bluuebunny/crossref_metadata_2025_split huggingface dataset:
In vivo and In vitro Regulation of Type I IFN Synthesis by Synergistic Effects of CD40 and Type II IFN
Authors: Greene Jennifer A. , DeVecchio Jennifer L. , Gould Meetha P. , Auletta Jeffery J. , Heinzel Frederick P. 
Published: April 2014

Abstract
During cognate interaction with CD40 ligand (CD154)-expressing T cells, Ag-presenting accessory cells are activated for increased cytokine synthetic and costimulatory function. We examined whether CD40 modulates in vivo innate immune function over time, hypothesizing that distinct cytokine responses evolve to delayed microbial exposure. C3H/HeN mice pretreated with activating anti-CD40 Ab (FGK45) produced 10-fold more serum IFN-γ and IL-12 p70 to delayed, but not synchronous, challenge with LPS. A novel finding was that LPS-induced IFN-α increased by 20-fold in mice pretreated for 24 h, but not 6 h or less, with anti-CD40. Anti-CD40-pretreated C57BL/6 RAG-2−/− mice similarly increased IFN-α responses to delayed LPS challenge, confirming mediation by innate immunity. Type I IFNR- and IFN-γ-deficient mice treated with anti-CD40 failed to expand serum IFN-α responses to LPS challenge. Combined pretreatment with anti-CD40 and anti-IFN-γ mAb showed that IFN-γ produced after anti-CD40 pretreatment, but before LPS challenge, was necessary for IFN-α synthetic enhancement. Anti-CD40 also increased polyinosinic-polycytidylic acid (poly(I:C))-inducible IFN-α by 5-fold in an IFN-γ-dependent fashion, but did not significantly increase IFN-α production to CpG or Pam3Cys challenges. Poly(IC)-stimulated splenocytes from anti-CD40-pretreated mice produced 4-fold more IFN-α than controls and production associated with CD11c+ cells. Finally, rIFN-γ and anti-CD40 combined synergistically to increase poly(IC)-inducible IFN-α synthetic capacity in bone marrow dendritic cells. We conclude that innate immune production of IFN-α is cooperatively regulated by CD40 and IFN-γ acting on dendritic cells, suggesting a unique mechanism by which innate immune function evolves in response to specific adaptive immune signals.
MyD88-Dependent Signaling for IL-15 Production Plays an Important Role in Maintenance of CD8αα TCRαβ and TCRγδ Intestinal Intraepithelial Lymphocytes
Authors: Yu Qingsheng , Tang Ce , Xun Sun , Yajima Toshiki , Takeda Kiyoshi , Yoshikai Yasunobu 
Published: April 2014

Abstract
Interaction between commensal bacteria and intestinal epithelial cells (i-ECs) via TLRs is important for intestinal homeostasis. In this study, we found that the numbers of CD8αα TCRαβ and TCRγδ intestinal intraepithelial lymphocytes (i-IELs) were significantly decreased in MyD88-deficient (−/−) mice. The expression of IL-15 by i-ECs was severely reduced in MyD88−/− mice. Introduction of IL-15 transgene into MyD88−/− mice (MyD88−/− IL-15 transgenic mice) partly restored the numbers of CD8αα TCRαβ and TCRγδ i-IELs. The i-IEL in irradiated wild-type (WT) mice transferred with MyD88−/− bone marrow (BM) cells had the same proportions of i-IEL as WT mice, whereas those in irradiated MyD88−/− mice transferred with WT BM cells showed significantly reduced proportions of CD8αα TCRαβ and TCRγδ i-IELs, as was similar to the proportions found in MyD88−/− mice. However, irradiated MyD88−/− IL-15 transgenic mice transferred with WT BM cells had increased numbers of CD8αα TCRαβ and TCRγδ subsets in the i-IEL. These results suggest that parenchymal cells such as i-ECs contribute to the maintenance of CD8αα TCRαβ and γδ i-IELs at least partly via MyD88-dependent IL-15 production.
TLR5-Mediated Phosphoinositide 3-Kinase Activation Negatively Regulates Flagellin-Induced Proinflammatory Gene Expression
Authors: Yu Yimin , Nagai Shigenori , Wu Huixia , Neish Andrew S. , Koyasu Shigeo , Gewirtz Andrew T. 
Published: April 2014

