bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glucocorticoids transform CD40-triggering of dendritic cells into an alternative activation pathway resulting in antigen-presenting cells that secrete IL-10
Authors: Rea Delphine , van Kooten Cees , van Meijgaarden Krista E. , Ottenhoff Tom H. M. , Melief Cornelis J. M. , Offringa Rienk 
Published: October 2019

AbstractDendritic cell (DC) activation through CD40-CD40 ligand interactions is a key regulatory step for the development of protective T-cell immunity and also plays an important role in the initiation of T-cell responses involved in autoimmune diseases and allograft rejection. In contrast to previous reports, we show that the immunosuppressive drug dexamethasone (DEX) redirects rather than simply blocks this DC activation process. We found that DCs triggered through CD40 in the presence of DEX were unable to acquire high levels of costimulatory, adhesion, and major histocompatibility complex class I and II molecules and failed to express the maturation marker CD83, whereas antigen uptake was not affected. Moreover, DEX strikingly modified the CD40-activated DC cytokine secretion profile by suppressing the production of the proinflammatory cytokine interleukin (IL)-12 and potentiating the secretion of the anti-inflammatory cytokine IL-10. Accordingly, DEX-exposed CD40-triggered DCs displayed a decreased T-cell allostimulatory potential and a dramatically impaired ability to activate cloned CD4+ T helper 1 (Th1) cells. Moreover, interaction between Th1 cells and these DCs rendered the T cells hyporesponsive to further antigen-specific restimulation. Collectively, our results demonstrate that DEX profoundly modulates CD40-dependent DC activation and suggest that the resulting alternatively activated DCs can be exploited for suppression of unwanted T-cell responses in vivo.
Deficiency of the Fas apoptosis pathway without Fas gene mutations is a familial trait predisposing to development of autoimmune diseases and cancer
Authors: Ramenghi Ugo , Bonissoni Sara , Migliaretti Giuseppe , DeFranco Simona , Bottarel Flavia , Gambaruto Caterina , DiFranco Daniela , Priori Roberta , Conti Fabrizio , Dianzani Irma , Valesini Guido , Merletti Franco , Dianzani Umberto 
Published: October 2019

AbstractFas/Apo-1 (CD95) triggers programmed cell death (PCD) and is involved in immune response control and cell-mediated cytotoxicity. In the autoimmune/lymphoproliferative syndrome (ALPS), inherited loss-of-function mutations of the Fas gene cause nonmalignant lymphoproliferation and autoimmunity. We have recently identified an ALPS-like clinical pattern (named autoimmune lymphoproliferative disease [ALD]) in patients with decreased Fas function, but noFas gene mutation. They also displayed decreased PCD response to ceramide, triggering a death pathway partially overlapping that used by Fas, which suggests that ALD is caused by downstream alterations of the Fas signaling pathway. Decreased Fas function is also involved in tumor development, because somatic mutations hitting the Fas system may protect neoplastic cells from immune surveillance. This work assessed the inherited component of the ALD defect by evaluating Fas- and ceramide-induced T-cell death in both parents and 4 close relatives of 10 unrelated patients with ALD. Most of them (22 of 24) displayed defective Fas- or ceramide-induced (or both) cell death. Moreover, analysis of the family histories showed that frequencies of autoimmunity and cancer were significantly increased in the paternal and maternal line, respectively. Defective Fas- or ceramide-induced T-cell death was also detected in 9 of 17 autoimmune patients from 7 families displaying more than a single case of autoimmunity within first- or second-degree relatives (multiple autoimmune syndrome [MAS] patients). Autoimmune diseases displayed by ALD and MAS families included several organ-specific and systemic forms. These data suggest that ALD is due to accumulation of several defects in the same subject and that these defects predispose to development of cancer or autoimmune diseases other than ALPS/ALD.
Interleukin-2 enhances the response of natural killer cells to interleukin-12 through up-regulation of the interleukin-12 receptor and STAT4
Authors: Wang Kathy S. , Frank David A. , Ritz Jerome 
Published: October 2019

