2 system. The transferred anti-B7-treated T cells appeared to be regulatory, decreasing responsiveness and generating clonal deviation in maternal recipient T cells. The transferred CFSE-labeled T cells were found to reside in the spleen and uterine draining lymph nodes, and a few were localized to the materno-fetal interface of the maternal recipient. Our findings suggest that the anti-B7-treated T cells not only function as potent suppresser cells, but also exert an immunoregulatory effect on the maternal recipient T cells, which cosuppresses maternal rejection to the fetus. This procedure might be considered potentially useful for fetal survival when used as an immunotherapy for human recurrent spontaneous abortion.
Fas-Fas Ligand Interactions Are Essential for the Binding to and Killing of Activated Macrophages by γδ T Cells
Authors: Dalton Jane E. , Howell Gareth , Pearson Jayne , Scott Phillip , Carding Simon R. 
Published: April 2014

Abstract
γδ T cells have a direct role in resolving the host immune response to infection by eliminating populations of activated macrophages. Macrophage reactivity resides within the Vγ1/Vδ6.3 subset of γδ T cells, which have the ability to kill activated macrophages following infection with Listeria monocytogenes (Lm). However, it is not known how γδ T cell macrophage cytocidal activity is regulated, or what effector mechanisms γδ T cells use to kill activated macrophages. Using a macrophage-T cell coculture system in which peritoneal macrophages from naive or Lm-infected TCRδ−/− mice were incubated with splenocytes from wild-type and Fas ligand (FasL)-deficient mice (gld), the ability of Vγ1 T cells to bind macrophages was shown to be dependent upon Fas-FasL interactions. Combinations of anti-TCR and FasL Abs completely abolished binding to and killing of activated macrophages by Vγ1 T cells. In addition, confocal microscopy showed that Fas and the TCR colocalized on Vγ1 T cells at points of contact with macrophages. Collectively, these studies identify an accessory or coreceptor-like function for Fas-FasL that is essential for the interaction of Vγ1 T cells with activated macrophages and their elimination during the resolution stage of pathogen-induced immune responses.
CD59a Is the Primary Regulator of Membrane Attack Complex Assembly in the Mouse
Authors: Baalasubramanian Sivasankar , Harris Claire L. , Donev Rossen M. , Mizuno Masashi , Omidvar Nader , Song Wen-Chao , Morgan B. Paul 
Published: April 2014

Abstract
Gene-deleted mice have provided a potent tool in efforts to understand the roles of complement and complement-regulating proteins in vivo. In particular, mice deficient in the membrane regulators complement receptor 1-related gene/protein y, decay-accelerating factor, or CD59 have demonstrated homeostatic relevance and backcrossing between the strains has revealed cooperativity in regulation. In mouse, genes encoding decay-accelerating factor and CD59 have been duplicated and show differential expression in tissues, complicating interpretation and extrapolation of findings to man. The first described form of CD59, CD59a, is broadly distributed and deletion of the cd59a gene causes a mild hemolytic phenotype with increased susceptibility in complement-mediated disease models. The distribution of the second form, CD59b, was originally described as testis specific, but later by some as widespread. Deletion of the cd59b gene caused a severe hemolytic and thrombotic phenotype. To apply data from these mouse models to man it is essential to know the relative distribution and functional roles of these two forms of CD59. We have generated new specific reagents and used them in sensitive quantitative analyses to comprehensively characterize expression of mRNA and protein and functional roles of CD59a and CD59b in wild-type (wt) and CD59a-negative mice. cd59b mRNA was detected only in testis and, at very low levels, in bone marrow. CD59b protein was present on mature spermatozoa and precursors and, in trace amounts, erythrocytes. Erythrocyte CD59b did not inhibit complement lysis except when CD59a was absent or blocked. These data confirm that CD59a is the primary regulator of complement membrane attack in mouse.
Differential Requirement for Tapasin in the Presentation of Leader- and Insulin-Derived Peptide Antigens to Qa-1b-Restricted CTLs
Authors: Li LiQi , Sullivan Barbara A. , Aldrich Carla J. , Soloski Mark J. , Forman James , Grandea Andres G. , Jensen Peter E. , Van Kaer Luc 
Published: April 2014