Abstract
Epithelial cells detect motile pathogens via TLR5 ligation of flagellin, resulting in rapid induction of antibacterial/proinflammatory gene expression. Although such flagellin-induced gene expression is quite transient, likely to avoid the negative consequences of inflammation, little is known regarding the molecular mechanisms that mediate its shutdown. We hypothesized that, analogous to the case for TLR4, phosphoinositide 3-kinase (PI3K) might negatively regulate TLR5 signaling. However, because PI3K is an essential positive mediator of some pathways of TLR-mediated gene expression, the opposite hypothesis was also considered. Herein, we observed that flagellin stimulation of epithelial cells indeed induced rapid (&lt;30 min) PI3K activation, as evidenced by Akt phosphorylation, via a TLR5-mediated mechanism. Blockade of PI3K with wortmannin resulted in marked enhancement of flagellin-induced gene expression as assessed by measuring levels of inducible NO synthase, IL-6, and IL-8. Such enhancement of gene expression by PI3K inhibition correlated with prolonged activation of MAPK (p38 and ERK1/2) and was ablated under MAPK inhibition. Such effect of inhibiting PI3K with wortmannin was mimicked by the PI3K inhibitor LY294002, and, conversely, a constitutively active PI3K prevented p38 activation in response to flagellin. Last, to test the significance of these results in vivo, we measured flagellin-induced gene expression in PI3K knockout mice. PI3K-null mice displayed increased levels of flagellin-induced serum IL-6, KC (IL-8 homolog), and nitrite as compared with heterozygous littermates. Thus, TLR5’s rapid activation of PI3K serves to limit MAPK signaling, thus limiting proinflammatory gene expression and reducing the potential negative consequences of proinflammatory gene expression.
TLRs Mediate IFN-γ Production by Human Uterine NK Cells in Endometrium
Authors: Eriksson Mikael , Meadows Sarah K. , Basu Satarupa , Mselle Teddy F. , Wira Charles R. , Sentman Charles L. 
Published: April 2014

Abstract
The human endometrium (EM) contains macrophages, NK cells, T cells, B cells, and neutrophils in contact with a variety of stromal and epithelial cells. The interplay between these different cell types and their roles in defense against pathogen invasion in this specialized tissue are important for controlling infection and reproduction. TLRs are a family of receptors able to recognize conserved pathogen-associated molecular patterns. In this study, we determined the expression of TLRs on uterine NK (uNK) cells from the human EM and the extent to which uNK cells responded to TLR agonist stimulation. uNK cells expressed TLRs 2, 3, and 4, and produced IFN-γ when total human endometrial cells were stimulated with agonists to TLR2 or TLR3 (peptidoglycan or poly(I:C), respectively). Activated uNK cell clones produced IFN-γ upon stimulation with peptidoglycan or poly(I:C). However, purified uNK cells did not respond directly to TLR agonists, but IFN-γ was produced by uNK cells in response to TLR stimulation when cocultured with APCs. These data indicate that uNK cells express TLRs and that they can respond to TLR agonists within EM by producing IFN-γ. These data also indicate that the uNK cells do not respond directly to TLR stimulation, but rather their production of IFN-γ is dependent upon interactions with other cells within EM.
C/EBP Homologous Protein (CHOP) Is Crucial for the Induction of Caspase-11 and the Pathogenesis of Lipopolysaccharide-Induced Inflammatio
Authors: Endo Motoyoshi , Mori Masataka , Akira Shizuo , Gotoh Tomomi 
Published: April 2014

