bluuebunny/crossref_metadata_2025_split huggingface dataset:
Inorganic Arsenic Activates Reduced NADPH Oxidase in Human Primary Macrophages through a Rho Kinase/p38 Kinase Pathway
Authors: Lemarie Anthony , Bourdonnay Emilie , Morzadec Claudie , Fardel Olivier , Vernhet Laurent 
Published: April 2014

Abstract
Inorganic arsenic is an immunotoxic environmental contaminant to which millions of humans are chronically exposed. We recently demonstrated that human primary macrophages constituted a critical target for arsenic trioxide (As2O3), an inorganic trivalent form. To specify the effects of arsenic on macrophage phenotype, we investigated in the present study whether As2O3 could regulate the activity of NADPH oxidase, a major superoxide-generating enzymatic system in human phagocytes. Our results show that superoxide levels were significantly increased in a time-dependent manner in blood monocyte-derived macrophages treated with 1 μM As2O3 for 72 h. Concomitantly, As2O3 induced phosphorylation and membrane translocation of the NADPH oxidase subunit p47phox and it also increased translocation of Rac1 and p67phox. Apocynin, a selective inhibitor of NADPH oxidases, prevented both p47phox translocation and superoxide production. NADPH oxidase activation was preceded by phosphorylation of p38-kinase in As2O3-treated macrophages. The p38-kinase inhibitor SB-203580 prevented phosphorylation and translocation of p47phox and subsequent superoxide production. Pretreatment of macrophages with the Rho-kinase inhibitor Y-27632 was found to mimic inhibitory effects of SB-203580 and to prevent As2O3-induced phosphorylation of p38 kinase. Treatment with As2O3 also resulted in an increased secretion of the proinflammatory chemokine CCL18 that was fully inhibited by both apocynin and SB-203580. Taken together, our results demonstrate that As2O3 induced a marked activation of NADPH oxidase in human macrophages, likely through stimulation of a Rho-kinase/p38-kinase pathway, and which may contribute to some of the deleterious effects of inorganic arsenic on macrophage phenotype.
Characterization of IL-10-Secreting T Cells Derived from Regulatory CD4+CD25+ Cells by the TIRC7 Surface Marker
Authors: Wakkach Abdelilah , Augier Séverine , Breittmayer Jean-Philippe , Blin-Wakkach Claudine , Carle Georges F. 
Published: April 2014

Abstract
Natural CD25+CD4+ regulatory T cells (Treg) are essential for self-tolerance and for the control of T cell-mediated immune pathologies. However, the identification of Tregs in an ongoing immune response or in inflamed tissues remains elusive. Our experiments indicate that TIRC7, T cell immune response cDNA 7, a novel membrane molecule involved in the regulation of T lymphocyte activation, identifies two Treg subsets (CD25lowTIRC7+ and CD25highTIRC7−) that are characterized by the expression of Foxp3 and a suppressive activity in vitro and in vivo. We also showed that the CD25lowTIRC7+ subset represents IL-10-secreting Tregs in steady state, which is accumulated intratumorally in a tumor-bearing mice model. Blockade of the effect of IL-10 reversed the suppression imposed by the CD25lowTIRC7+ subset. Interestingly, these IL-10-secreting cells derived from the CD25highTIRC7− subset, both in vitro and in vivo, in response to tumoral Ags. Our present results strongly support the notion that, in the pool of natural Tregs, some cells can recognize foreign Ags and that this recognition is an essential step in their expansion and suppressive activity in vivo.
Suppression of Normal and Malignant Kit Signaling by a Bispecific Antibody Linking Kit with CD300a
Authors: Bachelet Ido , Munitz Ariel , Berent-Maoz Beata , Mankuta David , Levi-Schaffer Francesca 
Published: April 2014

