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Expressão de receptores toll-like 2 e função quimiotáxica de neutrófilos na doença de Behçet / Expression of toll-like receptor 2 and neutrophil chemotaxis in Behçet´s diseaseNeves, Fabrício de Souza 11 May 2009 (has links)
A doença de Behçet tem sua fisiopatologia caracterizada por hiperatividade neutrofílica, particularmente em relação à quimiotaxia, e períodos de atividade da doença podem ser desencadeados por exposição a estreptococos. Uma vez que células do sistema imune inato são ativadas pelo ácido lipoteicoico (LTA) de bactérias gram-positivas via receptor toll-like (TLR) 2 e CD14, cujas expressões são reguladas pelos fatores estimulantes de colônias de granulócitos (G-CSF) e granulócitos-macrófagos (GM-CSF), o objetivo principal deste estudo foi determinar se há hiperexpressão de TLR2 em neutrófilos de DB ativa e se a quimiotaxia de polimorfonucleares (PMN) neutrófilos na DB poderia ser hiperestimulada pelo LTA. Além do TLR2, foram medidas as expressões de TLR4, CD14, CD114 (receptor de G-CSF) e CD116 (receptor de GM-CSF) nos neutrófilos e nos monócitos de pacientes com doença de Behçet (DB), as concentrações séricas de CD14 solúvel (CD14s) e as respostas quimiotáxicas dos PMNs de DB sob diferentes estímulos. A expressão dos receptores foi medida pela citometria de fluxo, as concentrações séricas por ELISA e as respostas quimiotáxicas foram avaliadas em câmara de Boyden. Nos PMNs, os receptores foram igualmente expressos nos dois grupos e, estimulados com LTA, suas respostas quimiotáxicas também foram similares. Somente à incubação com plasma os PMNs de DB desenvolveram hiperquimiotaxia em relação aos PMNs controles. A expressão do TLR2 foi maior em monócitos de DB em relação aos controles, e a concentração de CD14s sérica, de origem monocitária, foi maior nos pacientes com DB ativa. Em conjunto, os resultados demonstram que PMNs de DB, isoladamente, não reagem exacerbadamente ao LTA, e suas respostas migratórias são estritamente dependentes de fatores estimulantes solúveis. / Expressions of toll-like receptor (TLR) 2, TLR4, CD14, CD114 and CD116 were assessed on polymorphonuclear (PMN) neutrophils and monocytes of patients with Behçets disease (BD). PMN chemotactic responses under different stimulations were also measured. The objective was to determine if BD PMN chemotaxis may be overstimulated by lipoteichoic acid (LTA) from gram-positive bacteria. Receptor expressions were measured by flow cytometry and PMN chemotaxis was assessed in a Boyden chamber. Only TLR2 expression was higher on monocytes of the BD group than in control group. On PMNs, however, TLR2 expression was similar in both groups and, when stimulated with LTA, BD PMN cells showed chemotactic responses similar to the controls. These cells only exhibited increased chemotaxis when incubated with plasma. In conclusion, isolated BD PMN did not overreact to LTA, and its hyperchemotaxis is strictly dependent on soluble stimulating factors
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Células dendríticas plasmocitóides, expressão de receptores \"Toll-like\" 9 e 3 e de podoplanina nas lesões cutâneas do Sarcoma de Kaposi associado à síndrome de imunodeficiência adquirida e esporádico / Plasmacytoid dendritic cells and the expression of toll-like receptors 9 and 3 and podoplaninin in cutaneous lesions of Aids-associated Kaposi\'s sarcoma and classic Kaposi\'s sarcomaSoares, Cinara Prata Cirino Castro 25 August 2014 (has links)
INTRODUÇÃO: O Sarcoma de Kaposi (SK) é a neoplasia mais frequente dos doentes com Aids. É causada pelo herpes-vírus 8 (HHV-8). As células dendríticas plasmocitóides (CDp) são especializadas na produção de interferon tipo 1 e participam da resposta imune aos vírus. Os receptores \"toll-like\" são os principais receptores de reconhecimento de padrão, sendo que os receptores toll-like (TLR) 3 e 9 têm função no reconhecimento de vírus. O D2-40 é o anticorpo que reconhece a podoplanina, uma proteína transmembrana, presente no endotélio linfático e que tem função na imunidade. OBJETIVO: Demonstrar e comparar os componentes da imunidade inata: CDp e TLR 3 e 9, nas lesões