bluuebunny/crossref_metadata_2025_split huggingface dataset:
Divergent regulation of HIV-1 replication in PBMC of infected individuals by CC chemokines: suppression by RANTES, MIP-1α, and MCP-3, and enhancement by MCP-1
Authors: Vicenzi Elisa , Alfano Massimo , Ghezzi Silvia , Gatti Alessandra , Veglia Fabrizio , Lazzarin Adriano , Sozzani Silvano , Mantovani Alberto , Poli Guido 
Published: September 2022

AbstractWe investigated the role of different CC chemokines, including regulated upon activation normal T cell expressed and secreted (RANTES), macrophage inflammatory protein-1α (MIP-1α), monocyte chemotactic protein-1 (MCP-1), and MCP-3 on virus replication in cultures established from CD8+ T cell-depleted peripheral blood mononuclear cells (PBMC) of HIV-infected individuals that were either cocultivated with allogeneic T cell blasts (ATCB) of uninfected individuals or directly stimulated by mitogen plus interleukin-2. RANTES was the only chemokine that showed a clear-cut suppressive effect on HIV replication in both culture systems, although inhibitory effects were frequently also observed with MIP-1α, MCP-3, and, occasionally, with MCP-1. In contrast, MCP-1 frequently enhanced HIV production in most patients’ cultures or cocultures that were characterized by secreting relatively low levels (&lt;20 ng/mL) of MCP-1. When CD8-depleted PBMC of HIV+ individuals were cocultivated with ATCB of uninfected healthy donors, a positive correlation was observed between MCP-1 concentrations and the enhancement of HIV-1 replication occurring after depletion of CD8+ cells from donors’ cells. Depletion of CD14+ cells (monocytes) from ATCB resulted in the down-regulation of virus replication during co-cultivation with CD8-depleted PBMC of infected individuals. Of interest, MCP-1 up-regulated HIV production in these CD14-depleted ATCB cocultures. Altogether these observations suggest that MCP-1 may represent an important factor enhancing HIV spreading, particularly in anatomical sites, such as the brain, where infection of macrophages and microglial cells plays a dominant role.
CD97 isoform expression in leukocytes
Authors: Eichler Wolfram 
Published: September 2022

AbstractDifferent adhesive capacity in interactions with CD55 has been ascribed to the isoforms of the leukocyte CD97 antigen, CD97 (EGF 1,2,5), CD97 (EGF 1,2,3,5), and CD97 (EGF 1,2,3,4,5). In the study, coexpression of the three CD97 isoforms and predominance of CD97 (EGF 1,2,5) transcripts in leukocytes are demonstrated. The contribution of CD97 (EGF 1,2,3,5) and CD97 (EGF 1,2,3,4,5) to total CD97 levels varied among most cell types only slightly, although relatively higher mRNA levels of both isoforms were detected in U 937 cells and monocytes. In peripheral blood lymphocytes, CD97 isoforms did not show clear variation after PMA stimulation and were down-regulated equally after CD97 cross-linking. Moreover, the CD97 isoform pattern was not altered in monocytes after interferon-γ stimulation and in synovial T cells from patients with rheumatoid arthritis. CD97 mRNA levels did not necessarily correspond to CD97 surface density. The findings suggest that adhesive activity of CD97 toward CD55 is unlikely to be regulated by differential CD97 isoform expression.
Cellular signaling in macrophage migration and chemotaxis
Authors: Jones Gareth E 
Published: September 2022

AbstractWhereas most cells in adult tissues are fixed in place by cell junctions, leukocytes are motile and able to migrate actively through the walls of blood vessels into surrounding tissues. The actin cytoskeleton of these cells plays a central role in locomotion, phagocytosis, and the regulation of cell shape that are crucial elements of neutrophil and monocyte/macrophage function. This review will concentrate on how macrophages in particular control the actin cytoskeleton to generate cell movement and the shape changes required for chemotaxis. It has recently become evident that a complex of seven proteins known as the Arp2/3 complex regulates the assembly of new actin filament networks at the leading front of moving cells. Proteins of the Wiskott-Aldrich Syndrome Protein (WASP) family bind directly to the Arp2/3 complex and stimulate its ability to promote the nucleation of new actin filaments. Upstream of the WASP family proteins, receptor tyrosine kinases, G-protein-coupled receptors, phosphoinositide-3-OH kinase (PI 3-kinase), and the Rho family of GTPases receive and transduce the signals that lead to actin nucleation through WASP-Arp2/3 action. Although many gaps remain in our understanding, we are now in a position to consider completing signaling pathways that are initiated from outside the cell to the actin rearrangements that drive cell motility and chemotaxis.
In vivopriming of FcαR functioning on eosinophils of allergic asthmatics
Authors: Bracke Madelon , van de Graaf Ed , Lammers Jan-Willem J , Coffer Paul J , Koenderman Leo 
Published: September 2022