Abstract
C/EBP homologous protein (CHOP)/growth arrest and DNA damage-inducible gene 153 is a C/EBP family transcription factor which is involved in endoplasmic reticulum (ER) stress-mediated apoptosis. To determine whether the ER stress-CHOP pathway is involved in the pathogenesis of the lung inflammation, mice were given LPS intratracheally. Treatment with LPS induced mRNAs for CHOP and BiP. The LPS-induced inflammation in lung, including the IL-1β activity in bronchoalveolar lavage fluid, was attenuated in the Chop knockout mice. Caspase-11, which is needed for the activation of procaspase-1 and pro-IL-1β, was induced by LPS treatment in the lung and primary cultured macrophages. The induction of caspase-11 by LPS was suppressed in Chop knockout mice. Caspase-11 was also induced by such ER stress inducers as thapsigargin or tunicamycin. These results show that CHOP plays a crucial role in the pathogenesis of inflammation through the induction of caspase-11.
Accelerated Macrophage Apoptosis Induces Autoantibody Formation and Organ Damage in Systemic Lupus Erythematosus
Authors: Denny Michael F. , Chandaroy Parthapratim , Killen Paul D. , Caricchio Roberto , Lewis Emily E. , Richardson Bruce C. , Lee Kyung-Dall , Gavalchin Jerrie , Kaplan Mariana J. 
Published: April 2014

Abstract
Increased monocyte/macrophage (Mφ) apoptosis occurs in patients with systemic lupus erythematosus (SLE) and is mediated, at least in part, by an autoreactive CD4+ T cell subset. Furthermore, autoreactive murine CD4+ T cells that kill syngeneic Mφ in vitro induce a lupus-like disease in vivo. However, it is unclear whether increased Mφ apoptosis in SLE per se is sufficient to accelerate/promote autoimmunity. We have investigated whether increased Mφ apoptosis in vivo, induced by the administration of clodronate liposomes, can exacerbate the autoimmune phenotype in NZB × SWR (SNF1) lupus-prone mice, and induce autoantibody production in haplotype-matched BALB/c × DBA1 (DBF1) non-lupus-prone mice. Lupus-prone mice SNF1 mice that were treated with clodronate liposomes, but not mice treated with vehicle, developed significant increases in autoantibodies to dsDNA, nucleosomes, and the idiotypically related family of nephritic Abs IdLNF1, when compared with untreated SNF1 mice. Furthermore, clodronate treatment hastened the onset of proteinuria and worsened SNF1 lupus nephritis. When compared with vehicle-treated controls, clodronate-treated non-lupus-prone DBF1 mice developed significantly higher levels of anti-nucleosome and IdLNF1 Abs but did not develop lupus nephritis. We propose that Mφ apoptosis contributes to the pathogenesis of autoantibody formation and organ damage through both an increase in the apoptotic load and impairment in the clearance of apoptotic material. This study suggests that mechanisms that induce scavenger cell apoptosis, such as death induced by autoreactive cytotoxic T cells observed in SLE, could play a pathogenic role and contribute to the severity of the disease.
LFA-1-Dependent HuR Nuclear Export and Cytokine mRNA Stabilization in T Cell Activation
Authors: Wang Jin Gene , Collinge Mark , Ramgolam Vinod , Ayalon Oran , Fan Xinhao Cynthia , Pardi Ruggero , Bender Jeffrey R. 
Published: April 2014

