bluuebunny/crossref_metadata_2025_split huggingface dataset:
Transcriptional Regulation of the Mouse IL-7 Receptor α Promoter by Glucocorticoid Receptor
Authors: Lee Hai-Chon , Shibata Hirofumi , Ogawa Shinya , Maki Kazushige , Ikuta Koichi 
Published: April 2014

Abstract
Expression of the IL-7R α-chain (IL-7Rα) is strictly regulated during the development and maturation of lymphocytes. Glucocorticoids (GC) have pleiotypic effects on the growth and function of lymphocytes. Although GC have been reported to induce the transcription of IL-7Rα gene in human T cells, its molecular mechanism is largely unknown. In this study, we show that GC up-regulate the levels of IL-7Rα mRNA and protein in mouse T cells. This effect does not require protein synthesis de novo, because protein synthesis inhibitors do not block the process. Mouse IL-7Rα promoter has striking homology with human and rat, containing consensus motifs of Ikaros, PU.1, and Runx1 transcription factors. In addition, a conserved noncoding sequence (CNS) of ∼270 bp was found 3.6-kb upstream of the promoter, which was designated as CNS-1. A GC receptor (GR) motif is present in the CNS-1 region. Importantly, we show by reporter assay that the IL-7Rα promoter has specific transcription activity in T cells. This activity highly depends on the PU.1 motif. Furthermore, GC treatment augments the transcriptional activity through the GR motif in the CNS-1 region. We also demonstrate that GR binds to the GR motif by EMSA. In addition, by chromatin immunoprecipitation assay, we show that GR is rapidly recruited to endogenous CNS-1 chromatin after GC stimulation. These results demonstrate that GR binds to the GR motif in the CNS-1 region after GC stimulation and then activates the transcription of the IL-7Rα promoter. Thus, this study identifies the IL-7Rα CNS-1 region as a GC-responsive element.
Differential Src Family Kinase Activity Requirements for CD3ζ Phosphorylation/ZAP70 Recruitment and CD3ε Phosphorylation
Authors: Lysechko Tara L. , Ostergaard Hanne L. 
Published: April 2014

AbstractThe current model of T cell activation is that TCR engagement stimulates Src family tyrosine kinases (SFK) to phosphorylate CD3ζ. CD3ζ phosphorylation allows for the recruitment of the tyrosine kinase ZAP70, which is phosphorylated and activated by SFK, leading to the phosphorylation of downstream targets. We stimulated mouse CTLs with plate-bound anti-CD3 and, after cell lysis, recovered proteins that associated with the CD3 complex. The protein complexes were not preformed, and a number of tyrosine-phosphorylated proteins were inducibly and specifically associated with the TCR/CD3 complex. These results suggest that complex formation only occurs at the site of TCR engagement. The recruitment and tyrosine phosphorylation of most proteins were abolished when T cells were stimulated in the presence of the SFK inhibitor PP2. Surprisingly, CD3ζ, but not CD3ε, was inducibly tyrosine phosphorylated in the presence of PP2. Furthermore, ZAP70 was recruited, but not phosphorylated, after TCR stimulation in the presence of PP2, thus confirming the phosphorylation status of CD3ζ. These data suggest that there is a differential requirement for SFK activity in phosphorylation of CD3ζ vs CD3ε. Consistent with this possibility, ZAP70 recruitment was also detected with anti-CD3-stimulated, Lck-deficient human Jurkat T cells. We conclude that TCR/CD3-induced CD3ζ phosphorylation and ZAP70 recruitment do not absolutely require Lck or other PP2-inhibitable SFK activity, but that SFK activity is absolutely required for CD3ε and ZAP70 phosphorylation. These data reveal the potential for regulation of signaling through the TCR complex by the differential recruitment or activation of SFK.
Differential Expression Regulation of the α and β Subunits of the PA28 Proteasome Activator in Mature Dendritic Cells
Authors: Ossendorp Ferry , Fu Nathalie , Camps Marcel , Granucci Francesca , Gobin Sam J. P. , van den Elsen Peter J. , Schuurhuis Danita , Adema Gosse J. , Lipford Grayson B. , Chiba Tomoki , Sijts Alice , Kloetzel Peter-M. , Ricciardi-Castagnoli Paola , Melief Cornelis J. M. 
Published: April 2014