Abstract
Through its receptor Kit (CD117), stem cell factor (SCF) critically regulates human mast cell (MC) differentiation, survival, priming, and activation. The dominance of SCF in setting these parameters compels stringent contra-regulation to maintain a balanced MC phenotype. We have synthesized a library of bispecific Ab fragments to examine the effect of linking Kit with CD300a. In this study, we report that CD300a exerts a strong inhibitory effect on Kit-mediated SCF-induced signaling, consequently impairing MC differentiation, survival, and activation in vitro. This effect derives from Kit-mediated tyrosine phosphorylation of CD300a and recruitment of the SHIP-1 but not of SH2-containing protein phosphatase 1. CD300a inhibits the constitutive activation of the human leukemic HMC-1 cells but not their survival. Finally, CD300a abrogates the allergic reaction induced by SCF in a murine model of cutaneous anaphylaxis. Our findings highlight CD300a as a novel regulator of Kit in human MC and suggest roles for this receptor as a suppressor of Kit signaling in MC-related disorders.
Loss of STAT3 in CD4+ T Cells Prevents Development of Experimental Autoimmune Diseases
Authors: Liu Xuebin , Lee Yun Sang , Yu Cheng-Rong , Egwuagu Charles E. 
Published: April 2014

Abstract
Th17 cells are implicated in CNS autoimmune diseases. We show that mice with targeted-deletion of Stat3 in CD4+ T cells (CD4Stat3−/−) do not develop experimental autoimmune uveoretinitis (EAU) or experimental autoimmune encephalomyelitis. Defective Th17 differentiation noted in CD4Stat3−/− mice is compensated by exaggerated increases in Foxp3-, IL-10-, IL-4-, and IFN-γ-expressing T cells, suggesting critical roles of STAT3 in shaping Ag-specific CD4+ T cell repertoire. In mice with EAU, a high percentage of IL-17-expressing T cells in their peripheral lymphoid organs also secrete IFN-γ while these double-expressors are absent in CD4Stat3−/− and wild-type mice without EAU, raising the intriguing possibility that uveitis maybe mediated by Th17 and IL-17-expressing Th1 cells. Resistance of Stat3-deficient mice to EAU derives in part from an inability of uveitogenic Th17 and Th1 cells to enter eyes or brain of the CD4Stat3−/− mouse because of the reduction in the expression of activated α4/β1 integrins on CD4Stat3−/− T cells. Adoptive transfer of activated interphotoreceptor retinoid-binding protein-specific uveitogenic T cells induced in CD4Stat3−/− mice a severe EAU characterized by development of retinal folds, infiltration of inflammatory cells into the retina, and destruction of retinal architecture, underscoring our contention that the loss of STAT3 in CD4+ T cells results in an intrinsic developmental defect that renders CD4Stat3−/− resistant to CNS inflammatory diseases. STAT3 requirement for IL-17 production by Th17, generation of double positive T cells expressing IL-17 and IFN-γ, and for T cell trafficking into CNS tissues suggests that STAT3 may be a therapeutic target for modulating uveitis, sceritis, or multiple sclerosis.
Carcinoembryonic Antigen-Related Cell Adhesion Molecule 1 Inhibits Proximal TCR Signaling by Targeting ZAP-70
Authors: Chen Zhangguo , Chen Lanfen , Qiao Shuo-Wang , Nagaishi Takashi , Blumberg Richard S. 
Published: April 2014

Abstract
The long cytoplasmic tail (CT) isoforms of carcinoembryonic Ag-related cell adhesion molecule 1 (CEACAM1) are expressed on activated human T cells and possess two ITIM motifs in the CT. These isoforms of CEACAM1 are inhibitory for T cell responses initiated by the TCR/CD3 complex with the inhibition dependent upon the ITIMs of CEACAM1 and Src homology 2 domain-containing phosphatase 1 (SHP-1). However, the mechanism by which this inhibition occurs in T cells is unknown. We demonstrate here that the Src family kinase, Lck, and the ability of CEACAM1 to bind homophilically are required for the ITIM phosphorylation of CEACAM1 that is a prerequisite for CEACAM1 association with SHP-1. We further show that CEACAM1 associates with and recruits SHP-1 to the TCR/CD3 complex leading to decreased phosphorylation of CD3-ζ and ZAP-70 and consequently decreased activation of the elements downstream of ZAP-70. This is physiologically relevant because extinction of SHP-1 expression or blockade of homophilic binding by CEACAM1 using a Fab that specifically recognizes the homophilic binding region of human CEACAM1 increases the cytolytic function initiated by the TCR/CD3 complex. These studies show that long CT isoforms of CEACAM1 orchestrate an inhibitory program that abrogates extremely proximal events downstream of the TCR/CD3 complex by focusing on the activation of ZAP-70.
Functional Activity of MD-2 Polymorphic Variant Is Significantly Different in Soluble and TLR4-Bound Forms: Decreased Endotoxin Binding by G56R MD-2 and Its Rescue by TLR4 Ectodomain
Authors: Vašl Jožica , Prohinar Polonca , Gioannini Theresa L. , Weiss Jerrold P. , Jerala Roman 
Published: April 2014

