bluuebunny/crossref_metadata_2025_split huggingface dataset:
Absence of Procarboxypeptidase R Induces Complement-Mediated Lethal Inflammation in Lipopolysaccharide-Primed Mice
Authors: Asai Suzuka , Sato Tomoo , Tada Toyohiro , Miyamoto Tomomi , Kimbara Noriaki , Motoyama Noboru , Okada Hidechika , Okada Noriko 
Published: April 2014

Abstract
Carboxypeptidase R (CPR) is a heat-labile enzyme found in serum in addition to stable carboxypeptidase N. CPR cleaves the C-terminal basic amino acids, arginine and lysine, from inflammatory peptides such as complement C3a and C5a, bradykinin, and enkephalin. This enzyme is generated from procarboxypeptidase R (proCPR), also known as thrombin-activatable fibrinolysis inhibitor, following cleavage by proteolytic enzymes such as thrombin, plasmin, and trypsin. We generated proCPR-deficient mice by knocking out exons 4 and 5 of the proCPR gene, which are regarded as essential for CPR function. At LPS challenge, there was virtually no difference in lethality among proCPR+/+, proCPR+/−, and proCPR−/− mice. However, challenge with cobra venom factor, which can activate and deplete almost all complement in vivo, induced a lethal effect on proCPR−/− mice following LPS sensitization which up-regulates C5a receptor expression. In contrast, proCPR+/+ and proCPR+/− mice were able to tolerate the cobra venom factor challenge with the limited dose (30 U). Although carboxypeptidase N plays a role in inactivation of inflammatory peptides in vivo, CPR may also be important in the regulation of hyperinflammation.
Serum Amyloid A-Activating Factor-1 (SAF-1) Transgenic Mice Are Prone to Develop a Severe Form of Inflammation-Induced Arthritis
Authors: Ray Alpana , Kumar Deepak , Shakya Arvind , Brown Charles R. , Cook James L. , Ray Bimal K. 
Published: April 2014

AbstractThe transcription factor serum amyloid A-activating factor-1 (SAF-1) has been identified as a regulator of a number of cellular genes. To assess the pleiotropic role of SAF-1 in vivo, we generated SAF-1 transgenic mice, in which CMV immediate-early promoter was used to direct expression of the SAF-1 transgene in multiple organs. Our study shows that overexpression of SAF-1 predisposes animals to arthritis. Although SAF-1 transgenic mice do not spontaneously develop arthritis, they develop a severe form of arthritis when challenged with the Lyme disease agent Borrelia burgdorferi, which is known to promote arthritis development in both humans and mice. CMV-SAF-1 transgenic mice, upon B. burgdorferi infection, showed increased joint swelling and synovial inflammation compared with nontransgenic littermates. Immunohistochemical analysis of joint tissues collected 21 days after B. burgdorferi infection revealed colocalization of matrix metalloproteinase-1, a degradative enzyme that destroys type II collagen, a major architectural component of articular cartilage, and SAF-1 in both SAF-1 transgenic and nontransgenic mice. Further analysis by RNase protection assay and Western immunoblot demonstrated the presence of higher levels of matrix metalloproteinase-1 and SAF-1 in the inflamed joints of SAF-1 transgenic mice compared with their levels in nontransgenic mice. Consistent with these findings, reduced levels of proteoglycans were detected in the inflamed joint cartilage of transgenic mice, indicating damage to the cartilage structure. Together these results suggest a role of SAF-1 in the pathogenesis of inflammation-induced arthritis.
Cutting Edge: Productive HIV-1 Infection of Dendritic Cells via Complement Receptor Type 3 (CR3, CD11b/CD18)
Authors: Bajtay Zsuzsa , Speth Cornelia , Erdei Anna , Dierich Manfred P. 
Published: April 2014

Abstract
In the present study, we demonstrate that macrophage-tropic HIV-1 opsonized by complement and limited amounts of anti-HIV-IgG causes up to 10-fold higher productive infection of human monocyte-derived dendritic cells than HIV treated with medium or HIV opsonized by Ab only. Enhanced infection is completely abolished by a mAb specific for the ligand-binding site of CD11b (i.e., α-chain of complement receptor 3, receptor for iC3b), proving the importance of complement receptor 3 in this process. Inhibition of complement activation by EDTA also prevents enhanced infection, further demonstrating the role of complement in virus uptake and productive infection. Since HIV is, even in the absence of Abs, regularly opsonized by complement, most probably the above-described mechanism plays a role during in vivo primary infection.
A Novel Pathway of Alloantigen Presentation by Dendritic Cells
Authors: Herrera Osquel Barroso , Golshayan Dela , Tibbott Rebecca , Ochoa Francisco Salcido , James Martha J. , Marelli-Berg Federica M. , Lechler Robert I. 
Published: April 2014

