194 research outputs found

    The histone deacetylase inhibitor valproic acid attenuates phospholipase Cγ2 and IgE-mediated mast cell activation.

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    Mast cell activation through the high-affinity IgE receptor (FcεRI) plays a central role in allergic reactions. FcεRI-mediated activation triggers multiple signaling pathways leading to degranulation and synthesis of different inflammatory mediators. IgE-mediated mast cell activation can be modulated by different molecules, including several drugs. Herein, we investigated the immunomodulatory activity of the histone deacetylase inhibitor valproic acid (VPA) on IgE-mediated mast cell activation. To this end, bone marrow-derived mast cells (BMMC) were sensitized with IgE and treated with VPA followed by FcεRI cross-linking. The results indicated that VPA reduced mast cell IgE-dependent degranulation and cytokine release. VPA also induced a significant reduction in the cell surface expression of FcεRI and CD117, but not other mast cell surface molecules. Interestingly, VPA treatment inhibited the phosphorylation of PLCγ2, a key signaling molecule involved in IgE-mediated degranulation and cytokine secretion. However, VPA did not affect the phosphorylation of other key components of the FcεRI signaling pathway, such as Syk, Akt, ERK1/2, or p38. Altogether, our data demonstrate that VPA affects PLCγ2 phosphorylation, which in turn decreases IgE-mediated mast cell activation. These results suggest that VPA might be a key modulator of allergic reactions and might be a promising therapeutic candidate

    El factor de transferencia como inductor de la expresión de RNAm de IFN-γ e IL-2 en pollos vacunados contra influenza aviar

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    Avian influenza is a disease of paramount economical importance for the poultry industry. In Mexico, only low pathogenicity H5N2 strain has been reported and it is controlled through inactivated-virus inoculation. This emulsified vaccine reduces clinical signs indeed, but not viral shedding. Over the last 50 years Transfer Factor (TF) has shown to be an efficient immunomodulator and has been used successfully in human clinical cases, and less commonly in animal models. The aim of this work was to establish an avian influenza-specific TF dose able to produce the highest percentage of mRNA expression of the following cytokines: IL-2 and IFN-γ. An experiment to show the mRNA expression of these cytokines in chicken previously inoculated with avian influenza-specific TF was set up. In the first experiment 0.1, 1 and 10 TF units were inoculated into 3 different groups of chickens; PCR for cytokines from splenic tissue was performed. For the second experiment, a second TF inoculation in combination with the vaccine was carried out using 3 new groups of chicken. Experiment 1: Only IL-2 expression was achieved in 58.33% of chickens using 1 TF unit (P < 0.05). In experiment 2, 75% of chickens showed IL-2 with 1 TF unit (P < 0.05) and all of them (100%) expressed IFN-γ (P < 0.01). From these results it can be concluded that IFN-γ and IL-2 expression can be induced by the inoculation of 1 TF unit (equivalent to 7.3 μg of protein) at the beginning of the experiment procedure and after a second inoculation of TF (10 days after) together with the inactivated virus vaccine.  La influenza aviar es una enfermedad de gran importancia económica para la industria avícola. En México sólo se ha reportado la cepa H5N2 de baja patogenicidad y ésta se controla mediante la vacunación con virus inactivado. Esta vacuna en emulsión reduce la presencia de signos, pero no la eliminación viral. Desde hace más de 50 años se ha informado acerca de la eficacia del Factor de Transferencia (FT) como inmunomodulador en casos clínicos humanos y en menor cantidad en modelos animales. El objetivo de este trabajo fue el de establecer la dosis que produce un mayor porcentaje de expresión del RNAm de dos citocinas: IL-2 y de IFN-γ. Se diseñó un experimento para evidenciar la expresión del RNAm de estas dos citocinas en pollos previamente inoculados con FT específico para influenza aviar. En la primera fase se aplicaron 0,1, 1, y 10 unidades de FT a diferentes grupos de pollos, posteriormente se realizó la PCR a partir de tejido esplénico. En la segunda fase se aplicó el FT junto con la vacuna a tres nuevos grupos de pollos. Del experimento 1 solamente IL-2 tuvo un porcentaje mayor de positivos (58,33%) con 1 unidad (P < 0,05). En cambio, en el experimento 2, con 1 unidad se obtuvo 75% de positivos para IL-2 (P < 0,05) y 100% para IFN-γ (P < 0,01). De estos resultados su puede concluir que al aplicar una unidad de FT (equivalente a 7,3 μg de proteína) al inicio del experimento y 10 días después otra unidad de FT junto con la vacuna inactivada de IA se indujo la expresión del RNAm de IFN-γ e IL-2. &nbsp

    Operation and performance of the ATLAS Tile Calorimeter in Run 1

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    The Tile Calorimeter is the hadron calorimeter covering the central region of the ATLAS experiment at the Large Hadron Collider. Approximately 10,000 photomultipliers collect light from scintillating tiles acting as the active material sandwiched between slabs of steel absorber. This paper gives an overview of the calorimeter’s performance during the years 2008–2012 using cosmic-ray muon events and proton–proton collision data at centre-of-mass energies of 7 and 8TeV with a total integrated luminosity of nearly 30 fb−1. The signal reconstruction methods, calibration systems as well as the detector operation status are presented. The energy and time calibration methods performed excellently, resulting in good stability of the calorimeter response under varying conditions during the LHC Run 1. Finally, the Tile Calorimeter response to isolated muons and hadrons as well as to jets from proton–proton collisions is presented. The results demonstrate excellent performance in accord with specifications mentioned in the Technical Design Report