cutâneas de SK associado a Aids e esporádico. Identificar a presença do HHV-8 nas CDp. Verificar o componente endotelial linfático na progressão das lesões de SK e comparar a expressão dos elementos da imunidade inata estudados, nas lesões com menor e maior componente endotelial linfático. MÉTODOS: Estudo retrospectivo de 50 biopsias de pacientes com diagnóstico de SK, todos com comprovação pelo exame histopatológico e demonstração do antígeno nuclear associado à latência (LANA) do HHV-8. Foram avaliados 11 biopsias de SK da forma clássica (SKc), 22 lesões de doentes com Aids (SK-Aids) e de 17 de doentes com Aids submetidos a tratamento com terapia antirretroviral altamente eficaz (SK-Aids/HAART). Os espécimes foram submetidos a exame por técnica imuno-histoquímica para evidenciar a presença de CDp (anticorpo CD303/BDCA-2), a expressão de TLR 3 e 9, bem como de podoplanina (anticorpo D2-40). Foi realizada também técnica de dupla marcação com CD303 e LANA, objetivando a identificação de CDp infectadas pelo HHV-8.Vinte e três espécimes de granuloma piogênico constituíram o grupo controle. A população de CDp e expressão de TLR 3 e TLR 9 também foi comparada nas lesões cutâneas de SK de doentes com e sem comprometimento visceral pela neoplasia; lesões não tumorais (máculo-papulares/placas) foram comparadas às lesões tumorais (nodulares) e de acordo com níveis sanguíneos de linfócitos T CD4+ (menor e igual ou maior que 350 células/mm3). RESULTADOS: As CDp foram mais numerosas nos espécimes de SK-Aids quando comparado com o granuloma piogênico. Foram identificadas CDp infectadas pelo HHV-8. A expressão de TLR 3 foi menor nas lesões de SK, independente da forma epidemiológica, do que no granuloma piogênico. Para todas as outras comparações da densidade de CDp e expressão de TLR 3 e de TLR 9 não houve diferença entre os grupos. Não houve diferença no componente endotelial linfático das lesões máculo-papulares/placas e tumorais do SK, assim como na expressão dos elementos da imunidade inata estudados entre as lesões com maior e menor componente endotelial linfático. CONCLUSÕES: Demonstrou-se pela primeira vez a presença de CDp e a expressão de TLR 3 e 9 em lesões cutâneas do Sarcoma de Kaposi, bem como a infecção de CDp pelo HHV-8 \"in situ\" nos tumores. Os resultados obtidos sugerem a participação das células CDp e do TLR 3 na patogênese das lesões cutâneas do Sarcoma de Kaposi, independente da presença do vírus da imunodeficiência humana. A imunomarcação de SK com o anticorpo D2-40, tanto nas fases precoce como tardia das lesões, confirma a natureza endotelial linfática das células neoplásicas. Esta parece não ter relação com a expressão dos elementos da imunidade inata estudados / Introduction: Kaposi\'s sarcoma (KS) is the most common Aids-associated malignancy. It is caused by human herpesvirus-8. Plasmacytoid dendritic cells (pDC) are professional interferon producing cells, and participate in the immune response against viruses. Toll-like receptors (TLR) are the main pattern recognition receptors, and TLR 3 and TLR 9 participate in the recognition of viruses. Podoplanin, recognized by antibody D2-40, is a transmembrane protein identified on lymphatic endothelial cells with functions inimmunity. Objective: Demonstrate and compare some innate immunity components: pDC, TLR 3 and TLR 9, in cutaneous lesions of Aids-associated Kaposi\'s sarcoma and classic Kaposi\'s sarcoma. Identify the infection of pDC by HHV-8. Compare the lymphatic endothelial component in the course of tumor progression and compare the expression of innate immunity elements in lesions with a predominance of lymphatic endothelial components or not. Methods: Retrospective study of 50 biopsies diagnosed as Kaposi\'s sarcoma withpositive staining for latency-associated nuclear antigen (LANA) of HHV-8. Eleven classic KS, 22 Aids-associated KS and 17 Aids-associated KS from patients undergoing highly active antiretroviral therapy (HAART) were assessed. Paraffinembedded tissue was submitted to immunohistochemistry technique in order to demonstrate pDC (CD303/BDCA-2 antibody), expression of TLR 3, TLR 9 and podoplanin (D2-40 antibody). We performed