bluuebunny/crossref_metadata_2025_split huggingface dataset:
Dual Role of the Jak1 FERM and Kinase Domains in Cytokine Receptor Binding and in Stimulation-Dependent Jak Activation
Authors: Haan Serge , Margue Christiane , Engrand Arnaud , Rolvering Catherine , Schmitz-Van de Leur Hildegard , Heinrich Peter C. , Behrmann Iris , Haan Claude 
Published: April 2014

Abstract
Jak1 is a tyrosine kinase that noncovalently forms tight complexes with a variety of cytokine receptors and is critically involved in signal transduction via cytokines. Jaks are predicted to have a 4.1, ezrin, radixin, moesin (FERM) domain at their N terminus. FERM domains are composed of three structurally unrelated subdomains (F1, F2, and F3) which are in close contact to one another and form the clover-shaped FERM domain. We generated a model structure of the Jak1 FERM domain, based on solved FERM structures and the alignments with other FERM domains. To destabilize different subdomains and to uncover their exact function, we mutated specific hydrophobic residues conserved in FERM domains and involved in hydrophobic core interactions. In this study, we show that the structural integrity of the F2 subdomain of the FERM domain of Jak1 is necessary to bind the IFN-γRα. By mutagenesis of hydrophobic residues in the hydrophobic core between the three FERM subdomains, we find that the structural context of the FERM domain is necessary for the inhibition of Jak1 phosphorylation. Thus, FERM domain mutations can have repercussions on Jak1 function. Interestingly, a mutation in the kinase domain (Jak1-K907E), known to abolish the catalytic activity, also leads to an impaired binding to the IFN-γRα when this mutant is expressed at endogenous levels in U4C cells. Our data show that the structural integrity of both the FERM domain and of the kinase domain is essential for both receptor binding and catalytic function/autoinhibition.
IFN-α Skews Monocytes into CD56+-Expressing Dendritic Cells with Potent Functional Activities In Vitro and In Vivo
Authors: Papewalis Claudia , Jacobs Benedikt , Wuttke Margret , Ullrich Evelyn , Baehring Thomas , Fenk Roland , Willenberg Holger S. , Schinner Sven , Cohnen Mathias , Seissler Jochen , Zacharowski Kai , Scherbaum Werner A. , Schott Matthias 
Published: April 2014

Abstract
The antitumor effect of IFN-α is mediated by the activation of CTLs, NK cells, and the generation of highly potent Ag-presenting dendritic cells (IFN-DCs). In this study, we show that IFN-DCs generated in vitro from monocytes express CD56 on their surface, a marker which has been thought to be specific for NK cells. FACS analyses of CD56+ and CD56− IFN-DCs showed a nearly identical pattern for most of the classical DC markers. Importantly, however, only CD56+ IFN-DCs exhibited cytolytic activity up to 24% that could almost completely be blocked (−81%) after coincubation with anti-TRAIL. Intracytoplasmatic cytokine staining revealed that the majority of IFN-DCs independently of their CD56 expression were IFN-γ positive as well. In contrast, CD56+ IFN-DCs showed stronger capacity in stimulating allogenic T cells compared with CD56− IFN-DC. Based on these results, five patients with metastasized medullary thyroid carcinoma were treated for the first time with monocyte-derived tumor Ag-pulsed IFN-DCs. After a long term follow-up (in mean 37 mo) all patients are alive. Immunohistochemical analyses of delayed-type hypersensitivity skin reaction showed a strong infiltration with CD8+ cells. In two patients no substantial change in tumor morphology was detected. Importantly, by analyzing PBMCs, these patients also showed an increase of Ag-specific IFN-γ-secreting T cells. In summary, we here describe for the first time that cytotoxic activity of IFN-DCs is mainly mediated by an IFN-DC subset showing partial phenotypic and functional characteristics of NK cells. These cells represent another mechanism of the antitumor effect induced by IFN-α.
A Peptide That Ameliorates Lupus Up-Regulates the Diminished Expression of Early Growth Response Factors 2 and 3
Authors: Sela Uri , Dayan Molly , Hershkoviz Rami , Lider Ofer , Mozes Edna 
Published: April 2014

