bluuebunny/crossref_metadata_2025_split huggingface dataset:
LFA-1 integrin and the microtubular cytoskeleton are involved in the Ca2+-mediated regulation of the activity of the tyrosine kinase PYK2 in T cells
Authors: Rodríguez-Fernández José Luis , Sánchez-Martín Lorena , de Frutos Cristina Alvarez , Sancho David , Robinson Martyn , Sánchez-Madrid Francisco , Cabañas Carlos 
Published: September 2022

AbstractLymphocyte function-associated antigen (LFA-1) is a member of the β2 family of integrins that is selectively expressed on leukocytes. Herein, we show that Ca2+ mobilizing agents A23187, thapsigargin, and ionomycin induce an increase in adhesion to the LFA-1 ligand intercellular adhesion molecule-1 (ICAM-1) and activation and redistribution of the proline-rich tyrosine kinase-2 (PYK2) to the microtubule-organizing center (MTOC) in T-lymphoblasts. These effects are similar to those observed upon direct induction of activation of LFA-1 with the stimulatory mAb KIM-127. Most importantly, Ca2+ mobilization did not induce activation of PYK2 when the LFA-1/ICAM-1 interaction was prevented with function-blocking mAb, implying that the Ca2+-induced activation of PYK2 requires integrin engagement. Furthermore, pretreatment of the cells with the Ca2+ chelator EGTA, which depletes the intracellular Ca2+, inhibited the effects of mAb KIM-127 on cell morphology and PYK2 activation. This inhibition with EGTA was not reversed by cross-linking integrin LFA-1 with specific antibodies, indicating that Ca2+ exerts its effects through a target downstream of this integrin. In this regard, immunofluorescence and Western blot analysis showed that Ca2+ chelators affect the organization of the microtubular cytoskeleton and the localization of PYK2 to the MTOC area, suggesting that these agents could inhibit the activation of PYK2 by interfering with the microtubular network of T cells. Taken together, our results demonstrate for the first time an important role for the integrin LFA-1 and the microtubular cytoskeleton in the Ca2+-mediated activation of PYK2 in T-lymphocytes.
β3-Mediated engulfment of apoptotic tumor cells by dendritic cells is dependent on CAMKII: inhibition by HIV-1 Tat
Authors: Poggi Alessandro , Carosio Roberta , Rubartelli Anna , Zocchi Maria Raffaella 
Published: September 2022

AbstractIn this paper, we show that the engulfment of apoptotic tumor cells by DC requires the activation of the calcium-calmodulin kinase II (CAMKII). Indeed, DC phagocytosis of apoptotic lymphoma cells is consistently inhibited by KN62 and KN93, two blockers of CAMKII, but not by the inactive compound KN92. Wortmannin and LY294002, two inhibitors of the phosphatidyl-inositol-3 kinase, slightly decrease the phagocytosis of apoptotic cells, at variance with PD98059, an inhibitor of the mitogen-activated protein kinase. It is interesting that the addition of synthetic HIV-1 Tat, which we demonstrated to inhibit phagocytosis and calcium influx in DC, blocks the activation of CAMKII elicited via β3 integrin, which is involved in apoptotic body engulfment by DC. Experiments performed with Tat-derived peptides showed that this inhibition is mediated by the C-terminal domain of Tat. Finally, pertussis toxin can prevent HIV-1 Tat-mediated inhibition, suggesting the involvement of a guanosine triphosphate-binding (G) protein in DC-mediated phagocytosis.
Rat monocyte-derived dendritic cells function and migrate in the same way as isolated tissue dendritic cells
Authors: Richters C D , Mayen I , Havenith C E G , Beelen R H J , Kamperdijk E W A 
Published: September 2022

