bluuebunny/crossref_metadata_2025_split huggingface dataset:
Murine CD4+CD25+ Regulatory T Cells Fail to Undergo Chromatin Remodeling Across the Proximal Promoter Region of the IL-2 Gene
Authors: Su Leon , Creusot Remi J. , Gallo Elena M. , Chan Steven M. , Utz Paul J. , Fathman C. Garrison , Ermann Joerg 
Published: April 2014

AbstractCD4+CD25+ regulatory T cells (Treg) acquire unique immunosuppressive properties while maintaining an anergy phenotype when activated in vitro under conditions that induce IL-2 production and proliferation in conventional CD4+ T cells. We investigated the mechanism underlying one component of this naturally anergic phenotype, the inability of the Treg cells to produce IL-2 following activation. Analysis of freshly isolated murine CD4+CD25+ Treg and conventional CD4+CD25− T cells following PMA/ionomycin stimulation demonstrated no differences in inducible AP-1 formation, an important transcriptional complex in regulating IL-2 gene expression. Although p38 MAPK and ERK1/2 protein kinases were phosphorylated with similar kinetics, we observed diminished activation of JNK in the CD4+CD25+ Treg cells. However, lentiviral-mediated reconstitution of the JNK pathway using a constitutively active construct did not overcome the block in IL-2 synthesis. Using a PCR-based chromatin accessibility assay we found that the minimal IL-2 promoter region of CD4+CD25+ Treg cells, unlike conventional CD4 T cells, did not undergo chromatin remodeling following stimulation, suggesting that the inability of CD4+CD25+ Treg cells to secrete IL-2 following activation is controlled at the chromatin level.
The Role of CTLs in Persistent Viral Infection: Cytolytic Gene Expression in CD8+ Lymphocytes Distinguishes between Individuals with a High or Low Proviral Load of Human T Cell Lymphotropic Virus Type 1
Authors: Vine Alison M. , Heaps Adrian G. , Kaftantzi Lambrini , Mosley Angelina , Asquith Becca , Witkover Aviva , Thompson Gillian , Saito Mineki , Goon Peter K. C. , Carr Laura , Martinez-Murillo Francisco , Taylor Graham P. , Bangham Charles R. M. 
Published: April 2014

Abstract
The proviral load in human T cell lymphotropic virus type 1 (HTLV-1) infection is typically constant in each infected host, but varies by &gt;1000-fold between hosts and is strongly correlated with the risk of HTLV-1-associated inflammatory disease. However, the factors that determine an individual’s HTLV-1 proviral load remain uncertain. Experimental evidence from studies of host genetics, viral genetics, and lymphocyte function and theoretical considerations suggest that a major determinant of the equilibrium proviral load is the CD8+ T cell response to HTLV-1. In this study, we tested the hypothesis that the gene expression profile in circulating CD8+ and CD4+ lymphocytes distinguishes between individuals with a low proviral load of HTLV-1 and those with a high proviral load. We show that circulating CD8+ lymphocytes from individuals with a low HTLV-1 proviral load overexpressed a core group of nine genes with strong functional coherence: eight of the nine genes encode granzymes or other proteins involved in cell-mediated lysis or Ag recognition. We conclude that successful suppression of the HTLV-1 proviral load is associated with strong cytotoxic CD8+ lymphocyte activity in the peripheral blood.
Protease-Activated Receptor Signaling Increases Epithelial Antimicrobial Peptide Expression
Authors: Chung Whasun O. , Hansen Stephen R. , Rao Divya , Dale Beverly A. 
Published: April 2014