Abstract
Lymphokine gene expression is a precisely regulated process in T cell-mediated immune responses. In this study we demonstrate that engagement of the β2 integrin LFA-1 in human peripheral T cells markedly extends the half-life of TNF-α, GM-CSF, and IL-3 mRNA, as well as a chimeric β-globin mRNA reporter construct containing a strongly destabilizing class II AU-rich element from the GM-CSF mRNA 3′-untranslated region. This integrin-enhanced mRNA stability leads to augmented protein production, as determined by TNF-α ELISPOT assays. Furthermore, T cell stimulation by LFA-1 promotes rapid nuclear-to-cytoplasmic translocation of the mRNA-stabilizing protein HuR, which in turn is capable of binding an AU-rich element sequence in vitro. Abrogation of HuR function by use of inhibitory peptides, or marked reduction of HuR levels by RNA interference, prevents LFA-1 engagement-mediated stabilization of T cell TNF-α or IFN-γ transcripts, respectively. Thus, HuR-mediated mRNA stabilization, stimulated by integrin engagement and controlled at the level of HuR nuclear export, is critically involved in T cell activation.
Hyperthermia Enhances CTL Cross-Priming
Authors: Shi Hongzhen , Cao Tinghua , Connolly John E. , Monnet Laurence , Bennett Lynda , Chapel Sylvie , Bagnis Claude , Mannoni Patrice , Davoust Jean , Palucka A. Karolina , Banchereau Jacques 
Published: April 2014

AbstractDendritic cells (DCs) loaded with killed allogeneic melanoma cells can cross-prime naive CD8+ T cells to differentiate into melanoma-specific CTLs in 3-wk cultures. In this study we show that DCs loaded with killed melanoma cells that were heated to 42°C before killing are more efficient in cross-priming of naive CD8+ T cells than DCs loaded with unheated killed melanoma cells. The enhanced cross-priming was demonstrated by several parameters: 1) induction of naive CD8+ T cell differentiation in 2-wk cultures, 2) enhanced killing of melanoma peptide-pulsed T2 cells, 3) enhanced killing of HLA-A*0201+ melanoma cells in a standard 4-h chromium release assay, and 4) enhanced capacity to prevent tumor growth in vitro in a tumor regression assay. Two mechanisms might explain the hyperthermia-induced enhanced cross-priming. First, heat-treated melanoma cells expressed increased levels of 70-kDa heat shock protein (HSP70), and enhanced cross-priming could be reproduced by overexpression of HSP70 in melanoma cells transduced with HSP70 encoding lentiviral vector. Second, hyperthermia resulted in the increased transcription of several tumor Ag-associated Ags, including MAGE-B3, -B4, -A8, and -A10. Thus, heat treatment of tumor cells permits enhanced cross-priming, possibly via up-regulation of both HSPs and tumor Ag expression.
B Cell Tolerance Checkpoints That Restrict Pathways of Antigen-Driven Differentiation
Authors: William Jacqueline , Euler Chad , Primarolo Nicole , Shlomchik Mark J. 
Published: April 2014

AbstractAutoreactive B cells can be regulated by deletion, receptor editing, or anergy. Rheumatoid factor (RF)-expressing B lymphocytes in normal mice are not controlled by these mechanisms, but they do not secrete autoantibody and were presumed to ignore self-Ag. Surprisingly, we now find that these B cells are not quiescent, but instead are constitutively and specifically activated by self-Ag. In BALB/c mice, RF B cells form germinal centers (GCs) but few Ab-forming cells (AFCs). In contrast, autoimmune mice that express the autoantigen readily generate RF AFCs. Most interestingly, autoantigen-specific RF GCs in BALB/c mice appear defective. B cells in such GCs neither expand nor are selected as efficiently as equivalent cells in autoimmune mice. Thus, our data establish two novel checkpoints of autoreactive B cell regulation that are engaged only after initial autoreactive B cell activation: one that allows GCs but prevents AFC formation and one that impairs selection in the GC. Both of these checkpoints fail in autoimmunity.
NF-κB-Dependent Regulation of the Timing of Activation-Induced Cell Death of T Lymphocytes
Authors: Mittal Akanksha , Papa Salvatore , Franzoso Guido , Sen Ranjan 
Published: April 2014