Abstract
Expansion of autoreactive T cells and their resistance to anergy was demonstrated in systemic lupus erythematosus (SLE). A pair of transcription factors, early growth response 2 (Egr-2) and 3 (Egr-3), are negative regulators of T cell activation that were shown to be important in anergy. A peptide (designated hCDR1 for human CDR1) based on the CDR-1 of an anti-DNA Ab ameliorated SLE in both induced and spontaneous lupus models. Our objectives were to determine the expression levels of Egr-2 and Egr-3 in autoreactive T cells following immunization with the lupus-inducing anti-DNA Ab that bears a common Id designated 16/6Id and also in a full-blown SLE and to determine the effect of hCDR1 on these transcription factors. We demonstrated diminished expression levels of Egr-2 and Egr-3 mRNA both early after immunization with the 16/6Id and in SLE-afflicted (NZB × NZW)F1 (New Zealand Black and New Zealand White) mice. Furthermore, by down-regulating Akt phosphorylation and up-regulating TGFβ secretion, treatment with hCDR1 significantly up-regulated Egr-2 and Egr-3 expression. This was associated with an increased expression of the E3 ligase Cbl-b. Inhibition of Akt in T cells of immunized mice decreased, whereas silencing of the Egr-2 and Egr-3 in T cells of hCDR1-treated mice increased IFN-γ secretion. Thus, hCDR1 down-regulates Akt phosphorylation, which leads to up-regulated expression of T cell Egr-2 and Egr-3, resulting in the inhibition of IFN-γ secretion that is required for the maintenance of SLE.
Human Mesenchymal Stem Cells License Adult CD34+ Hemopoietic Progenitor Cells to Differentiate into Regulatory Dendritic Cells through Activation of the Notch Pathway
Authors: Li Yin-Ping , Paczesny Sophie , Lauret Evelyne , Poirault Sonia , Bordigoni Pierre , Mekhloufi Fatiha , Hequet Olivier , Bertrand Yves , Ou-Yang Jing-Ping , Stoltz Jean-François , Miossec Pierre , Eljaafari Assia 
Published: April 2014

Abstract
The mechanisms underlying the immunomodulatory functions of mesenchymal stem cells (MSC) on dendritic cells (DC) have been shown to involve soluble factors, such as IL-6 or TGF-β, or cell-cell contact, or both depending on the report referenced. In this study, we intend to clarify these mechanisms by examining the immunosuppressive effect of human adult MSC on adult DC differentiated from CD34+ hemopoietic progenitor cells (HPC). MSC have been shown to inhibit interstitial DC differentiation from monocytes and umbilical CD34+ HPC. In this study, we confirm that MSC not only halt interstitial DC but also Langerhans cell differentiation from adult CD34+ HPC, as assessed by the decreased expression of CD1a, CD14, CD86, CD80, and CD83 Ags on their cell surface. Accordingly, the functional capacity of CD34+ HPC-derived DC (CD34-DC) to stimulate alloreactive T cells was impaired. Furthermore, we showed that 1) MSC inhibited commitment of CD34+ HPC into immature DC, but not maturation of CD34-DC, 2) this inhibitory effect was reversible, and 3) DC generated in coculture with MSC (MSC-DC) induced the generation of alloantigen-specific regulatory T cells following secondary allostimulation. Conditioned medium from MSC cultures showed some inhibitory effect independent of IL-6, M-CSF, and TGF-β. In comparison, direct coculture of MSC with CD34+ HPC resulted in much stronger immunosuppressive effect and led to an activation of the Notch pathway as assessed by the overexpression of Hes1 in MSC-DC. Finally, DAPT, a γ-secretase inhibitor that inhibits Notch signaling, was able to overcome MSC-DC defects. In conclusion, our data suggest that MSC license adult CD34+ HPC to differentiate into regulatory DC through activation of the Notch pathway.
The Soluble Leukocyte-Associated Ig-Like Receptor (LAIR)-2 Antagonizes the Collagen/LAIR-1 Inhibitory Immune Interaction
Authors: Lebbink Robert Jan , van den Berg Maaike C. W. , de Ruiter Talitha , Raynal Nicolas , van Roon Joel A. G. , Lenting Peter J. , Jin Boquan , Meyaard Linde 
Published: April 2014