AbstractActivation of dendritic cells (DC) by Th-dependent (CD40) or -independent (LPS, CpG, or immune complexes) agonistic stimuli strongly enhances the expression of the proteasome activator PA28αβ complex. Upon activation of DC, increased MHC class I presentation occurred of the melanocyte-associated epitope tyrosinase-related protein 2180-188 in a PA28αβ-dependent manner. In contrast to other cell types, regulation of PA28αβ expression in DC after maturation was found to be IFN-γ independent. In the present study, we show that expression of PA28α and β subunits was differentially regulated. Firstly, PA28α expression is high in both immature and mature DC. In contrast, PA28β expression is low in immature DC and strongly increased in mature DC. Secondly, we show the presence of a functional NF-κB site in the PA28β promoter, which is absent in the PA28α promoter, indicating regulation of PA28β expression by transcription factors of the NF-κB family. In addition, glycerol gradient analysis of DC lysates revealed elevated PA28αβ complex formation upon maturation. Thus, induction of PA28β expression allows proper PA28αβ complex formation, thereby enhancing proteasome activity in activated DC. Therefore, maturation of DC not only improves costimulation but also MHC class I processing. This mechanism enhances the CD8+ CTL (cross)-priming capacity of mature DC.
STAT-1 Mediates the Stimulatory Effect of IL-10 on CD14 Expression in Human Monocytic Cells
Authors: Rahimi Ali Akbar Rahim , Gee Katrina , Mishra Sasmita , Lim Wilfred , Kumar Ashok 
Published: April 2014

AbstractIL-10, an anti-inflammatory cytokine, has been shown to exhibit stimulatory functions including CD14 up-regulation on human monocytic cells. CD14-mediated signaling following LPS stimulation of monocytic cells results in the synthesis of proinflammatory cytokines. Our results show that LPS-induced CD14 expression on monocytic cells may be mediated by endogenously produced IL-10. To investigate the molecular mechanism by which IL-10 enhances CD14 expression, both human monocytes and the promyelocytic HL-60 cells were used as model systems. IL-10 induced the phosphorylation of PI3K and p42/44 ERK MAPK. By using specific inhibitors for PI3K (LY294002) and ERK MAPKs (PD98059), we demonstrate that LY294002 either alone or in conjunction with PD98059 inhibited IL-10-induced phosphorylation of STAT-1 and consequently CD14 expression. However, IL-10-induced STAT-3 phosphorylation remained unaffected under these conditions. Finally, STAT-1 interfering RNA inhibited IL-10-induced CD14 expression. Taken together, these results suggest that IL-10-induced CD14 up-regulation in human monocytic cells may be mediated by STAT-1 activation through the activation of PI3K either alone or in concert with the ERK MAPK.
Qualitative and Quantitative Differences in Peptides Bound to HLA-B27 in the Presence of Mouse versus Human Tapasin Define a Role for Tapasin as a Size-Dependent Peptide Editor
Authors: Sesma Laura , Galocha Begoña , Vázquez Miriam , Purcell Anthony W. , Marcilla Miguel , McCluskey James , de Castro José A. López 
Published: April 2014