AbstractIn the context of transplantation, dendritic cells (DCs) can sensitize alloreactive T cells via two pathways. The direct pathway is initiated by donor DCs presenting intact donor MHC molecules. The indirect pathway results from recipient DCs processing and presenting donor MHC as peptide. This simple dichotomy suggests that T cells with direct and indirect allospecificity cannot cross-regulate each other because distinct APCs are involved. In this study we describe a third, semidirect pathway of MHC alloantigen presentation by DCs that challenges this conclusion. Mouse DCs, when cocultured with allogeneic DCs or endothelial cells, acquired substantial levels of class I and class II MHC:peptide complexes in a temperature- and energy-dependent manner. Most importantly, DCs acquired allogeneic MHC in vivo upon migration to regional lymph nodes. The acquired MHC molecules were detected by Ab staining and induced proliferation of Ag-specific T cells in vitro. These data suggest that recipient DCs, due to acquisition of donor MHC molecules, may link T cells with direct and indirect allospecificity.
Human Cytomegalovirus Induces Inhibition of Macrophage Differentiation by Binding to Human Aminopeptidase N/CD13
Authors: Gredmark Sara , Britt William B. , Xie Xun , Lindbom Lennart , Söderberg-Nauclér Cecilia 
Published: April 2014

AbstractHuman CMV (HCMV) infection in immunocompromised patients is frequently associated with impaired immunological functions. We have recently found that HCMV inhibits cytokine-induced differentiation of monocytes into macrophages. In this study, we demonstrate that HCMV-induced inhibition of macrophage differentiation was dependent on binding of virus particles to the cell surface molecule CD13/aminopeptidase N, which involved Ca2+-dependent intracellular signaling pathways. We found that treatment of cells with the CD13-specific mAbs My7 and WM15 inhibited macrophage differentiation, and that My7 and WM15 induced a rise in intracellular Ca2+ in similar ways as HCMV. In contrast, binding of the CD13-specific Ab clone SJ1D1 blocked the ability of HCMV to inhibit macrophage differentiation, and blocked the HCMV-induced intracellular Ca2+ response. In addition, the Ca2+ modulator thapsigargin partially blocked the ability of HCMV to inhibit cellular differentiation. Furthermore, we demonstrate that recombinant viral glycoprotein gB was able to inhibit macrophage differentiation in similar ways as the virus. Thus, these results suggest that binding of HCMV to monocytes induces an intracellular rise of Ca2+, of which one result is a block in the ability of the cells to differentiate into macrophages. These observations suggest an efficient viral strategy to interfere with cellular differentiation pathways, and may also in part explain the generalized immunosuppression that is often observed in HCMV-infected patients.
Blocking Programmed Death-1 Ligand-PD-1 Interactions by Local Gene Therapy Results in Enhancement of Antitumor Effect of Secondary Lymphoid Tissue Chemokine
Authors: He Yu-Fei , Zhang Gui-Mei , Wang Xiao-Hong , Zhang Hui , Yuan Ye , Li Dong , Feng Zuo-Hua 
Published: April 2014

AbstractThe negative signal provided by interactions of programmed death-1 (PD-1) and its ligands, costimulatory molecules PD-L1 (also B7-H1) and PD-L2 (also B7-DC), is involved in the mechanisms of tumor immune evasion. In this study, we found that this negative signal was also involved in immune evasion in tumor immunotherapy. When we used different doses of a constructed eukaryotic expression plasmid, pSLC, which expresses functional murine secondary lymphoid tissue chemokine (SLC, CCL21), to treat BALB/c mice inoculated with H22 murine hepatoma cells, the inhibitory effect was enhanced along with the increase of pSLC dosage. Unexpectedly, however, the best complete inhibition rate of tumor was reached when pSLC was used at the dosage of 50 μg but not 100 or 200 μg. RT-PCR and real-time PCR revealed that both PD-L1 and PD-L2 genes were expressed in tumor and vicinal muscle tissues of tumor-bearing mice and the expression level was significantly increased if a higher dosage of pSLC was administered. We then constructed a eukaryotic expression plasmid (pPD-1A) that expresses the extracellular domain of murine PD-1 (sPD-1). sPD-1 could bind PD-1 ligands, block PD-Ls-PD-1 interactions, and enhance the cytotoxicity of tumor-specific CTL. Local gene transfer by injection of pPD-1A mediated antitumor effect and improved SLC-mediated antitumor immunity. The combined gene therapy with SLC plus sPD-1 did not induce remarkable autoimmune manifestations. Our findings provide a potent method of improving the antitumor effects of SLC and possibly other immunotherapeutic methods by local blockade of negative costimulatory molecules.
MIP-3α Transfection into a Rodent Tumor Cell Line Increases Intratumoral Dendritic Cell Infiltration but Enhances (Facilitates) Tumor Growth and Decreases Immunogenicity
Authors: Bonnotte Bernard , Crittenden Marka , Larmonier Nicolas , Gough Michael , Vile Richard G. 
Published: April 2014