AbstractInflammation in allergic asthma is characterized by an influx of eosinophils and the presence of eosinophil products in the bronchial tissue. Orchestration of this inflammatory response is in part mediated by cytokines and chemoattractants, but final activation can require additional stimuli. IgA, the most abundant immunoglobulin at mucosal surfaces, is potentially a potent trigger for eosinophil activation. Previously, we have shown that binding IgA-coated targets is dependent on in vitro stimulation of cells with cytokines. Here, we demonstrate that eosinophils isolated from the blood of allergic asthmatic patients bind IgA beads independently of prior in vitro stimulation. Furthermore, we found that the proinflammatory cytokine, TNF-α, is a potent enhancer of IgA binding to eosinophils from allergic asthmatics, and it does not activate FcαR on eosinophils isolated from normal donors. The difference in IgA binding by FcαRs on normal and patient eosinophils might be explained by the activation of different signal transduction pathways. Studying intracellular signaling, we found an enhanced basal activity of phosphatidylinositol 3-kinase (PI3K) in eosinophils derived from allergic asthmatics. Moreover, inhibition of PI3K in these cells blocked the background and the TNF-α-induced IgA binding completely. In summary, these data demonstrate that the responsiveness of human eosinophils to TNF-α might be an important contribution for fine-tuning the allergic inflammatory reaction. Furthermore, the preactivation of PI3K results in a broader sensitivity to subsequent challenge with inflammatory cytokines.
Monoclonal Lym-1 antibody-targeted lysis of B lymphoma cells by neutrophils. Evidence for two mechanisms of FcγRII-dependent cytolysis
Authors: Ottonello Luciano , Epstein Alan L , Mancini Marina , Amelotti Massimo , Dapino Patrizia , Dallegri Franco 
Published: September 2022

AbstractHuman neutrophils incubated with the anti-HLA-DR mAb Lym-1, plus PMA, induced significant cytolysis of B lymphoma cells compared with Lym-1 and PMA alone. The effect of PMA was independent of the ability of the compound to stimulate neutrophil-respiratory burst. In fact, first, neutrophils from a patient with chronic granulomatous disease were cytolytically effective in spite of their inability to produce oxidants. Second, various kinase inhibitors exerted different effects on the PMA-stimulated cytolytic system and neutrophil-oxidative burst. Previous studies have shown the involvement of the FcγRII, CD11b-CD18 integrins, and CD66b glycoproteins in the Lym-1 mAb-dependent cytolysis by GM-CSF-stimulated neutrophils. The present PMA-stimulated system was inhibited by the anti-FcγRII mAb IV.3, the anti-CD18 mAb MEM 48, and the anti-CD11b mAb 2LPM19c but not by the anti-CD66b mAb 80H3 andN-acetyl-d-glucosamine. Furthermore, the PMA- and GM-CSF-stimulated cytolysis was insensitive and sensitive to inhibition by pertussis toxin, respectively. Thus, the use of PMA and GM-CSF as neutrophil stimulants uncovers the existence of distinct mechanisms of Lym-1 mAb-mediated cytolysis.
MCP-1 receptor binding affinity is up-regulated by pre-stimulation with MCP-1 in an actin polymerization-dependent manner
Authors: Kito Keiji , Morishita Kaoru , Nishida Kenichi 
Published: September 2022

AbstractMonocyte chemoattractant protein-1 (MCP-1) induces monocyte chemotaxisvia interaction with the MCP-1 receptor CCR2. We found that MCP-1binding to monocytic THP-1 cells was increased by pre-treatment withMCP-1. The amount of CCR2 mRNA and the cell-surface expression of CCR2were not affected by MCP-1 stimuli. In contrast, the MCP-1-treatedTHP-1 cells showed a sixfold increase in MCP-1 binding affinitycompared with untreated cells. MCP-1 binding to CCR2B-transfectedHEK-293 cells was also enhanced by pre-treatment with MCP-1, and MCP-1binding affinity increased by sixfold. In both cell lines, theenhancement of MCP-1 binding by stimulation with MCP-1 was blocked bycytochalasin D, an inhibitor of actin polymerization. This effect ofpre-treatment with MCP-1 is insensitive to pertussis toxin andpartially blocked by U73122, an inhibitor of phospholipase C. Theseresults demonstrate that the MCP-1 receptor binding affinity isup-regulated by MCP-1 stimuli in an actin polymerization-dependentmanner.
Assessment of neutrophilN-formyl peptide receptors by using antibodies and fluorescent peptides
Authors: Loitto Vesa-Matti , Rasmusson Birgitta , Magnusson Karl-Eric 
Published: September 2022

