bluuebunny/crossref_metadata_2025_split huggingface dataset:
Adjuvant Arthritis Induces Down-Regulation of G Protein-Coupled Receptor Kinases in the Immune System
Authors: Lombardi Maria Stella , Kavelaars Annemieke , Cobelens Pieter M. , Schmidt Reinhold E. , Schedlowski Manfred , Heijnen Cobi J. 
Published: April 2014

Abstract
G protein-coupled receptors (GPCR) play a crucial role in the regulation of the immune response by, e.g., chemokines, PGs, and β2-adrenergic agonists. The responsiveness of these GPCRs is turned off by the family of G protein-coupled receptor kinases (GRK1–6). These kinases act by phosphorylating the GPCR in an agonist-dependent manner, resulting in homologous desensitization of the receptor. Although GRKs are widely expressed throughout the body, leukocytes express relatively high levels of GRKs, in particular GRK2, -3, and -6. We investigated whether in vivo the inflammatory disease adjuvant arthritis (AA) induces changes in GRK expression and function in the immune system. In addition, we analyzed whether the systemic effects of AA also involve changes in GRKs in nonimmune organs. At the peak of the inflammatory process, we observed a profound down-regulation of GRK2, -3, and -6 in splenocytes and mesenteric lymph node cells from AA rats. Interestingly, no changes in GRK were observed in thymocytes and in nonimmune organs such as heart and pituitary. During the remission phase of AA, GRK levels in spleen and mesenteric lymph nodes are returning to baseline levels. The decrease in GRK2 at the peak of AA is restricted to CD45RA+ B cells and CD4+ T cells, and was not observed in CD8+ T cells. In conclusion, we demonstrate in this study, for the first time, that an inflammatory process in vivo induces a tissue-specific down-regulation of GRKs in the immune system.
Prevention of Anti-IgM-Induced Apoptosis Accompanying G1 Arrest in B Lymphoma Cells Overexpressing Dominant-Negative Mutant Form of c-Jun N-Terminal Kinase 1
Authors: Takada Eiko , Toyota Hiroko , Suzuki Jun , Mizuguchi Junichiro 
Published: April 2014

AbstractA family of mitogen-activated protein (MAP) kinases comprising the extracellular signal-regulated kinases (ERKs), c-Jun N-terminal kinases (JNKs), and p38 MAP kinases are involved in proliferation and apoptosis. However, there are some arguments concerning the role of these kinases in Ag-induced B cell apoptosis. Two of the B lymphoma cell lines (CH31 and WEHI-231) susceptible to anti-IgM-induced apoptosis were used as a model. To address these issues, we examined the kinetics of anti-IgM-induced activation of MAP kinases and established cell lines overexpressing a dominant-negative (dn) mutant form of JNK1 (dnJNK1). Anti-IgM induced a sustained JNK1 activation with a peak at 8 h, with a marginal activation of ERK1/ERK2 in CH31 cells. The sustained JNK1 activation was not a secondary event through a caspase activation. The peak point of the JNK1 activation was just before the onset of a decline in mitochondrial membrane potential, which preceded anti-IgM-induced cell death. Following anti-IgM stimulation, dnJNK1 prevented a decline in mitochondrial membrane potential at 24 h, with a prolonged inhibition up to 72 h in WEHI-231, although it did so only partially during a later time period in CH31. The dnJNK1 cells also demonstrated diminished procaspase-3 activation and a decreased rate of apoptosis upon anti-IgM stimulation, with a concomitant increased arrest in G1 phase, which could be explained by enhanced levels of cyclin-dependent kinase inhibitor p27Kip1 protein. Thus, anti-IgM-induced JNK activation might be implicated in cell cycle progression as well as in apoptosis regulation, probably involving p27Kip1 protein.
T Cell Studies in a Peptide-Induced Model of Systemic Lupus Erythematosus
Authors: Khalil Magi , Inaba Kayo , Steinman Ralph , Ravetch Jeffrey , Diamond Betty 
Published: April 2014