Abstract
Epithelial tissues provide both a physical barrier and an antimicrobial barrier. Antimicrobial peptides of the human β-defensin (hBD) family are part of the innate immune responses that play a role in mucosal defense. hBDs are made in epithelia including oral epithelium where the bacterial load is particularly great. hBD-2 and hBD-3 are up-regulated in response to bacterial stimuli. Previous studies show that hBD-2 expression in human gingival epithelial cells (GEC) is stimulated by both nonpathogenic and pathogenic bacteria, including Porphyromonas gingivalis, a Gram-negative pathogen associated with periodontitis. Present evidence suggests that hBD-2 expression in GEC uses several signaling pathways, including an NF-κB-mediated pathway but without apparent LPS-TLR4 signaling. Protease-activated receptors (PAR) are G-protein-coupled receptors that mediate cellular responses to extracellular proteinases. P. gingivalis secretes multiple proteases that contribute to its virulence mechanisms. To determine whether PAR signaling is used in hBD-2 induction, GEC were stimulated with wild-type P. gingivalis or mutants lacking one or more proteases. hBD-2 mRNA expression was reduced in GEC stimulated with single protease mutants (11–67% compared with wild type), strongly reduced in double mutants (0.1–16%), and restored to wild-type levels (93%) in mutant with restored protease activity. Stimulation by wild type was partially blocked by inhibitors of phospholipase C, a main signaling pathway for PARs. Expression of hBD-3 was unaffected. Peptide agonist of PAR-2, but not PAR-1 activator, also induced hBD-2 in GEC. Thus, P. gingivalis proteases are directly involved in regulation of hBD-2 in cultured GEC, and this induction partially uses the PAR-2 receptor and signaling pathway.
Impaired Immunity to Intestinal Bacterial Infection in Stromelysin-1 (Matrix Metalloproteinase-3)-Deficient Mice
Authors: Li Chris K. F. , Pender Sylvia L. F. , Pickard Karen M. , Chance Victoria , Holloway Judith A. , Huett Alan , Gonçalves Nathalie S. , Mudgett John S. , Dougan Gordon , Frankel Gad , MacDonald Thomas T. 
Published: April 2014

Abstract
Infection of mice with the intestinal bacterial pathogen Citrobacter rodentium results in colonic mucosal hyperplasia and a local Th1 inflammatory response similar to that seen in mouse models of inflammatory bowel disease. Matrix metalloproteinases (MMPs) have been shown to mediate matrix remodeling and cell migration during tissue injury and repair in the intestine. We have previously shown enhanced pathology in infected TNFRp55−/−, IL-12p40−/−, and IFN-γ−/− mice, and here we show that this is associated with an increase in stromelysin-1 (MMP3) transcripts in colonic tissues. We have therefore investigated the role of MMP3 in colonic mucosal hyperplasia and the local Th1 responses using MMP3−/− mice. In MMP3−/− mice, similar mucosal thickening was observed after infection as in wild-type (WT) mice. Colonic tissues from MMP3−/− mice showed a compensatory increase in the expression of other MMP transcripts, such as MMP7 and MMP12. However, MMP3−/− mice showed delayed clearance of bacteria and delayed appearance of CD4+ T lymphocytes into intestinal lamina propria. CSFE-labeled mesenteric lymph node CD4+ T lymphocytes from infected WT mice migrated in fewer numbers into the mesenteric lymph nodes and colon of MMP3−/− mice than into those of WT mice. These studies show that mucosal remodeling can occur in the absence of MMP3, but that MMP3 plays a role in the migration of CD4+ T lymphocytes to the intestinal mucosa.
Key Metalloproteinases Are Expressed by Specific Cell Types in Experimental Autoimmune Encephalomyelitis
Authors: Toft-Hansen Henrik , Nuttall Robert K. , Edwards Dylan R. , Owens Trevor 
Published: April 2014