AbstractEnrichment of chemoattractant receptors on the neutrophil surface has been difficult to assess, primarily because of limitations in sensitivity of visualization. Using an ultrasensitive, cooled charge-coupled device camera, we investigated spatial-temporal relationships between N-formyl peptide receptor distribution and directional motility of human neutrophils. Live cells were labeled with fluorescent receptor ligands, i.e., fluoresceinated tert-butyl-oxycarbonyl-Phe-(d)-Leu-Phe-(d)-Leu-Phe-OH (Boc-FLFLF) and formyl-Nle-Leu-Phe-Nle-Tyr-Lys (fnLLFnLYK), while fixed cells were labeled with either fluorescent peptides or monoclonal antibodies. Double labeling of receptors and filamentous actin (F-actin) was done to investigate possible colocalization. N-Formyl peptide receptors on unstimulated cells were randomly distributed. However, on polarized neutrophils, the receptors accumulated toward regions involved in motility and distributed nonuniformly. In fixed neutrophils, antibody-labeled receptors colocalized with the F-actin-rich leading edge whereas peptide-labeled receptors lagged behind this region. We suggest that neutrophils use an asymmetric receptor distribution for directional sensing and sustained migration. A separation between receptors labeled with peptides and those labeled with antibodies reflects two functionally distinct receptor populations at the membrane of motile neutrophils.
Involvement of cytosolic prolyl endopeptidase in degradation of p40-phox splice variant protein in myeloid cells
Authors: Hasebe Takeshi , Hua Jian , Someya Akimasa , Morain Philippe , Checler Frédéric , Nagaoka Isao 
Published: September 2022

AbstractOur previous studies indicated that an alternatively spliced variant mRNA of p40-phox, a cytosolic component of NADPH oxidase, is expressed but its protein is hardly detected in myeloid cells such as promyelocytic HL-60 cells and neutrophils. Here, we have examined the stability of p40-phox variant protein in undifferentiated HL-60 cells. When in vitro-translated proteins were incubated with subcellular fractions of HL-60 cells, p40-phox variant protein but not native p40-phox was degraded by the cytosol and granule fractions. The degradation of variant protein by the granule fraction was observed using sonicated but not intact granules, suggesting that the variant protein is unlikely to be degraded by the granules in intact cells. To identify the enzyme(s) involved, we examined the effects of various enzyme inhibitors on the degradation of variant protein by the cytosol fraction. Degradation was completely inhibited by proline-specific serine protease (prolyl endopeptidase) inhibitors but not by proteasome, calpain, and metalloprotease inhibitors. Furthermore, the variant protein was degraded by a purified prolyl endopeptidase, and the degradation was protected by treating HL-60 cells with a cell-permeable inhibitor (S17092-1) for prolyl endopeptidase. These observations suggest that a cytosolic prolyl endopeptidase is involved in the degradation of p40-phox variant protein in myeloid cells.
Regulated expression of galectin-1 during B-cell activation and implications for T-cell apoptosis
Authors: Zuñiga Elina , Rabinovich Gabriel A , Iglesias M Mercedes , Gruppi Adriana 
Published: September 2022

AbstractGalectin-1 (GAL-1), a highly conserved β-galactoside-binding protein, has shown immunomodulatory properties. In this study, we investigated the regulation of GAL-1 expression within the B-cell compartment usingTrypanosoma cruzi infection as a natural model of in vivo B-cell activation. GAL-1 was found to be expressed on activated B cells from T. cruzi-infected mice, mainly localized at the cytosolic compartment. Expression of this protein was found to be modulated according to the activation state of the cells, revealing a significant increase in stimulated B cells that received signals via cross-linking of the B-cell receptor and CD40. It was found that GAL-1 was secreted by B cells to the extracellular milieu upon activation. Finally, purified GAL-1 produced by activated B cells induced apoptosis of T cells but not B cells and also influenced interferon-γ cytokine production. Hence, the present study describes a potential mechanism by which B cells can regulate T-cell function and survival.
CCR1 chemokine receptor expression isolates erythroid from granulocyte-macrophage progenitors
Authors: de Wynter Erika A , Heyworth Clare M , Mukaida Naofumi , Jaworska Ewa , Weffort-Santos Almeriane , Matushima Kouji , Testa Nydia G 
Published: September 2022