double staining with CD303 and LANA in order to identify pDC infection with HHV-8. Twenty-three pyogenic granuloma(PG) specimens were analyzed as a control group. Plasmacytoid dendritic cells population, TLR 3 and TLR 9 expressions were compared between patients with and without visceral disease, nodular stageandpatch/plaque stage and according to bloodlymphocytes T CD4 count(=350 cells/mm3). Results: Plasmacytoid dendritic cells density in Aids-associated SK was higher than in PG. We could identify pDC infection by HHV-8. The expression of TLR 3 in all forms of KS was less extensive than PG. All others comparisons about pDC density, TLR 3 and 9expressions were similar. We found no difference in D2-40 expression between nodular and patch/plaque stages. When comparing tumors with extensive expression of D2-40 (>= 50% of cells) and tumors with less expression (<50% of cells), we found no differences in density of pDC and expression of TLR 3 and TLR 9. Conclusion: This is the first time that pDC, TLR 3 and TLR 9 have been demonstrated in skin lesions of KS, as well as the infection of pDC in the lesions. Our results suggest that pDC and TLR 3 participate in the pathogenesis of KS, independently of HIV presence. The positive staining with D2-40 antibody, in all the stages of KS, confirmsthe lymphatic nature of neoplastic cells. It seems that podoplanin is not related to the innate immunity elements studied here
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Efeito do peptídeo liberador de gastrina na resposta inflamatória local e sistêmica : envolvimento na sinalização do receptor Toll-like 4Petronilho, Fabrícia Cardoso January 2010 (has links)
É bem estabelecido que respostas imunes possam ser influenciadas pelo sistema nervoso. O neuropeptídeo, peptídeo liberador de gastrina (GRP) tem sido detectado na produção e liberação de citocinas, em modelo animal e em humanos com doenças inflamatórias e sabe-se que o antagonista do receptor de GRP, RC-3095 modula a resposta de citocinas pro-inflamatórias em macrófagos ativados por lipopolissacarídeo (LPS) molhando a sobrevivência em modelo animal de sepse induzida por ligação e perfuração cecal (CLP). Neste contexto, neste estudo avaliamos o efeito modulatório de GRP em modelos animais de doenças inflamatórias agudas: injúria pulmonar associada à pleurisia induzida por carragenina e sepse induzida por CLP e adicionalmente, em pacientes sépticos através da correlação dos seus níveis com o desfecho clínico. Para esta proposta, no Capítulo 1 avaliamos em pleurisia induzida por carragenina os seguintes parâmetros: migração celular, atividade da lactato desidrogenase, conteúdo de proteínas totais, concentração de nitrito/nitrato e níveis de TNF-α e IL- β no exsudato pleural e atividade da mieloperoxidade e marcadores de dano oxidativo em lipídios e proteínas no tecido pulmonar. Assim, o RC-3095 exibiu significante ação anti-inflamatória através da inibição do influxo de leucócitos e bloqueio da mieloperoxidade, conteúdo de nitrito/nitrato e níveis de citocinas. Além disso, os resultados mostraram que RC-3095 exerce ação contra o dano oxidativo em lipídios e proteínas, bem como o aumento na viabilidade celular. Isto sugere que RC- 3095 tem propriedades anti-inflamatórias que podem estar relacionadas com a redução do dano oxidativo. No Capítulo 2, entretanto, nós seguimos no modelo animal de sepse onde buscamos o entendimento do papel protetor que exerce o RC-3095. Vários estudos sugerem o envolvimento de TLR-4 como um importante elemento de defesa do hospedeiro durante a infecção, e importantes eviências indicam que esses receptores também possuem um papel na patofisiologia da sepse, onde camundongos deficientes de TLR-4 não apresentam falência na migração de neutrófilos para a cavidade peritoneal durante a sepse polimicrobiana induzida por CLP letal, e como conseqüência, foram mais resistentes para sepse que controles. Nossos resultados indicam que este efeito protetor pode ser atribuído para uma atenuação de sinalização de TLR-4 em cultura de células RAW 264.7 estimuladas por LPS e tecido pulmonar em ratos CLP, levando a uma diminuição de citocinas proinflamatórias as quais