AbstractDendritic cells (DC) are the most potent antigen-presenting cells and are therefore useful to induce immune responses against tumor cells in patients. DC can be generated in vitro from monocytes using GM-CSF and IL-4, the so-called monocyte-derived DC (MoDC). To achieve antitumor responses, MoDC must be able to migrate to the draining lymph nodes after injection to induce cytotoxic T cells. Therefore, we studied migration of MoDC in a rat model. Functional rat MoDC were generated from PVG-RT7B rats and injected subcutaneously into PVG rats. These rat strains differ only at one epitope of the leukocyte-common antigen, which can be recognized by the antibody His 41. The advantage is that migrated cells can be detected in the draining lymph nodes by staining sections with His 41+; thus, migration is not influenced by labeling procedures. Rat MoDC migrated to the T-cell areas of the draining lymph nodes, just as isolated Langerhans cells or spleen DC do. In contrast, monocytes also migrated to the B-cell areas and the medulla.
Effect of pentoxifylline on polarization and migration of human leukocytes
Authors: Domínguez-Jiménez Carmen , Sancho David , Nieto Marta , Montoya María C , Barreiro Olga , Sánchez-Madrid Francisco , González-Amaro Roberto 
Published: September 2022

AbstractLeukocyte polarization has a key role in the induction and effector phases of immune response. We assessed the effect of pentoxifylline (PTX) on the polarization and migration of human lymphocytes and neutrophils. A dose-dependent, inhibitory effect on the polarization of lymphoid cells induced by chemokines or IL-15 was found. In addition, PTX interfered with the chemotaxis of peripheral blood T cells and T lymphoblasts. A similar effect was observed on the transendothelial migration of these cells. In addition, the polarization of neutrophils, its adherence to endothelium, and their transendothelial migration, induced by different stimuli, were inhibited by PTX. By contrast, this drug had only a mild effect on endothelial cells and a partial inhibition on the induction of ICAM-1 expression by TNF-α. The inhibitory effect of PTX on leukocyte polarization and extravasation may contribute significantly to the anti-inflammatory and immunoregulatory activity of this drug.
Ambient pCO2 modulates intracellular pH, intracellular oxidant generation, and interleukin-8 secretion in human neutrophils
Authors: Coakley R J , Taggart C , Greene C , McElvaney N G , O'Neill S J 
Published: September 2022

AbstractAlthough neutrophils are a critical component of the inflammatory process, their functional regulation is incompletely understood. Of note, although pCO2 varies physiologically and pathologically in the neutrophilic milieu, its affect on neutrophil biological processes is unresolved. We demonstrate here that neutrophils respond to hypo- and hypercarbia, (0.04% and 10%) by increasing and decreasing, respectively, intracellular oxidant production (basally and in response to opsonized Escherichia coli and phorbol esters). Further, hypo- and hypercarbia increase and decrease, respectively, the release of IL-8 from LPS-stimulated cells; both effects are attenuated by the carbonic anhydrase inhibitor, acetazolamide. Anion exchange did not restore pHi under hypocarbic conditions, however partial restoration of pHi under hypercarbic conditions was achieved by Na+/H+ exchange and vacuolar ATPases. Abrogation of pCO2-induced changes in pHi prevented hypocarbia-induced generation of reactive oxidant species. These observations suggest that CO2 modifies neutrophil activity significantly by altering pHi.
Nitric oxide synthase and nitric oxide production in in vivo-derived mast cells
Authors: Gilchrist Mark , Savoie Michelle , Nohara Osamu , Wills Fiona L , Wallace John L , Befus A D 
Published: September 2022