AbstractTapasin (Tpn) is a chaperone of the endoplasmic reticulum involved in peptide loading to MHC class I proteins. The influence of mouse Tpn (mTpn) on the HLA-B*2705-bound peptide repertoire was analyzed to characterize the species specificity of this chaperone. B*2705 was expressed on Tpn-deficient human 721.220 cells cotransfected with human (hTpn) or mTpn. The heterodimer to β2-microglobulin-free H chain ratio on the cell surface was reduced with mTpn, suggesting lower B*2705 stability. The B*2705-bound peptide repertoires loaded with hTpn or mTpn shared 94–97% identity, although significant differences in peptide amount were observed in 16–17% of the shared ligands. About 3–6% of peptides were bound only with either hTpn or mTpn. Nonamers differentially bound with mTpn had less suitable anchor residues and bound B*2705 less efficiently in vitro than those loaded only with hTpn or shared nonamers. Decamers showed a different pattern: those found only with mTpn had similarly suitable residues as shared decamers and bound B*2705 with high efficiency. Peptides differentially presented by B*2705 on human or mouse cells showed an analogous pattern of residue suitability, suggesting that the effect of mTpn on B*2705 loading is comparable in both cell types. Thus, mTpn has quantitative and qualitative effects on the B*2705-bound peptide repertoire, impairing presentation of some suitable ligands and allowing others with suboptimal anchor residues and lower affinity to be presented. Our results favor a size-dependent peptide editing role of Tpn for HLA-B*2705 that is species-dependent and suboptimally performed, at least for nonamers, by mTpn.
Sustained Pre-TCR Expression in Notch1IC-Transgenic Rats Impairs T Cell Maturation and Selection
Authors: van den Brandt Jens , Kwon Soon-Hwan , Hünig Thomas , McPherson Kirsty G. , Reichardt Holger M. 
Published: April 2014

Abstract
Notch1 is involved in directing cell fate decisions in a variety of developmental scenarios. Extending previous experiments in mice, we generated transgenic rats expressing the intracellular domain of Notch1 in the thymus. Importantly, this leads to sustained expression of the pre-TCR throughout thymocyte development, accompanied by a reduction of αβTCR complexes. In addition, re-expression of RAG-1 and RAG-2 in TCRβ+ cells is impaired, and the Vα repertoire is altered. Consequently, thymocytes in transgenic rats do not undergo positive selection and largely fail to progress to the single positive stage. According to our model, the previously reported effects of Notch1 on the CD4/CD8 cell fate decision may be explained by a differential sensitivity of the two lineages toward altered TCR signaling.
T Cell Retargeting with MHC Class I-Restricted Antibodies: The CD28 Costimulatory Domain Enhances Antigen-Specific Cytotoxicity and Cytokine Production
Authors: Willemsen Ralph A. , Ronteltap Cees , Chames Patrick , Debets Reno , Bolhuis Reinder L. H. 
Published: April 2014

AbstractT cells require both primary and costimulatory signals for optimal activation. The primary Ag-specific signal is delivered by engagement of the TCR. The second Ag-independent costimulatory signal is mediated by engagement of the T cell surface costimulatory molecule CD28 with its target cell ligand B7. However, many tumor cells do not express these costimulatory molecules. We previously constructed phage display derived FAB, G8, and Hyb3, Ab-based receptors with identical specificity but distinct affinities for HLA-A1/MAGE-A1, i.e., “TCR-like” specificity. These chimeric receptors comprised the FcεRI-γ signaling element. We analyzed whether linking the CD28 costimulation structure to it (γ + CD28) could affect the levels of MHC-restricted cytolysis and/or cytokine production. Human scFv-G8POS T lymphocytes comprising the γ + CD28 vs the γ signaling element alone produced substantially more IL-2, TNF-α, and IFN-γ in response to HLA-A1/MAGE-A1POS melanoma cells. Also a drastic increase in cytolytic capacity of scFv-G8POS T cells, equipped with γ + CD28 vs the γ-chain alone was observed.
Enhanced Expression of CD20 in Human Tumor B Cells Is Controlled through ERK-Dependent Mechanisms
Authors: Wojciechowski Wojciech , Li Huifen , Marshall Shannon , Dell’Agnola Chiara , Espinoza-Delgado Igor 
Published: April 2014