AbstractInterleukin (IL)-12 plays a critical role in modulating the activities of natural killer (NK) cells and T lymphocytes. In animal models, IL-12 has potent antitumor effects that are likely mediated by its ability to enhance the cytotoxic activity of NK cells and cytotoxic T lymphocytes, and to induce the production of interferon (IFN)-γ by NK and T cells. In addition to IL-12, NK cells are responsive to IL-2, and may mediate some of the antitumor effects of IL-2. In this study, we examine the interaction between IL-2 and the signaling events induced by IL-12 in NK cells. We find that IL-2 not only up-regulates the expression of IL-12Rβ1 and IL-12Rβ2, it also plays an important role in up-regulating and maintaining the expression of STAT4, a critical STAT protein involved in IL-12 signaling in NK cells. In contrast to the effects of IL-2 alone, expression of IL-12 receptors and STAT4 are unaffected or decreased by IL-12 or the combination of IL-2 and IL-12. Through expression of high levels of IL-12 receptors and STAT4, IL-2–primed NK cells show enhanced functional responses to IL-12 as measured by IFN-γ production and the killing of target cells. NK cells from cancer patients who received low-dose IL-2 treatment also exhibited increased expression of IL-12 receptor chains, suggesting that IL-2 may enhance the response to IL-12 in vivo. These findings provide a molecular framework to understand the interaction between IL-2 and IL-12 in NK cells, and suggest strategies for improving the effectiveness of these cytokines in the immunotherapy of cancer.
RasGRP links T-cell receptor signaling to Ras
Authors: Ebinu Julius O. , Stang Stacey L. , Teixeira Christine , Bottorff Drell A. , Hooton Jonathan , Blumberg Peter M. , Barry Michele , Bleakley R. Chris , Ostergaard Hanne L. , Stone James C. 
Published: October 2019

AbstractStimulation of the T-cell receptor (TCR) alters a number of intracellular signaling pathways including one that involves protein tyrosine kinases, phospholipase C-γ1 (PLC-γ1), diacylglycerol (DAG), and calcium messengers. By a divergent pathway, TCR-stimulated protein tyrosine kinase activity is thought to result independently in recruitment of the Ras activator Sos to the plasma membrane, leading to Ras activation. Here we show that RasGRP, a Ras activator that contains calcium-binding EF hands and a DAG-binding domain, is expressed in T cells. A PLC-γ1 inhibitor diminished activation of Ras following TCR stimulation. Membranes from TCR-stimulated Jurkat T cells exhibited increased RasGRP and increased Ras-guanyl nucleotide association activity that was inhibited by antibodies directed against RasGRP. Overexpression of RasGRP in T cells enhanced TCR-Ras-Erk signaling and augmented interleukin-2 secretion in response to calcium ionophore plus DAG analogues phorbol ester myristate or bryostatin-1. Thus, RasGRP links TCR and PLC-γ1 to Ras-Erk signaling, a pathway amenable to pharmacologic manipulation.
Chronic neutropenia mediated by Fas ligand
Authors: Liu Jin Hong , Wei Sheng , Lamy Thierry , Epling-Burnette P. K. , Starkebaum Gordon , Djeu Julie Y. , Loughran Thomas P. 
Published: October 2019

AbstractChronic neutropenia, often associated with rheumatoid arthritis, is a characteristic finding in large granular lymphocyte (LGL) leukemia. The mechanism of neutropenia is not known. Normal neutrophil survival is regulated by the Fas–Fas ligand apoptotic system. We hypothesized that neutropenia in LGL leukemia is mediated by dysregulated expression of Fas ligand. Levels of Fas ligand in serum samples from patients with LGL leukemia were measured with a Fas ligand enzyme-linked immunosorbent assay. The effects of serum from patients with LGL leukemia on apoptosis of normal neutrophils were determined by flow cytometry and morphologic assessment. High levels of circulating Fas ligand were detected in 39 of 44 serum samples from patients with LGL leukemia. In contrast, Fas ligand was undetectable in 10 samples from healthy donors. Serum from the patients triggered apoptosis of normal neutrophils that depended partly on the Fas pathway. Resolution of neutropenia was associated with disappearance or marked reduction in Fas ligand levels in 10 of 11 treated patients. These data suggest that high levels of Fas ligand are a pathogenetic mechanism in human disease.
Up-regulation of vascular endothelial growth factor receptor Flt-1 after endothelial denudation: role of transcription factor Egr-1
Authors: Vidal Felipe , Aragonés Julián , Alfranca Arántzazu , de Landázuri Manuel O. 
Published: October 2019

