bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutting Edge: Modulation of Intestinal Autoimmunity and IL-2 Signaling by Sphingosine Kinase 2 Independent of Sphingosine 1-Phosphate
Authors: Samy Eileen T. , Meyer Claas A. , Caplazi Patrick , Langrish Claire L. , Lora Jose M. , Bluethmann Horst , Peng Stanford L. 
Published: April 2014

Abstract
Sphingosine kinase (Sphk) phosphorylates sphingosine into sphingosine-1-phosphate (S1P), but its recently identified isoform Sphk2 has been suggested to have distinct subcellular localization and substrate specificity. We demonstrate here that, surprisingly, Sphk2−/− CD4+ T cells exhibit a hyperactivated phenotype with significantly enhanced proliferation and cytokine secretion in response to IL-2 as well as reduced sensitivity to regulatory T cell-mediated suppression in vitro, apparently independent of effects upon S1P. Such findings appear to reflect a requirement for Sphk2 to suppress IL-2 signaling because, in Sphk2−/− CD4+ T cells, IL-2 induced abnormally accentuated STAT5 phosphorylation and small interfering RNA knockdown of STAT5 abrogated their hyperactive phenotype. This pathway physiologically modulates autoinflammatory responses, because Sphk2−/− T cells induced more rapid and robust inflammatory bowel disease in scid recipients. Thus, Sphk2 regulates IL-2 pathways in T cells, and the modulation of Sphk2 activity may be of therapeutic utility in inflammatory and/or infectious diseases.
Cutting Edge: Atypical PKCs Regulate T Lymphocyte Polarity and Scanning Behavior
Authors: Real Eliana , Faure Sophie , Donnadieu Emmanuel , Delon Jérôme 
Published: April 2014

Abstract
Leukocyte locomotion is a polarized process with diverse regulatory assemblies segregating along an anterior-posterior axis that defines two regions within the cell, the leading edge and the uropod. However, the mechanisms that generate T cell asymmetry downstream of chemokine receptors are ill defined. In this study we show that the atypical protein kinases C (aPKCs), PKCι and PKCζ, are required for an early symmetry breaking step. Once the polarity is established, aPKCs also drive uropod formation. These effects depend on the interaction between Par6 and aPKCs. Finally, failure to transduce aPKC-dependent signals reduces T cell motility and their ability to scan dendritic cells. Altogether, our findings suggest that lymphocyte motor activity is regulated by a signaling cascade that relays chemokinetic input to aPKCs.
Histone Acetylation at theIfngPromoter in Tolerized CD4 Cells Is Associated with Increased IFN-γ Expression during Subsequent Immunization to the Same Antigen
Authors: Long Meixiao , Slaiby Aaron M. , Wu Shuang , Hagymasi Adam T. , Mihalyo Marianne A. , Bandyopadhyay Suman , Vella Anthony T. , Adler Adam J. 
Published: April 2014

AbstractWhen naive CD4+ Th cells encounter cognate pathogen-derived Ags they expand and develop the capacity to express the appropriate effector cytokines for neutralizing the pathogen. Central to this differentiation process are epigenetic modifications within the effector cytokine genes that allow accessibility to the transcriptional machinery. In contrast, when mature self-reactive CD4 cells encounter their cognate epitopes in the periphery they generally undergo a process of tolerization in which they become hyporesponsive/anergic to antigenic stimulation. In the current study, we used a TCR transgenic adoptive transfer system to demonstrate that in a dose-dependent manner parenchymal self-Ag programs cognate naive CD4 cells to acetylate histones bound to the promoter region of the Ifng gene (which encodes the signature Th1 effector cytokine) during peripheral tolerization. Although the Ifng gene gains transcriptional competence, these tolerized CD4 cells fail to express substantial amounts of IFN-γ in response to antigenic stimulation apparently because a blockage in TCR-mediated signaling also develops. Nevertheless, responsiveness to antigenic stimulation is partially restored when self-Ag-tolerized CD4 cells are retransferred into mice infected with a virus expressing the same Ag. Additionally, there is preferential boosting in the ability of these CD4 cells to express IFN-γ relative to other cytokines with expression that also becomes impaired. Taken together, these results suggest that epigenetic modification of the Ifng locus during peripheral CD4 cell tolerization might allow for preferential expression of IFN-γ during recovery from tolerance.
Evidence for In Vivo Primed and Expanded Autoreactive T Cells as a Specific Feature of Patients with Type 1 Diabetes
Authors: Monti Paolo , Scirpoli Miriam , Rigamonti Andrea , Mayr Anya , Jaeger Annika , Bonfanti Riccardo , Chiumello Giuseppe , Ziegler Anette G. , Bonifacio Ezio 
Published: April 2014