AbstractRituximab, a chimeric Ab directed against CD20, induces apoptosis in targeted cells. Although the majority of B cell malignancies express the CD20 Ag, only ∼50% of patients will respond to single-agent rituximab. The available data suggest that a decreased CD20 expression could account for the lack of response observed in some patients treated with rituximab. Despite the potential critical role of CD20 in the biology of B cell malignancies, the mechanisms controlling its expression are poorly understood. We evaluated the effect of the immune modulator agent bryostatin-1 on the expression of CD20 in non-Hodgkin’s lymphoma cells. Using the B cell lines, DB and RAMOS, as well as tumor cells derived from a chronic lymphocytic leukemia patient, we demonstrated that bryostatin-1 enhanced the expression of both CD20 mRNA and protein. The enhanced expression of CD20 was associated with increased transcriptional activity of the CD20 gene, whereas the stability of CD20 mRNA was not affected. The effect of bryostatin-1 on CD20 expression in non-Hodgkin’s lymphoma cells was mediated through the MAPK kinase/ERK signal transduction pathway and involved protein kinase C, but was independent of p38 MAPK and was insensitive to dexamethasone. Cells pretreated with bryostatin-1 were more susceptible to the proapoptotic effect of anti-CD20 Ab. Overall, these data demonstrate for the first time that ERK phosphorylation is required for the up-regulated expression of CD20 on B cell malignancies. The findings also suggest that bryostatin-1 and rituximab could be a valuable combined therapy for B cell malignancies.
Glucocorticoid-Induced TNF Receptor Functions as a Costimulatory Receptor That Promotes Survival in Early Phases of T Cell Activation
Authors: Esparza Edward M. , Arch Robert H. 
Published: April 2014

Abstract
Glucocorticoid-induced TNFR (GITR) is a member of the TNFR family that can inhibit the suppressive function of regulatory T cells and promote the survival and activation of T cells. However, little is known about the molecular mechanisms regulating T cell survival and activation downstream of GITR. To gain further insight into the cellular events and signaling pathways triggered by GITR, survival, proliferation, and cytokine production as well as activation of MAPKs and NF-κB were monitored after cross-linking of the receptor on naive and activated T cells. GITR cross-linking provided costimulation of naive and activated T cells and resulted in activation of MAPKs and NF-κB. Although GITR-induced signaling pathways augmented the survival of naive T cells, they were not sufficient to inhibit activation-induced cell death triggered by CD3 cross-linking of activated T cells. Differences in the contributions of GITR to cell survival between naive and activated T cells suggest that the receptor triggers specific pathways depending on the activation state of the T cell.
Glucocorticoid-Induced TNF Receptor, a Costimulatory Receptor on Naive and Activated T Cells, Uses TNF Receptor-Associated Factor 2 in a Novel Fashion as an Inhibitor of NF-κB Activation
Authors: Esparza Edward M. , Arch Robert H. 
Published: April 2014

Abstract
Glucocorticoid-induced TNFR (GITR) has been implicated as an essential regulator of immune responses to self tissues and pathogens. We have recently shown that GITR-induced cellular events promote survival of naive T cells, but are insufficient to protect against activation-induced cell death. However, the molecular mechanisms of GITR-induced signal transduction that influence physiologic and pathologic immune responses are not well understood. TNFR-associated factors (TRAFs) are pivotal adapter proteins involved in signal transduction pathways of TNFR-related proteins. Yeast two-hybrid assays and studies in HEK293 cells and primary lymphocytes indicated interactions between TRAF2 and GITR mediated by acidic residues in the cytoplasmic domain of the receptor. GITR-induced activation of NF-κB is blocked by A20, an NF-κB-inducible protein that interacts with TRAFs and functions in a negative feedback mechanism downstream of other TNFRs. Interestingly, in contrast with its effects on signaling triggered by other TNFRs, our functional studies revealed that TRAF2 plays a novel inhibitory role in GITR-triggered NF-κB activation.
Structure/Function Analysis of Tristetraprolin (TTP): p38 Stress-Activated Protein Kinase and Lipopolysaccharide Stimulation Do Not Alter TTP Function
Authors: Rigby William F. C. , Roy Kristen , Collins Jane , Rigby Sam , Connolly John E. , Bloch Donald B. , Brooks Seth A. 
Published: April 2014

