bluuebunny/crossref_metadata_2025_split huggingface dataset:
Cutting Edge: Lentiviral Short Hairpin RNA Silencing of PTEN in Human Mast Cells Reveals Constitutive Signals That Promote Cytokine Secretion and Cell Survival
Authors: Furumoto Yasuko , Brooks Steve , Olivera Ana , Takagi Yasuomi , Miyagishi Makoto , Taira Kazunari , Casellas Rafael , Beaven Michael A. , Gilfillan Alasdair M. , Rivera Juan 
Published: April 2014

Abstract
Engagement of the FcεRI expressed on mast cells induces the production of phosphatidylinositol 3, 4, 5-trisphosphate by PI3K, which is essential for the functions of the cells. PTEN (phosphatase and tensin homologue deleted on chromosome ten) directly opposes PI3K by dephosphorylating phosphatidylinositol 3, 4, 5-trisphosphate at the 3′ position. In this work we used a lentivirus-mediated short hairpin RNA gene knockdown method to study the role of PTEN in CD34+ peripheral blood-derived human mast cells. Loss of PTEN caused constitutive phosphorylation of Akt, p38 MAPK, and JNK, as well as cytokine production and enhancement in cell survival, but not degranulation. FcεRI engagement of PTEN-deficient cells augmented signaling downstream of Src kinases and increased calcium flux, degranulation, and further enhanced cytokine production. PTEN-deficient cells, but not control cells, were resistant to inhibition of cytokine production by wortmannin, a PI3K inhibitor. The findings demonstrate that PTEN functions as a key regulator of mast cell homeostasis and FcεRI- responsiveness.
CTLA-4 Engagement and Regulatory CD4+CD25+ T Cells Independently Control CD8+-Mediated Responses under Costimulation Blockade
Authors: Coenen Jeroen J. A. , Koenen Hans J. P. M. , van Rijssen Esther , Boon Louis , Joosten Irma , Hilbrands Luuk B. 
Published: April 2014

Abstract
Blockade of costimulatory signals is a promising therapeutic target to prevent allograft rejection. In this study, we sought to characterize to what extent CTLA-4 engagement contributes to the development of transplantation tolerance under the cover of CD40/CD40L and CD28/CD86 blockade. In vitro, we found that inhibition of the primary alloresponse and induction of alloantigen hyporesponsiveness by costimulation blockade was abrogated by anti-CTLA-4 mAb. In addition, regulatory CD4+CD25+ T cells (TREG) were confirmed to play a critical role in the induction of hyporesponsiveness by anti-CD40L and anti-CD86 mAb. Our data indicated that CTLA-4 engagement is not required for activation or suppressor function of TREG. Instead, in the absence of either CTLA-4 signaling or TREG, CD8+ T cell division was enhanced, whereas the inhibition of CD4+ T cell division by costimulation blockade remained largely unaffected. In vivo, the administration of additional anti-CTLA-4 mAb abrogated anti-CD40L- and anti-CD86 mAb-induced cardiac allograft survival. Correspondingly, rejection was accompanied by enhanced allograft infiltration of CD8+ cells. We conclude that CTLA-4 signaling and TREG independently cooperate in the inhibition of CD8+ T cell expansion under costimulation blockade.
IL-4 Induces In Vivo Production of IFN-γ by NK and NKT Cells
Authors: Morris Suzanne C. , Orekhova Tatyana , Meadows Michelle J. , Heidorn Stephanie M. , Yang Junqi , Finkelman Fred D. 
Published: April 2014

AbstractAlthough IL-4 and IFN-γ often have opposite effects and suppress each other’s production by T cells, IL-4 can stimulate IFN-γ production. To characterize this, we injected mice with IL-4 and quantified IFN-γ production with the in vivo cytokine capture assay. IL-4 induced Stat6-dependent IFN-γ production by NK and, to a lesser extent, NKT cells, but not conventional T cells, in 2–4 h. Increased IFN-γ production persisted at a constant rate for &gt;24 h, but eventually declined, even with continuing IL-4 stimulation. This eventual decline in IFN-γ production was accompanied by a decrease in NK and T cell numbers. Consistent with a dominant role for NK cells in IL-4-stimulated IFN-γ secretion, IL-4 induction of IFN-γ was B and T cell-independent; suppressed by an anti-IL-2Rβ mAb that eliminates most NK and NKT cells; reduced in Stat4-deficient mice, which have decreased numbers of NK cells; and absent in Rag2/γc-double-deficient mice, which lack T, B, and NK cells. IL-4-induced IFN-γ production was not affected by neutralizing IL-12p40 and was increased by neutralizing IL-2. IL-13, which signals through the type 2 IL-4R and mimics many IL-4 effects, failed to stimulate IFN-γ production and, in most experiments, suppressed basal IFN-γ production. Thus, IL-4, acting through the type 1 IL-4R, induces Stat6-dependent IFN-γ secretion by NK and NKT cells. This explains how IL-4 can contribute to Th1 cytokine-associated immune effector functions and suggests how IL-13 can have stronger proallergic effects than IL-4.
Induction of CTLA-4-Mediated Anergy Contributes to Persistent Colonization in the Murine Model of GastricHelicobacter pyloriInfection
Authors: Anderson Kathleen M. , Czinn Steven J. , Redline Raymond W. , Blanchard Thomas G. 
Published: April 2014