Abstract
Identifying β cell autoantigen-reactive T cells that are involved in the pathogenesis of type 1 diabetes has been troublesome for many laboratories. Disease-relevant autoreactive T cells should be in vivo Ag experienced. The aim of this study was to test this hypothesis and then use this principle as a strategy for identifying diabetes-relevant autoreactive T cells. In this study, a CSFE dilution assay was used to detect glutamic acid decarboxylase 65 (GAD65)- and insulin-responsive T cells and HLA-0201*-GAD65114–122 pentamers were used to detect CD8+ GAD-responsive T cells in memory CD45RO+ and naive CD45RO− cell populations from patients with type 1 diabetes and healthy control subjects. T cell proliferative history was evaluated by flow cytometry telomere length measurement. CD4+ and CD8+ T cells specific for GAD65 and insulin were present in patients with type 1 diabetes and control subjects. Within the naive CD45RO− cells, CD4+ and CD8+ T cell responses were similar between patients and controls. Within the memory CD45RO+ cells, CD4+ T cell responses against whole GAD65 and insulin and HLA-0201*-GAD65114–122 pentamer-positive CD8+ T cells were found in patients with type 1 diabetes, but not in control subjects (p &lt; 0.05 for all). Responding cells from the CD45RO+ T cell population had substantially shorter telomere lengths than responding cells from the CD45RO− cell population. Diabetes-specific autoreactive T cells in the circulation have uniquely undergone sustained in vivo proliferation and differentiation into memory T cells. Prior selection of these cells is possible and is a way to identify diabetes-relevant target Ags and epitopes.
IL-6 and Maturation Govern TLR2 and TLR4 Induced TLR Agonist Tolerance and Cross-Tolerance in Dendritic Cells
Authors: Geisel Julia , Kahl Frauke , Müller Martina , Wagner Hermann , Kirschning Carsten J. , Autenrieth Ingo B. , Frick Julia-Stefanie 
Published: April 2014

Abstract
Stimulation of naive mouse dendritic cells (DC) with LPS or Pam3CSK4 (P3C) induces production of TNF-α via TLR4- or TLR2-signaling. Although tolerance in macrophages has been studied in detail, we investigated the role of TLR agonist concentration and IL-6 for tolerance in DC. P3C- or LPS-primed DC were nonresponsive to P3C or LPS restimulation in terms of TNF-α but not IL-6 production. The mechanisms involved in tolerance were dependent on the concentration of the TLR ligand used for DC priming. DC primed with LPS or P3C at high concentrations developed a maturation dependent, IL-6 independent tolerance associated with inhibition of TLR signaling upstream of IκB as indicated by decreased IκB degradation. In contrast, priming of DC with LPS or P3C at low concentrations resulted in IL-6-dependent tolerance, which was abolished in IL-6 deficient DC, and was not accompanied by maturation of DC or by down-regulation of TLR2 or TLR4. In homotolerogenic DC primed with LPS or P3C at high concentrations, degradation of IκB upon restimulation with LPS or P3C was inhibited suggesting tolerance mechanism(s) upstream of IκB; in contrast, cross-tolerance in DC primed with LPS or P3C at low concentrations was not associated with reduced IκB degradation suggesting tolerance mechanisms downstream of IκB. Our data indicate that in naive DC TLR4- and TLR2-stimulation results in homo- and cross-tolerance; the mechanisms involved in tolerance depend on the concentration of the TLR agonist used for DC priming and are governed by IL-6 and maturation.
Quantitative Time-Resolved Phosphoproteomic Analysis of Mast Cell Signaling
Authors: Cao Lulu , Yu Kebing , Banh Cindy , Nguyen Vinh , Ritz Anna , Raphael Benjamin J. , Kawakami Yuko , Kawakami Toshiaki , Salomon Arthur R. 
Published: April 2014