AbstractWe have previously reported that immunization with a peptide mimetope of dsDNA on a branched polylysine backbone (DWEYSVWLSN-MAP) induces a systemic lupus erythematosus-like syndrome in the nonautoimmune BALB/c mouse strain. To understand the mechanism underlying this breakdown in self tolerance, we examined the role of T cells in the response. Our results show that the anti-foreign and anti-self response induced by immunization is T cell dependent and is mediated by I-Ed-restricted CD4+ T cells of the Th1 subset. In addition, generation of the critical T cell epitope requires processing by APCs and depends on the presence of both DWEYSVWLSN and the MAP backbone. The breakdown in self tolerance does not occur through cross-reactivity between the T cell epitope of DWEYSVWLSN-MAP and epitopes derived from nuclear Ags. In this induced-model of SLE, therefore, autoreactivity results from the activation of T cells specific for foreign Ag and of cross-reactive anti-foreign, anti-self B cells. Despite the fact that tissue injury is mediated by Ab, the critical initiating T cell response is Th1.
Broad Programming by IL-2 Receptor Signaling for Extended Growth to Multiple Cytokines and Functional Maturation of Antigen-Activated T Cells
Authors: Malek Thomas R. , Yu Aixin , Scibelli Paul , Lichtenheld Mathias G. , Codias Elaine K. 
Published: April 2014

AbstractCoincident production of IL-2 and induction of high-affinity IL-2R upon TCR engagement has precluded a clear distinction for the biological outcome of signaling through TCR/costimulatory molecules vs the IL-2R. Using a novel transgenic mouse on the IL-2Rβ−/− genetic background, this study has separated the relative outcome of signaling through the TCR and IL-2R. We show that stimulation through the TCR and CD28 or CD40 ligand directly leads to T cell activation and several rounds of proliferation in an IL-2-independent fashion. However, this stimulation is insufficient for extended T cell growth to multiple cytokines or differentiation into CTL or IFN-γ-secreting effector T cells. IL-2 is required for these functions in part by regulation of cyclin D3 and granzyme B. Somewhat less efficiently, IL-4 stimulation of these transgenic T cells redundantly rescued many of these activities. These data demonstrate a fundamental requirement for IL-2 and perhaps other common γ-chain-dependent cytokines to promote selective gene expression by Ag-activated T cells for their subsequent growth and differentiation into effector T lymphocytes.
Signal Via Lymphotoxin-βR on Bone Marrow Stromal Cells Is Required for an Early Checkpoint of NK Cell Development
Authors: Wu Qiang , Sun Yonglian , Wang Jing , Lin Xiaoqi , Wang Yang , Pegg Lyle E. , Fütterer Agnes , Pfeffer Klaus , Fu Yang-Xin 
Published: April 2014

Abstract
NK cells play an important role in the immune system but the cellular and molecular requirements for their early development are poorly understood. Lymphotoxin-α (LTα)−/− and LTβR−/− mice show a severe systemic reduction of NK cells, which provides an excellent model to study NK cell development. In this study, we show that the bone marrow (BM) or fetal liver cells from LTα−/− or LTβR−/− mice efficiently develop into mature NK cells in the presence of stromal cells from wild-type mice but not from LTα−/− or LTβR−/− mice. Direct activation of LTβR-expressing BM stromal cells is shown to promote to early NK cell development in vitro. Furthermore, the blockade of the interaction between LT and LTβR in adult wild-type mice by administration of LTβR-Ig impairs the development of NK cells in vivo. Together, these results indicate that the signal via LTβR on BM stromal cells by membrane LT is an important pathway for early NK cell development.
Molecular Basis for Paradoxical Carriers of Adenosine Deaminase (ADA) Deficiency That Show Extremely Low Levels of ADA Activity in Peripheral Blood Cells Without Immunodeficiency
Authors: Ariga Tadashi , Oda Noriko , Sanstisteban Ines , Arredondo-Vega Francisco X. , Shioda Mitsutaka , Ueno Hideki , Terada Kihei , Kobayashi Kunihiko , Hershfield Michael S. , Sakiyama Yukio 
Published: April 2014

Abstract
Adenosine deaminase (ADA) deficiency causes an autosomal recessive form of severe combined immunodeficiency and also less severe phenotypes, depending to a large degree on genotype. In general, ADA activity in cells of carriers is approximately half-normal. Unexpectedly, healthy first-degree relatives of two unrelated ADA-deficient severe combined immunodeficient patients (mother and brother in family I; mother in family II) had only 1–2% of normal ADA activity in PBMC, lower than has previously been found in PBMC of healthy individuals with so-called “partial ADA deficiency.” The level of deoxyadenosine nucleotides in erythrocytes of these paradoxical carriers was slightly elevated, but much lower than levels found in immunodeficient patients with ADA deficiency. ADA activity in EBV-lymphoblastoid cell lines (LCL) and T cell lines established from these carriers was 10–20% of normal. Each of these carriers possessed two mutated ADA alleles. Expression of cloned mutant ADA cDNAs in an ADA-deletion strain of Escherichia coli indicated that the novel mutations G239S and M310T were responsible for the residual ADA activity. ADA activity in EBV-LCL extracts of the paradoxical carriers was much more labile than ADA from normal EBV-LCL. Immunoblotting suggested that this lability was due to denaturation rather than to degradation of the mutant protein. These results further define the threshold level of ADA activity necessary for sustaining immune function.
A Role for Calnexin in the Assembly of the MHC Class I Loading Complex in the Endoplasmic Reticulum
Authors: Diedrich Gundo , Bangia Naveen , Pan Mary , Cresswell Peter 
Published: April 2014