Abstract
Tristetraprolin (TTP) is the only trans-acting factor shown to be capable of regulating AU-rich element-dependent mRNA turnover at the level of the intact animal; however, the mechanism by which TTP mediated RNA instability is unknown. Using an established model system, we performed structure/function analysis with TTP as well as examined the current hypothesis that TTP function is regulated by p38-MAPKAP kinase 2 (MK2) activation. Deletion of either the N- or C-terminal domains inhibited TTP function. Extensive mutagenesis, up to 16%, of serines and threonines, some of which were predicted to mediate proteasomal targeting, did not alter human TTP function. Mutation of the conserved MK2 phosphorylation sites enhanced human TTP function in both resting and p38-stress-activated protein kinase-MK2-activated cells. However, p38-stress-activated protein kinase-MK2 activation did not alter the activity of either wild-type or mutant TTP. TTP localized to the stress granules, with arsenite treatment reducing this localization. In contrast, arsenite treatment enhanced stress granule localization of the MK2 mutant, consistent with the involvement of additional pathways regulating this event. Finally, we determined that, in response to LPS stimulation, human TTP moves onto the polysomes, and this movement occurs in the absence of 14-3-3. Taken together, these data indicate that, although p38 activation alters TTP entry into the stress granule, it does not alter TTP function. Moreover, the interaction of TTP with 14-3-3, which may limit entry into the stress granule, is not involved in the downstream message stabilization events.
The Non-MHC Quantitative Trait LocusCia5Contains Three Major Arthritis Genes That Differentially Regulate Disease Severity, Pannus Formation, and Joint Damage in Collagen- and Pristane-Induced Arthritis
Authors: Brenner Max , Meng Hsiang-Chi , Yarlett Nuriza C. , Joe Bina , Griffiths Marie M. , Remmers Elaine F. , Wilder Ronald L. , Gulko Pércio S. 
Published: April 2014

AbstractCia5 is a locus on rat chromosome 10 which regulates the severity of collagen- and pristane-induced arthritis (CIA and PIA). To refine the region toward positional identification, Cia5 subcongenic strains were generated and studied in PIA and CIA. The protective effect of the telomeric locus Cia5a was confirmed in both models. A second arthritis severity locus (Cia5d) was identified within the most centromeric portion of Cia5. DA.F344(Cia5d) rats had a significantly lower median arthritis severity index in PIA, but not in CIA, compared with DA. On histologic analyses DA.F344(Cia5a) and DA.F344(Cia5d) congenics with PIA preserved a nearly normal joint architecture compared with DA, including significant reduction in synovial hyperplasia, pannus, angiogenesis, inflammatory infiltration, bone and cartilage erosions. Cia5 and Cia5a synovial levels of IL-1β mRNA were reduced. Although both DA.F344(Cia5) and DA.F344(Cia5a) rats were protected in CIA, the arthritis scores of DA.F344(Cia5) were significantly higher than those of DA.F344(Cia5a), suggesting the existence of a third locus where F344-derived alleles centromeric from Cia5a contribute to increased arthritis severity. The existence of the third locus was further supported by higher levels of autoantibodies against rat type II collagen in DA.F344(Cia5) congenics compared with DA.F344(Cia5a). Our results determined that Cia5 contains three major arthritis severity regulatory loci regulating central events in the pathogenesis of arthritis, and differentially influencing CIA and PIA. These loci are syntenic to regions on human chromosomes 17q and 5q implicated in the susceptibility to rheumatoid arthritis, suggesting that the identification of these genes will be relevant to human disease.
Exacerbated Susceptibility to Infection-Stimulated Immunopathology in CD1d-Deficient Mice
Authors: Smiley Stephen T. , Lanthier Paula A. , Couper Kevin N. , Szaba Frank M. , Boyson Jonathan E. , Chen Wangxue , Johnson Lawrence L. 
Published: April 2014

