bluuebunny/crossref_metadata_2025_split huggingface dataset:
Senescence in innate immune responses: reduced neutrophil phagocytic capacity and CD16 expression in elderly humans
Authors: Butcher S K , Chahal H , Nayak L , Sinclair A , Henriquez N V , Sapey E , O'Mahony D , Lord J M 
Published: September 2022

AbstractElderly humans are more susceptible to bacterial infections because of declining immune status. We have investigated the effect of aging on neutrophil bactericidal responses, comparing neutrophil function in healthy, young (23–35 years) and elderly (&gt;65 years) volunteers. Superoxide generation in response to fMLP was slightly increased in neutrophils from elderly donors, and serum from the elderly was able to opsonize E. coli efficiently. In contrast, phagocytic index was significantly lower in neutrophils from the elderly, compared with young donors (P&lt;0.005). CD11a and CD11b expression was not affected by age, but CD16 was significantly reduced in neutrophils from elderly donors (P&lt;0.0001). CD16 expression and phagocytic index were measured in the same neutrophils using FITC-labeled E. coli, PE-conjugated anti-CD16 antibody, and CD16 expression correlated with phagocytic index (r=0.83;P&lt;0.05). In elderly patients with bacterial infection, CD16 expression remained low. We propose that reduced neutrophil CD16 expression and phagocytosis contribute to human immunesenescence.
Enhancing effects of anti-CD40 treatment on the immune response of SCID-bovine mice toTrypanosoma congolenseinfection
Authors: Haas Karen M , Taylor Katherine A , MacHugh Niall D , Kreeger John M , Estes D Mark 
Published: September 2022

AbstractAfrican trypansosomes are tsetse-transmitted parasites of chief importance in causing disease in livestock in regions of sub-Saharan Africa. Previous studies have demonstrated that certain breeds of cattle are relatively resistant to infection with trypanosomes, and others are more susceptible. Because of its extracellular location, the humoral branch of the immune system dominates the response againstTrypanosoma congolense. In the following study, we describe the humoral immune response generated against T. congolense in SCID mice reconstituted with a bovine immune system (SCID-bo). SCID-bo mice infected with T. congolense were treated with an agonistic anti-CD40 antibody and monitored for the development of parasitemia and survival. Anti-CD40 antibody administration resulted in enhanced survival compared with mice receiving the isotype control. In addition, we demonstrate that the majority of bovine IgM+ B cells in SCID-bo mice expresses CD5, consistent with a neonatal phenotype. It is interesting that the percentage of bovine CD5+ B cells in the peripheral blood of infected SCID-bo mice was increased following anti-CD40 treatment. Immunohistochemical staining also indicated increased numbers of Ig+ cells in the spleens of anti-CD40-treated mice. Consistent with previous studies demonstrating high IL-10 production during high parasitemia levels in mice and cattle, abundant IL-10 mRNA message was detected in the spleens and peripheral blood of T. congolense-infected SCID-bo mice during periods of high parasitemia. In addition, although detected in plasma when parasites were absent or low in number, bovine antibody was undetectable during high parasitemia. However, Berenil treatment allowed for the detection of VSG-specific IgG 14 days postinfection in T. congolense-infected SCID-bo mice. Overall, the data indicate that survival of trypanosome-infected SCID-bo mice is prolonged when an agonistic antibody against bovine CD40 (ILA156) is administered. Thus, stimulation of B cells and/or other cell types through CD40 afforded SCID-bo mice a slight degree of protection during T. congolense infection.
Allogeneic reconstitution after nonmyeloablative conditioning: mitigation of graft-versus-host and host-versus-graft reactivity by anti-CD44v6
Authors: Christ Oliver , Günthert Ursula , Schmidt Dirk-Steffen , Zöller Margot 
Published: September 2022