Abstract
Heterodimers of MHC class I glycoprotein and β2-microglobulin (β2m) bind short peptides in the endoplasmic reticulum (ER). Before peptide binding these molecules form part of a multisubunit loading complex that also contains the two subunits of the TAP, the transmembrane glycoprotein tapasin, the soluble chaperone calreticulin, and the thiol oxidoreductase ERp57. We have investigated the assembly of the loading complex and provide evidence that after TAP and tapasin associate with each other, the transmembrane chaperone calnexin and ERp57 bind to the TAP-tapasin complex to generate an intermediate. These interactions are independent of the N-linked glycan of tapasin, but require its transmembrane and/or cytoplasmic domain. This intermediate complex binds MHC class I-β2m dimers, an event accompanied by the loss of calnexin and the acquisition of calreticulin, generating the MHC class I loading complex. Peptide binding then induces the dissociation of MHC class I-β2m dimers, which can be transported to the cell surface.
Cloning and Characterization of Integrin α Subunits from the Solitary Ascidian,Halocynthia roretzi
Authors: Miyazawa Seita , Azumi Kaoru , Nonaka Masaru 
Published: April 2014

AbstractRecent molecular and biochemical analysis has revealed the presence of an opsonic complement system in the solitary ascidian, Halocynthia roretzi, composed of at least C3, two mannan binding protein-associated serine proteases, and factor B. To elucidate further the structure and function of this apparently primitive complement system in the urochordates, we looked for the ascidian complement receptor type 3 (CR3), or type 4 (CR4), which are members of the leukocyte integrin family in mammals. Using degenerate primers, we isolated two integrin α subunits (αHr1 and αHr2) from the hemocyte mRNA of H. roretzi, by RT-PCR, and the entire coding sequence of αHr1 was determined from cDNA clones. αHr1 contains an I domain, the inserted domain characteristic of a subset of mammalian α subunits, including the leukocyte integrin family. A phylogenetic tree constructed for the α subunits also supports the ancestral position of αHr1 in the monophyletic cluster of I domain-containing α integrins. The αHr1 gene shows hemocyte-specific expression on Northern blot analysis. Western blot analysis and immunocytochemical staining of the hemocytes of H. roretzi using anti-αHr1 Ab showed that αHr1 subunits exist on the surface of a subpopulation of phagocytic hemocytes. Furthermore, anti-αHr1 Ab inhibited C3-dependent phagocytosis, but not basic phagocytosis, of yeast cells by ascidian hemocytes. These observations strongly suggest that αHr1 constitutes an integrin molecule on the hemocytes of H. roretzi that functions as an ancestral form of CR3 and CR4 and mediates phagocytosis in the primitive complement system of the ascidian.
Thermal Stability of MHC Class I-β2-Microglobulin Peptide Complexes in the Endoplasmic Reticulum Is Determined by the Peptide Occupancy of the Transporter Associated with Antigen Processing Complex
Authors: Owen Barbara A. L. , Pease Larry R. 
Published: April 2014

Abstract
Once MHC class I heavy chain binds β2-microglobulin (β2m) within the endoplasmic reticulum, an assembly complex comprising the class I heterodimer, TAP, TAPasin, calreticulin, and possibly Erp57 is formed before the binding of high affinity peptide. TAP-dependent delivery of high affinity peptide to in vitro translated Kbβ2m complexes within microsomes (TAP+/TAPasin+) was studied to determine at which point peptide binding becomes resistant to thermal denaturation. It was determined that the thermal stability of Kb-β2m-peptide complexes depends on the timing of peptide binding to Kbβ2m relative to TAP binding high affinity peptide. Premature exposure of the TAP complex to high affinity peptide before its association with class I heavy chain results in Kbβ2m-peptide-TAP complexes that lose peptide upon exposure to elevated temperature after solubilization away from microsome-associated proteins. These findings suggest that the order in which class I heavy chain associates with endoplasmic reticulum-resident chaperones and peptide determines the stability of Kbβ2m-peptide complexes.
Role of the Complementarity-Determining Region 3 (CDR3) of the TCR-β Chains Associated with the Vα14 Semi-Invariant TCR α-Chain in the Selection of CD4+ NK T Cells
Authors: Ronet Catherine , Mempel Martin , Thieblemont Nathalie , Lehuen Agnès , Kourilsky Philippe , Gachelin Gabriel 
Published: April 2014