Abstract
Mast cells play a central role in type I hypersensitivity reactions and allergic disorders such as anaphylaxis and asthma. Activation of mast cells, through a cascade of phosphorylation events, leads to the release of mediators of the early phase allergic response. Understanding the molecular architecture underlying mast cell signaling may provide possibilities for therapeutic intervention in asthma and other allergic diseases. Although many details of mast cell signaling have been described previously, a systematic, quantitative analysis of the global tyrosine phosphorylation events that are triggered by activation of the mast cell receptor is lacking. In many cases, the involvement of particular proteins in mast cell signaling has been established generally, but the precise molecular mechanism of the interaction between known signaling proteins often mediated through phosphorylation is still obscure. Using recently advanced methodologies in mass spectrometry, including automation of phosphopeptide enrichments and detection, we have now substantially characterized, with temporal resolution as short as 10 s, the sites and levels of tyrosine phosphorylation across 10 min of FcεRI-induced mast cell activation. These results reveal a far more extensive array of tyrosine phosphorylation events than previously known, including novel phosphorylation sites on canonical mast cell signaling molecules, as well as unexpected pathway components downstream of FcεRI activation. Furthermore, our results, for the first time in mast cells, reveal the sequence of phosphorylation events for 171 modification sites across 121 proteins in the MCP5 mouse mast cell line and 179 modification sites on 117 proteins in mouse bone marrow-derived mast cells.
Glucocorticoid-Induced TNFR-Related Protein Lowers the Threshold of CD28 Costimulation in CD8+ T Cells
Authors: Ronchetti Simona , Nocentini Giuseppe , Bianchini Rodolfo , Krausz L. Tibor , Migliorati Graziella , Riccardi Carlo 
Published: April 2014

Abstract
CD28 is well characterized as a costimulatory molecule in T cell activation. Recent evidences indicate that TNFR superfamily members, including glucocorticoid-induced TNFR-related protein (GITR), act as costimulatory molecules. In this study, the relationship between GITR and CD28 has been investigated in murine CD8+ T cells. When suboptimal doses of anti-CD3 Ab were used, the absence of GITR lowered CD28-induced activation in these cells whereas the lack of CD28 did not affect the response of CD8+ T cells to GITR costimulus. In fact, costimulation of CD28 in anti-CD3-activated GITR−/− CD8+ T cells resulted in an impaired increase of proliferation, impaired protection from apoptosis, and an impaired rise of activation molecules such as IL-2R, IL-2, and IFN-γ. Most notably, CD28-costimulated GITR−/− CD8+ T cells revealed lower NF-κB activation. As a consequence, up-regulation of Bcl-xL, one of the major target proteins of CD28-dependent NF-κB activation, was defective in costimulated GITR−/− CD8+ T cells. What contributed to the response to CD28 ligation in CD8+ T cells was the early up-regulation of GITR ligand on the same cells, the effect of which was blocked by the addition of a recombinant GITR-Fc protein. Our results indicate that GITR influences CD8+ T cell response to CD28 costimulation, lowering the threshold of CD8+ T cell activation.
In Vitro and In Vivo Activation Induces BAFF and APRIL Expression in B Cells
Authors: Chu Van Trung , Enghard Philipp , Riemekasten Gabriela , Berek Claudia 
Published: April 2014

Abstract
B cell-activating factor (BAFF) and a proliferation-inducing ligand (APRIL) play key roles in peripheral B cell survival, maturation, and differentiation. BAFF and APRIL are produced by a variety of cell types such as macrophages/monocytes and dendritic cells. Our analysis shows that BAFF mRNA is also expressed in all B cell subsets isolated from bone marrow, spleen, and peritoneal cavity of BALB/c mice. APRIL expression is restricted to early stages of B cell development in the bone marrow and the peritoneal B1 subset. Stimulation of B2 and B1 cells with LPS or CpG-oligodeoxynucleotides induced MyD88-dependent plasma cell differentiation and intracellular expression of BAFF and APRIL. Furthermore, activation of B cells up-regulated membrane expression of BAFF. The finding that in vitro activation of B cells is inhibited by the antagonist transmembrane activator and calcium modulator ligand interactor Ig, indicates that BAFF and/or APRIL are released into the culture supernatants. It shows that B cell survival, proliferation, and differentiation are supported by an autocrine pathway. In vivo activation of B cells with a T-dependent Ag- induced BAFF expression in germinal center B cells. In (NZB × NZW)F1 mice with established autoimmune disease, marginal zone, germinal center B cells, as well as splenic plasma cells expressed high levels of BAFF. In (NZB × NZW)F1 mice, the continuous activation of B cells and thus overexpression of BAFF and APRIL may contribute to the development of autoimmune disease.
Molecular Mechanism of Lipopolysaccharide-Induced SOCS-3 Gene Expression in Macrophages and Microglia
Authors: Qin Hongwei , Roberts Kevin L. , Niyongere Sandrine A. , Cong Yingzi , Elson Charles O. , Benveniste Etty N. 
Published: April 2014