Abstract
MD-2 is an essential component of endotoxin (LPS) sensing, binding LPS independently and when bound to the ectodomain of the membrane receptor TLR4. Natural variation of proteins involved in the LPS-recognition cascade such as the LPS-binding protein, CD14, and TLR4, as well as proteins involved in intracellular signaling downstream of LPS binding, affect the cellular response to endotoxin and host defense against bacterial infections. We now describe the functional properties of two nonsynonymous coding polymorphisms of MD-2, G56R and P157S, documented in HapMap. As predicted from the MD-2 structure, the P157S mutation had little or no effect on MD-2 function. In contrast, the G56R mutation, located close to the LPS-binding pocket, significantly decreased cellular responsiveness to LPS. Soluble G56R MD-2 showed markedly reduced LPS binding that was to a large degree rescued by TLR4 coexpression or presence of TLR4 ectodomain. Thus, cells that express TLR4 without MD-2 and whose response to LPS depends on ectopically produced MD-2 were most affected by expression of the G56R variant of MD-2. Coexpression of wild-type and G56R MD-2 yielded an intermediate phenotype with responses to LPS diminished to a greater extent than that resulting from expression of the D299G TLR4 polymorphic variant.
Single and Dual Amino Acid Substitutions in TCR CDRs Can Enhance Antigen-Specific T Cell Functions
Authors: Robbins Paul F. , Li Yong F. , El-Gamil Mona , Zhao Yangbing , Wargo Jennifer A. , Zheng Zhili , Xu Hui , Morgan Richard A. , Feldman Steven A. , Johnson Laura A. , Bennett Alan D. , Dunn Steven M. , Mahon Tara M. , Jakobsen Bent K. , Rosenberg Steven A. 
Published: April 2014

Abstract
Single and dual amino acid substitution variants were generated in the TCR CDRs of three TCRs that recognize tumor-associated Ags. Substitutions that enhance the reactivity of TCR gene-modified T cells to the cognate Ag complex were identified using a rapid RNA-based transfection system. The screening of a panel of variants of the 1G4 TCR, that recognizes a peptide corresponding to amino acid residues 157–165 of the human cancer testis Ag NY-ESO-1 (SLLMWITQC) in the context of the HLA-A*02 class I allele, resulted in the identification of single and dual CDR3α and CDR2β amino acid substitutions that dramatically enhanced the specific recognition of NY-ESO-1+/HLA-A*02+ tumor cell lines by TCR gene-modified CD4+ T cells. Within this group of improved TCRs, a dual substitution in the 1G4 TCR CDR3α chain was identified that enhanced Ag-specific reactivity in gene-modified CD4+ and CD8+ T cells. Separate experiments on two distinct TCRs that recognize the MART-1 27–35 (AAGIGILTV) peptide/HLA-A*02 Ag complex characterized single amino acid substitutions in both TCRs that enhanced CD4+ T cell Ag-specific reactivity. These results indicate that simple TCR substitution variants that enhance T cell function can be identified by rapid transfection and assay techniques, providing the means for generating potent Ag complex-specific TCR genes for use in the study of T cell interactions and in T cell adoptive immunotherapy.
Mannose-Binding Lectin (MBL)-Associated Serine Protease (MASP)-1 Contributes to Activation of the Lectin Complement Pathway
Authors: Takahashi Minoru , Iwaki Daisuke , Kanno Kazuko , Ishida Yumi , Xiong Jie , Matsushita Misao , Endo Yuichi , Miura Shigeto , Ishii Naoto , Sugamura Kazuo , Fujita Teizo 
Published: April 2014