AbstractMetalloproteinases (MPs) include matrix metalloproteinases (MMPs) and metalloproteinase-disintegrins (ADAMs). Their physiological inhibitors are tissue inhibitor of metalloproteinases (TIMPs). MPs are thought to be mediators of cellular infiltration in the pathogenesis of multiple sclerosis and its animal model, experimental autoimmune encephalomyelitis (EAE). We used real-time RT-PCR to profile the expression of all 22 known mouse MMPs, seven ADAMs, and all four known TIMPs in spinal cord from SJL/J mice and mice with adoptively transferred myelin basic protein (MBP)-specific EAE. A significant and &gt;3-fold alteration in expression was observed for MMP-8, MMP-10, MMP-12, ADAM-12, and TIMP-1, which were up-regulated, and for MMP-15, which was down-regulated. Expression levels correlated with disease course, with all but ADAM-12 returning toward control levels in remission. To examine potential cellular sources of these strongly affected proteins in the inflamed CNS, we isolated macrophages, granulocytes, microglia, and T cells by cell sorting from the CNS of mice with EAE and analyzed their expression by real-time RT-PCR. This identified macrophages as a major source of MMP-12 and TIMP-1. Granulocytes were a major source of MMP-8. ADAM-12 was expressed primarily by T cells. Cellular localization of MMP-10, TIMP-1, and ADAM-12 in perivascular infiltrates was confirmed by immunostaining or in situ hybridization. Microglia from control mice expressed strong signal for MMP-15. Strikingly, the expression of MMP-15 by microglia was significantly down-regulated in EAE, which was confirmed by immunostaining. Our study identifies the cellular sources of key MPs in CNS inflammation.
Differential Regulation of Th1/Th2 Cytokine Responses by Placental Protein 14
Authors: Mishan-Eisenberg Galit , Borovsky Zipora , Weber Matthew C. , Gazit Roi , Tykocinski Mark L. , Rachmilewitz Jacob 
Published: April 2014

AbstractThe potency of TCR signaling during primary CD4+ T cell activation influences initial cytokine expression patterns and subsequent polarization toward either Th1 or Th2 subsets. In this study, we demonstrate that the T cell inhibitor placental protein 14 (PP14; glycodelin) preferentially inhibits Th1 cytokine responses and chemokine expression when present during ex vivo priming of CD4+ T cells. PP14 synergizes with exogenously added IL-4 in skewing T cell responses. Significantly, PP14 impairs the down-regulation of GATA-3 transcriptional regulator expression that normally accompanies T cell activation, which is a prerequisite for Th1 development. Taken together, these data document for the first time the ability of PP14 to skew Th responses.
Roles of TNF Receptor-Associated Factor 3 in Signaling to B Lymphocytes by Carboxyl-Terminal Activating Regions 1 and 2 of the EBV-Encoded Oncoprotein Latent Membrane Protein 1
Authors: Xie Ping , Bishop Gail A. 
Published: April 2014

Abstract
TNFR-associated factor (TRAF)3, an adaptor protein that binds the cytoplasmic domains of both CD40 and the EBV-encoded oncoprotein latent membrane protein (LMP)1, is required for positive signaling by LMP1 but not CD40 in B lymphocytes. The present study further investigated how TRAF3 participates in LMP1 signaling. We found that TRAF3 mediates signaling both through direct interactions with the C-terminal activating region (CTAR)1 of LMP1 and through indirect interactions with the CTAR2 region of LMP1 in mouse B cells. Notably, our results demonstrated that the CTAR2 region appears to inhibit the recruitment of TRAF1 and TRAF2 to membrane rafts by the CTAR1 region. Additionally, the absence of TRAF2 in B cells resulted in only a modest reduction in CTAR1-mediated signals and no detectable effect on CTAR2-mediated signals. CTAR1 and CTAR2 cooperated to achieve the robust signaling activity of LMP1 when recruited to the same membrane microdomains in B cells. Interestingly, TRAF3 deficiency completely abrogated the cooperation between CTAR1 and CTAR2, supporting the hypothesis that TRAF3 participates in the physical interaction between CTAR1 and CTAR2 of LMP1. Together, our findings highlight the central importance of TRAF3 in LMP1-mediated signaling, which is critical for EBV persistent infection and EBV-associated pathogenesis.
The B Lymphocyte Adaptor Molecule of 32 Kilodaltons (Bam32) Regulates B Cell Antigen Receptor Internalization
Authors: Niiro Hiroaki , Allam Atef , Stoddart Angela , Brodsky Frances M. , Marshall Aaron J. , Clark Edward A. 
Published: April 2014