Abstract
Dendritic cells are powerful APCs for activation of specific antitumor T lymphocytes. To present tumor Ags efficiently, they have first to migrate to the tumor site, engulf Ag, and then process them. To attract immature DCs to the tumor site, we transfected tumor cells with MIP-3α which is strongly chemotactic for DCs. Surprisingly, MIP-3α-transfected tumor cells grew faster than the mock-transfected tumor cells. Histological analysis and tumor dissociation confirmed that the MIP-3α-transfected tumors contain three to four times more DCs than mock-transfected tumors. FACS analysis of the intratumor DCs showed that they were predominantly immature. Functional analysis showed that the alloreactivity mediated by these infiltrating MIP-3α-transfected tumor DCs is strongly reduced. In conclusion, MIP-3α is an efficient chemokine for attracting DCs in vivo, but the high density of DCs in the tumor site injection is not a sufficient condition to induce an immune response. Furthermore, this attraction of immature DCs may always have an adverse effect by inducing a tolerance to the tumor cells.
Geranylgeraniol Regulates Negatively Caspase-1 Autoprocessing: Implication in the Th1 Response against Mycobacterium tuberculosis
Authors: Montero María T. , Matilla Joaquín , Gómez-Mampaso Enrique , Lasunción Miguel A. 
Published: April 2014

Abstract
Caspase-1 is a cysteine protease composed by two 20-kDa and two 10-kDa subunits that processes pro-IL-1β and pro-IL-18 to their mature forms. This enzyme is present in cells as a latent zymogen that becomes active through a tightly regulated proteolytic cascade. Activation is initiated by the oligomerization of an adaptor molecule, or by the formation of a multiprotein complex named inflammasome. Negative regulation of caspase-1 activation is exerted by proteins that compete with the adaptor molecule or with the inflammasome formation. We previously reported that fluvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl coenzyme A reductase, increases caspase-1 activity in PBMC. This effect was strengthened by Mycobacterium tuberculosis, rending an exacerbated IL-1β, IL-18, and IFN-γ production. Mevalonate, the product of 3-hydroxy-3-methylglutaryl coenzyme A reductase, is a precursor for both nonsterol isoprenoid and sterol formation. In this study, we studied the involvement of mevalonate derivatives in the regulation of caspase-1 activation. Inhibition of sterol formation by SKF-104976 or haloperidol had no effect on IL-1β release. However, the isoprenoid geranylgeraniol prevented both caspase-1 activation and the exacerbated IL production induced by fluvastatin. This isoprenoid significantly reduced the release of IL-18 and IFN-γ by PBMC treated with mycobacteria, even in the absence of fluvastatin. In correlation with the increased caspase-1 activity, fluvastatin stimulated the proforms cleavage, enhancing the formation of active subunit p10. Geranylgeraniol not only prevented this effect, but induced proforms accumulation. Present results suggest that, once the proteolytic cascade is initiated, geranylgeraniol may exert an additional negative regulation on caspase-1 cleavage process.
Reversal in the Immunodominance Hierarchy in Secondary CD8+ T Cell Responses to Influenza A Virus: Roles for Cross-Presentation and Lysis-Independent Immunodomination
Authors: Chen Weisan , Pang Ken , Masterman Kelly-Anne , Kennedy Gina , Basta Sameh , Dimopoulos Nektaria , Hornung Felicita , Smyth Mark , Bennink Jack R. , Yewdell Jonathan W. 
Published: April 2014