Abstract
Leukocyte-associated Ig-like receptor (LAIR)-1 is a collagen-receptor that inhibits immune cell function upon collagen binding. Next to LAIR-1, the human genome encodes LAIR-2, a putative soluble homolog. In this study we show, for the first time, that the LAIR-2 gene is broadly transcribed in human PBMC, mirroring the expression profile of LAIR-1. LAIR-2 protein is expressed as a soluble receptor exhibiting high affinity for various collagen molecules to which it binds in a hydroxyproline-dependent manner. In vitro stimulation of PBMC induces secretion of LAIR-2. We detect high amounts of LAIR-2 in urine of pregnant women, indicating that the soluble receptor is indeed produced in vivo and can be cleared from the body via urine. Furthermore, LAIR-2 levels are increased in synovial fluid of patients with rheumatoid arthritis as compared with osteoarthritis patients. We hypothesize that soluble LAIR-2 may function as a natural competitor for LAIR-1, thereby regulating its inhibitory potential. Indeed, LAIR-2 prevents binding of human LAIR-1 to collagens and LAIR-1 cross-linking in vitro, suggesting that the protein has an immunoregulatory function in vivo. Hence, we reveal a novel mechanism of immune regulation by a soluble LAIR receptor regulating the inhibitory potential of the membrane-bound LAIR-1 via competition for ligands.
Infection with Trypanosoma cruzi Restricts the Repertoire of Parasite-Specific CD8+ T Cells Leading to Immunodominance
Authors: Tzelepis Fanny , de Alencar Bruna C. G. , Penido Marcus L. O. , Claser Carla , Machado Alexandre V. , Bruna-Romero Oscar , Gazzinelli Ricardo T. , Rodrigues Mauricio M. 
Published: April 2014

Abstract
Interference or competition between CD8+ T cells restricted by distinct MHC-I molecules can be a powerful means to establish an immunodominant response. However, its importance during infections is still questionable. In this study, we describe that following infection of mice with the human pathogen Trypanosoma cruzi, an immunodominant CD8+ T cell immune response is developed directed to an H-2Kb-restricted epitope expressed by members of the trans-sialidase family of surface proteins. To determine whether this immunodominance was exerted over other non-H-2Kb-restricted epitopes, we measured during infection of heterozygote mice, immune responses to three distinct epitopes, all expressed by members of the trans-sialidase family, recognized by H-2Kb-, H-2Kk-, or H-2Kd-restricted CD8+ T cells. Infected heterozygote or homozygote mice displayed comparably strong immune responses to the H-2Kb-restricted immunodominant epitope. In contrast, H-2Kk- or H-2Kd-restricted immune responses were significantly impaired in heterozygote infected mice when compared with homozygote ones. This interference was not dependent on the dose of parasite or the timing of infection. Also, it was not seen in heterozygote mice immunized with recombinant adenoviruses expressing T. cruzi Ags. Finally, we observed that the immunodominance was circumvented by concomitant infection with two T. cruzi strains containing distinct immunodominant epitopes, suggesting that the operating mechanism most likely involves competition of T cells for limiting APCs. This type of interference never described during infection with a human parasite may represent a sophisticated strategy to restrict priming of CD8+ T cells of distinct specificities, avoiding complete pathogen elimination by host effector cells, and thus favoring host parasitism.
Inhibition of HIV-1 Infectivity through an Innate Mechanism Involving Naturally Occurring IgM Anti-Leukocyte Autoantibodies
Authors: Lobo Peter I. , Schlegel Kailo H. , Yuan Wen , Townsend Gregory C. , White Jennifer A. 
Published: April 2014