a via de ativação de GRPR mostra seletividade como verificado no Capítulo 3, possibilitando a explicação dos baixos níveis de citocinas pro-inflamatórias em pacientes sépticos tratados com RC-3095. Esta atenuação favorece a infiltração de neutrófilos, resultando na diminuição de bacteremia preservando o controle da infecção no local melhorando o desfecho da sepse. Nossos resultados ainda mostram que níveis plasmáticos de GRP podem predizer o desfecho na sepse, mas não em pacientes SIRS sugerindo que GRP exerce funções diferenciais nas duas condições e sugere que o antagonismo de GRPR modula a inflamação incontrolada por agir em respostas mediadas por TLR-4 e funcionalidade imunoregulatória. Em conclusão, os presentes resultados indicam que o antagonista de GRPR exerce um papel na inflamação aguda e pode ser utilizado como uma nova terapia alternativa para sepse bacteriana Gram-negativa. / It is well established that immune responses may be influenced by the nervous system. The neuropeptide gastrin-releasing peptide (GRP) has been detected on the production and release of cytokines, both in animal models and humans with inflammatory diseases and reported that the GRP receptor antagonist RC-3095 modulates the response of proinflammatory cytokines in activated macrophages by lipopolysaccharide and improved the survival in an animal model of sepsis induced by cecal ligation and puncture (CLP). Within this context, in this work we evaluate the GRP modulatory effect in animal models of acute inflammatory illnesses: lung injury associated with carrageenan-induced pleurisy, and in CLP-induced sepsis and additionally in septic patients through the correlations of its levels with the clinical outcome. For this purpose, in Chapter 1 we evaluated in carrageenan-induced pleurisy the following parameters: cell migration, lactate dehydrogenase activity, total protein content, nitrite/nitrate concentration, TNF-α and interleukin-1β (IL-1β) levels in pleural exudates; myeloperoxidase activity and lipid and protein oxidative damage markers in lung tissue. Thus, RC-3095 exhibited pronounced anti-inflammatory actions by inhibition of leukocyte influx and blockade of myeloperoxidase, nitrite/nitrate content and cytokine levels. Moreover, the results showed that RC-3095 elicits action against oxidative damage in lipids and proteins, as well as increases cell viability. These suggest that RC-3095 has anti-inflammatory properties that can be related with the reduction of oxidative damage. In Chapter 2, however, we follow the animal model of sepsis where we search the agreement of the protective role that RC-3095 exerts. Increasing evidences suggest the evolvement of TLR-4 as an important element of host defense during an infection, a growing body of evidence indicates that these receptors also may play a role in the pathophysiology of sepsis where TLR-4 defective mice did not present failure of neutrophil migration to the peritoneal cavity during polymicrobial sepsis induced by lethal CLP, and as consequence, they were more resistant to sepsis than controls Our results further indicate that this protective effect can be attributed to an attenuation of TLR-4 signaling in RAW 264.7 cell culture stimulated by LPS and lung tissue in CLP rats, leading to a decrease of release of proinflammatory cytokines which the pathway of activation of GRPR shows selectivity as verified in Chapter 3, and can additionally explain the lower levels of the proinflammatory cytokine in RC-3095-treated septic patients. This attenuation favors neutrophil infiltration, resulting in decreased bacteremia preserving the control of infection in situ improving sepsis outcome. Our finding still show that plasma GRP levels could predict outcome in sepsis but not SIRS patients suggesting that GRP plays different roles in the two conditions and suggest that GRPR antagonism modulates uncontrolled inflammation by targeting TLR-4-mediated responses and immunoregulatory functionality. Taken together, the present results indicate that a GRPR antagonist plays a role in acute inflammation and could be developed as a new alternative therapy for Gram-negative bacterial sepsis.