Abstract
Immunodominance is a central feature of CD8+ T cell (TCD8+) responses to pathogens, transplants, and tumors. Determinants occupy a stable position in an immunodominance hierarchy (α-, β-, etc.) defined by the frequencies of responding TCD8+. In this paper, we study the mechanistic basis for place-swapping between α- (acid polymerase (PA)224–233) and β-determinants (nuclear protein 366–374) in primary vs secondary anti-influenza A virus (IAV) responses in mice. This phenomena was recently correlated with the inability of IAV-infected nondendritic cells (DCs) to generate PA224–233, and it was proposed that secondary TCD8+ are principally activated by IAV-infected epithelial cells, while primary TCD8+ are activated by IAV-infected DCs. In this study, we show that the inability of non-DCs to generate PA224–232 is relative rather than absolute, and that the preferential use of cross-priming in secondary anti-IAV responses can also account for the revised hierarchy. We further show that immunodomination of PA224–233-specific TCD8+ by nucleoprotein 366–374-specific TCD8+ plays a critical role in the phenomena, and that this is unlikely to be mediated by TCD8+ lysis of APCs or other cells.
Sonic Hedgehog Regulates Early Human Thymocyte Differentiation by Counteracting the IL-7-Induced Development of CD34+ Precursor Cells
Authors: Gutiérrez-Frías Cruz , Sacedón Rosa , Hernández-López Carmen , Cejalvo Teresa , Crompton Tessa , Zapata Agustín G. , Varas Alberto , Vicente Angeles 
Published: April 2014

Abstract
The Hedgehog (Hh) family of signaling molecules normally functions in the development of numerous tissues by regulating cellular differentiation and proliferation. Recent results have demonstrated that the different components of the Hh signaling pathway are expressed in the human thymus. In this study, we investigate the potential role of Sonic hedgehog (Shh) in human intrathymic T cell maturation. Results show that the expression of the two components of the Hh receptor, Patched and Smoothened, is mostly restricted to CD34+ precursor cells that are committing to the T cell lineage. Shh significantly increased the viability of CD34+ T cell precursors modulating bcl-2 and bax protein expression, and also inhibited their proliferation. The treatment of chimeric human-mouse fetal thymus organ cultures with Shh resulted in an arrested thymocyte differentiation and an accumulation of CD34+ progenitor cells. This effect was mainly attributed to the ability of Shh to counteract the IL-7-induced proliferation and differentiation of CD34+ cells. Shh down-regulated in the precursor cell population the expression of IL-7R as well as stromal-derived factor-1 chemokine receptor, CXCR4, and inhibited IL-7-dependent STAT5 phosphorylation. Therefore, Shh may function as a maintenance factor for intrathymic CD34+ precursor cells.
Developmental Activation of the TCR α Enhancer Requires Functional Collaboration among Proteins Bound Inside and Outside the Core Enhancer
Authors: Balmelle Nadège , Zamarreño Noelia , Krangel Michael S. , Hernández-Munain Cristina 
Published: April 2014

AbstractThe TCR δ enhancer (Eδ) and TCR α enhancer (Eα) play critical roles in the temporal and lineage-specific control of V(D)J recombination and transcription at the TCR αδ locus, working as a developmental switch controlling a transition from TCR δ to TCR α activity during thymocyte development. Previous experiments using a transgenic reporter substrate revealed that substitution of the 116-bp minimal Eα, denoted Tα1-Tα2, for the entire 1.4-kb Eα led to a premature activation of V(D)J recombination. This suggested that binding sites outside of Tα1-Tα2 are critical for the strict developmental regulation of TCR α rearrangement. We have further analyzed Eα to better understand the mechanisms responsible for appropriate developmental regulation in vivo. We found that a 275-bp Eα fragment, denoted Tα1-Tα4, contains all binding sites required for proper developmental regulation in vivo. This suggests that developmentally appropriate enhancer activation results from a functional interaction between factors bound to Tα1-Tα2 and Tα3-Tα4. In support of this, EMSAs reveal the formation of a large enhanceosome complex that reflects the cooperative assembly of proteins bound to both Tα1-Tα2 and Tα3-Tα4. Our data suggest that enhanceosome assembly is critical for developmentally appropriate activation of Eα in vivo, and that transcription factors, Sp1 and pCREB, may play unique roles in this process.
Identification of Seventeen New Simian Immunodeficiency Virus-Derived CD8+ T Cell Epitopes Restricted by the High Frequency Molecule, Mamu-A*02, and Potential Escape from CTL Recognition
Authors: Loffredo John T. , Sidney John , Wojewoda Christina , Dodds Elizabeth , Reynolds Matthew R. , Napoé Gnankang , Mothé Bianca R. , O’Connor David H. , Wilson Nancy A. , Watkins David I. , Sette Alessandro 
Published: April 2014