AbstractSimple methods that separate progenitor cells of different hemopoietic lineages would facilitate studies on lineage commitment and differentiation. We used an antibody specific for the chemokine receptor CCR1 to examine mononuclear cells isolated from cord blood samples. When CD34+ cells were separated into CD34+CCR1+ and CD34+CCR1− cells and plated in colony-forming assays, the granulocyte/macrophage progenitors were found almost exclusively in the CD34+CCR1+ cells. In contrast, the CD34+CCR1− cells contained the majority of the erythroid progenitors. There was a highly significant difference (P&lt;0.002) in the total percentage distribution of both granulocyte-macrophage colony-forming cells and erythroid burst-forming units between the two populations. This is the first report of separation of erythroid progenitors from granulocyte/macrophage progenitors using a chemokine receptor antibody in cord blood samples. These results suggest that at the clonogenic progenitor cell stage the expression of CCR1 might be lineage-specific. This method should prove useful for studies on erythroid progenitor and granulocyte/macrophage differentiation.
Eosinophils, eosinophil ribonucleases, and their role in host defense against respiratory virus pathogens
Authors: Rosenberg Helene F , Domachowske Joseph B 
Published: September 2022

AbstractEosinophils remain among the most enigmatic of cells, as our appreciation of their detrimental activities—e.g., asthma and allergic disease—far outweighs our understanding of their beneficial effects. Among the major secretory effector proteins of eosinophils are the ribonucleases eosinophil-derived neurotoxin (EDN) and eosinophil cationic protein (ECP) in primates and their orthologs, the eosinophil-associated ribonucleases (EARs) in rodents. The rapid diversification observed among these ribonucleases suggested that the ultimate target(s) might be similarly efficient at generating sequence diversity while maintaining an unalterable susceptibility to ribonucleolytic cleavage. This has prompted us to consider a role for these proteins and by extension, for eosinophils, in host defense against single-stranded RNA virus pathogens. We detail our studies of the antiviral activity of eosinophils and eosinophil ribonucleases against respiratory syncytial virus (RSV) in vitro and the related, natural rodent pathogen, pneumonia virus of mice (PVM), in vivo, and consider the possibility that antiviral host defense and the dysregulated responses leading to asthma represent opposing sides of an eosinophil-mediated double-edged sword.
Unlocking the secrets of galectins: a challenge at the frontier of glyco-immunology
Authors: Rabinovich Gabriel A , Rubinstein Natalia , Fainboim Leonardo 
Published: September 2022

AbstractOver the last decade, we have witnessed an explosion of information regarding the function of glycoconjugates, carbohydrate-binding proteins, and the elucidation of the sugar code. This progress has yielded not only important insights into fundamental areas of glycobiology but has also influenced other fields such as immunology and molecular medicine. A family of galactoside-binding proteins, called galectins, has emerged recently as a novel kind of bioactive molecules with powerful, immunoregulatory functions. Different members of this family have been shown to modulate positively or negatively multiple steps of the inflammatory response, such as cell-matrix interactions, cell trafficking, cell survival, cell-growth regulation, chemotaxis, and proinflammatory cytokine secretion. To introduce a comprehensive overview of these new advances, here we will explore the molecular mechanisms and biochemical pathways involved in these functions. We will also examine the role of these proteins in the modulation of different pathological processes, such as chronic inflammation, autoimmunity, infection, allergic reactions, and tumor spreading. Understanding the intimate mechanisms involved in galectin functions will help to delineate selective and novel strategies for disease intervention and diagnosis.
In vitroassessment of chemokine receptor-ligand interactions mediating mouse eosinophil migration
Authors: Borchers Michael T , Ansay Tracy , DeSalle Rob , Daugherty Bruce L , Shen Huahao , Metzger Michael , Lee Nancy A , Lee James J 
Published: September 2022