AbstractVascular endothelial growth factor (VEGF) is highly expressed in vascular remodeling processes and accelerates reendothelialization after mechanical denudation. Two VEGF tyrosine kinase receptors have been reported—fms-like–tyrosine kinase-1 (Flt-1) and kinase domain region (KDR). Little is known about the regulation of the expression of these receptors after vascular injury. Herein, we have analyzed the expression of Flt-1 after mechanical denudation of primary cultures of endothelial cells, which has been considered a useful in vitro model to study endothelium responses to vascular injury. After denudation, the Flt-1 protein and mRNA levels are clearly up-regulated, and transient transfection experiments showed a strong induction of theflt-1 promoter-dependent transcription. Analysis of the flt-1 promoter sequence revealed the presence of a putative binding site for the early growth response factor-1 (Egr-1) at positions −24 to −16. Electrophoretic mobility shift and supershift assays showed that Egr-1 was able to bind to this DNA sequence, and cotransfection of the flt-1 promoter reporter plasmid with an Egr-1 expression vector resulted in enhancement of its transcriptional activity. Furthermore, the mutation of the Egr-1 binding site markedly reduced the denudation-induced flt-1promoter activity. These data demonstrate that Flt-1 is up-regulated after endothelial denudation and that Egr-1 plays a relevant role in this process.
Endostatin-induced tyrosine kinase signaling through the Shb adaptor protein regulates endothelial cell apoptosis
Authors: Dixelius Johan , Larsson Helena , Sasaki Takako , Holmqvist Kristina , Lu Lingge , Engström Åke , Timpl Rupert , Welsh Michael , Claesson-Welsh Lena 
Published: October 2019

AbstractEndostatin, which corresponds to the C-terminal fragment of collagen XVIII, is a potent inhibitor of angiogenesis. Fibroblast growth factor-2 (FGF-2)–induced angiogenesis in the chicken chorioallantoic membrane was inhibited by endostatin, but not by an endostatin mutant R158/270A, lacking heparin-binding ability. Endostatin was internalized by endothelial cells, but not by mouse fibroblasts. Treatment of murine brain endothelial (IBE) cells with endostatin reduced the proportion of cells in S phase, whereas growth-arrested IBE cells in collagen gels treated with endostatin displayed enhanced tubular morphogenesis. IBE cells overexpressing Shb, an adaptor protein implicated in angiostatin-induced apoptosis, displayed elevated apoptosis and decreased tubular morphogenesis in collagen gels in response to endostatin when added together with FGF-2. Induction of apoptosis was dependent on the heparin-binding ability of endostatin and the expression of Shb with a functional Src homology 2 (SH2)-domain. Endostatin treatment for 10 minutes or 24 hours induced tyrosine phosphorylation of Shb and formation of multiprotein complexes. An Shb SH2 domain fusion protein precipitated a 125-kd phosphotyrosyl protein in endostatin-treated cells. The 125-kd component either contained intrinsic tyrosine kinase activity or occurred in complex with a tyrosine kinase. In conclusion, our data show that endostatin induces tyrosine kinase activity and enhanced apoptosis in FGF-treated endothelial cells.
Modulation of factor VII levels by intron 7 polymorphisms: population and in vitro studies
Authors: Pinotti Mirko , Toso Raffaella , Girelli Domenico , Bindini Debora , Ferraresi Paolo , Papa Maria L. , Corrocher Roberto , Marchetti Giovanna , Bernardi Francesco 
Published: October 2019

AbstractPrevious studies have established that factor VII gene (F7) polymorphisms (5′F7 and R353Q) contribute about one-third of factor VII (FVII) level variation in plasma. However, F7 genotyping in patients with cardiovascular disease has produced conflicting results. Population and expression studies were used to investigate the role of intron 7 (IVS7 ) polymorphisms, including repeat and sequence variations, in controlling activated FVII (FVIIa) and antigen (FVIIag) levels. Genotype–phenotype studies performed in 438 Italian subjects suggested a positive relation between the IVS7 repeat number and FVII levels. The lowest values were associated with theIVS7 + 7G allele. The screening of 52 patients with mild FVII deficiency showed an 8-fold increase in frequency (8%) of this allele, and among heterozygotes for identical mutations, lower FVII levels were observed in the IVS7 + 7G carriers. This frequent genetic component participates in the phenotypic heterogeneity of FVII deficiency. The evaluation of the individual contribution of polymorphisms was assisted by the expression of each IVS7variant, as a minigene, in eukaryotic cells. The novel quantitative analysis revealed that higher numbers of repeats were associated with higher mRNA expression levels and that the IVS7 + 7Gallele, previously defined as a functionally silent polymorphism, was responsible for the lowest relative mRNA expression. Taken together, these findings indicate that the IVS7 polymorphisms contribute to the plasmatic variance of FVII levels via differential efficiency of mRNA splicing. These studies provide further elements to understand the control of FVII levels, which could be of importance to ensure the hemostatic balance under pathologic conditions.
Interleukin-13 fusion cytotoxin as a potent targeted agent for AIDS-Kaposi's sarcoma xenograft
Authors: Husain Syed R. , Puri Raj K. 
Published: October 2019