Abstract
The NK1.1+TCRαβint CD4+, or double negative T cells (NK T cells) consist of a mixture of CD1d-restricted and CD1d-unrestricted cells. The relationships between CD4+NK1.1+ T cells and conventional T cells are not understood. To compare their respective TCR repertoires, NK1.1+TCRαβint, CD4+ T cells have been sorted out of the thymus, liver, spleen, and bone marrow of C57BL/6 mice. Molecular analysis showed that thymus and liver used predominantly the Vα14-Jα281 and Vβ 2, 7, and 8 segments. These cells are CD1d restricted and obey the original definition of NK T cells. The complementarity-determining region 3 (CDR3) sequences of the TCR Vβ8.2-Jβ2.5 chain of liver and thymus CD4+ NK T cells were determined and compared with those of the same rearrangements of conventional CD4+ T cells. No amino acid sequence or usage characteristic of NK T cells could be evidenced: the Vβ8.2-Jβ2.5 diversity regions being primarily the same in NK T and in T cells. No clonal expansion of the β-chains was observed in thymus and liver CD1d-restricted CD4+NK T cells, suggesting the absence of acute or chronic Ag-driven stimulation. Molecular analysis of the TCR used by Vα14-Jα281 transgenic mice on a Cα−/− background showed that the α-chain can associate with β-chains using any Vβ segment, except in NK T cells in which it paired predominately with Vβ 2, 7, and 8+ β-chains. The structure of the TCR of NK T cells thus reflects the affinity for the CD1d molecule rather than a structural constraint leading to the association of the invariant α-chain with a distinctive subset of Vβ segment.
Constitutive Association of SHP-1 with Leukocyte-Associated Ig-Like Receptor-1 in Human T Cells
Authors: Sathish Jean G. , Johnson Kenneth G. , Fuller Kerensa J. , LeRoy Frances G. , Meyaard Linde , Sims Martin J. , Matthews R. James 
Published: April 2014

Abstract
The intracellular Src homology 2 (SH2) domain-containing protein tyrosine phosphatase (SHP-1) is a negative regulator of cell signaling and contributes to the establishment of TCR signaling thresholds in both developing and mature T lymphocytes. Although there is much functional data implicating SHP-1 as a regulator of TCR signaling, the molecular basis for SHP-1 activation in T lymphocytes is poorly defined. A modification of the yeast two-hybrid system was employed to identify in T cells phosphotyrosine-containing proteins capable of binding the SH2 domains of SHP-1. From this yeast tri-hybrid screen, the p85β subunit of phosphatidylinositol 3-kinase and the immunoreceptor tyrosine-based inhibitory motif-containing receptors, leukocyte-associated Ig-like receptor-1 (LAIR-1) and programmed death-1 (PD-1), were identified. Coimmunoprecipitation studies demonstrated that the exclusive phosphotyrosine-containing protein associated with SHP-1 in Jurkat T cells under physiological conditions is LAIR-1. Significantly, this interaction is constitutive and was detected only in the membrane-enriched fraction of cell lysates. Ligand engagement of the SH2 domains of SHP-1 is a prerequisite to activation of the enzyme, and, consistent with an association with LAIR-1, SHP-1 was found to be constitutively active in unstimulated Jurkat T cells. Importantly, a constitutive interaction between LAIR-1 and SHP-1 was also detected in human primary T cells. These results illustrate the sustained recruitment and activation of SHP-1 at the plasma membrane of resting human T cells by an inhibitory receptor. We propose that this mechanism may exert a constitutive negative regulatory role upon T cell signaling.
Differential Transcriptional Regulation of Individual TCR Vβ Segments Before Gene Rearrangement
Authors: Chen Fei , Rowen Lee , Hood Lee , Rothenberg Ellen V. 
Published: April 2014