AbstractImmunological activation of macrophages/microglia within the CNS leads to the production of cytokines and chemokines that ultimately impact on glial and neuronal function. Suppressor of cytokine signaling (SOCS) proteins are negative regulators of adaptive and innate immune responses. Our previous studies demonstrated that SOCS-3 attenuates macrophage/microglial activation in vitro, suggesting that SOCS-3 may exert beneficial effects for immune-mediated CNS diseases in vivo. In this study, we describe LPS as a potent inducer of SOCS-3 transcription and expression in macrophages/microglia. An analysis of the SOCS-3 promoter indicates that AP-1 and IFN-γ activation sequence (GAS) elements are involved in LPS-induced SOCS-3 transcription. LPS-induced SOCS-3 expression was diminished in IL-10-deficient macrophages at later time points, indicating the involvement of endogenous IL-10 in this response. Blocking STAT-3 expression and activation using STAT-3 small interfering RNA reduced LPS-induced SOCS-3 gene expression. LPS activated the MAPK-ERK1/2, JNK, and p38 pathways that, in addition to STAT-3, were also involved in LPS-induced SOCS-3 expression. LPS treatment of cells led to the acetylation of histones H3 and H4 on the SOCS-3 promoter and the recruitment of STAT-3, c-Jun, c-Fos, CREB-binding protein, p300, and RNA polymerase II to the endogenous SOCS-3 promoter in a time-dependent manner. These results indicate that LPS-induced MAPK activation, the production of endogenous IL-10, and STAT-3 activation play critical roles in SOCS-3 expression, which provides for feedback attenuation of cytokine-induced immune and inflammatory responses in macrophages and microglia.
Hierarchy of the Human Natural Killer Cell Response Is Determined by Class and Quantity of Inhibitory Receptors for Self-HLA-B and HLA-C Ligands
Authors: Yu Junli , Heller Glenn , Chewning Joseph , Kim Sungjin , Yokoyama Wayne M. , Hsu Katharine C. 
Published: April 2014

Abstract
The interaction of NK inhibitory killer Ig-like receptors (KIRs) with self-MHC class I molecules mediates NK tolerance to self while conferring functional competence. Through single-cell analysis of intracellular IFN-γ production and NK clone cytotoxicity we evaluated the resting NK repertoire, analyzing the responsiveness of NK subgroups expressing discrete combinations of non-KIR and KIR class I-specific receptors. CD94:NKG2A and Ig-like transcript 2 (ILT2)-expressing cells have a modest response to class I-negative target cells, but NK cells expressing inhibitory KIRs to self-MHC class I ligands, both HLA-B and HLA-C ligands, achieve significantly higher effector capacity. There is a dose effect of KIR for self-MHC on effector capacity, but even in the most highly responsive NK cells expressing more than one inhibitory KIR for self-MHC the presentation of only one cognate MHC ligand is sufficient to abolish response. Among KIR+ cells there is preferential expression for inhibitory KIR for self-MHC. The likelihood of KIR expression is influenced by whether other KIRs are already expressed on the same cell, supporting a model of serial acquisition of KIR expression. These findings define how inhibitory receptor and autologous HLA interactions impact single-cell function and demonstrate that the resting human NK repertoire is highly attuned but variegated in response. These findings have important implications for the resting NK response to viral pathogens and malignancy, for donor selection in allogeneic hemopoietic cell transplantation, and for models of NK tolerance.
A Crucial Role for Dendritic Cell (DC) IL-10 in Inhibiting Successful DC-Based Immunotherapy: Superior Antitumor Immunity against Hepatocellular Carcinoma Evoked by DC Devoid of IL-10
Authors: Chen Yu-Xiao , Man Kwan , Ling Guang Sheng , Chen Yichen , Sun Bai-Shun , Cheng Qiao , Wong On Hong , Lo Chi-Kin , Ng Irene Oi-Lin , Chan Li Chong , Lau George K. , Lin Chen-Lung Steve , Huang Fanglu , Huang Fang-Ping 
Published: April 2014