AbstractHelicobacter pylori infection induces gastric inflammation but the host fails to generate protective immunity. Therefore, we evaluated the immunologic mechanisms that contribute to the failure of the T cells to promote active immunity to H. pylori in the mouse model of H. pylori infection. Spleen cells from infected C57BL/6 mice underwent significantly less proliferation and cytokine production than cells from immune mice upon in vitro stimulation with H. pylori lysate. Similar results were observed when stimulating with Ag-pulsed macrophages demonstrating that hyporesponsiveness was not due to a direct effect of H. pylori virulence factors on the T cells. Ag-specific hyporesponsiveness could be reversed by the addition of high-dose IL-2 but not by removal of CD4+CD25+ T cells, indicating that hyporesponsiveness was due to anergy and not due to active suppression. Cells from infected mice lacked significant suppressor activity as shown by the failure to reduce the recall response of cells from immune mice in coculture at physiologic ratios. Direct blockade of CTLA-4 using anti-CTLA-4 Fabs or indirect blockade using CTLA-4 Ig plus anti-CD28 Ab resulted in significantly increased T cell activation in vitro. The importance of CTLA-4 in establishing anergy was confirmed in an in vivo model of H. pylori infection in which mice that received anti-CTLA-4 Fabs responded to H. pylori challenge with significantly greater inflammation and significantly reduced bacterial load. These results suggest that CTLA-4 engagement induces and maintains functional inactivation of H. pylori-specific T cells during H. pylori infection resulting in a reduced immune response.
RhoG Regulates the Neutrophil NADPH Oxidase
Authors: Condliffe Alison M. , Webb Louise M. C. , Ferguson G. John , Davidson Keith , Turner Martin , Vigorito Elena , Manifava Maria , Chilvers Edwin R. , Stephens Len R. , Hawkins Phillip T. 
Published: April 2014

Abstract
RhoG is a Rho family small GTPase implicated in cytoskeletal regulation, acting either upstream of or in parallel to Rac1. The precise function(s) of RhoG in vivo has not yet been defined. We have identified a novel role for RhoG in signaling the neutrophil respiratory burst stimulated by G protein-coupled receptor agonists. Bone marrow-derived neutrophils from RhoG knockout (RhoG−/−) mice exhibited a marked impairment of oxidant generation in response to C5a or fMLP, but normal responses to PMA or opsonized zymosan and normal bacterial killing. Activation of Rac1 and Rac2 by fMLP was diminished in RhoG−/− neutrophils only at very early (5 s) time points (by 25 and 32%, respectively), whereas chemotaxis in response to soluble agonists was unaffected by lack of RhoG. Additionally, fMLP-stimulated phosphorylation of protein kinase B and p38MAPK, activation of phospholipase D, and calcium fluxes were equivalent in wild-type and RhoG−/− neutrophils. Our results define RhoG as a critical component of G protein-coupled receptor-stimulated signaling cascades in murine neutrophils, acting either via a subset of total cellular Rac relevant to oxidase activation and/or by a novel and as yet undefined interaction with the neutrophil NADPH oxidase.
Cooperation between TNF Receptor-Associated Factors 1 and 2 in CD40 Signaling
Authors: Xie Ping , Hostager Bruce S. , Munroe Melissa E. , Moore Carissa R. , Bishop Gail A. 
Published: April 2014