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Dopad mýta na náklady v MKD / Toll impact on the costs in international truck transportMruz, Peter January 2010 (has links)
The aim of the Master's thesis is to compare and quantify the impact of the introduction of electronic toll collection system at the costs of the carrier's export transport of Prešov (SK) - Werlte (DE). Attention is devoted to a detailed analysis of the cost of toll truck emission standards Euro II, Euro III and Euro V. Analysis of the toll costs consists of quantifying the unit costs per kilometer, the total annual costs and transport costs in the period of the years 2003 and 2010.
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Analýza projektu mýtného v Praze z pohledu internalizace externalit / Analysis of congestin toll project in Prague from internalization of externalities perspectiveRychetský, David January 2010 (has links)
This paper is about introduction of congestion toll in centre of Prague. I look at the toll as an internalization of externalities instrument. Car transport causes high externalities in centres of cities, so there exists a tendency to solve this problem by different arrangements. Altough particular congestion toll project in Prague brings internalization of automobile externalities, this project is not profitable for the society because of high costs.
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Expressão de receptores toll-like 2 e função quimiotáxica de neutrófilos na doença de Behçet / Expression of toll-like receptor 2 and neutrophil chemotaxis in Behçet´s diseaseFabrício de Souza Neves 11 May 2009 (has links)
A doença de Behçet tem sua fisiopatologia caracterizada por hiperatividade neutrofílica, particularmente em relação à quimiotaxia, e períodos de atividade da doença podem ser desencadeados por exposição a estreptococos. Uma vez que células do sistema imune inato são ativadas pelo ácido lipoteicoico (LTA) de bactérias gram-positivas via receptor toll-like (TLR) 2 e CD14, cujas expressões são reguladas pelos fatores estimulantes de colônias de granulócitos (G-CSF) e granulócitos-macrófagos (GM-CSF), o objetivo principal deste estudo foi determinar se há hiperexpressão de TLR2 em neutrófilos de DB ativa e se a quimiotaxia de polimorfonucleares (PMN) neutrófilos na DB poderia ser hiperestimulada pelo LTA. Além do TLR2, foram medidas as expressões de TLR4, CD14, CD114 (receptor de G-CSF) e CD116 (receptor de GM-CSF) nos neutrófilos e nos monócitos de pacientes com doença de Behçet (DB), as concentrações séricas de CD14 solúvel (CD14s) e as respostas quimiotáxicas dos PMNs de DB sob diferentes estímulos. A expressão dos receptores foi medida pela citometria de fluxo, as concentrações séricas por ELISA e as respostas quimiotáxicas foram avaliadas em câmara de Boyden. Nos PMNs, os receptores foram igualmente expressos nos dois grupos e, estimulados com LTA, suas respostas quimiotáxicas também foram similares. Somente à incubação com plasma os PMNs de DB desenvolveram hiperquimiotaxia em relação aos PMNs controles. A expressão do TLR2 foi maior em monócitos de DB em relação aos controles, e a concentração de CD14s sérica, de origem monocitária, foi maior nos pacientes com DB ativa. Em conjunto, os resultados demonstram que PMNs de DB, isoladamente, não reagem exacerbadamente ao LTA, e suas respostas migratórias são estritamente dependentes de fatores estimulantes solúveis. / Expressions of toll-like receptor (TLR) 2, TLR4, CD14, CD114 and CD116 were assessed on polymorphonuclear (PMN) neutrophils and monocytes of patients with Behçets disease (BD). PMN chemotactic responses under different stimulations were also measured. The objective was to determine if BD PMN chemotaxis may be overstimulated by lipoteichoic acid (LTA) from gram-positive bacteria. Receptor expressions were measured by flow cytometry and PMN chemotaxis was assessed in a Boyden chamber. Only TLR2 expression was higher on monocytes of the BD group than in control group. On PMNs, however, TLR2 expression was similar in both groups and, when stimulated with LTA, BD PMN cells showed chemotactic responses similar to the controls. These cells only exhibited increased chemotaxis when incubated with plasma. In conclusion, isolated BD PMN did not overreact to LTA, and its hyperchemotaxis is strictly dependent on soluble stimulating factors