Abstract
The loading of MHC class I molecules with peptides involves a variety of accessory proteins, including TAP-associated glycoprotein (tapasin), which tethers empty MHC class I molecules to the TAP peptide transporter. We have evaluated the role of tapasin for the assembly of peptides with the class Ib molecule Qa-1b. In normal cells, Qa-1b is predominantly bound by a peptide, the Qa-1 determinant modifier (Qdm), derived from the signal sequence of class Ia molecules. Our results show that tapasin links Qa-1b to the TAP peptide transporter, and that tapasin facilitates the delivery of Qa-1b molecules to the cell surface. Tapasin was also required for the presentation of endogenous Qdm peptides to Qdm-specific, Qa-1b-restricted CTLs. In sharp contrast, tapasin expression was dispensable for the presentation of an insulin peptide to insulin-specific, Qa-1b-restricted CTL isolated from TCR transgenic mice. However, tapasin deficiency significantly impaired the positive selection of these insulin-specific, Qa-1b-restricted transgenic CD8+ T cells. These findings reveal that tapasin plays a differential role in the loading of Qdm and insulin peptides onto Qa-1b molecules, and that tapasin is dispensable for retention of empty Qa-1b molecules in the endoplasmic reticulum, and are consistent with the proposed peptide-editing function of tapasin.
Expansion and Function of CD8+ T Cells Expressing Ly49 Inhibitory Receptors Specific for MHC Class I Molecules
Authors: Anfossi Nicolas , Robbins Scott H. , Ugolini Sophie , Georgel Philippe , Hoebe Kasper , Bouneaud Cécile , Ronet Catherine , Kaser Arthur , DiCioccio Catherine B. , Tomasello Elena , Blumberg Richard S. , Beutler Bruce , Reiner Steven L. , Alexopoulou Lena , Lantz Olivier , Raulet David H. , Brossay Laurent , Vivier Eric 
Published: April 2014

AbstractMHC class I-specific Ly49 inhibitory receptors regulate NK cell activation, thereby preventing autologous damage to normal cells. Ly49 receptors are also expressed on a subset of CD8+ T cells whose origin and function remain unknown. We report here that, despite their phenotypic and cytolytic similarities, Ly49+CD8+ T cells and conventional Ly49−CD44high memory-phenotype CD8+ T cells present strikingly distinct features. First, under steady state conditions Ly49+CD8+ T cells are poor cytokine producers (TNF-α and IFN-γ) upon TCR triggering. Second, Ly49+CD8+ T cells are not induced upon various settings of Ag immunization or microbial challenge. However, Ly49 can be induced on a fraction of self-specific CD8+ T cells if CD4+ T cells are present. Finally, the size of the Ly49+CD8+ T cell subset is selectively reduced in the absence of STAT1. These results indicate that Ly49 expression is associated with a differentiation program of cytolytic CD8+ T cells triggered upon chronic antigenic exposure. They further suggest that the size of the Ly49+CD8+ T cell subset marks a history of CD8+ T cell activation that might preferentially result from endogenous inducers of inflammation rather than from microbial infections.
Enhanced Responses of Glycosylphosphatidylinositol Anchor-Deficient T Lymphocytes
Authors: Hazenbos Wouter L. W. , Murakami Yoshiko , Nishimura Jun-ichi , Takeda Junji , Kinoshita Taroh 
Published: April 2014

AbstractThe functions of GPI-anchored proteins in T lymphocyte activation have been controversial. This issue was addressed by studying the responses of T lymphocytes from T lymphocyte-specific GPI anchor-deficient mice to different stimuli that normally allow coligation of TCR and GPI-anchored proteins. Stimulation of GPI anchor-deficient T lymphocytes with ConA induced 2-fold higher proliferative responses than did normal cells. In response to allogeneic stimulation, proliferation of GPI anchor-deficient T lymphocytes was enhanced 2- to 3-fold. The response to ConA of a GPI anchor-deficient anti-OVA T lymphocyte clone generated from these mice was ∼3-fold higher than that of cells from the same clone in which GPI anchor expression was restored by retroviral transduction. The response of the GPI anchor-deficient cloned anti-OVA T lymphocytes to antigenic stimulation was similar to that of the retrovirally restored cells. These results indicate that coligation with GPI-anchored proteins counteracts the response to TCR stimulation by ConA or alloantigen but not protein Ag.
HIV-1 Tat Protein Modulates the Generation of Cytotoxic T Cell Epitopes by Modifying Proteasome Composition and Enzymatic Activity
Authors: Gavioli Riccardo , Gallerani Eleonora , Fortini Cinzia , Fabris Marina , Bottoni Arianna , Canella Alessandro , Bonaccorsi Angela , Marastoni Mauro , Micheletti Fabiola , Cafaro Aurelio , Rimessi Paola , Caputo Antonella , Ensoli Barbara 
Published: April 2014