AbstractThe promoter sequences of individual murine TCR Vβ segments are dissimilar, but any functional differences between them are masked after productive gene rearrangement by the dominance of the TCRβ 3′ enhancer. However, thymocytes of recombination-activating gene-2 (Rag2)-deficient mice allow the transcriptional activity of Vβ promoters to be studied before rearrangement. Here we report that many Vβ segments are detectably transcribed in Rag2−/− thymocytes and that there are significant differences in expression among different Vβ segments. Primer extension and characterization of cDNA clones from SCID thymocytes suggest that these germline Vβ transcripts generally use the same start sites as those previously determined in mature T cells. The strength of expression before rearrangement does not correlate with proximity to the known enhancer, because members of the most distal Vβ cluster (Vβ2.1, Vβ1.1, Vβ4.1) are relatively strongly expressed and more proximal Vβ segments (Vβ14.1, Vβ3.1, Vβ7.1, Vβ6.1) are only weakly expressed. Different Vβ segments also show different developmental programs of activation in different thymocyte subsets, with the Vβ5.1(L)-8.2(V) spliced transcript expressed earliest as well as most strongly overall. Comparison with Rag+ MHC class I−/− and class II−/− thymocytes confirms that many of these expression differences are leveled by rearrangement and/or by β selection, before MHC-dependent selection. However, the expression pattern of Vβ2.1 is highly distinctive and includes cell types apparently outside the T lineage, suggesting potential acquisition of specialized roles.
Yersinia Outer Protein P of Yersinia enterocolitica Simultaneously Blocks the Nuclear Factor-κB Pathway and Exploits Lipopolysaccharide Signaling to Trigger Apoptosis in Macrophages
Authors: Ruckdeschel Klaus , Mannel Oliver , Richter Kathleen , Jacobi Christoph A. , Trülzsch Konrad , Rouot Bruno , Heesemann Jürgen 
Published: April 2014

Abstract
Exposure of macrophages to bacteria or LPS mediates activation of signaling pathways that induce expression of self defense-related genes. Pathogenic Yersinia species impair activation of transcription factor NF-κB and trigger apoptosis in macrophages. In this study, we dissected the mechanism of apoptosis induction by Yersinia. Selectively, Yersinia enterocolitica strains producing the effector protein Yersinia outer protein P (YopP) hampered NF-κB activation and subsequently conferred apoptosis to J774A.1 macrophages. Thereby, YopP bound and inhibited the macrophage NF-κB-activating kinase IKKβ. YopP- and Yersinia-, but not Salmonella-induced apoptosis was specifically prevented by transient overexpression of NF-κB p65, giving evidence that YopP mediates cell death by disrupting the NF-κB signaling pathway. Transfection of J774A.1 macrophages with YopP induced a moderate, but significant degree of apoptosis (40–50% of transfected cells). This effect was strongly enhanced by additional initiation of LPS signaling (80–90%), indicating a synergism between LPS-induced signal transduction and inhibition of NF-κB by YopP. This reflects a strategy of a bacterial pathogen that takes advantage of LPS, serving as cofactor, to impair the macrophage.
Antifungal and Airway Remodeling Roles for Murine Monocyte Chemoattractant Protein-1/CCL2 During Pulmonary Exposure toAsperigillus fumigatusConidia
Authors: Blease Kate , Mehrad Borna , Lukacs Nicholas W. , Kunkel Steven L. , Standiford Theodore J. , Hogaboam Cory M. 
Published: April 2014

AbstractAsperigillus fumigatus spores or conidia are quickly eliminated from the airways of nonsensitized individuals but persist in individuals with allergic pulmonary responsiveness to fungus. A. fumigatus-induced allergic airway disease is characterized by persistent airway hyperreactivity, inflammation, and fibrosis. The present study explored the role of CCR2 ligands in the murine airway response to A. fumigatus conidia. Nonsensitized and A. fumigatus-sensitized CBA/J mice received an intratracheal challenge of A. fumigatus conidia, and pulmonary changes were analyzed at various times after conidia. Whole lung levels of monocyte chemoattractant protein-1 (MCP-1/CCL2), but neither MCP-3/CCL7 nor MCP-5/CCL12, were significantly elevated at days 3 and 7 after conidia in nonsensitized mice. MCP-1/CCL2 was significantly increased in lung samples from A. fumigatus-sensitized mice at days 14 and 30 after a conidia challenge. Administration of anti-MCP-1/CCL2 antiserum to nonsensitized mice for14 days after the conidia challenge attenuated the clearance of conidia and significantly increased airway hyperreactivity, eosinophilia, and peribronchial fibrosis compared with nonsensitized mice that received conidia and normal serum. Adenovirus-directed overexpression of MCP-1/CCL2 in A. fumigatus-sensitized mice markedly reduced the number of conidia, airway inflammation, and airway hyperresponsiveness at day 7 after the conidia challenge in these mice. Immunoneutralization of MCP-1/CCL2 levels in A. fumigatus-sensitized mice during days14–30 after the conidia challenge did not affect the conidia burden but significantly reduced airway hyperreactivity, lung IL-4 levels, and lymphocyte recruitment into the airways compared with the control group. These data suggest that MCP-1/CCL2 participates in the pulmonary antifungal and allergic responses to A. fumigatus conidia.