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Investigation on the multiscale multiphysics based approach to modelling and analysis of precision machining of metal matrix composites (MMCs) and its application perspectivesNiu, Zhichao January 2018 (has links)
Over the last two decades or so, metal matrix composites (MMCs) have been drawing the attention of the industry due to their potentials in fulfilling demands for high performance industrial materials, products and advanced engineering applications. On the other hand, the high precision machining is becoming one of the most effective methods for enabling these difficult-to-machine composites to be applied particularly in precision engineering. Therefore, in-depth scientific understanding of MMC precision machining is essential and much needed so as to fulfil the gap between fundamental issues in precision machining of MMCs and their industrial scale applications. This thesis focuses on development of a multiscale multiphysics based approach to investigating the machinability of particulate MMCs and the machining process optimisation. In order to investigate the surface generation in relation to the process variables, this PhD study covers the key fundamental issues including chip formation process, dynamic cutting force, cutting temperature partition and tool wear by means of combining modelling, simulation and experimental study. The chip formation mechanisms and the minimum chip thickness in precision machining of SiCp/Al and B4Cp/Al MMCs by using PCD tools are investigated through a holistic approach. Minimum chip thickness (MCT) value is firstly identified based on the modified mathematical model. The certain threshold of the uncut chip thickness, i.e. chips starting to form at this chip thickness point, is then established. The chip formation process including the matrix material breakage, particles fracture, debonding, sliding or removal and their interfacial interactions are further simulated using finite element analysis (FEA). The minimum chip thickness and chip formation simulations are evaluated and validated via well-designed experimental trials on a diamond turning machine. The chips and surface profiles formed under varied process variables in periodic material removals are inspected and measured in order to obtain a better understanding on MMC chip formation mechanisms. The improved dynamic cutting force model is developed based on the micro cutting mechanics involving the size effect, undeformed chip thickness effects and the influence of cutting parameters in the micro scale. Cutting process variables, particle form, size and volume fraction at different scales are taken into account in the modelling. The cutting force multiscale modelling is proposed to have a better understanding on the MMCs cutting mechanics and to predict the cutting force accurately. The cutting forces are modelled and analysed in three cutting regimes: elastic recovery zone, ploughing zone and shearing zone. A novel instantaneous chip thickness algorithm including real chip thickness and real tool trajectory is developed by taking account of the tool runout. Well-designed cutting trials are carried out under varied process variables to evaluate and validate the force model. In order to obtain the actual cutting forces accurately, transfer function technique is employed to compensate the measured cutting forces. The cutting force model is further applied to correlate the cutting tool wear and the prediction of the machined surface generation. Multiphysics coupled thermal-mechanical-tribological model and FE analysis are developed to investigate the cutting stress, cutting temperature, tool wear and their intrinsic relationships in MMCs precision machining process. Heat generation, heat transfer and cutting temperature partition in workpiece, chips and cutting tool are simulated. A modified tool wear rate model is proposed, tool wear characteristics, wear mechanisms and dominate tool wear are further investigated against the real machining process. Cutting tool wear is monitored and assessed offline after machining experiments. The experimental study on the machined surface generation is presented covering cutting force, tool wear, tool life, surface roughness and machining efficiency. Process optimisation is explored by considering the variation of cutting parameters, cutting tool conditions and workpiece materials in order to achieve the desired outcomes and machinability.