Abstract
The complement system plays an important role in innate immunity. In the lectin complement pathway, mannose-binding lectin (MBL) and ficolins act as recognition molecules, and MBL-associated serine protease (MASP) is a key enzyme. It has been suggested that MASP-2 is responsible for the activation of C4. Other serine proteases (MASP-1 and MASP-3) are also associated with MBL or ficolins; however, their functions are still controversial. In this study, a MASP-1- and MASP-3-deficient mouse model (MASP1/3−/−) was generated by a gene targeting strategy to investigate the roles of MASP-1 and MASP-3 in the lectin pathway. Serum derived from MASP1/3−/− mice showed significantly lower activity of both C4 and C3 deposition on mannan-agarose, and this low activity was restored by the addition of recombinant MASP-1. MASP-1/3-deficient serum showed a significant delay for activation of MASP-2 compared with normal serum. Reconstitution of recombinant MASP-1 in MASP-1/3-deficient serum was able to promote the activation of MASP-2. From these results, we propose that MASP-1 contributes to the activation of the lectin pathway, probably through the activation of MASP-2.
Lipoproteins Are Critical TLR2 Activating Toxins in Group B Streptococcal Sepsis
Authors: Henneke Philipp , Dramsi Shaynoor , Mancuso Giuseppe , Chraibi Kamila , Pellegrini Elisabeth , Theilacker Christian , Hübner Johannes , Santos-Sierra Sandra , Teti Giuseppe , Golenbock Douglas T. , Poyart Claire , Trieu-Cuot Patrick 
Published: April 2014

Abstract
Group B streptococcus (GBS) is the most important cause of neonatal sepsis, which is mediated in part by TLR2. However, GBS components that potently induce cytokines via TLR2 are largely unknown. We found that GBS strains of the same serotype differ in released factors that activate TLR2. Several lines of genetic and biochemical evidence indicated that lipoteichoic acid (LTA), the most widely studied TLR2 agonist in Gram-positive bacteria, was not essential for TLR2 activation. We thus examined the role of GBS lipoproteins in this process by inactivating two genes essential for bacterial lipoprotein (BLP) maturation: the prolipoprotein diacylglyceryl transferase gene (lgt) and the lipoprotein signal peptidase gene (lsp). We found that Lgt modification of the N-terminal sequence called lipobox was not critical for Lsp cleavage of BLPs. In the absence of lgt and lsp, lipoprotein signal peptides were processed by the type I signal peptidase. Importantly, both the Δlgt and the Δlsp mutant were impaired in TLR2 activation. In contrast to released factors, fixed Δlgt and Δlsp GBS cells exhibited normal inflammatory activity indicating that extracellular toxins and cell wall components activate phagocytes through independent pathways. In addition, the Δlgt mutant exhibited increased lethality in a model of neonatal GBS sepsis. Notably, LTA comprised little, if any, inflammatory potency when extracted from Δlgt GBS. In conclusion, mature BLPs, and not LTA, are the major TLR2 activating factors from GBS and significantly contribute to GBS sepsis.
Tick Saliva Inhibits Dendritic Cell Migration, Maturation, and Function while Promoting Development of Th2 Responses
Authors: Skallová Anna , Iezzi Giandomenica , Ampenberger Franziska , Kopf Manfred , Kopecký Jan 
Published: April 2014