AbstractTNFR-associated factor 1 (TRAF1) is unique among the TRAF family, lacking most zinc-binding features, and showing marked up-regulation following activation signals. However, the biological roles that TRAF1 plays in immune cell signaling have been elusive, with many reports assigning contradictory roles to TRAF1. The overlapping binding site for TRAFs 1, 2, and 3 on many TNFR superfamily molecules, together with the early lethality of mice deficient in TRAFs 2 and 3, has complicated the quest for a clear understanding of the functions of TRAF1. Using a new method for gene targeting by homologous recombination in somatic cells, we produced and studied signaling by CD40 and its viral oncogenic mimic, latent membrane protein 1 (LMP1) in mouse B cell lines lacking TRAF1, TRAF2, or both TRAFs. Results indicate that TRAFs 1 and 2 cooperate in CD40-mediated activation of the B cell lines, with a dual deficiency leading to a markedly greater loss of function than that of either TRAF alone. In the absence of TRAF1, an increased amount of TRAF2 was recruited to lipid rafts, and subsequently, more robust degradation of TRAF2 and TRAF3 was induced in response to CD40 signaling. In contrast, LMP1 did not require either TRAFs 1 or 2 to induce activation. Taken together, our findings indicate that TRAF1 and TRAF2 cooperate in CD40 but not LMP1 signaling and suggest that cellular levels of TRAF1 may play an important role in modulating the degradation of TRAF2 and TRAF3 in response to signals from the TNFR superfamily.
Regulation of N-Formyl Peptide Receptor Signaling and Trafficking by Individual Carboxyl-Terminal Serine and Threonine Residues
Authors: Potter Ross M. , Maestas Diane C. , Cimino Daniel F. , Prossnitz Eric R. 
Published: April 2014

Abstract
Adaptation, defined as the diminution of receptor signaling in the presence of continued or repeated stimulation, is critical to cellular function. G protein-coupled receptors (GPCRs) undergo multiple adaptive processes, including desensitization and internalization, through phosphorylation of cytoplasmic serine and threonine residues. However, the relative importance of individual and combined serine and threonine residues to these processes is not well understood. We examined this mechanism in the context of the N-formyl peptide receptor (FPR), a well-characterized member of the chemoattractant/chemokine family of GPCRs critical to neutrophil function. To evaluate the contributions of individual and combinatorial serine and threonine residues to internalization, desensitization, and arrestin2 binding, 30 mutant forms of the FPR, expressed in the human promyelocytic U937 cell line, were characterized. We found that residues Ser328, Ser332, and Ser338 are individually critical, and indeed sufficient, for internalization, desensitization, and arrestin2 binding, but that the presence of neighboring threonine residues can inhibit these processes. Additionally, we observed no absolute correlation between arrestin binding and either internalization or desensitization, suggesting the existence of arrestin-independent mechanisms for these processes. Our results suggest C-terminal serine and threonine residues of the FPR represent a combinatorial code, capable of both positively and negatively regulating signaling and trafficking. This study is among the first detailed analyses of a complex regulatory site in a GPCR, and provides insight into GPCR regulatory mechanisms.
Enhancement of LFA-1-Mediated T Cell Adhesion by Human T Lymphotropic Virus Type 1 p12I1
Authors: Kim Seung-jae , Nair Amrithraj M. , Fernandez Soledad , Mathes Lawrence , Lairmore Michael D. 
Published: April 2014

Abstract
Cell-to-cell transmission of retroviruses, such as human T lymphotropic virus type 1 (HTLV-1), is well documented, but the roles of viral regulatory or other nonstructural proteins in the modulation of T cell adhesion are incompletely understood. In this study we tested the role of the HTLV-1 accessory protein, p12I, on LFA-1-mediated cell adhesion. p12I is critical for early HTLV-1 infection by causing the release of calcium from the endoplasmic reticulum to activate NFAT-mediated transcription. We tested the role of this novel viral protein in mediating LFA-1-dependent cell adhesion. Our data indicated that T cells expressing a mutant HTLV-1 provirus that does not produce p12I mRNA (ACH.p12I) exhibited reduced LFA-1-mediated adhesion compared with wild-type HTLV-1-expressing cells (ACH). Furthermore, the expression of p12I in Jurkat T cells using lentiviral vectors enhanced LFA-1-mediated cell adhesion, which was inhibited by the calcium chelator BAPTA-AM, the calcium channel blocker SK&F 96365, and calpeptin, an inhibitor of the calcium-dependent protease calpain. Similar to the intracellular calcium mobilizer, thapsigargin, the expression of p12I in Jurkat T cells induced cell surface clustering of LFA-1 without changing the level of integrin expression. Our data are the first to indicate that HTLV-1 p12I, in addition to enhancing T cell activation, promotes cell-to-cell spread by inducing LFA-1 clustering on T cells via calcium-dependent signaling.
Reduced Nitric Oxide Synthase 2 (NOS2) Promoter Activity in the Syrian Hamster Renders the Animal Functionally Deficient in NOS2 Activity and Unable to Control an Intracellular Pathogen
Authors: Perez Luis E. , Chandrasekar Bysani , Saldarriaga Omar A. , Zhao Weiguo , Arteaga Lourdes T. , Travi Bruno L. , Melby Peter C. 
Published: April 2014