Abstract
In prior studies, we show that naturally occurring IgM anti-leukocyte autoantibodies (IgM-ALA) bind to CD3, CD4, CCR5, and CXCR4 receptors. These observations prompted us to determine whether IgM-ALA have a role in inhibiting HIV-1 infectivity by inhibiting viral entry into cells. We show that purified IgM, but not IgG, from individual sera of both normal and HIV-1 infected individuals is highly inhibitory (&gt;95%) to HIV-1 viral infectivity both in vitro using PHA plus IL-2 activated PBL and in vivo using the human PBL-SCID mouse. Inhibition was observed with physiological doses of purified serum IgM and even after IgM was added 3 days postinfection in the in vitro assays. Absorbing purified serum IgM either with leukocytes or immobilized recombinant CD4 significantly decreased (&gt;80%) the inhibitory effect on HIV-1 infectivity. IgM inhibited by &gt;90% syncytia formation with the X4-IIIB infected SupT-1 cells indicating therefore that IgM inhibits viral attachment to core-receptors. IgM mediated anti-HIV-1 activity was highly specific as only certain IgM-ALA, obtained from human B cell clones inhibited HIV-1. IgM from certain HIV-1 infected individuals were not inhibitory to some R5-HIV-1 viral strains indicating that certain HIV-IgM may lack Abs reactive to strain specific coreceptor epitopes. These data indicate that an innate immune mechanism which is present from birth i.e., IgM-ALA, has a role in inhibiting HIV-1 viral entry into cells. Validation of this data with other in vivo models will be needed to determine whether in vivo administration or enhancement of IgM-ALA, e.g., through a vaccine, could prolong the asymptomatic state in HIV-1 infected individuals.
Vitamin A Deficiency Decreases and High Dietary Vitamin A Increases Disease Severity in the Mouse Model of Asthma
Authors: Schuster Gertrud U. , Kenyon Nicholas J. , Stephensen Charles B. 
Published: April 2014

Abstract
The Th1/Th2 paradigm has become an important issue in the pathogenesis of asthma, characterized by normal Th1 and elevated Th2 cytokine expression. Vitamin A deficiency (VAD) can produce a Th1 bias, whereas high-level dietary vitamin A can promote a Th2 bias. We used the OVA exposure mouse model to determine the contributions of vitamin A-deficient, control (4IU/g), and high-level vitamin A (250-IU/g) diets to the development of allergic airway inflammation and hyperresponsiveness. VAD reduced serum IgE and IgG1 responses, pulmonary eosinophilia, and the levels of IL-4 and IL-5 in bronchoalveolar lavage specimens, whereas the 250-IU/g diet increased serum IgE. Also, VAD blocked pulmonary hyperresponsiveness following methacholine challenge while the 250-IU/g diet exacerbated pulmonary hyperresponsiveness. In conclusion, VAD diminished and high-level dietary vitamin A enhanced the development of experimental asthma in this model system. These data suggest that excessive intake of vitamin A may increase the risk or severity of asthma in industrialized countries whereas vitamin A deficiency continues to increase mortality from infectious diseases in developing countries.
Activation of Peroxisome Proliferator-Activated Receptor γ (PPARγ) Suppresses Rho GTPases in Human Brain Microvascular Endothelial Cells and Inhibits Adhesion and Transendothelial Migration of HIV-1 Infected Monocytes
Authors: Ramirez Servio H. , Heilman David , Morsey Brenda , Potula Raghava , Haorah James , Persidsky Yuri 
Published: April 2014