AbstractMHC class I-restricted CD8+ T cells play an important role in controlling HIV and SIV replication. In SIV-infected Indian rhesus macaques (Macaca mulatta), comprehensive CD8+ T cell epitope identification has only been undertaken for two alleles, Mamu-A*01 and Mamu-B*17. As a result, these two molecules account for virtually all known MHC class I-restricted SIV-derived CD8+ T cell epitopes. SIV pathogenesis research and vaccine testing have intensified the demand for epitopes restricted by additional MHC class I alleles due to the shortage of Mamu-A*01+ animals. Mamu-A*02 is a high frequency allele present in over 20% of macaques. In this study, we characterized the peptide binding of Mamu-A*02 using a panel of single amino acid substitution analogues and a library of 497 unrelated peptides. Of 230 SIVmac239 peptides that fit the Mamu-A*02 peptide-binding motif, 75 peptides bound Mamu-A*02 with IC50 values of ≤500 nM. We assessed the antigenicity of these 75 peptides using an IFN-γ ELISPOT assay with freshly isolated PBMC from eight Mamu-A*02+ SIV-infected macaques and identified 17 new epitopes for Mamu-A*02. The synthesis of five Mamu-A*02 tetramers demonstrated the discrepancy between tetramer binding and IFN-γ secretion by SIV-specific CD8+ T cells during chronic SIV infection. Bulk sequencing determined that 2 of the 17 epitopes accumulated amino acid replacements in SIV-infected macaques by the chronic phase of infection, suggestive of CD8+ T cell escape in vivo. This work enhances the use of the SIV-infected macaque model for HIV and increases our understanding of the breadth of CD8+ T cell responses in SIV infection.
Caspase Inhibition Blocks Human T Cell Proliferation by Suppressing Appropriate Regulation of IL-2, CD25, and Cell Cycle-Associated Proteins
Authors: Falk Markus , Ussat Sandra , Reiling Norbert , Wesch Daniela , Kabelitz Dieter , Adam-Klages Sabine 
Published: April 2014

AbstractCaspases have been described as proteases essential for the release of certain cytokines and for initiation as well as execution of apoptosis. Increasing evidence indicates, however, that caspase activity is also required for activation-induced proliferation of mature T lymphocytes. The molecular mechanism, how caspase activity facilitates T cell proliferation, is still controversially discussed. In this study, we show that proliferation of human T cells in response to a specific antigenic stimulus is completely prevented by caspase inhibition. In addition, we demonstrate that this lack of proliferation is due to a failure to initiate cell cycle progression, but not the result of increased T cell death. Our results demonstrate that caspase inhibition leads to strongly reduced IL-2 release, failure to up-regulate CD25, and a lack of proper regulation of cell cycle-associated proteins. Furthermore, T cell proliferation was partially rescued by addition of exogenous IL-2. Using Jurkat cells, we show that in the absence of caspase-8, the mitogen-induced activation of the transcription factor NF-κB is moderately diminished, while the activity of the composite element CD28 response element and NF-IL-2B AP-1 sites is strongly reduced. Finally, we provide evidence that caspase inhibition suppresses the activation of purified monocytes by bacterial Ags.
Linker for Activation of T Cells Integrates Positive and Negative Signaling in Mast Cells
Authors: Malbec Odile , Malissen Marie , Isnardi Isabelle , Lesourne Renaud , Mura Anne-Marie , Fridman Wolf H. , Malissen Bernard , Daëron Marc 
Published: April 2014

AbstractThe transmembrane adapter linker for activation of T cells (LAT) is thought to couple immunoreceptors to intracellular signaling pathways. In mice, its intracytoplasmic domain contains nine tyrosines which, when phosphorylated upon receptor aggregation, recruit Src-homology 2 domain-containing cytosolic enzymes and adapters. The four distal tyrosines are critical for both TCR and FcεRI signaling. Unexpectedly, knock-in mice expressing LAT with a point mutation of the first or of the last three of these tyrosines exhibited an abnormal T cell development characterized by a massive expansion of TH2-like αβ or γδ T cells, respectively. This phenotype suggests that, besides positive signals, LAT might support negative signals that normally regulate terminal T cell differentiation and proliferation. We investigated here whether LAT might similarly regulate mast cell activation, by generating not only positive but also negative signals, following FcR engagement. To this end, we examined IgE- and/or IgG-induced secretory and intracellular responses of mast cells derived from knock-in mice expressing LAT with combinations of tyrosine mutations (Y136F, Y(175, 195, 235)F, or Y(136, 175, 195, 235)F). A systematic comparison of pairs of mutants enabled us to dissect the respective roles played by the five proximal and the four distal tyrosines. We found that LAT tyrosines differentially contribute to exocytosis and cytokine secretion and differentially regulate biological responses of mucosal- and serosal-type mast cells. We also found that, indeed, both positive and negative signals may emanate from distinct tyrosines in LAT, whose integration modulates mast cell secretory responses.