AbstractNitric oxide (NO) is a potent mediator synthesized by a variety of cells involved in inflammatory reactions. We investigated the expression of NO synthase (NOS) in rat peritoneal mast cells (PMC). Small amounts of eNOS mRNA were detected basally, whereas neither mRNA for iNOS nor nNOS was detected in unstimulated PMC. Following stimulation by antigen, interferon-γ (IFN-γ), or anti-CD8 antibody, PMC up-regulated iNOS mRNA expression. In situ RT-PCR confirmed that iNOS mRNA originated from PMC. Production of iNOS protein was confirmed in stimulated PMC by immunohistochemistry. Upon stimulation with antigen, IFN-γ, or anti-CD8, nitrite production was increased significantly (8.4±0.6, 7.6±0.9, and 6.6±0.9 μM/2×105 cells/48 h NO2−, respectively; P&lt;0.01), whereas unstimulated PMC released 2.1 ± 0.3 μM/2 × 105 cells/48 h NO2−. These findings demonstrate that in vivo-derived PMC transcribe and translate mRNA for NOS and produce NO.
Regulation of murine macrophage proinflammatory and anti-inflammatory cytokines by ligands for peroxisome proliferator-activated receptor-γ: counter-regulatory activity by IFN-γ
Authors: Alleva David G , Johnson Eric B , Lio Francisco M , Boehme Stefen A , Conlon Paul J , Crowe Paul D 
Published: September 2022

AbstractThe prostaglandin, 15-deoxy Δ12,14-prostaglandin J2 (15d-PGJ2)1, and thiazolidinediones are ligands for the nuclear receptor, peroxisome proliferator-activated receptor (PPAR)-γ, which mediates anti-inflammatory activity by suppressing murine macrophage (Mφ) production of the inflammatory mediator, nitric oxide (NO). Here, we elucidated this anti-inflammatory activity further by investigating whether PPAR-γ ligands regulated a panel of proinflammatory and anti-inflammatory cytokines produced by primary inflammatory murine Mφ (thioglycollate-elicited peritoneal exudate Mφ; PEM). Thiazolidinediones and 15d-PGJ2 suppressed lipopolysaccharide (LPS)-induced PEM production of NO and IL-12(p40) to a greater extent than IL-6 and TNF-α production. Whereas 15d-PGJ2 showed the greatest extent of suppression of proinflammatory mediator production, the thiazolidinedione, BRL49653, was the most potent compound studied. Surprisingly, treatment with the Mφ-activation cytokine, IFN-γ, prevented PPAR-γ ligands from suppressing the proinflammatory cytokines completely and reduced their suppression of NO production substantially, demonstrating that activation conditions affect PPAR-γ-mediated, anti-inflammatory activity. Western analysis demonstrated that the antagonistic activity of IFN-γ did not involve modulation of PPAR-γ expression but showed that IFN-γ interfered with PPAR-γ ligand regulation of p42/p44 MAP kinase activation and the cytosolic disappearance of NF-κB upon LPS stimulation. Finally, we showed that PPAR-γ ligands did not substantially modulate production of the anti-inflammatory cytokine, IL-10, and that antibody-mediated neutralization of IL-10 did not prevent the ligands from suppressing proinflammatory mediator production. In contrast to studies with noninflammatory human monocytes and Mφ, our results demonstrate that primary murine inflammatory Mφ are extremely sensitive to the anti-inflammatory activity of PPAR-γ ligands. These results suggest that drugs such as thiazolidinediones may be most effective in suppressing Mφ activity early (i.e., in the absence of lymphocyte-derived IFN-γ) in the inflammatory process.
Inhibition of murine macrophage nitric oxide production by synthetic oligonucleotides
Authors: Zhu Fu-Gang , Reich Charles F , Pisetsky David S 
Published: September 2022

AbstractSynthetic 30-mer phosphorothioate (Ps) oligonucleotides (ODN) comprised of single bases (SdA30, SdC30, SdG30, and SdT30) were assessed for their effects on nitric oxide (NO) production by murine bone marrow macrophages (BMMC) and macrophage cell lines J774 and RAW264.7. Pretreatment of these cells with any of the four Ps ODN inhibited NO production induced by CpG ODN, E. coli DNA (EC DNA), or LPS. This inhibition was time- and dose-dependent and was observed even if the Ps ODN were added as long as 12 h after stimulation. As in the case of stimulatory ODN, inhibition was dependent on backbone structure and length. Thus, all four 30-mer, single-base Ps ODN were inhibitory, and only dG30 among phosphodiester ODN was inhibitory. Together, these observations indicate that Ps ODN can inhibit macrophage production of inflammatory mediators, suggesting a role of these compounds as immunomodulatory agents.
Contribution of phopholipase D and a brefeldin A-sensitive ARF to chemoattractant-induced superoxide production and secretion of human neutrophils
Authors: Káldi Krisztina , Szeberényi Júlia , Rada Balázs K , Kovács Péter , Geiszt Miklós , Mócsai Attila , Ligeti Erzsébet 
Published: September 2022