AbstractT-cell maturation is accelerated in transgenic mice expressingrat CD44v4-v7 on T cells, the effect being blocked by anti-CD44v6. Thisfinding suggested functional activity of CD44v6 in thymocytedevelopment. We tested the hypothesis by antibody blocking and usingmice with targeted deletion of CD44v6/v7 exon products(CD44v6/v7−/−). When lethally irradiatedCD44v6/v7-competent (CD44v6/v7+/+) mice were reconstitutedsyngeneically, higher numbers of CD44v6/v7−/− thanCD44v6/v7+/+ BMC were required for survival, the period of reconstitution was prolonged, and regain of immunocompetence wasdelayed. Similar findings were observed in lethally irradiated, anti-CD44v6-treated syngeneic CD44v6/v7+/+ hosts. Thus, CD44v6/v7 supports maturation and expansion of hematopoietic progenitorcells. Surprisingly, reconstitution with CD44v6/v7−/− BMCor anti-CD44v6 treatment of the nonlethally irradiated allogeneicCD44v6/v7+/+ host had only a minor impact on survivalrates. When nonlethally irradiated CD44v6/v7−/− hostsreceived an allogeneic graft, survival rates were improved. Thesephenomena have been a result of reduced GvH reactivities when the donorwas CD44v6/v7−/− and reduced HvG reactivities in the CD44v6/v7−/− host. Thus, although a deficit or blockadeof CD44v6/v7 has a negative impact on hematopoietic reconstitution, atransient blockade will be of benefit for the allogeneicallyreconstituted host because of a strong reduction in GvH and HvGreactivities.
(−)Epigallocatechin-3-gallate inhibits leukocyte elastase: potential of the phyto-factor in hindering inflammation, emphysema, and invasion
Authors: Sartor Luigi , Pezzato Elga , Garbisa Spiridione 
Published: September 2022

AbstractFlavanol (−)epigallocatechin-3-gallate is shown to be a potent naturalinhibitor of leukocyte elastase that may be used to reduceelastase-mediated progression to emphysema and tumor invasion. Thisphyto-factor, abundant in green tea, exerts a dose-dependent, noncompetitive inhibition of leukocyte elastase at a noncytotoxicconcentration and is effective in neutrophil culture. This inhibitionshows an IC50 of 0.4 μM, 30 times higher than theα1-protease inhibitor but lower than other known natural andsynthetic elastase inhibitors. The flavanol inhibits leukocyte elastaseat concentrations of 50, 150, and 2500 times lower than that effectiveon gelatinases (MMP-2 and MMP-9), thrombin, and cathepsin G, respectively, and also blocks elastase-mediated activation of MMP-9.
Myosin-V colocalizes with MHC class II in blood mononuclear cells and is up-regulated by T-lymphocyte activation
Authors: Bizario João C S , Castro Fabíola A , Sousa Josane F , Fernandes Rafael N , Damião Alexandre D , Oliveira Márika K , Palma Patrícia V B , Larson Roy E , Voltarelli Júlio C , Espreafico Enilza M 
Published: September 2022

AbstractMyosin-V is involved in organelle and vesicle trafficking inSaccharomyces cerevisiae and in other eukaryotic cells from yeast to human. In the present study, we determined by FACS that the major subpopulations of the peripheral blood mononuclear cells express myosin-V with similar fluorescence intensity. Confocal microscopy showed intense labeling for myosin-V at the centrosomal region and a punctate staining throughout the cytoplasm, frequently associated with the central microtubule arrays and the actin-rich cortex. Some degree of overlap with an endolysosomal marker and dynein light-chain 8 k was found at the cell center. Striking colocalization was observed with the major histocompatibility complex (MHC) class II molecules near the cell surface. Treatment with phytohemagglutinin, which induces T-lymphocyte activation, associated with MHC class II expression, increased the levels of myosin-V protein and mRNA for the three members of class V myosins. These data suggest that class V myosins might be involved in relevant functions in the immune response.
Sorting for storage in myeloid cells of nonmyeloid proteins and chimeras with the propeptide of myeloperoxidase precursor
Authors: Bülow E , Nauseef W M , Goedken M , McCormick S , Calafat J , Gullberg U , Olsson I 
Published: September 2022