AbstractThe B lymphocyte adaptor molecule of 32 kDa (Bam32) is an adaptor that plays an indispensable role in BCR signaling. In this study, we found that upon BCR ligation, Bam32 is recruited to the plasma membrane where it associates with BCR complexes and redistributes and internalizes with BCRs. BCR ligation induced colocalization of Bam32 with lipid rafts, clathrin, and actin filaments. An inhibitor of Src family protein tyrosine kinases (PTKs) blocked both BCR-induced tyrosine phosphorylation of Bam32 and BCR internalization. Moreover, BCR internalization is impaired in Bam32−/− and Lyn−/− cells, and expression of Bam32 with a mutation of its tyrosine phosphorylation site (Y139F) inhibited BCR internalization. These data suggest that Bam32 functions downstream of Src family PTKs to regulate BCR internalization. Bam32 deficiency does not affect tyrosine phosphorylation of clathrin or the association of clathrin with lipid rafts upon BCR cross-linking. However, BCR-induced actin polymerization is impaired in Bam32−/− cells. Collectively, these findings indicate a novel role of Bam32 in connecting Src family PTKs to BCR internalization by an actin-dependent mechanism.
Polymorphonuclear Cell Transmigration Induced by Pseudomonas aeruginosa Requires the Eicosanoid Hepoxilin A3
Authors: Hurley Bryan P. , Siccardi Dario , Mrsny Randall J. , McCormick Beth A. 
Published: April 2014

Abstract
Lung inflammation resulting from bacterial infection of the respiratory mucosal surface in diseases such as cystic fibrosis and pneumonia contributes significantly to the pathology. A major consequence of the inflammatory response is the recruitment and accumulation of polymorphonuclear cells (PMNs) at the infection site. It is currently unclear what bacterial factors trigger this response and exactly how PMNs are directed across the epithelial barrier to the airway lumen. An in vitro model consisting of human PMNs and alveolar epithelial cells (A549) grown on inverted Transwell filters was used to determine whether bacteria are capable of inducing PMN migration across these epithelial barriers. A variety of lung pathogenic bacteria, including Klebsiella pneumoniae, Escherichia coli, and Pseudomonas aeruginosa are indeed capable of inducing PMN migration across A549 monolayers. This phenomenon is not mediated by LPS, but requires live bacteria infecting the apical surface. Bacterial interaction with the apical surface of A549 monolayers results in activation of epithelial responses, including the phosphorylation of ERK1/2 and secretion of the PMN chemokine IL-8. However, secretion of IL-8 in response to bacterial infection is neither necessary nor sufficient to mediate PMN transepithelial migration. Instead, PMN transepithelial migration is mediated by the eicosanoid hepoxilin A3, which is a PMN chemoattractant secreted by A549 cells in response to bacterial infection in a protein kinase C-dependent manner. These data suggest that bacterial-induced hepoxilin A3 secretion may represent a previously unrecognized inflammatory mechanism occurring within the lung epithelium during bacterial infections.
Protein Kinase Cδ Is Required for p47phox Phosphorylation and Translocation in Activated Human Monocytes
Authors: Bey Erik A. , Xu Bo , Bhattacharjee Ashish , Oldfield Claudine M. , Zhao Xiaoxian , Li Qing , Subbulakshmi Venkita , Feldman Gerald M. , Wientjes Frans B. , Cathcart Martha K. 
Published: April 2014