AbstractWe show that blockers of phospholipase D (PLD) reduce fMLP-triggered exocytosis of secretory vesicles effectively. In accordance with this, the PLD product phosphatidic acid (PA) was able to induce mobilization of secretory vesicles. Although PLD seems to play a role in the release of all neutrophil granule types, exogenous PA alone was not sufficient to activate the exocytosis of primary and secondary granules, suggesting that in the case of these granules, additional signaling factors are required to initiate the secretory responses. The ADP-ribosylation factor (ARF)-inhibitor brefeldin A (BFA) inhibited the fMLP-stimulated O2·− production strongly, whereas it did not influence any of the exocytic responses, and no significant effect of BFA was detected on the O2·− generation induced by other stimuli. On the basis of these results, we propose that upon chemoattractant stimulation, PLD activity is involved in induction of degranulation and O2·− production, but a BFA-sensitive ARF is only required to the activation of the NADPH oxidase. This ARF action seems to participate exclusively in the signaling pathway between the fMLP receptor and the oxidase.
Signaling to localized degranulation in neutrophils adherent to immune complexes
Authors: Nauclér Claes , Grinstein Sergio , Sundler Roger , Tapper Hans 
Published: September 2022

AbstractThe present study demonstrates that the secretion of azurophilic granules occurring during Fc receptor-mediated attachment and spreading of neutrophils is highly localized to the adhering region of the cell. In contrast, the secretion of specific granules occurs in a nonpolarized way. This implies that unique signals are involved in the regulation of azurophilic degranulation. Assembly of actin filaments, as visualized by staining with rhodamine phalloidin, neither hindered nor facilitated degranulation. Further, the azurophilic secretory response remained localized in the presence of cytochalasin B. Release of azurophilic-granule content was inhibited by genistein and erbstatin, inhibitors of tyrosine kinases, and by GF109203X, a protein kinase C (PKC) inhibitor. We could also demonstrate a relative enrichment of syk tyrosine kinase and the PKC isoforms α and β1 in adherent plasma membranes.
The Cbl family of ubiquitin ligases: critical negative regulators of tyrosine kinase signaling in the immune system
Authors: Rao Navin , Dodge Ingrid , Band Hamid 
Published: September 2022

AbstractThe Cbl family of proteins are evolutionarily conserved negative regulators of activated tyrosine kinase-coupled receptors. Antigen receptors are prominent targets of negative regulation by the Cbl family members, Cbl and Cbl-b, which proteins function as ubiquitin ligases. Cbl and Cbl-b contain substrate recognition domains that interact specifically with activated protein tyrosine kinases of the Src and Syk/ZAP-70 families. Cbl-mediated ubiquitination of these kinases leads to their degradation, resulting in attenuation of receptor signals. Cbl may also control activation-induced monoubiquitination of antigen receptors, thus facilitating their delivery to lysosomes for subsequent degradation. Finally, the interactions of Cbl proteins with downstream targets of tyrosine kinases, such as PI-3-kinase and Vav, could provide an additional mechanism to attenuate receptor signaling. By targeting multiple components of antigen receptor signaling for degradation, the Cbl protein family provides a critical mechanism to ensure an appropriate immune response. The hyperresponsiveness of Cbl−/− and Cbl-b−/− lymphocytes and the autoimmune phenotype of Cbl-b−/− mice lend strong support for this proposal. The ability to control early receptor signals through regulated protein degradation provides a novel paradigm of immunoregulation.
Different Gi-coupled chemoattractant receptors signal qualitatively different functions in human neutrophils
Authors: Berger Miles , Budhu Sadna , Lu Emily , Li Yongmei , Loike Devora , Silverstein Samuel C , Loike John D 
Published: September 2022