Abstract
The dendritic cell (DC)-based tumor immunotherapy has been a new promise of cure for cancer patients, but animal studies and clinical trials have thus far only shown limited success, especially in treating established tumors. Certain immunosuppressive mechanisms triggered by tumor cells or the derivatives are believed to be a major obstacle. We studied the role of DC-derived IL-10 and its negative impact on vaccine efficacy in mouse models. Liver tumor cells were injected via the portal vein, giving rise to disseminated intrahepatic tumors, or s.c. to form solid but extrahepatic tumors. Bone marrow-derived DCs were generated from normal or IL-10-deficient mice and used as the vector to deliver tumor Ags. We demonstrate here that DCs devoid of IL-10, a potent immunosuppressive cytokine, are superior over conventional DCs in triggering antitumor immunity. The IL-10−/−DCs were highly immunogenic, expressed enhanced levels of surface MHC class II molecules, and secreted increased amounts of Th1-related cytokines. By inducing tumor-specific killing and through the establishment of immunological memory, the vaccines delivered by IL-10−/−DCs could evoke strong therapeutic and protective immunity against hepatocellular carcinoma in the mouse models. These findings will have great clinical impact once being translated into the treatment of malignant, and potentially infectious, diseases in humans.
Geranylgeranylation but Not GTP Loading Determines Rho Migratory Function in T Cells
Authors: Waiczies Sonia , Bendix Ivo , Prozorovski Timour , Ratner Maya , Nazarenko Irina , Pfueller Caspar F. , Brandt Alexander U. , Herz Josephine , Brocke Stefan , Ullrich Oliver , Zipp Frauke 
Published: April 2014

Abstract
Rho GTPases orchestrate signaling pathways leading to cell migration. Their function depends on GTP loading and isoprenylation by geranylgeranyl pyrophosphate (GGpp). In this study, we show that in human T cells, geranylgeranylation—and not GTP loading—is necessary for RhoA-mediated downstream events. As a result of GGpp depletion with the 3-hydroxy-3-methylglutaryl-CoA reductase inhibitor atorvastatin, RhoA was sequestered from the membrane to the cytosol and, notwithstanding increased GTP loading, the constitutive activation of its substrate Rho-associated coiled-coil protein kinase-1 was blocked. In line with this, T cells expressing increased GTP-RhoA failed to form an intact cytoskeleton and to migrate toward a chemokine gradient. In vivo treatment with atorvastatin in the rodent model of multiple sclerosis markedly decreased the capacity of activated T cells to traffic within the brain, as demonstrated by multiphoton analysis. Thus, tethering of RhoA to the membrane by GGpp is determinant for T cell migration and provides a mechanism for preventing T cell infiltration into inflamed compartments by 3-hydroxy-3-methylglutaryl-CoA reductase inhibitors,
The 3′ IgH Locus Control Region Is Sufficient to Deregulate a c-myc Transgene and Promote Mature B Cell Malignancies with a Predominant Burkitt-Like Phenotype
Authors: Truffinet Véronique , Pinaud Eric , Cogné Nadine , Petit Barbara , Guglielmi Laurence , Cogné Michel , Denizot Yves 
Published: April 2014

Abstract
Burkitt lymphoma (BL) features translocations linking c-myc to an Ig locus. Breakpoints in the H chain locus (IgH) stand either close to JH or within switch regions and always link c-myc to the 3′ IgH locus control region (3′ LCR). To test the hypothesis that the 3′ LCR alone was sufficient to deregulate c-myc, we generated mice carrying a 3′ LCR-driven c-myc transgene and specifically up-regulating c-myc in B cells. Splenic B cells from mice proliferated exaggeratedly in response to various signals had an elevated apoptosis rate but normal B220/IgM/IgD expression. Although all Ig levels were lowered in vivo, class switching and Ig secretion proved normal in vitro. Beginning at the age of 12 wk, transgenic mice developed clonal lymphoblastic lymphomas or diffuse anaplastic plasmacytomas with an overall incidence of 80% by 40 wk. Lymphoblastic lymphomas were B220+IgM+IgD+ with the BL “starry sky” appearance. Gene expression profiles revealed broad alterations in the proliferation program and the Ras-p21 pathway. Our study demonstrates that 3′ IgH enhancers alone can deregulate c-myc and initiate the development of BL-like lymphomas. The rapid and constant occurrence of lymphoma in this model makes it valuable for the understanding and the potential therapeutic manipulation of c-myc oncogenicity in vivo.