AbstractClinically advanced and rapidly progressive AIDS-associated Kaposi sarcoma (AIDS-KS) tumors require an aggressive tumor-directed therapy. We have observed that AIDS-KS cells express high levels of receptors for immune regulatory cytokine, interleukin-13 (IL-13). Two tumorigenic AIDS-KS cell lines, KS Y-1 and KS-imm, expressed 4560 and 9480 IL-13 binding sites per cell with an affinity (kd) of ∼0.9 and 3.7 nmol/L, respectively. IL-13 cytotoxin IL13-PE38QQR, consisting of human IL-13 and a derivative of Pseudomonas exotoxin, is specifically cytotoxic to KS tumor cells. Systemic and loco regional administration of IL13-PE38QQR in immunodeficient mice with established human KS tumors produced remarkable antitumor activity. Three intratumoral (IT) injections of IL-13 toxin (250 μg/kg per dose) on alternate days (qod) or 5 daily (qd) IT injections with lower doses (50 or 100 μg/kg per dose) resulted in a complete regression of established subcutaneous tumors in most animals. Daily IT treatment with 250 μg/kg of IL-13 toxin in another KS-derived cell line also produced complete responses. Twice daily intraperitoneal injections of IL13-PE38QQR (25 or 50 μg/kg per dose) for 10 days (total injections = 20) also completely eradicated KS Y-1 tumors. Intravenous administration of IL13-PE38QQR also suppressed tumor growth; however, complete responses were not observed. All animals tolerated the therapeutic doses of IL-13 toxin without any visible signs of toxicity. The efficacy of receptor-directed IL13-PE38QQR therapy in mice warrants further exploration of this drug for AIDS-KS treatment.
Phenotypic and functional characteristics of hematopoietic cell lineages in CD69-deficient mice
Authors: Lauzurica Pilar , Sancho David , Torres Miguel , Albella Beatriz , Marazuela Mónica , Merino Teresa , Bueren Juan A. , Martı́nez-A Carlos , Sánchez-Madrid Francisco 
Published: October 2019

AbstractAIM/CD69 is the earliest leukocyte activation antigen and is expressed mainly by activated T, B, and natural killer (NK) cells. It is also constitutively expressed by platelets, by bone marrow myeloid precursors, and by small subsets of resident lymphocytes in the secondary lymphoid tissues. The engagement of CD69 by specific antibodies induces intracellular signals, including Ca++ flux, cytokine synthesis, and cell proliferation. To investigate the physiological relevance of CD69, we generated mice deficient in CD69 (CD69-/-) by gene targeting in embryonic stem cells. CD69 (-/-) mice showed largely normal hematopoietic cell development and normal T-cell subpopulations in thymus and periphery. Furthermore, studies of negative- and positive-thymocyte selection using a T-cell receptor transgenic model demonstrated that these processes were not altered in CD69 (-/-) mice. In addition, natural killer and cytotoxic T lymphocyte cells from CD69-deficient mice displayed cytotoxic activity similar to that of wild-type mice. Interestingly, B-cell development was affected in the absence of CD69. The B220hiIgMneg bone marrow pre-B cell compartment was augmented in CD69 (-/-) mice. In addition, the absence of CD69 led to a slight increase in immunoglobulin (Ig) G2a and IgM responses to immunization with T-dependent and T-independent antigens. Nevertheless, CD69-deficient lymphocytes had a normal proliferative response to different T-cell and B-cell stimuli. Together, these observations indicate that CD69 plays a role in B-cell development and suggest that the putative stimulatory activity of this molecule on bone marrow-derived cells may be replaced in vivo by other signal transducing receptors.
Granule exocytosis, and not the Fas/Fas ligand system, is the main pathway of cytotoxicity mediated by alloantigen-specific CD4+ as well as CD8+ cytotoxic T lymphocytes in humans
Authors: Yasukawa Masaki , Ohminami Hideki , Arai Junko , Kasahara Yoshihito , Ishida Yasushi , Fujita Shigeru 
Published: October 2019