AbstractfMLP- or TNF-α-stimulated neutrophils produced H2O2 when they adhered to fibrinogen-coated surfaces but not when they adhered to collagen I-, collagen IV-, or Matrigel-coated surfaces. In contrast, LTB4- or IL-8-stimulated neutrophils did not produce H2O2 when they adhered to any of these surfaces. fMLP and TNF-α were much more potent than LTB4 and IL-8 in stimulating neutrophils to up-regulate and to activate their αMβ2 integrins, as measured by the binding of specific monoclonal antibodies. Pretreatment of neutrophils with pertussis toxin completely blocked their production of H2O2 on fibrinogen-coated surfaces in response to fMLP and their migration through Matrigel in response to fMLP, LTB4, and IL-8. These data show that although the fMLP, LTB4, and IL-8 receptors are coupled to pertussis toxin-sensitive Gα proteins, they signal neutrophils to initiate qualitatively different effector functions. We propose that the qualitative differences in effector functions signaled by different chemoattractants reflect qualitative differences in using G-protein β and/or γ subunits or other factors by their cognate receptors.
Glycosylphosphatidylinositol-anchored mucin-like glycoproteins isolated fromTrypanosoma cruzitrypomastigotes induce in vivo leukocyte recruitment dependent on MCP-1 production by IFN-γ-primed-macrophages
Authors: Coelho Patrícia S , Klein André , Talvani André , Coutinho Sibele F , Takeuchi Osamu , Akira Shizuo , Silva João S , Canizzaro Hélia , Gazzinelli Ricardo T , Teixeira Mauro M 
Published: September 2022

AbstractGlycosylphosphatidylinositol-anchoredmucin-like glycoproteins from Trypanosoma cruzi trypomastigotes (tGPI-mucins) activate macrophages in vitro to produce proinflammatory cytokines, chemokines, and nitric oxide. These effects of tGPI-mucins may be important in the ensuing immune response to T. cruzi. Here, we have sought evidence for a role of tGPI-mucins in mediating leukocyte recruitment in vivo. tGPI-mucins are highly effective in promoting cell recruitment in the pleural cavity of mice primed with IFN-γ-inducing agents but not in naïve mice. Maximal recruitment was observed at a dose between 250 and 1250 ng tGPI-mucins. There was a significant elevation in the levels of MCP-1 in the pleural cavity of primed animals injected with tGPI-mucins, and in vivo neutralization of MCP-1 abolished leukocyte recruitment. Pretreatment with anti-MIP-1α or anti-RANTES had no effect on the recruitment induced by tGPI-mucins. MCP-1 immunoreactivity was detected in pleural macrophages, and macrophages produced MCP-1 in vitro, especially after priming with IFN-γ. Finally, tGPI-mucins induced significant leukocyte recruitment in primed C3H/HeJ but not in TLR2-deficient mice. Together, our results suggest that T. cruzi-derived GPI-mucins in conjunction with IFN-γ may drive tissue chemokine production and inflammation and bear a significant role in the pathogenesis of Chagas disease.
The expression pattern of the ITIM-bearing lectin CLECSF6 in neutrophils suggests a key role in the control of inflammation
Authors: Richard Manon , Veilleux Patricia , Rouleau Michèle , Paquin Robert , Beaulieu André D 
Published: September 2022