AbstractDuring formation of polymorphonuclear neutrophils, proteins are synthesized for storage in granules. Whereas sorting of proteins into distinct subtypes of cytoplasmic granules may reflect the coordinated expression of the proteins contained in them, still the mechanism(s) for the retrieval of proteins from the constitutive secretion is unknown. To investigate the mechanisms of retrieval, nonmyeloid secretory proteins were expressed in myeloid cell lines, and their subcellular fate was assessed. The contribution of the propeptide (MPOpro) of the myeloperoxidase (MPO) precursor was investigated by determining the fate of chimeras containing MPOpro. The nonmyeloid protein α1-microglobulin (α1-m) was targeted to storage organelles in 32D cells and colocalized with the lysosomal marker LAMP-1, whereas soluble TNF receptor 1 (sTNFR1) was secreted without granule targeting. Fusion of MPOpro to α1-m delayed exit from endoplasmic reticulum (ER), but subsequent targeting to dense organelles was indistinguishable from that of α1-m alone. Fusion proteins between MPOpro and sTNFR1 or green fluorescent protein expressed in myeloid 32D, K562, or PLB-985 cells did not associate stably with calreticulin or calnexin, molecular chaperones that normally interact transiently with the MPO precursor, but were still efficiently retained in the ER followed by degradation. We conclude that normally secreted, nonmyeloid proteins can be targeted efficiently to storage organelles in myeloid cells, that myeloid cells selectively target some proteins for storage but not others, and that MPOpro may contribute to the prolonged ER retention of the MPO precursor independent of the ER-molecular chaperones calreticulin and calnexin.
Intercellular cell adhesion molecule-1 and selectin ligands in acute cardiac allograft rejection: a study on gene-deficient mouse models
Authors: Lácha Jiří , Bushell Andrew , Smetana Karel , Rossmann Pavel , Přibylová Petra , Wood Kathryn , Malý Petr 
Published: September 2022

AbstractCell adhesion molecules and their ligands are essential for regulating lymphocyte recirculation and leucocyte emigration into an inflamed or injured tissue. Vascular endothelial selectins as mediators of leucocyte rolling and intercellular cell adhesion molecule-1 (ICAM-1) have been found to be up-regulated on activated endothelium during acute allograft rejection. This study was designed to investigate whether ICAM-1 or selectin-ligand deficiency, or a combination of both, affected graft survival during acute cardiac allograft rejection. To this goal, we performed cardiac transplantation using mice deficient in genes for ICAM-1 or α(1,3)fucosyltransferase Fuc-TVII, representing a model for general absence of selectin-ligand expression, and a newly developed strain with a double mutation in Fuc-TVII and ICAM-1 alleles. Transplantation of a heart from ICAM-1 −/− or Fuc-TVII/ICAM-1 double-mutated mice into allogeneic recipients resulted in limited (2–2.5 days) but nevertheless significant prolongation of the graft survival (P&lt;0.01 and P&lt;0.01 in log-rank test) compared with the survival of unmodified hearts. When ICAM-1 −/− hearts were transplanted into Fuc-TVII −/− recipients, the median survival time was prolonged by 8 days (P&lt;0.01). These data indicate that endothelial ICAM-1 is involved in adhesion events during acute cardiac allograft rejection but reveal that the loss of one type, selectin/leucocyte ligand or selectin/endothelial ligand interaction, does not markedly affect graft survival, thereby suggesting a role for other compensatory adhesion molecule/ligand interactions.
Thioglycollate peritonitis in mice lacking C5, 5-lipoxygenase, or p47phox: complement, leukotrienes, and reactive oxidants in acute inflammation
Authors: Segal Brahm H , Kuhns Douglas B , Ding Li , Gallin John I , Holland Steven M 
Published: September 2022