AbstractEosinophil migration from circulation is controlled, in part, by chemokines through a family of G-protein-coupled chemokine receptors (CCR). Studies of human eosinophils have demonstrated that signaling through CCR3 receptors is a prominent pathway leading to chemotaxis, although several other receptor-ligand interactions also appear to mediate eosinophil recruitment. The availability of genetically unique strains of mice permits a reductionist approach to assess the signaling pathways in experimental models of human disease. However, despite similarities in these pathways between mice and humans, significant species differences exist, complicating the translation of results from animal models to humans. Purified mouse eosinophils were used in this study to investigate the chemokine receptor expression and the activities of 18 chemokines. Mouse eosinophils isolated from IL-5 transgenic mice expressed transcripts encoding the chemokine receptors CCR1, CCR2, CCR3, CCR5, CCR8, CXCR2, and CXCR4, but not CCR4. Mouse eosinophils also migrated in response to human and mouse eotaxin-1 and -2, but not human eotaxin-3. In addition, the induced migration of mouse eosinophils by TARC, MIP-1β, and KC suggests that unidentified receptor-ligand interactions contribute to eosinophil recruitment. It is interesting that the potent chemoattractant of human eosinophils, RANTES, was unable to mediate mouse eosinophil migration. Furthermore, despite the ability of MIP-1α to bind receptors on purified mouse eosinophils, it was only able to induce significant eosinophil migration in a mixed splenocyte population and was unable to induce migration of highly purified eosinophils. Collectively, these observations reveal physiologically relevant distinctions in mechanisms mediating human and mouse eosinophil migration that potentially reflect evolutionary disparities between these species.
Differential localization of IL-2- and -15 receptor chains in membrane rafts of human T cells
Authors: Goebel Jens , Forrest Kathy , Morford Lorri , Roszman Thomas L 
Published: September 2022

AbstractWe studied whether cytokine receptors (Rs) on T cells associate with lipid microdomains (“rafts”). Low-dose phytohemagglutinin (PHA)-stimulated human T cells were separated into cytoplasmic, membrane, and raft fractions by buoyant density centrifugation. Examination of these fractions for the presence of interleukin (IL)-2- and -15R chains and associated signaling molecules by Western blotting revealed marked, selective enrichment of the IL-2/15R β-chain in rafts before IL-2 stimulation. After IL-2 stimulation, a substantial amount of the β-chain was found in the membrane fraction. This partial translocation was also observed for the β-chain-associated molecules JAK-1, p56lck, and grb-2. Finally, raft disruption with methyl-β-cyclodextrin (MBCD) attenuated IL-2-induced tyrosine phosphorylation events and selectively decreased the surface expression of the IL-2/15R β-chain detected by flow cytometry. These results show that the IL-2/15R β-chain is enriched in rafts obtained from low-dose, PHA-stimulated T cells, that IL-2 binding alters this enrichment, and that this enrichment may be functionally relevant as a possible mechanism to ensure cytokine selectivity and specificity.
Rate and extent of phagocytosis in macrophages lacking vamp3
Authors: Allen Lee-Ann H , Yang Chunmei , Pessin Jeffrey E 
Published: September 2022

AbstractDuring phagocytosis, macrophages rapidly internalize a substantial fraction of plasma membrane without a net loss of surface area, suggesting that membranes are targeted to the cell surface from intracellular sites. Nevertheless, a requirement for mobilization of specific membrane compartments has not been demonstrated. We used bone marrow-derived macrophages (BMM) from wild type and vamp3 null mice to evaluate directly the requirement for this v-SNARE in phagocytosis of zymosan, IgG-beads, complement-opsonized particles, or latex microspheres. Regardless of the phagocytic receptor engaged or particle load, BMM lacking vamp3 exhibited no phagocytic defects when assayed after 1 h at 37°C, and phagosome maturation was unimpaired as judged by acquisition of lamp-1. In contrast, at early time points (5–15 min), internalization of zymosan (but not other particles tested) was significantly slower in vamp3 null BMM. These data indicate that vamp3 modulates efficient uptake of zymosan, but is not absolutely required for phagocytosis in primary macrophages.
Gap junctions and connexins: potential contributors to the immunological synapse
Authors: Oviedo-Orta Ernesto , Evans W Howard 
Published: September 2022

AbstractGap junctional communication is a widespread mechanism for metabolic coupling of adjoining cells. In the immune system, evidence has built up showing that lymphocytes possess the protein building blocks of gap junctions, the connexins. The most widespread is connexin 43, but connexin 40 is also present in secondary lymphoid organs. Inhibitors of gap junctional communication, especially the highly specific connexin mimetic peptides, have been shown to decrease the secretion of immunoglobulins and cytokines by T and B lymphocyte cocultures, indicating that connexins may play a fundamental role in lymphocyte physiology. Traditionally, connexins function when assembled into gap junction-intercellular channels. However, the possibility is now arising that gap junction hemichannels, previously viewed as plasma membrane precursors of gap junctions, are also involved in the release from cells of small metabolites, e.g., adenosine 5′-triphosphate and nicotinamide adenine dinucleotide+, and this opens up a second, possible paracrine function for connexins detected in lymphocytes. The increasing structural and functional evidence points to a potential role that lymphocyte gap junctional intercellular communication may play within the complex signaling components of the immunological synapse.