AbstractOne of the mechanisms by which activated T cells die is activation-induced cell death (AICD). This pathway requires persistent stimulation via the TCR and engagement of death receptors. We found that TCR stimulation led to transient nuclear accumulation of the NF-κB component p65/RelA. In contrast, nuclear c-Rel levels remained high even after extended periods of activation. Loss of nuclear p65/RelA correlated with the onset of AICD, suggesting that p65/RelA target genes may maintain cell viability. Quantitative RNA analyses showed that three of several putative NF-κB-dependent antiapoptotic genes were expressed with kinetics that paralleled nuclear expression of p65/RelA. Of these three, ectopic expression only of Gadd45β protected significantly against AICD, whereas IEX-1 and Bcl-xL were much less effective. We propose that the timing of AICD, and thus the length of the effector phase, are regulated by transient expression of a subset of p65/RelA-dependent antiapoptotic genes.
Expression and Regulation of the Orphan Receptor RDC1 and Its Putative Ligand in Human Dendritic and B Cells
Authors: Infantino Simona , Moepps Barbara , Thelen Marcus 
Published: April 2014

Abstract
Based on phylogenetic analysis and chromosomal mapping, the orphan receptor RDC1 was proposed to be a chemokine receptor. In this study we examined the expression of RDC1 on leukocytes by measuring mRNA levels and receptor expression using a new specific mAb. Both mRNA and protein levels were high in monocytes and B cells, relatively low on immature dendritic cells (DC), and up-regulated during final stages of maturation. Strikingly, in mature plasmacytoid DC the mRNA was up-regulated, but did not correlate with protein surface expression. We indeed report that CpG-activated plasmacytoid DC produce a putative ligand for RDC1, which selectively down-regulates RDC1, but not CXCR4 on primary human B cells. RDC1 expression was found to be tightly regulated during B cell development and differentiation. In blood-derived switch memory B cells, the expression of RDC1 appeared to correlate with the ability to differentiate into plasma cells upon activation, suggesting that RDC1 is a marker for memory B cells, which are competent to become Ab-secreting cells.
Differential Role for Cyclic AMP Response Element Binding Protein-1 in Multiple Stages of B Cell Development, Differentiation, and Survival
Authors: Chen Hui-Chen , Byrd John C. , Muthusamy Natarajan 
Published: April 2014

Abstract
CREB-1 is expressed in the bone marrow and in developing B cells. To determine the role of CREB-1 in developing B cells in the bone marrow, several lines of transgenic (Tg) mice overexpressing a dominant-negative Ser119-ala phosphomutant CREB-1 in the bone marrow were generated. Analysis of RNA and protein revealed expression of the transgene in the bone marrow. Flow cytometric analysis of bone marrow cells from Tg mice revealed ∼70% increase in pre-B1 (CD43+B220+CD24+(int)) and ∼60% decreased pre-BII (CD43+B220+CD24++(high)) cells, indicating a developmental block in pre-BI to pre-BII transition. Consistent with this, the Tg mice showed ∼4-fold decrease in immature and mature B cells in the bone marrow. RT-PCR analysis of RNA from Tg mice revealed increased JunB and c-Jun in pre-BII cells associated with decreased S-phase entry. Adoptive transfer of bone marrow cells into RAG-2−/− mice resulted in reconstitution of non-Tg but not Tg bone marrow-derived CD43+B220+CD24high population that is normally absent in RAG-2−/− mice. In the periphery, the Tg mice exhibited decreased CD21dimCD23highIgM+ follicular B cells in the spleen and increased B1a and B1b B cells in the peritoneum. While exhibiting normal Ab responses to T-independent Ags and primary response to the T-dependent Ag DNP-keyhole limpet hemocyanin, the Tg mice exhibited severely impaired secondary Ab responses. These studies provide the first evidence for a differential role for CRE-binding proteins in multiple stages of B cell development, functional maturation, and B1 and B2 B cells.
The JNK Are Important for Development and Survival of Macrophages
Authors: Himes S. Roy , Sester David P. , Ravasi Timothy , Cronau Stephen L. , Sasmono Tedjo , Hume David A. 
Published: April 2014