AbstractProgressive disease in the hamster model of visceral leishmaniasis, caused by Leishmania donovani, in contrast to infection in mice, mimics the progressive disease observed in untreated humans. During progressive infection in hamsters, there was a vigorous type 1 cellular immune response, which is typically associated with control of infection, suggesting that there was ineffective IFN-γ-mediated macrophage activation. Indeed, at the site of infection, hamsters did not express NO synthase 2 (NOS2), which is the primary mechanism for control of infection in mice. Furthermore, in striking contrast to mouse macrophages, IFN-γ-activated hamster macrophages did not did not express NOS2 nor generate NO, and were unable to restrict the replication of intracellular L. donovani. The absent hamster NOS2 expression was not the result of NOS2 gene deletion and the NOS2 cDNA had an intact open reading frame. Furthermore, the impaired transcription of NOS2 mRNA was selective and not due to global impairment of IFN-γ signaling (members of the IFN-γ-signaling pathway were expressed and functional and IFN-γ up-regulated several primary and secondary response genes). Strikingly, the proximal hamster NOS2 promoter, like the human ortholog, had &gt;20-fold less basal and IFN-γ/LPS-inducible activity than the corresponding mouse promoter. Thus, reduced basal and IFN-γ-induced activity of the hamster NOS2 transcriptional unit, which is unique to this small animal and similar to the human counterpart, accompanies the inability of the animal to control an intracellular pathogen.
Nitrotyrosine Proteome Survey in Asthma Identifies Oxidative Mechanism of Catalase Inactivation
Authors: Ghosh Sudakshina , Janocha Allison J. , Aronica Mark A. , Swaidani Shadi , Comhair Suzy A. A. , Xu Weiling , Zheng Lemin , Kaveti Suma , Kinter Michael , Hazen Stanley L. , Erzurum Serpil C. 
Published: April 2014

AbstractReactive oxygen species and reactive nitrogen species produced by epithelial and inflammatory cells are key mediators of the chronic airway inflammation of asthma. Detection of 3-nitrotyrosine in the asthmatic lung confirms the presence of increased reactive oxygen and nitrogen species, but the lack of identification of modified proteins has hindered an understanding of the potential mechanistic contributions of nitration/oxidation to airway inflammation. In this study, we applied a proteomic approach, using nitrotyrosine as a marker, to evaluate the oxidation of proteins in the allergen-induced murine model of asthma. Over 30 different proteins were targets of nitration following allergen challenge, including the antioxidant enzyme catalase. Oxidative modification and loss of catalase enzyme function were seen in this model. Subsequent investigation of human bronchoalveolar lavage fluid revealed that catalase activity was reduced in asthma by up to 50% relative to healthy controls. Analysis of catalase isolated from asthmatic airway epithelial cells revealed increased amounts of several protein oxidation markers, including chloro- and nitrotyrosine, linking oxidative modification to the reduced activity in vivo. Parallel in vitro studies using reactive chlorinating species revealed that catalase inactivation is accompanied by the oxidation of a specific cysteine (Cys377). Taken together, these studies provide evidence of multiple ongoing and profound oxidative reactions in asthmatic airways, with one early downstream consequence being catalase inactivation. Loss of catalase activity likely amplifies oxidative stress, contributing to the chronic inflammatory state of the asthmatic airway.
Lactobacilli-Expressed Single-Chain Variable Fragment (scFv) Specific for Intercellular Adhesion Molecule 1 (ICAM-1) Blocks Cell-Associated HIV-1 Transmission across a Cervical Epithelial Monolayer
Authors: Chancey Caren J. , Khanna Kristen V. , Seegers Jos F. M. L. , Zhang Guang Wen , Hildreth James , Langan Abigail , Markham Richard B. 
Published: April 2014