AbstractWe investigated the cytotoxicity mechanisms of alloantigen-specific human CD4+ and CD8+ cytotoxic T lymphocytes (CTLs) using cells from family members with the Fas gene mutation. Alloantigen-specific CD4+ and CD8+ CTL bulk lines and clones were generated from 2 individuals by stimulation of their peripheral blood lymphocytes with allogeneic Fas−/− or Fas+/− cell lines that were established from B-lymphocytes of a patient with Fas deficiency and her mother, respectively. Both CD4+ and CD8+CTL bulk lines and clones directed against allogeneic HLA antigens exerted cytotoxicity against Fas−/− and Fas+/− cells to almost the same degree. The cytotoxicity of CD4+ and CD8+ CTLs appeared to be Ca2+-dependent and was completely inhibited by concanamycin A, an inhibitor of perforin-mediated cytotoxicity. Messenger RNAs for the major mediators of CTL cytotoxicity, Fas ligand, perforin, and granzyme B were all detected in these CD4+CTLs with the use of the reverse transcriptase polymerase chain reaction. The majority of CD4+ CTL clones that showed Fas-independent cytotoxicity were TH0, as determined by their cytokine production profile. These data, obtained with the use of a novel experimental system, clearly show that the main pathway of cytotoxicity mediated by alloantigen-specific human CD4+as well as by CD8+ CTLs is granule exocytosis, and not the Fas/Fas ligand system.
Retroviral transfer of the hENT2 nucleoside transporter cDNA confers broad-spectrum antifolate resistance in murine bone marrow cells
Authors: Patel Divyen H. , Allay James A. , Belt Judith A. , Sorrentino Brian P. 
Published: October 2019

Abstract
Antifolate drugs such as methotrexate are commonly used in cancer chemotherapy. It may be possible to increase the antitumor activity of antifolates by the coadministration of drugs that inhibit nucleoside transport, thereby blocking the capacity of tumor cells to salvage nucleotide precursors. An important limitation of this approach is severe myelosuppression caused by many of these drug combinations. For this reason, we have developed a gene therapy strategy to protect bone marrow cells against combined treatment with antifolates and nitrobenzylmercaptopurine riboside (NBMPR), a potent inhibitor of thees nucleoside transporter. A retroviral vector (MeiIRG) was constructed that expressed the NBMPR-insensitive eitransporter, hypothesizing that transduced bone marrow cells would survive drug treatment because of the preservation of nucleoside salvage pathways. In vitro clonogenic assays confirmed that the MeiIRG vector did protect myeloid progenitors against the toxic effects of 3 different antifolates when each was combined with NBMPR. On testing this system in vivo, decreased myelosuppression was observed in mice transplanted with MeiIRG-transduced bone marrow cells and subsequently treated with trimetrexate and NBMPR-P. In these mice, significant increases were noted in absolute neutrophil count nadirs, reticulocyte indices, and the numbers of myeloid progenitors in the bone marrow. Furthermore, a survival advantage was associated with transfer of the MeiIRG vector, indicating that significant dose intensification was possible with this approach. In summary, the MeiIRG vector can decrease the toxicity associated with the combined use of antifolates and NBMPR-P and thereby may provide a strategy for simultaneously sensitizing tumor cells while protecting hematopoietic cells.
Lysophosphatidic acid opens a Ca++ channel in human erythrocytes
Authors: Yang Lu , Andrews Dina A. , Low Philip S. 
Published: October 2019

AbstractLysophosphatidic acid (LPA) is a lipid-derived second messenger that mobilizes many cells of the circulatory and vascular systems to assist in thrombus development and wound healing. LPA, however, has not been tested on human erythrocytes, largely because erythrocytes are considered to be both biologically inert and inactive in intercellular communication. To test this presumption, we have examined the impact of LPA on signaling reactions within the human red blood cell (RBC). Using both 45Ca++ and a Ca++-sensitive fluorescent probe (Fluo-3), we demonstrated that LPA, but not phosphatidic acid or the closely related sphingosine-1–phosphate, stimulates the influx of micromolar quantities of extracellular Ca++ into fresh RBCs. This Ca++ influx was shown to be channel mediated rather than leak promoted because the influx was observed at LPA concentrations too low to perturb membrane integrity, it was inhibited by P-type but not L-type Ca++ channel blockers, it was inhibited by broad-specificity protein kinase inhibitors, and it was not induced by inactive analogues of LPA. Further characterization reveals that only approximately 25% of the RBCs participate in LPA-induced Ca++ entry and that within this active population, Ca++ gating occurs in an all-or-nothing manner. Because the stimulation of Ca++ uptake occurs at LPA concentrations (1-5 μmol/L) known to occur near a developing thrombus and because the internalized Ca++can potentially promote prothrombic properties in the stimulated RBCs, we conclude that RBCs are not insensitive to signals released from other cells.