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Mechanisms of TLR signaling and cooperation in B lymphocytesBuchta, Claire Marie 01 May 2014 (has links)
B lymphocytes play important roles in antibody production, cytokine production, and antigen presentation to T cells. Ligation of Toll-like receptors (TLRs) on B cells stimulates cellular activation and B cell effector functions. Synergistic activation of other receptors such as CD40 or the B cell receptor (BCR) with TLR ligation further enhances B cell activation and effector functions. The tumor necrosis factor receptor associated factor (TRAF) family of proteins act as cytoplasmic signaling adaptor molecules and moderate downstream signaling from both the tumor necrosis factor receptor (TNFR) superfamily of proteins, including CD40, and the IL-1R/TLR superfamily of proteins.
To date, only TRAFs 3 and 6 have been shown to be involved in TLR signaling, with TRAF6 providing positive regulation and TRAF3 providing negative regulation of TLR signaling in B cells. Deficiency in another TRAF family member, TRAF5, has been implicated in the development of atherosclerosis, a disease developed in part due to TLR dysregulation. Here, we addressed the hypothesis that TRAF5 is a negative regulator of TLR signaling.
We found that TRAF5 negatively regulated TLR-mediated cytokine and antibody production in B lymphocytes. The enhanced cytokine production seen in TLR-stimulated TRAF5 KO B cells was not attributable to altered cellular survival or proliferation, but instead more cytokine was produced on a per-cell basis, likely due to enhanced MAPK pathways after TLR ligation. Additionally, TRAF5 deficiency did not dramatically affect cytokine production in TLR-stimulated bone marrow-derived macrophages or dendritic cells, suggesting that TRAF5 plays a greater role in TLR signaling in lymphoid versus myeloid cells. TRAF5 associated with the TLR signaling proteins MyD88 and TAB2, and negatively regulated the association of TAB2 with its binding partner TRAF6.
Furthermore, we manipulated B cell activation via ligation of various TLRs, CD40, and/or the BCR in order to activate the cells to effectively present antigen. Activated B cells pulsed with antigen served as an effective cellular vaccine and offered protection against both an infectious pathogen (Listeria monocytogenes) and a model of murine melanoma. We identified two candidate activation criteria for B cell vaccines (Bvacs): stimulation through the BCR and TLR7, and stimulation through CD40 and TLR4. Additionally, we found that high IL-6 production by the activated Bvac was essential for inducing optimal CD8+ T cell memory. These B cell activation protocols offer significant advantages over those currently being tested for clinical use. Understanding B cell activation through TLRs is a critical step in developing new therapies against cancer and infectious disease.
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Neutrophil priming and host inflammation: The roles of NOX2 and toll-like receptorsWhitmore, Laura Christine 01 May 2014 (has links)
Neutrophils, essential innate immune cells, recognize danger signals through receptors on their surface. Upon receptor ligation, neutrophils may undergo priming, a process involving limited reactive oxygen species (ROS) generation and partial degranulation. Priming facilitates neutrophil migration and prepares the cell for an enhanced response to a secondary stimulus, including a spike in ROS generation by NADPH oxidase 2 (NOX2). It is well established that NOX2-derived oxidants are involved in pathogen killing and that off-target effects can cause host tissue damage; however, several lines of recent evidence also support an anti-inflammatory function for NOX2 oxidants. First, patients with chronic granulomatous disease exhibit sterile inflammatory phenomena. Second, neutrophils lacking NOX2 function (genetically or pharmacologically) have an inflammatory phenotype under resting conditions. Finally, NOX2-deficient mice exhibit enhanced localized inflammation in several disease models. The goals of this thesis were to investigate an anti-inflammatory function for NOX2 during systemic inflammation and to further elucidate mechanisms of neutrophil priming, with particular focus on priming through Toll-like receptor 2 (TLR2). Using a murine model of sterile systemic inflammatory response syndrome (SIRS), we observed that NOX2-deficient mice had dramatically increased mortality compared to WT mice. While both genotypes developed SIRS, characterized by hypothermia, hypotension, and leukopenia, the WT mice recovered within 48 h whereas the NOX2-deficient mice did not. Moreover, NOX2 function limited