Abstract
Under inflammatory conditions (including HIV-1 encephalitis and multiple sclerosis), activated brain endothelium enhances the adhesion and transmigration of monocytes across the blood-brain barrier (BBB). Synthetic ligands that activate the peroxisome proliferator-activated receptors (PPARs) have anti-inflammatory properties, and PPAR stimulation prevents the interaction of leukocytes with cytokine stimulated-endothelium. However, the mechanism underlying these effects of PPAR ligands and their ability to intervene with leukocyte adhesion and migration across brain endothelial cells has yet to be explored. For the first time, using primary human brain endothelial cells (BMVEC), we demonstrated that monocyte adhesion and transendothelial migration across inflamed endothelium were markedly reduced by PPARγ activation. In contrast to non-brain-derived endothelial cells, PPARα activation in the BMVEC had no significant effect on monocyte-endothelial interaction. Previously, our work indicated a critical role of Rho GTPases (like RhoA) in BMVEC to control migration of HIV-1 infected monocytes across BBB. In this study, we show that in the BMVEC PPARγ stimulation prevented activation of two GTPases, Rac1 and RhoA, which correlated with decreased monocyte adhesion to and migration across brain endothelium. Relevant to HIV-1 neuropathogenesis, enhanced adhesion and migration of HIV-1 infected monocytes across the BBB were significantly reduced when BMVEC were treated with PPARγ agonist. These findings indicate that Rac1 and RhoA inhibition by PPARγ agonists could be a new approach for treatment of neuroinflammation by preventing monocyte migration across the BBB.
TNF Receptor-Associated Factor 1 Expressed in Resident Lung Cells Is Required for the Development of Allergic Lung Inflammation
Authors: Oyoshi Michiko K. , Bryce Paul , Goya Sho , Pichavant Muriel , Umetsu Dale T. , Oettgen Hans C. , Tsitsikov Erdyni N. 
Published: April 2014

Abstract
TNF is a major therapeutic target in a range of chronic inflammatory disorders, including asthma. TNFR-associated factor (TRAF)1 is an intracellular adaptor molecule important for signaling by TNFR. In this study, we investigated the role of TRAF1 in an adoptive transfer model of allergic lung inflammation. Mice deficient in TRAF1 (TRAF1−/−) and wild-type (WT) control animals were adoptively transferred with WT OVA-immune CD4+ T cells, exposed to an aerosol of LPS-free OVA, and analyzed for the development of allergic lung inflammation. In contrast to WT mice, TRAF1−/− recipients failed to display goblet cell hyperplasia, eosinophilic inflammation, and airway hyperresponsiveness in this model of asthma. Neither T cell recruitment nor expression of the proinflammatory cytokines IL-4, IL-5, IL-13, or TNF occurred in the lungs of TRAF1−/− mice. Although purified myeloid TRAF1−/− dendritic cells (DCs) exhibited normal Ag-presenting function and transmigratory capacity in vitro and were able to induce OVA-specific immune responses in the lung draining lymph nodes (LNs) following adoptive transfer in vivo, CD11c+CD11b+ DCs from airways of TRAF1−/− recipients were not activated, and purified draining LN cells did not proliferate in vitro. Moreover, transfer of WT or TRAF1−/− DCs failed to restore T cell recruitment and DC activation in the airways of TRAF1−/− mice, suggesting that the expression of TRAF1 in resident lung cells is required for the development of asthma. Finally, we demonstrate that T cell-transfused TRAF1−/− recipient mice demonstrated impaired up-regulation of ICAM-1 expression on lung cells in response to OVA exposure.
Activated Renal Macrophages Are Markers of Disease Onset and Disease Remission in Lupus Nephritis
Authors: Schiffer Lena , Bethunaickan Ramalingam , Ramanujam Meera , Huang Weiqing , Schiffer Mario , Tao Haiou , Madaio Michael M. , Bottinger Erwin P. , Davidson Anne 
Published: April 2014