    TENEDORES DE FAUNA SILVESTRE EN CAUTIVERIO EN EL MUNICIPIO DE EL PAUJIL - CAQUETÁ

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    El Municipio de Paujil- Caquetá esta ubicado en el piedemonte amazónico, por lo que cuenta con una abundante biodiversidad; sin embargo, por sus características sociales y culturales, se hace fiecuente la tenencia en cautiverio de fauna silvestre, principalmente con fines de amansamientos para ser conservados como animales de compañía o para su comercialización ilegal. La investigación fue desarrollada a principio del año 2010, en el perímetro urbano de El paujil - Caquetá mediante el uso de listas de chequeo, demostró que los animales mas frecuentemente mantenidos en cautiverio son aves, especialmente loras. seguidas por reptiles y en último lugar los mamífero, contrario a los reportes de la Policía del Departamento del Caquetá, que para el primer periodo del año 2010, reportó mayores índices de decomisos en reptiles, especialmente Chelonios. Se confirmó que la razón de tenencia corresponde a necesidades antrópicas no vitales, como servir de animales de compañía, y que la práctica se concentra en los estratos uno y dos, La falta de conocimiento específico de las especies y su manejo, hace que los tenedores de fauna silvestre en cautiverio estén expuestos a todos los riesgos que supone la interacción con este tipo de animales, entre los que se encuentran las agresiones físicas, pero muy especialmente la transmisión de enfermedades zoontiticos

    Valproic acid restricts mast cell activation by Listeria monocytogenes.

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    Mast cells (MC) play a central role in the early containment of bacterial infections, such as that caused by Listeria monocytogenes (L.m). The mechanisms of MC activation induced by L.m infection are well known, so it is possible to evaluate whether they are susceptible to targeting and modulation by different drugs. Recent evidence indicates that valproic acid (VPA) inhibits the immune response which favors L.m pathogenesis in vivo. Herein, we examined the immunomodulatory effect of VPA on L.m-mediated MC activation. To this end, bone marrow-derived mast cells (BMMC) were pre-incubated with VPA and then stimulated with L.m. We found that VPA reduced MC degranulation and cytokine release induced by L.m. MC activation during L.m infection relies on Toll-Like Receptor 2 (TLR2) engagement, however VPA treatment did not affect MC TLR2 cell surface expression. Moreover, VPA was able to decrease MC activation by the classic TLR2 ligands, peptidoglycan and lipopeptide Pam3CSK4. VPA also reduced cytokine production in response to Listeriolysin O (LLO), which activates MC by a TLR2-independent mechanism. In addition, VPA decreased the activation of critical events on MC signaling cascades, such as the increase on intracellular Ca2+ and phosphorylation of p38, ERK1/2 and -p65 subunit of NF-κB. Altogether, our data demonstrate that VPA affects key cell signaling events that regulate MC activation following L.m infection. These results indicate that VPA can modulate the functional activity of different immune cells that participate in the control of L.m infection

    Low-Dose Amphotericin B and Murine Dialyzable Spleen Extracts Protect against SystemicCandidaInfection in Mice

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    Candida albicans causes opportunistic systemic infections with high mortality (30%–50%). Despite significant nephrotoxicity, amphotericin (AmB) is still used for the treatment of this serious fungal infection. Therefore, alternative treatments are urgently needed. Dialyzable leukocyte extracts have been used successfully to treat patients with mucocutaneous candidiasis, but their effectiveness in systemic candidiasis has not been evaluated. In this study, low-dose AmB (0.1 mg/kg) plus 10 pg of murine dialyzable spleen extracts (mDSE) were tested in a systemic candidiasis mouse model. Survival, tissue fungal burden, kidney damage, kidney cytokines, and serum levels of IL-6 and hepcidin were evaluated. Our results showed that the combined treatment of low-dose AmB plus mDSE improved survival and reduced kidney fungal burden and histopathology; these effects correlated with increased kidney concentration of IFN-γ and TGF-β1, decreased levels of TNF-α, IL-6, and IL-10, as well as high levels of systemic IL-6 and hepcidin. Low-dose AmB and mDSE synergized to clear the infectious agent and reduced tissue damage, confirming the efficacy of a low dose of AmB, which might decrease the risk of drug toxicity. Further studies are necessary to explore these findings and its implications in future therapeutic approaches

    Molecular insights on the interference of simplified lung surfactant models by gold nanoparticle pollutants

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    YesInhaled nanoparticles (NPs) are experienced by the first biological barrier inside the alveolus known as lung surfactant (LS), a surface tension reducing agent, consisting of phospholipids and proteins in the form of the monolayer at the air-water interface. The monolayer surface tension is continuously regulated by the alveolus compression and expansion and protects the alveoli from collapsing. Inhaled NPs can reach deep into the lungs and interfere with the biophysical properties of the lung components. The interaction mechanisms of bare gold nanoparticles (AuNPs) with the LS monolayer and the consequences of the interactions on lung function are not well understood. Coarse-grained molecular dynamics simulations were carried out to elucidate the interactions of AuNPs with simplified LS monolayers at the nanoscale. It was observed that the interactions of AuNPs and LS components deform the monolayer structure, change the biophysical properties of LS and create pores in the monolayer, which all interfere with the normal lungs function. The results also indicate that AuNP concentrations >0.1 mol% (of AuNPs/lipids) hinder the lowering of the LS surface tension, a prerequisite of the normal breathing process. Overall, these findings could help to identify the possible consequences of airborne NPs inhalation and their contribution to the potential development of various lung diseases.University of Technology Sydney (UTS) FEIT Research Scholarship, UTS IRS (S.I.H.), 2018 Blue Sky scheme–Suvash Saha (Activity 2232368), N.S.G is supported by the Vice-Chancellor fellowship funded by QUT
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