AbstractIn our study of the modulation of the expression of inflammation-related genes in neutrophils, we have found a gene called CLECSF6 (C-type lectin superfamily 6). CLECSF6 expresses two mRNA species at low levels in resting neutrophils. Here, we describe for the first time the sequence of the short mRNA version. It lacks amino acids that are likely to affect the functionality of its protein product. GM-CSF, IL-3, IL-4, and IL-13 caused an accumulation of the short CLECSF6 mRNA in neutrophils. The surface expression of the CLECSF6 protein was reduced by TNF-α, IL-1α, LPS, and Matrigel®. CLECSF6 bears the immunoreceptor tyrosine-based inhibition motif (ITIM) involved in signal transduction resulting in the inhibition of leukocyte activation. We propose that some neutrophil activators modulate the expression of CLECSF6 at the mRNA (GM-CSF, IL-3, IL-4, and IL-13) or protein (TNF-α, IL-1α, LPS, and Matrigel®) levels in ways that block ITIM-based transduction of anti-inflammatory signals and therefore promote inflammation.
Increased responsiveness of murine eosinophils to MIP-1β (CCL4) and TCA-3 (CCL1) is mediated by their specific receptors, CCR5 and CCR8
Authors: Oliveira Sandra H P , Lira Sergio , Martinez-A Carlos , Wiekowski Maria , Sullivan Lee , Lukacs Nicholas W 
Published: September 2022

AbstractIn the present study, we investigated the regulation of chemokine-mediated responses and receptor expression on eosinophils from mice. MIP-1α (CCL3) and eotaxin (CCL11) induced a significant and only partially overlapping intracellular calcium flux in antigen-elicited and peripheral blood eosinophils, and MCP-1 (CCL2), MDC (CCL22), MIP-1β (CCL4), and TCA-3 (CCL1) did not. To demonstrate functional use of the specific receptors, we examined chemotactic responses. Peripheral blood eosinophils migrated toward MIP-1α (CCL3) and eotaxin (CCL11) but not MCP-1 (CCL2), MDC (CCL22), MIP-1β (CCL4), and TCA-3 (CCL1). Antigen-elicited eosinophils migrated toward MIP-1α (CCL3) and eotaxin (CCL11), but also migrated in response to MIP-1β (CCL4) and TCA-3 (CCL1), suggesting the up-regulation of additional chemokine receptors on antigen-elicited eosinophils. The up-regulation of the additional chemokine-receptor responses appeared to be in part because of cytokine activation, because TNF-α and/or IL-4 were able to up-regulate CCR1, -3, -5, and -8 mRNA expression in eosinophils as well as migration responses to the appropriate ligands. Using antibodies specific for CCR5 and CCR8, the chemotactic response to MIP-1β and TCA-3, respectively, was reduced significantly. Finally, the expression of these new receptors appears to have an effect on activation and degranulation because MIP-1β (CCL4) and TCA-3 (CCL1) induce significant levels of LTC4 from elicited eosinophils. These results suggest that eosinophils may up-regulate and use additional chemokine receptors during progression of inflammatory, allergic responses for migration and activation.
Protein kinase A regulates β2 integrin avidity in neutrophils
Authors: Jones Samuel L 
Published: September 2022

AbstractThe adhesive phenotype of neutrophils (PMN) depends largely on activating and deactivating intracellular signals regulating β2 integrin avidity for ligand. Our hypothesis is that PKA is a negative regulator of β2 integrin avidity. In this work, we examined the role of PKA in PMN αMβ2 integrin activation. Elevation of cAMP inhibited αMβ2 integrin-dependent adhesion of PMN to immune complexes (IC), but not PMA-induced adhesion. The PKA inhibitor KT5720 reversed the ability of cAMP to suppress adhesion to IC. Moreover, inhibition of PKA activity was sufficient to activate αMβ2 integrin-dependent adhesion and increase β2 integrin expression and binding of the monoclonal antibody CBRM1/5, which recognizes activated αMβ2 specifically. However, PKA activity was necessary for sustained adhesion. Disruption of A kinase-anchoring, protein-PKA binding with a cell-permeant peptide derived from the AKAP Ht31 also activated adhesion. Unlike pharmacologic inhibition of PKA, AKAP peptide-induced adhesion was PKC dependent and did not affect β2 integrin expression or CBRM1/5 binding. These data demonstrate that PKA appears to have a dual role in the mechanism regulating αMβ2 integrin avidity and adhesion.