Abstract
Tat, the trans activation protein of HIV, is produced early upon infection to promote and expand HIV replication and transmission. However, Tat appears to also have effects on target cells, which may affect Ag recognition both during infection and after vaccination. In particular, Tat targets dendritic cells and induces their maturation and Ag-presenting functions, increasing Th1 T cell responses. We show in this work that Tat modifies the catalytic subunit composition of immunoproteasomes in B and T cells either expressing Tat or treated with exogenous biological active Tat protein. In particular, Tat up-regulates latent membrane protein 7 and multicatalytic endopeptidase complex like-1 subunits and down-modulates the latent membrane protein 2 subunit. These changes correlate with the increase of all three major proteolytic activities of the proteasome and result in a more efficient generation and presentation of subdominant MHC-I-binding CTL epitopes of heterologous Ags. Thus, Tat modifies the Ag processing and modulates the generation of CTL epitopes. This may have an impact on both the control of virally infected cells during HIV-1 infection and the use of Tat for vaccination strategies.
An Indispensable Role for STAT1 in IL-27-Induced T-bet Expression but Not Proliferation of Naive CD4+ T Cells
Authors: Kamiya Sadahiro , Owaki Toshiyuki , Morishima Noriko , Fukai Fumio , Mizuguchi Junichiro , Yoshimoto Takayuki 
Published: April 2014

AbstractIL-27 is a novel IL-12 family member that plays a role in the early regulation of Th1 initiation, induces proliferation of naive CD4+ T cells, and synergizes with IL-12 in IFN-γ production. It has been recently reported that IL-27 induces T-bet and IL-12Rβ2 expression through JAK1/STAT1 activation. In the present study, we further investigated the JAK/STAT signaling molecules activated by IL-27 and also the role of STAT1 in IL-27-mediated responses using STAT1-deficient mice. In addition to JAK1 and STAT1, IL-27-activated JAK2, tyrosine kinase-2, and STAT2, -3, and -5 in naive CD4+ T cells. The activation of STAT2 and STAT5, but not of STAT3, was greatly diminished in STAT1-deficient naive CD4+ T cells. Comparable proliferative response to IL-27 was observed between STAT1-deficient and wild-type naive CD4+ T cells. In contrast, IL-27 hardly induced T-bet and subsequent IL-12Rβ2 expression, and synergistic IFN-γ production by IL-27 and IL-12 was impaired in STAT1-deficient naive CD4+ T cells. Moreover, IL-27 augmented the expression of MHC class I on naive CD4+ T cells in a STAT1-dependent manner. These results suggest that IL-27 activates JAK1 and -2, tyrosine kinase-2, STAT1, -2, -3, and -5 in naive CD4+ T cells and that STAT1 plays an indispensable role in IL-27-induced T-bet and subsequent IL-12Rβ2 expression and MHC class I expression as well but not proliferation, while STAT3 presumably plays an important role in IL-27-induced proliferation.
Unraveling the Consecutive Recombination Events in the HumanIGKLocus
Authors: Langerak Anton W. , Nadel Bertrand , de Torbal Anneke , Wolvers-Tettero Ingrid L. M. , van Gastel-Mol Ellen J. , Verhaaf Brenda , Jäger Ulrich , van Dongen Jacques J. M. 
Published: April 2014

AbstractIn addition to the classical Vκ-Jκ, Vκ-κ deleting element (Kde), and intron-Kde gene rearrangements, atypical recombinations involving Jκ recombination signal sequence (RSS) or intronRSS elements can occur in the Igκ (IGK) locus, as observed in human B cell malignancies. In-depth analysis revealed that atypical JκRSS-intronRSS, Vκ-intronRSS, and JκRSS-Kde recombinations not only occur in B cell malignancies, but rather reflect physiological gene rearrangements present in normal human B cells as well. Excision circle analysis and recombination substrate assays can discriminate between single-step vs multistep rearrangements. Using this combined approach, we unraveled that the atypical Vκ-intronRSS and JκRSS-Kde pseudohybrid joints most probably result from ongoing recombination following an initial aberrant JκRSS-intronRSS signal joint formation. Based on our observations in normal and malignant human B cells, a model is presented to describe the sequential (classical and atypical) recombination events in the human IGK locus and their estimated relative frequencies (0.2–1.0 vs &lt;0.03). The initial JκRSS-intronRSS signal joint formation (except for Jκ1RSS-intronRSS) might be a side event of an active V(D)J recombination mechanism, but the subsequent formation of Vκ-intronRSS and JκRSS-Kde pseudohybrid joints can represent an alternative pathway for IGK allele inactivation and allelic exclusion, in addition to classical Cκ deletions. Although usage of this alternative pathway is limited, it seems essential for inactivation of those IGK alleles that have undergone initial aberrant recombinations, which might otherwise hamper selection of functional Ig L chain proteins.
Microglia Initiate Central Nervous System Innate and Adaptive Immune Responses through Multiple TLRs
Authors: Olson Julie K. , Miller Stephen D. 
Published: April 2014