AbstractLeukotriene B4 (LTB4) is an easily diffusible proinflammatory chemotactic factor that has been posited to prime the initial inflammatory response for the action of other mediators, including C5a. 5-Lipoxygenase-deficient (5LX−/−) and C5-deficient mice only generated about 50% as much peritoneal leukocytosis as wild-type mice following intraperitoneal (IP) challenge with the sterile irritant, thioglycollate (P&lt;0.005). Pretreatment of C5− mice with the specific 5-lipoxygenase inhibitor, zileuton, reduced peritoneal leukocytosis to almost unstimulated levels, suggesting that LTB4 can act independently of C5a. Previously, LTB4 and C5a have been shown in vitro to be inactivated by metabolites of superoxide. In the current study, we examined the fate of LTB4 in the p47phox−/− mouse model of chronic granulomatous disease (CGD) in which the phagocyte NADPH oxidase is unable to produce superoxide. p47phox−/− mice generated more thioglycollate-elicited peritoneal leukocytosis than wild-type mice. Pretreatment with zileuton caused a 76% reduction in peritoneal leukocytosis in p47phox−/− mice (P&lt;0.005) and a 54% reduction in wild-type mice (P&lt;0.05), whereas pretreatment with dexamethasone or toradol (a cyclooxygenase inhibitor) had no effect. Following IP LTB4 (1 μg/mouse), total recovered peritoneal LTB4 was similar between p47phox−/− and wild-type mice at 10 and 30 min, but was approximately fivefold greater in p47phox−/− mice at 180 min. These data suggest that LTB4 and C5a have separate but overlapping roles in thioglycollate-elicited peritonitis, and at least the leukotriene component is, in turn, regulated by reactive oxidants.
Functional characterization of podia formation in normal and malignant hematopoietic cells
Authors: Fruehauf S , Srbic K , Seggewiss R , Topaly J , Ho A D 
Published: September 2022

AbstractHematopoietic cells extend multiple podia of yet unknown function. Our morphological studies using scanning electron microscopy and functional studies using time-lapse video microscopy suggest that podia formed by CD34+ hematopoietic stem cells (HSC) on the bone marrow stroma component fibronectin are characteristic of lamellipodia at the leading edge and uropodia at the trailing edge, cytoskeletal structures that have previously been shown to be responsible for cell locomotion of lymphocytes. In the leukemic cells studied here, stroma-derived factor-1α (SDF-1α) led to a significant eightfold increase in transmigration (BCR-ABL-positive BV173 leukemia cell line;P&lt;0.05) and podia formation in all BCR-ABL-positive leukemic cell lines studied (BV173, K562, 32Dp210) and in two of three BCR-ABL-negative lines (HL60, 32D, not KG1a). We could show that SDF-1α exposure led to a down-regulation of the gene expression of the chemokine receptors CCR4, CXCR4, and CXCR5, which are associated with cell motility and podia formation, indicating a negative feedback control. In BCR-ABL-positive leukemic cells, the effects of SDF-1α on podia formation and cell migration were independent of BCR-ABL-tyrosine kinase activity. Our data are compatible with the hypothesis that formation of specific podia by hematopoietic cells is associated with egression of these cells from the bone marrow.
Hypertonicity suppresses ionophore-induced product formation and translocation of 5-lipoxygenase in human leukocytes
Authors: Bürkert Eva , Rådmark Olof , Samuelsson Bengt , Steinhilber Dieter , Werz Oliver 
Published: September 2022