Abstract
Our laboratory is interested in understanding the regulation of NADPH oxidase activity in human monocyte/macrophages. Protein kinase C (PKC) is reported to be involved in regulating the phosphorylation of NADPH oxidase components in human neutrophils; however, the regulatory roles of specific isoforms of PKC in phosphorylating particular oxidase components have not been determined. In this study calphostin C, an inhibitor for both novel PKC (including PKCδ, -ε, -θ, and -η) and conventional PKC (including PKCα and -β), inhibited both phosphorylation and translocation of p47phox, an essential component of the monocyte NADPH oxidase. In contrast, GF109203X, a selective inhibitor of classical PKC and PKCε, did not affect the phosphorylation or translocation of p47phox, suggesting that PKCδ, -θ, or -η is required. Furthermore, rottlerin (at doses that inhibit PKCδ activity) inhibited the phosphorylation and translocation of p47phox. Rottlerin also inhibited O⨪2 production at similar doses. In addition to pharmacological inhibitors, PKCδ-specific antisense oligodeoxyribonucleotides were used. PKCδ antisense oligodeoxyribonucleotides inhibited the phosphorylation and translocation of p47phox in activated human monocytes. We also show, using the recombinant p47phox-GST fusion protein, that p47phox can serve as a substrate for PKCδ in vitro. Furthermore, lysate-derived PKCδ from activated monocytes phosphorylated p47phox in a rottlerin-sensitive manner. Together, these data suggest that PKCδ plays a pivotal role in stimulating monocyte NADPH oxidase activity through its regulation of the phosphorylation and translocation of p47phox.
The Inhibitory Receptor PIR-B Negatively Regulates Neutrophil and Macrophage Integrin Signaling
Authors: Pereira Shalini , Zhang Hong , Takai Toshiyuki , Lowell Clifford A. 
Published: April 2014

Abstract
The Ig-like receptor family member, PIR-B, has been shown to play an inhibitory role in receptor signaling within B cells, mast cells, and dendritic cells. As it has been implicated in integrin-mediated responses, we investigated the effect of loss of the PIR-B protein on integrin-mediated signaling in primary murine myeloid cells. The pir-b−/− neutrophils displayed enhanced respiratory burst, secondary granule release, and a hyperadhesive phenotype when plated on surfaces coated with either extracellular matrix proteins or cellular adhesion molecules in the presence or absence of the soluble inflammatory agonist TNF-α. The pir-b−/− and wild-type cells responded equivalently when stimulated with TNF-α in suspension, indicating that the hyperresponsive phenotype of the pir-b−/− cells during adhesion was due to enhanced integrin signaling. Both wild-type and pir-b−/− neutrophils expressed similar levels of integrin subunits. Primary bone marrow-derived macrophages from pir-b−/− mice were also hyperadhesive and spread more rapidly than wild-type cells following plating on surfaces that cross-linked cellular β2 integrins. Biochemical analysis of macrophages from pir-b−/− mice revealed enhanced phosphorylation and activation of proteins involved in integrin signaling. These observations point to a nonredundant role for PIR-B in the regulation of leukocyte integrin signaling.
Mixed Xenogeneic Chimerism Induces Donor-Specific Humoral and Cellular Immune Tolerance for Cardiac Xenografts
Authors: Colson Yolonda L. , Xu Hong , Huang Yiming , Ildstad Suzanne T. 
Published: April 2014