AbstractMicroglia are the resident macrophage-like population in the CNS. Microglia remain quiescent until injury or infection activates the cells to perform effector inflammatory and APC functions. Our previous studies have shown that microglia infected with a neurotropic strain of Theiler’s murine encephalomyelitis virus secreted innate immune cytokines and up-regulated costimulatory molecules and MHC class II, enabling the cells to present viral and myelin Ags to CD4+ T cells. Recently, TLRs have been shown to recognize pathogen-associated molecular patterns and initiate innate immune responses upon interaction with infectious agents. We examined TLR expression on brain microglia and their functional responses upon stimulation with various TLR agonists. We report that mouse microglia express mRNA for all of the recently identified TLRs, TLR1–9, used for recognition of bacterial and viral molecular patterns. Furthermore, stimulation of quiescent microglia with various TLR agonists, including LPS (TLR4), peptidoglycan (TLR2), polyinosinic-polycytidylic acid (TLR3), CpG DNA (TLR9), and infection with viable Theiler’s murine encephalomyelitis virus, activated the cells to up-regulate unique patterns of innate and effector immune cytokines and chemokines at the mRNA and protein levels. In addition, TLR stimulation activated up-regulation of MHC class II and costimulatory molecules, enabling the microglia to efficiently present myelin Ags to CD4+ T cells. Thus, microglia appear to be a unique and important component of both the innate and adaptive immune response, providing the CNS with a means to rapidly and efficiently respond to a wide variety of pathogens.
Analysis of Notch1 Function by In Vitro T Cell Differentiation ofPax5Mutant Lymphoid Progenitors
Authors: Höflinger Sonja , Kesavan Kamala , Fuxa Martin , Hutter Caroline , Heavey Barry , Radtke Freddy , Busslinger Meinrad 
Published: April 2014

AbstractSignaling through the Notch1 receptor is essential for T cell development in the thymus. Stromal OP9 cells ectopically expressing the Notch ligand Delta-like1 mimic the thymic environment by inducing hemopoietic stem cells to undergo in vitro T cell development. Notch1 is also expressed on Pax5−/− pro-B cells, which are clonable lymphoid progenitors with a latent myeloid potential. In this study, we demonstrate that Pax5−/− progenitors efficiently differentiate in vitro into CD4+CD8+ αβ and γδ T cells upon coculture with OP9-Delta-like1 cells. In vitro T cell development of Pax5−/− progenitors strictly depends on Notch1 function and progresses through normal developmental stages by expressing T cell markers and rearranging TCRβ, γ, and δ loci in the correct temporal sequence. Notch-stimulated Pax5−/− progenitors efficiently down-regulate the expression of B cell-specific genes, consistent with a role of Notch1 in preventing B lymphopoiesis in the thymus. At the same time, Notch signaling rapidly induces cell surface expression of the c-Kit receptor and transcription of the target genes Deltex1 and pre-Tα concomitant with the activation of TCR Vβ germline transcription and the regulatory genes GATA3 and Tcf1. These data suggest that Notch1 acts upstream of GATA3 and Tcf1 in early T cell development and regulates Vβ-DJβ rearrangements by controlling the chromatin accessibility of Vβ genes at the TCRβ locus.
IL-13 Activates a Mechanism of Tissue Fibrosis That Is Completely TGF-β Independent
Authors: Kaviratne Mallika , Hesse Matthias , Leusink Mary , Cheever Allen W. , Davies Stephen J. , McKerrow James H. , Wakefield Lalage M. , Letterio John J. , Wynn Thomas A. 
Published: April 2014

AbstractFibrosis is a characteristic feature in the pathogenesis of a wide spectrum of diseases. Recently, it was suggested that IL-13-dependent fibrosis develops through a TGF-β1 and matrix metalloproteinase-9-dependent (MMP-9) mechanism. However, the significance of this pathway in a natural disorder of fibrosis was not investigated. In this study, we examined the role of TGF-β in IL-13-dependent liver fibrosis caused by Schistosoma mansoni infection. Infected IL-13−/− mice showed an almost complete abrogation of fibrosis despite continued and undiminished production of TGF-β1. Although MMP-9 activity was implicated in the IL-13 pathway, MMP-9−/− mice displayed no reduction in fibrosis, even when chronically infected. To directly test the requirement for TGF-β, studies were also performed with neutralizing anti-TGF-β Abs, soluble antagonists (soluble TGF-βR-Fc), and Tg mice (Smad3−/− and TGF-βRII-Fc Tg) that have disruptions in all or part of the TGF-β signaling cascade. In all cases, fibrosis developed normally and with kinetics similar to wild-type mice. Production of IL-13 was also unaffected. Finally, several genes, including interstitial collagens, several MMPs, and tissue inhibitors of metalloprotease-1 were up-regulated in TGF-β1−/− mice by IL-13, demonstrating that IL-13 activates the fibrogenic machinery directly. Together, these studies provide unequivocal evidence of a pathway of fibrogenesis that is IL-13 dependent but TGF-β1 independent, illustrating the importance of targeting IL-13 directly in the treatment of infection-induced fibrosis.