Abstract
The vaginal and cervical epithelia provide an initial barrier to sexually acquired HIV-1 infection in women. To study the interactions between HIV-1-infected cells or cell-free HIV-1 and the reproductive epithelium, the transmission of HIV-1 by infected cells or cell-free virus across human cervical epithelial cells was examined using a Transwell culture system. Cell-associated HIV-1 was transmitted more efficiently than cell-free virus, and monocyte-associated virus was transmitted most efficiently. Abs to ICAM-1 added to the apical side of the epithelium blocked cell-mediated transepithelial HIV-1 transmission in vitro. When used in a previously described model of vaginal HIV-1 transmission in human PBL-SCID mice, anti-murine ICAM-1 Abs (0.4 μg/10 μl) also blocked vaginal transmission of cell-associated HIV-1 in vivo. To evaluate a candidate delivery system for the use of this Ab as an anti-HIV-1 microbicide, anti-ICAM single-chain variable fragment Abs secreted by transformed lactobacilli were evaluated for their protective efficacy in the Transwell model. Like the intact Ab and Fab derived from it, the single-chain variable fragment at a concentration of 6.7 μg/100 μl was able to reduce HIV-1 transmission by 70 ± 5%. These data support the potential efficacy of an anti-ICAM Ab delivered by lactobacilli for use as an anti-HIV-1 microbicide.
Tumor-Derived TGFβ-1 Induces Dendritic Cell Apoptosis in the Sentinel Lymph Node
Authors: Ito Manabu , Minamiya Yoshihiro , Kawai Hideki , Saito Satoshi , Saito Hajime , Nakagawa Taku , Imai Kazuhiro , Hirokawa Makoto , Ogawa Jun-ichi 
Published: April 2014

Abstract
Lymphatic flux from a primary tumor initially flows into a tumor-draining lymph node (LN), the so-called sentinel LN (SLN). Carried by the lymph fluid are a variety of mediators produced by the tumor that can influence immune responses within the SLN, making it a good model with which to investigate tumor-related immunology. For instance, dendritic cell (DC) numbers are reduced in SLNs from melanoma and breast cancer patients. In the present study, we investigated the mechanism by which DC numbers were reduced within SLNs from patients with non-small cell lung cancer. We found that the incidence of apoptosis among DCs was higher in SLNs than in non-SLNs, as were levels of TGFβ-1. In contrast, levels of TGFβ-1 mRNA did not differ between SLNs and non-SLNs, but were 30 times higher in tumors than in either LN type. In vitro, incubation for 2 days with TGFβ-1 induced apoptosis among both cultured DCs and DCs acutely isolated from normal thoracic LNs, effects that were blocked by the TGFβ-1 inhibitor DAN/Fc chimera. Taken together, these results suggest that tumor-derived TGFβ-1 induces immunosuppression within SLNs before the movement of tumor cells into the SLNs, thereby facilitating metastasis within those nodes.
How Plausible Is It That Conscious Control Is Illusory?
Authors: Navon David 
Published: April 2014

Abstract
Findings in a number of neuropsychological studies involving reports of decisions to initiate spontaneous movement (e.g., Fried, Mukamel, and Kreiman, 2011; Libet, Gleason, Wright, and Pearl, 1983; Soon, Brass, Heinze, & Haynes, 2008) are often interpreted as putting in question the reality of conscious control and, by extension, the time-honored concept of free will. I suggest that several problems with the basic paradigm used by most such studies, elaborated on in some recent articles (prominently Miller, Shepherdson, & Trevena, 2011, and Schurger, Sitt, & Dehaene, 2012), as well as some other arguments, raise doubt that conscious control is in fact a gratuitous byproduct of preconscious brain activity.
High‐Stability van Der Waals Structures of GeTe/Sb2Te3 Superlattices for 100× Increased Durability Phase‐Change Memory (PCM) by Low‐Temperature Atomic Layer Deposition
Authors: Zhu Rong‐Jiang , Zhao Rui‐Zhe , Gao Ke , Zhang Zhuo‐Ran , He Qiang , Tong Hao , Miao Xiang‐Shui 
Published: July 2024

AbstractThe superlattices phase‐change memory (SL‐PCM), based on GeTe/Sb2Te3 superlattices (SLs), garners considerable attention within the academic community owing to its exceptional electrical properties. While the exact mechanism remains a topic of ongoing debate, researchers widely acknowledge that the presence of van der Waals (vdW) gap structures within SLs plays a pivotal role. However, the formation of vertical nanoparticles (VNPs) from the random orientation of Sb2Te3 and the substantial intermixing between GeTe and Sb2Te3 due to high‐temperature fabrication processes leads to pronounced elemental intermixing during electrical operations, causing a loss of SLs properties. This investigation uses atomic layer deposition techniques, specifically Sb‐atomic seed layer and periodic quintuple layers stacking, to address issues from random orientation Sb2Te3 grains and anomalous VNPs. This approach yields Sb2Te3 crystalline films with a high‐stability vdW gap structures. By leveraging these films, SLs with a preferred crystallographic orientation at a notable low temperature of 90 °C are successfully fabricated. The optimized SLs exhibit remarkable structural stability and mitigate alloy phase emergence during electrical operations, resulting in a 100‐fold enhancement in device durability. This work advances reliable SL‐PCM understanding and implementation, propelling this memory technology into the next generation.