AbstractXenotransplantation has been suggested as a potential solution to the critical shortage of donor organs. However, success has been limited by the vigorous rejection response elicited against solid organs transplanted across species barriers. Mixed xenogeneic bone marrow chimeras resulting from the transplantation of a mixture of host and donor marrow (B10 mouse + F344 rat → B10 mouse) results in donor-specific cross-species transplantation tolerance for subsequent nonvascularized skin and islet grafts. Furthermore, compared with fully xenogeneic chimeras (rat → mouse), mixed xenogeneic chimeras exhibit superior immunocompetence for infectious agents in vivo and in vitro, suggesting that the immune system is intact. The ability to establish long-term humoral and cellular tolerance for primarily vascularized xenografts in vivo, in the setting of both recipient and donor Ig and effector cell production, has not previously been characterized. Mixed xenogeneic chimeras exhibit donor-specific humoral tolerance as evident by the absence of anti-donor Ab and Ab-dependent donor-specific cytotoxicity in vitro and intravascular IgM deposition within donor-strain (F344) cardiac xenografts in vivo. F344 cardiac xenografts are accepted (median ≥180 days) without clinical or histologic evidence of rejection, suggesting cellular tolerance. In contrast, MHC-disparate third-party mouse (B10.BR) and rat (ACI or WF) grafts are rejected (median of 23 and 41 days, respectively) in association with extensive mononuclear cell infiltration and vascular deposits of mouse IgM. These results demonstrate that mixed xenogeneic chimerism establishes donor-specific humoral and cellular tolerance and permits the successful transplantation of even primarily vascularized xenografts in the setting of intact Ab production.
Intravenous Injection of a D1 Protein of the Smith Proteins Postpones Murine Lupus and Induces Type 1 Regulatory T Cells
Authors: Riemekasten Gabriela , Langnickel Dirk , Enghard Philipp , Undeutsch Reinmar , Humrich Jens , Ebling Fanny M. , Hocher Berthold , Humaljoki Tiina , Neumayer Hans , Burmester Gerd-R. , Hahn Bevra H. , Radbruch Andreas , Hiepe Falk 
Published: April 2014

AbstractT cells that recognize nucleoproteins are required for the production of anti-dsDNA Abs involved in lupus development. SmD183–119 (a D1 protein of the Smith (Sm) proteins, part of small nuclear ribonucleoprotein) was recently shown to provide T cell help to anti-dsDNA Abs in the NZB/NZW model of lupus. Using this model in the present study, we showed that high dose tolerance to SmD1 (600–1000 μg i.v. of SmD183–119 peptide/mo) delays the production of autoantibodies, postpones the onset of lupus nephritis as confirmed by histology, and prolongs survival. Tolerance to SmD183–119 was adoptively transferred by CD90+ T cells, which also reduce T cell help for autoreactive B cells in vitro. One week after SmD183–119 tolerance induction in prenephritic mice, we detected cytokine changes in cultures of CD90+ T and B220+ B cells with decreased IFN-γ and IL-4 expression and an increase in TGFβ. Increased frequencies of regulatory IFN-γ+ and IL10+ CD4+ T cells were later detected. Such regulatory IL-10+/IFN-γ+ type 1 regulatory T cells prevented autoantibody generation and anti-CD3-induced proliferation of naive T cells. In conclusion, these results indicate that SmD183–119 peptide may play a dominant role in the activation of helper and regulatory T cells that influence autoantibody generation and murine lupus.
BCL-6 Negatively Regulates Expression of the NF-κB1 p105/p50 Subunit
Authors: Li Zhiping , Wang Xing , Yu Raymond Yick-Loi , Ding B. Belinda , Yu J. Jessica , Dai Xu-Ming , Naganuma Akira , Stanley E. Richard , Ye B. Hilda 
Published: April 2014

Abstract
BCL-6 is a transcription repressor frequently deregulated in non-Hodgkin’s B cell lymphomas. Its activity is also critical to germinal center development and balanced Th1/Th2 differentiation. Previous studies have suggested that NF-κB activity is suppressed in germinal center and lymphoma B cells that express high levels of BCL-6, and yet the reason for this is unknown. We report in this study that BCL-6 can bind to three sequence motifs in the 5′ regulatory region of NF-κB1 in vitro and in vivo, and repress NF-κB1 transcription both in reporter assays and in lymphoma B cell lines. BCL-6−/− mice further confirm the biological relevance of BCL-6-dependent regulation of NF-κB1 because BCL-6 inactivation caused notable increase in p105/p50 proteins in several cell types. Among these, BCL-6−/− macrophage cell lines displayed a hyperproliferation phenotype that can be reversed by NF-κB inhibitors, e.g., N-tosyl-l-phenylalanine chloromethyl ketone and SN50, a result that is consistent with increased nuclear κB-binding activity of p50 homodimer and p50/p65 heterodimer. Our results demonstrate that BCL-6 can negatively regulate NF-κB1 expression, thereby inhibiting NF-κB-mediated cellular functions.