Abstract
Similarly to other blood-feeding arthropods, ticks have evolved immunosuppressive mechanisms enabling them to overcome the host immune system. Although the immunomodulatory effect of tick saliva on several cell populations of the immune system has been extensively studied, little is known about its impact on dendritic cells (DCs). We have examined the effect of Ixodes ricinus tick saliva on DC function in vitro and in vivo. Exposure of DCs to tick saliva in vitro resulted in impaired maturation, upon CD40 or TLR9, TLR3 and TLR7 ligation, as well as reduced Ag presentation capacity. Administration of tick saliva in vivo significantly inhibited maturation and early migration of DCs from inflamed skin to draining lymph nodes, and decreased the capacity of lymph node DCs to present soluble Ag to specific T cells. Moreover, saliva-exposed DCs failed to induce efficient Th1 and Th17 polarization and promoted development of Th2 responses. Our data reveal a complex inhibitory effect exerted by tick saliva on DC function. Given the role of DCs as the key instigators of adaptive immune responses, alteration of their function might represent a major mechanism of tick-mediated immune evasion.
Leukotriene B4 Induces Release of Antimicrobial Peptides in Lungs of Virally Infected Mice
Authors: Gaudreault Éric , Gosselin Jean 
Published: April 2014

Abstract
Leukotriene B4 (LTB4) is a lipid mediator of inflammation that was recently shown to exert antiviral activities. In this study, we demonstrate that the release of antimicrobial proteins by neutrophils contribute to an early host defense against influenza virus infection in vitro as well as in vivo. Daily i.v. treatments with LTB4 lead to a significant decrease in lung viral loads at day 5 postinfection in mice infected with influenza A virus compared with the placebo-treated group. This reduction in viral load was not present in mice deficient in the high-affinity LTB4 receptor. Viral clearance in lungs was associated with up-regulated presence of antimicrobial peptides such as β-defensin-3, members of the mouse eosinophil-related RNase family, and the mouse cathelicidin-related antimicrobial peptide. Our results also indicate that neutrophils are important in the antiviral effect of LTB4. Viral loads in neutrophil-depleted mice were not diminished by LTB4 administration, and a substantial reduction in the presence of murine cathelicidin-related antimicrobial peptide and the murine eosinophil-related RNase family in lung tissue was observed. Moreover, in vitro treatment of human neutrophil cultures with LTB4 led rapidly to the secretion of the human cathelicidin LL-37 and eosinophil-derived neurotoxin, known as antiviral peptides. Pretreatment of cell cultures with specific LTB4 receptor antagonists clearly demonstrate the implication of the high-affinity LTB4 receptor in the LTB4-mediated activity. Together, these results demonstrate the importance of neutrophils and the secretion of antimicrobial peptides during the early immune response mediated by LTB4 against a viral pathogen.
Identification of Pendrin as a Common Mediator for Mucus Production in Bronchial Asthma and Chronic Obstructive Pulmonary Disease
Authors: Nakao Isao , Kanaji Sachiko , Ohta Shoichiro , Matsushita Hidetomo , Arima Kazuhiko , Yuyama Noriko , Yamaya Mutsuo , Nakayama Katsutoshi , Kubo Hiroshi , Watanabe Mika , Sagara Hironori , Sugiyama Kumiya , Tanaka Hiroyuki , Toda Shuji , Hayashi Hiroaki , Inoue Hiromasa , Hoshino Tomoaki , Shiraki Aya , Inoue Makoto , Suzuki Koichi , Aizawa Hisamichi , Okinami Satoshi , Nagai Hiroichi , Hasegawa Mamoru , Fukuda Takeshi , Green Eric D. , Izuhara Kenji 
Published: April 2014

Abstract
Excessive production of airway mucus is a cardinal feature of bronchial asthma and chronic obstructive pulmonary disease (COPD) and contributes to morbidity and mortality in these diseases. IL-13, a Th2-type cytokine, is a central mediator in the pathogenesis of bronchial asthma, including mucus overproduction. Using a genome-wide search for genes induced in airway epithelial cells in response to IL-13, we identified pendrin encoded by the SLC26A4 (PDS) gene as a molecule responsible for airway mucus production. In both asthma and COPD mouse models, pendrin was up-regulated at the apical side of airway epithelial cells in association with mucus overproduction. Pendrin induced expression of MUC5AC, a major product of mucus in asthma and COPD, in airway epithelial cells. Finally, the enforced expression of pendrin in airway epithelial cells in vivo, using a Sendai virus vector, rapidly induced mucus overproduction in the lumens of the lungs together with neutrophilic infiltration in mice. These findings collectively suggest that pendrin can induce mucus production in airway epithelial cells and may be a therapeutic target candidate for bronchial asthma and COPD.
Unique Expression of Suppressor of Cytokine Signaling 3 Is Essential for Classical Macrophage Activation in Rodents In Vitro and In Vivo
Authors: Liu Yu , Stewart Keith N. , Bishop Eileen , Marek Carylyn J. , Kluth David C. , Rees Andrew J. , Wilson Heather M. 
Published: April 2014