Abstract
Costimulatory blockade with CTLA4Ig and anti-CD40L along with a single dose of cyclophosphamide induces remission of systemic lupus erythematosus nephritis in NZB/W F1 mice. To understand the mechanisms for remission and for impending relapse, we examined the expression profiles of 61 inflammatory molecules in the perfused kidneys of treated mice and untreated mice at different stages of disease. Further studies using flow cytometry and immunohistochemistry allowed us to determine the cellular origins of several key markers. We show that only a limited set of inflammatory mediators is expressed in the kidney following glomerular immune complex deposition but before the onset of proteinuria. Formation of a lymphoid aggregate in the renal pelvis precedes the invasion of the kidney by inflammatory cells. Regulatory molecules are expressed early in the disease process and during remission but do not prevent the inevitable progression of active inflammation. Onset of proliferative glomerulonephritis and proteinuria is associated with activation of the renal endothelium, expression of chemokines that mediate glomerular cell infiltration, and infiltration by activated dendritic cells and macrophages that migrate to different topographical areas of the kidney but express a similar profile of inflammatory cytokines. Increasing interstitial infiltration by macrophages and progressive tubular damage, manifested by production of lipocalin-2, occur later in the disease process. Studies of treated mice identify a type II (M2b)-activated macrophage as a marker of remission induction and impending relapse and suggest that therapy for systemic lupus erythematosus nephritis should include strategies that prevent both activation of monocytes and their migration to the kidney.
Induction of CD56 and TCR-Independent Activation of T Cells with Aging
Authors: Lemster Bonnie H. , Michel Joshua J. , Montag David T. , Paat John J. , Studenski Stephanie A. , Newman Anne B. , Vallejo Abbe N. 
Published: April 2014

Abstract
Degeneration of the thymus and severe contraction of the T cell repertoire with aging suggest that immune homeostasis in old age could be mediated by distinct effectors. Therefore, receptors expressed on T cells as they undergo senescence in vitro, as well as those displayed by circulating T cells during normal chronologic aging, were examined. Monitoring of T cells driven to senescence showed de novo induction of CD56, the prototypic receptor of NK cells. Analysis of fresh T cells in peripheral blood showed an age-dependent induction of CD56. These unusual T cells expressed high levels of Bcl2, p16, and p53, and had limited, or completely lost, ability to undergo cell division, properties consistent with senescence. CD56 cross-linking without TCR ligation on CD56+ T cells resulted in extensive protein phosphorylation, NF-κB activation, and Bax down-regulation. CD56 cross-linking was also sufficient to drive production of various humoral factors. These data suggest that the immunologic environment in old age is functionally distinct, rather than being a dysfunctional version of that seen at a young age. CD56+ T cells are unique effectors capable of mediating TCR-independent immune cascades that could be harnessed to enhance protective immunity in the elderly.
Tumor Immunotherapy by Epicutaneous Immunization Requires Langerhans Cells
Authors: Stoitzner Patrizia , Green Laura K. , Jung Jae Y. , Price Kylie M. , Tripp Christoph H. , Malissen Bernard , Kissenpfennig Adrien , Hermans Ian F. , Ronchese Franca 
Published: April 2014

Abstract
A role for Langerhans cells (LC) in the induction of immune responses in the skin has yet to be conclusively demonstrated. We used skin immunization with OVA protein to induce immune responses against OVA-expressing melanoma cells. Mice injected with OVA-specific CD8+ T cells and immunized with OVA onto barrier-disrupted skin had increased numbers of CD8+ T cells in the blood that produced IFN-γ and killed target cells. These mice generated accelerated cytotoxic responses after secondary immunization with OVA. Prophylactic or therapeutic immunization with OVA onto barrier-disrupted skin inhibited the growth of B16.OVA tumors. LC played a critical role in the immunization process because depletion of LC at the time of skin immunization dramatically reduced the tumor-protective effect. The topically applied Ag was presented by skin-derived LC in draining lymph nodes to CD8+ T cells. Thus, targeting of tumor Ags to LC in vivo is an effective strategy for tumor immunotherapy.