Abstract5-Lipoxygenase (5-LO) initiates the biosynthesis of proinflammatory leukotrienes from arachidonic acid (AA). Here, we demonstrate that hypertonicity suppresses ionophore-induced 5-LO product formation reversibly in isolated human polymorphonuclear leukocytes (PMNL) and in Mono Mac 6 cells. Hypertonicity blocked the liberation of AA and abrogated translocation of 5-LO to the nuclear membrane. Accordingly, in the presence of exogenous AA, 5-LO product formation was less affected. The effects of hypertonicity were a result of cell shrinkage and not cytosolic hyperosmolarity. Hypertonicity did not inhibit the rapid increase in intracellular Ca2+ induced by ionophores but prevented the ionophore-induced activation of p38 MAPK-regulated MAPKAP kinases, which can phosphorylate and activate 5-LO (and cPLA2). In summary, we show that hypertonicity blocks agonist-induced release of AA, 5-LO product formation, and translocation and in parallel, prevents activation of p38 MAPK and downstream 5-LO kinases in leukocytes.
Inhibitory actions of glucosamine, a therapeutic agent for osteoarthritis, on the functions of neutrophils
Authors: Hua Jian , Sakamoto Koji , Nagaoka Isao 
Published: September 2022

AbstractGlucosamine, an amino monosaccharide naturally occurring in the connective and cartilage tissues, contributes to maintaining the strength, flexibility, and elasticity of these tissues. In recent years, glucosamine has been used widely to treat osteoarthritis in humans and animal models. Neutrophils, which usually function as the primary defenders in bacterial infections, are also implicated in the destructive, inflammatory responses in arthritis. In this study, we have evaluated the effects of glucosamine on neutrophil functions using human peripheral blood neutrophils. Glucosamine (0.01–1 mM) dose-dependently suppressed the superoxide anion generation induced by formyl-Met-Leu-Phe (fMLP) or complement-opsonized zymosan and inhibited the phagocytosis of complement-opsonized zymosan or IgG-opsonized latex particles. Furthermore, glucosamine inhibited the release of granule enzyme lysozyme from phagocytosing neutrophils and suppressed neutrophil chemotaxis toward zymosan-activated serum. In addition, glucosamine inhibited fMLP-induced up-regulation of CD11b significantly, polymerization of actin, and phosphorylation of p38 mitogen-activated protein kinase (MAPK). In contrast, N-acetyl-glucosamine, an analogue of glucosamine, did not affect these neutrophil functions (superoxide generation, phagocytosis, granule enzyme release, chemotaxis, CD11b expression, actin polymerization, and p38 MAPK phosphorylation) at the concentrations examined (1–10 mM). Together these observations likely suggest that glucosamine suppresses the neutrophil functions, thereby possibly exhibiting anti-inflammatory actions in arthritis.
ARNO but not cytohesin-1 translocation is phosphatidylinositol 3-kinase-dependent in HL-60 cells
Authors: Bourgoin Sylvain G , Houle Martin G , Singh Indrapal N , Harbour Danielle , Gagnon Steve , Morris Andrew J , Brindley David N 
Published: September 2022

AbstractCytohesin-1 and ARNO are guanine nucleotide-exchange factors (GEFs) for ADP-ribosylation factor (Arf). Here, we show that ARNO is expressed in HL-60 cells and established that granulocytic differentiation induced with Me2SO stimulated cytohesin-1 but not ARNO expression. Cytohesin-1 levels in HL-60 granulocytes were similar to those in human neutrophils. Me2SO-differentiated HL-60 cells expressed ARNO and cytohesin-1 isoforms with a diglycine and a triglycine motif in their PH domains, respectively. In vitro, ARNO diglycine and cytohesin-1 triglycine enhanced phospholipase D1 (PLD1) activation by Arf1 with near-maximal effects at 250 nM. These effects were marked particularly at low Mg2+ concentrations. PLD activation was well-correlated with GTP binding to Arf1, and cytohesin-1 was always more potent than ARNO in the PLD- and GTP-binding assays. Increasing Mg2+ concentrations reduced PLD and Arf1 activation by Arf-GEFs. fMetLeuPhe and phorbol 12-myristate 13-acetate stimulated ARNO and cytohesin-1 as well as Arf1 translocation to HL-60 cell membranes. fMetLeuPhe-mediated ARNO recruitment, but not cytohesin-1 and Arf1 translocation, was blocked by phosphatidylinositol 3-kinase inhibitors. The combined results demonstrate that cytohesin-1 triglycine participates in a major phosphatidylinositol 3-kinase-independent pathway linking cell-surface receptors to Arf1 activation and translocation in human granulocytes.
Oxidant-mediated phosphatidylserine exposure and macrophage uptake of activated neutrophils: possible impairment in chronic granulomatous disease
Authors: Hampton Mark B , Vissers Margret C M , Keenan Jacqueline I , Winterbourn Christine C 
Published: September 2022