Abstract
We report in this study that activation of the JNK by the growth factor, CSF-1 is critical for macrophage development, proliferation, and survival. Inhibition of JNK with two distinct classes of inhibitors, the pharmacological agent SP600125, or the peptide D-JNKI1 resulted in cell cycle inhibition with an arrest at the G2/M transition and subsequent apoptosis. JNK inhibition resulted in decreased expression of CSF-1R (c-fms) and Bcl-xL mRNA in mature macrophages and repressed CSF-1-dependent differentiation of bone marrow cells to macrophages. Macrophage sensitivity to JNK inhibitors may be linked to phosphorylation of the PU.1 transcription factor. Inhibition of JNK disrupted PU.1 binding to an element in the c-fms gene promoter and decreased promoter activity. Promoter activity could be restored by overexpression of PU.1. A comparison of expression profiles of macrophages with 22 other tissue types showed that genes that signal JNK activation downstream of tyrosine kinase receptors, such as focal adhesion kinase, Nck-interacting kinase, and Rac1 and scaffold proteins are highly expressed in macrophages relative to other tissues. This pattern of expression may underlie the novel role of JNK in macrophages.
Mast Cells Enhance T Cell Activation: Importance of Mast Cell Costimulatory Molecules and Secreted TNF
Authors: Nakae Susumu , Suto Hajime , Iikura Motoyasu , Kakurai Maki , Sedgwick Jonathon D. , Tsai Mindy , Galli Stephen J. 
Published: April 2014

Abstract
We recently reported that mast cells stimulated via FcεRI aggregation can enhance T cell activation by a TNF-dependent mechanism. However, the molecular mechanisms responsible for such IgE-, Ag- (Ag-), and mast cell-dependent enhancement of T cell activation remain unknown. In this study we showed that mouse bone marrow-derived cultured mast cells express various costimulatory molecules, including members of the B7 family (ICOS ligand (ICOSL), PD-L1, and PD-L2) and the TNF/TNFR families (OX40 ligand (OX40L), CD153, Fas, 4-1BB, and glucocorticoid-induced TNFR). ICOSL, PD-L1, PD-L2, and OX40L also are expressed on APCs such as dendritic cells and can modulate T cell function. We found that IgE- and Ag-dependent mast cell enhancement of T cell activation required secreted TNF; that TNF can increase the surface expression of OX40, ICOS, PD-1, and other costimulatory molecules on CD3+ T cells; and that a neutralizing Ab to OX40L, but not neutralizing Abs to ICOSL or PD-L1, significantly reduced IgE/Ag-dependent mast cell-mediated enhancement of T cell activation. These results indicate that the secretion of soluble TNF and direct cell-cell interactions between mast cell OX40L and T cell OX40 contribute to the ability of IgE- and Ag-stimulated mouse mast cells to enhance T cell activation.
A Polymeric Bacterial Protein Activates Dendritic Cells via TLR4
Authors: Berguer Paula M. , Mundiñano Juliana , Piazzon Isabel , Goldbaum Fernando A. 
Published: April 2014

Abstract
The enzyme lumazine synthase from Brucella spp. (BLS) is a highly immunogenic protein that folds as a stable dimer of pentamers. It is possible to insert foreign peptides and proteins at the 10 N terminus of BLS without disrupting its general folding, and these chimeras are very efficient to elicit systemic and oral immunity without adjuvants. In this study, we show that BLS stimulates bone marrow dendritic cells from mice in vitro to up-regulate the levels of costimulatory molecules (CD40, CD80, and CD86) and major histocompatibility class II Ag. Furthermore, the mRNA levels of several chemokines are increased, and proinflammatory cytokine secretion is induced upon exposure to BLS. In vivo, BLS increases the number of dendritic cells and their expression of CD62L in the draining lymph node. All of the observed effects are dependent on TLR4, and clearly independent of LPS contamination. The described characteristics of BLS make this protein an excellent candidate for vaccine development.