AbstractMice lacking functional CD1d genes were used to study mechanisms of resistance to the protozoan parasite Toxoplasma gondii. Wild-type (WT) BALB/c mice, CD1d-deficient BALB/c mice, and WT C57BL/6 mice all survived an acute oral infection with a low dose of mildly virulent strain ME49 T. gondii cysts. In contrast, most CD1d-deficient C57BL/6 mice died within 2 wk of infection. Despite having parasite burdens that were only slightly higher than WT mice, CD1d-deficient C57BL/6 mice displayed greater weight loss and intestinal pathology. In C57BL/6 mice, CD4+ cells can cause intestinal pathology during T. gondii infection. Compared with WT mice, infected CD1d-deficient C57BL/6 mice had higher frequencies and numbers of activated (CD44high) CD4+ cells in mesenteric lymph nodes. Depletion of CD4+ cells from CD1d-deficient mice reduced weight loss and prolonged survival, demonstrating a functional role for CD4+ cells in their increased susceptibility to T. gondii infection. CD1d-deficient mice are deficient in Vα14+ T cells, a major population of NKT cells. Involvement of these cells in resistance to T. gondii was investigated using gene-targeted Jα18-deficient C57BL/6 mice, which are deficient in Vα14+ T cells. These mice did not succumb to acute infection, but experienced greater weight loss and more deaths than B6 mice during chronic infection, indicating that Vα14+ cells contribute to resistance to T. gondii. The data identify CD4+ cells as a significant component of the marked susceptibility to T. gondii infection observed in CD1d-deficient C57BL/6mice, and establish T. gondii as a valuable tool for deciphering CD1d-dependent protective mechanisms.
B Lymphocyte Activation by Human Papillomavirus-Like Particles Directly Induces Ig Class Switch Recombination via TLR4-MyD88
Authors: Yang Rongcun , Murillo Francisco Martinez , Delannoy Michael J. , Blosser R. Lee , Yutzy William H. , Uematsu Satoshi , Takeda Kiyoshi , Akira Shizuo , Viscidi Raphael P. , Roden Richard B. S. 
Published: April 2014

AbstractVaccination with human papillomavirus type 16 (HPV16) L1 virus-like particles (VLP) induces both high titer neutralizing IgG and protective immunity. Because protection from experimental infection by papillomavirus is mediated by neutralizing IgG, we sought the mechanisms that trigger humoral immunity to HPV16 L1 VLP. We find that HPV16 L1 VLP bind to murine B lymphocytes thereby inducing activation-induced cytidine deaminase expression and Ig class switch recombination to cause the generation of IgG. HPV16 L1 VLP also activate production of proinflammatory factors IFN-α, IL-6, MIP-1α, RANTES, and KC, up-regulate the expression of costimulatory molecules by naive B cells, and increase the B1 B cell subpopulation. These B cell responses to HPV16 L1 VLP are dependent upon MyD88. Although MyD88−/− B cells produce only μ transcript after exposure to HPV16 L1 VLP, MyD88+/+ B cells express α, γ, and μ Ig H chain and activation-induced cytidine deaminase transcripts. Notably, TLR4 mutant C3H/HeJ mice exhibited significantly reduced HPV16 VLP-specific IgG1, IgG2a, IgG2b, and IgG3 titers after vaccination as compared with the control C3H/HeOuJ mice. HPV16 L1 VLP directly activated class switch recombination and costimulatory molecule expression by B cells of C3H/HeOuJ mice but not C3H/HeJ mice. Thus HPV16 L1 VLP directly activate B cells to induce CD4+ T cell independent humoral immune responses via TLR4- and MyD88-dependent signaling.