AbstractThe removal of neutrophils from inflammatory sites is essential for the resolution of inflammation. Surface changes, including phosphatidylserine exposure, label neutrophils for phagocytosis by macrophages. Here, we demonstrate that externalization of phosphatidylserine and uptake by monocyte-derived macrophages occurred in human neutrophils ingesting Staphylococcus aureus. Both processes were dependent on oxidant production from the neutrophil NADPH oxidase. There was no requirement for myeloperoxidase, and H2O2 was identified as the most likely trigger for PS exposure. We hypothesize that clearance of stimulated neutrophils would be delayed in chronic granulomatous disease (CGD) neutrophils, which lack a functional NADPH oxidase. To explore this possibility, heat-killed S. aureus were injected into the peritoneum of CGD and normal mice. Elevated neutrophil numbers were observed in the inflammatory exudate of the CGD animals, consistent with impaired recognition and clearance.
Activation-induced expression of MICA on T lymphocytes involves engagement of CD3 and CD28
Authors: Molinero Luciana L , Fuertes Mercedes B , Rabinovich Gabriel A , Fainboim Leonardo , Zwirner Norberto W 
Published: September 2022

AbstractMICA is an HLA-related cell stress-regulated antigen recognized by cytotoxic cells expressing the NKG2D molecule. Although resting lymphocytes do not express MICA, it can be induced on PHA-activated T cells. Here, we demonstrate by Western blot that MICA is induced on allogeneic-activated CD4+ and CD8+ T lymphocytes. Blocking activation with anti-HLA class I, anti-HLA-DR, or anti-CD86 mAb affected the expression of MICA slightly. When T cells were stimulated with anti-CD3 or anti-CD28 mAb plus PMA, a sustained up-regulation of MICA was observed by Western blot, RT-PCR, and flow cytometry. The expression of MICA reached a plateau at day 4 after CD3 engagement and at day 3 after anti-CD28/PMA stimulation. Conversely, the proliferative response reached a peak at day 4. Hence, CD3 or CD28 engagement induces MICA expression on T lymphocytes. This activation-induced expression might participate in NKG2D-mediated cytotoxicity toward activated T cells to maintain homeostasis during an ongoing immune response.
Neutrophils from MMP-9- or neutrophil elastase-deficient mice show no defect in transendothelial migration under flow in vitro
Authors: Allport Jennifer R , Lim Yaw-Chyn , Shipley J Michael , Senior Robert M , Shapiro Steven D , Matsuyoshi Norihisa , Vestweber Dietmar , Luscinskas Francis W 
Published: September 2022

AbstractRecent evidence has suggested a role for neutrophil proteases during certain inflammatory responses. We demonstrated previously that neutrophil proteases can degrade components of the adherens junctions during neutrophil-endothelial adhesion. We tested the hypothesis that degradation of VE-cadherin at lateral junctions by elastase or MMP-9 facilitates neutrophil transendothelial migration. Neutrophils from MMP-9 or elastase null mice and strain-matched control mice expressed high levels of LFA-1, Mac-1, and L-selectin on their cell surface. Under flow conditions, wild-type and deficient neutrophils rolled, arrested, and transmigrated activated murine endothelium. There was no difference in the total numbers of interacting neutrophils or in the percentage of transmigrated cells. In addition, deficient neutrophils remained capable of degrading murine endothelial VE-cadherin. These results indicate that although neutrophil proteases may play a role in the acute inflammatory response, neutrophil elastase or MMP-9 is not essential for neutrophil transendothelial migration in this murine system.