Abstract
On infiltrating inflamed tissue, macrophages respond to the local microenvironment and develop one of two broad phenotypes: classically activated (M1) macrophages that cause tissue injury and alternatively activated macrophages that promote repair. Understanding how this polarization occurs in vivo is far from complete, and in this study, using a Th1-mediated macrophage-dependent model of acute glomerulonephritis, nephrotoxic nephritis, we examine the role of suppressor of cytokine signaling (SOCS)1 and SOCS3. Macrophages in normal kidneys did not express detectable SOCS proteins but those infiltrating inflamed glomeruli were rapidly polarized to express either SOCS1 (27 ± 6%) or SOCS3 (54 ± 12%) but rarely both (10 ± 3%). Rat bone marrow-derived macrophages incubated with IFN-γ or LPS expressed SOCS1 and SOCS3, whereas IL-4 stimulated macrophages expressed SOCS1 exclusively. By contrast, incubation with IFN-γ and LPS together suppressed SOCS1 while uniquely polarizing macrophages to SOCS3 expressing cells. Macrophages in which SOCS3 was knocked down by short interfering RNA responded to IFN-γ and LPS very differently: they had enhanced STAT3 activity; induction of macrophage mannose receptor, arginase and SOCS1; restoration of IL-4 responsiveness that is inhibited in M1 macrophages; and decreased synthesis of inflammatory mediators (NO and IL-6) and costimulatory molecule CD86, demonstrating that SOCS3 is essential for M1 activation. Without it, macrophages develop characteristic alternatively activated markers when exposed to classical activating stimuli. Lastly, increased glomerular IL-4 in nephrotoxic nephritis inhibits infiltrating macrophages from expressing SOCS3 and was associated with attenuated glomerular injury. Consequently, we propose that SOCS3 is essential for development of M1 macrophages in vitro and in vivo.
Requirement for Vav Proteins in Post-Recruitment Neutrophil Cytotoxicity in IgG but Not Complement C3-Dependent Injury
Authors: Utomo Ahmad , Hirahashi Junichi , Mekala Divya , Asano Kenichi , Glogauer Michael , Cullere Xavier , Mayadas Tanya N. 
Published: April 2014

Abstract
The signals linking neutrophil opsonic receptors, FcγRs and complement receptor 3 (Mac-1) to cellular cytotoxic responses are poorly understood. Furthermore, because a deficiency in activating FcγRs reduces both IgG-mediated neutrophil recruitment and tissue injury, the role of FcγRs specifically in mediating neutrophil cytotoxicity in vivo remains unclear. In this study, we demonstrate that neutrophil Vav 1 and 3, guanine exchange factors for Rac GTPases, are required for IgG/FcγR-mediated hemorrhage and edema in the reverse passive Arthus in the lung and skin. Rac GTPases are also required for development of the reverse passive Arthus reaction. A deficiency in Vav 1 and 3 does not affect neutrophil accumulation at the site of immune complex deposition, thus uncoupling neutrophil recruitment and tissue injury. Surprisingly, Vav and Rac proteins are dispensable for the development of the local Shwartzman reaction in vivo and phagocytosis of complement-opsonized RBC in vitro, processes strictly dependent on Mac-1 and complement C3. Thus, FcγR signaling through the Vav and Rac proteins in neutrophils is critical for stimulating immune complex disease while Vav- and Rac-independent pathways promote Mac-1/complement C3-dependent functions.