the extent of pulmonary pathology as significant lung injury was noted in the NOX2-deficient mice compared to the WT mice. Plasma analysis revealed that several inflammatory cytokines were persistently elevated in the NOX2-deficient mice, likely contributing to the ongoing inflammatory response. One of the complications seen in human SIRS patients is the development of multiple organ dysfunction syndrome (MODS). Thus, we next investigated the role of NOX2 in the progression from SIRS to MODS. Cellular analysis revealed continued neutrophil recruitment to the peritoneum and lungs of the NOX2-deficient mice and altered activation states of both neutrophils and macrophages. Histology showed multiple organ pathology indicative of MODS in the NOX2-deficient mice, and several inflammatory cytokines were elevated in lungs of the NOX2-deficient mice. Overall, these data suggest that NOX2 function protects against the development of MODS and is required for normal resolution of systemic inflammation. As we utilized a TLR2/6 agonist (zymosan) to induce SIRS in our in vivo model, we wanted to investigate neutrophil priming through TLR2 in an in vitro model. Notably, we determined that a TLR2/6 agonist, FSL-1, primed neutrophils from all donors to a similar extent, evidenced by direct and primed ROS generation, MAPK signaling, limited degranulation, and cytokine secretion. Surprisingly, Pam3CSK4, a TLR2/1 agonist, primed neutrophils from a subset of donors to a much greater extent than neutrophils from other donors. We demonstrated that the different neutrophil priming responses were the consequence of a common TLR1 polymorphism. In sum, the data presented here significantly advance our understanding of the roles of NOX2 and TLR2 signaling in host inflammation and neutrophil priming. This research could advance the development of therapies that target pathogenic neutrophil subsets in inflammatory conditions without compromising innate immune function
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Regulation of TLR-induced macrophage responses by cytoskeleton-associated phosphoproteins / Regulation der Antwort von Makrophagen auf TLR-Stimulation durch Zytoskelett-assoziierte PhosphoproteineWenzel, Jens January 2014 (has links) (PDF)
Toll-like receptors (TLR) are pattern recognition receptors (PRR) by which macrophages (MØ) sense pathogen-associated molecular patterns (PAMPs). The recognition of lipopolysaccharide (LPS), the PAMP of gram negative bacteria, by TLR4 triggers signaling cascades and leads to the pro-inflammatory activation of the cells. A recent quantitative and kinetic analysis of the phosphoproteome of LPS-activated primary macrophages highlighted the cytoskeleton as a cell compartment with an enriched protein phosphorylation. In total 44 cytoskeleton-associated proteins were regulated by this post-translational modification and thus might be involved in the control and regulation of key macrophage functions like spreading, motility and phagocytosis.
To investigate the control of cytoskeleton-associated cell functions by TLR4 activation, we first developed a method to quantitatively measure the spreading response of bone marrow MØ after stimulation with LPS. Fluorescence microscopy was used for cell imaging and visualisation of the MØ contact area. In collaboration with the Fraunhofer Institute Erlangen, we developed and validated a software tool for the semi-automated segmentation and quantitation of MØ fluorescence microscopy data, which allowed fast, robust and objective image analysis. Using this method, we observed that LPS caused time-dependent spreading, which was detectable after 1-2 h and maximal after 24 h. Next, the impact of genetic or pharmacological inhibition of known TLR signaling components was investigated. Deficiency in the adapter protein MYD88 strongly reduced spreading activity at the late time points, but had no impact early after LPS-stimulation. A similar effect was observed upon pharmacological inhibition of ERK1/2 signaling, indicating that ERK1/2 mediates MYD88-dependent MØ spreading. In contrast, MØ lacking the MAPK p38 were impaired in the initial spreading response but responded normally 8-24 h after stimulation. The genetic deletion of the MAPK phosphatases DUSP1 and DUSP16 resulted in impaired late spreading, corroborating the essential role for functional MAPK signaling in TLR4-driven MØ spreading.
To identify the contribution of other cytoskeletal phosphoproteins to MØ spreading, siRNA knockdown of selected candidate genes in primary murine MØ was employed and combined with automated quantitative image analysis. These experiments revealed a functional role for the Myosins MYO1e and MYO1f in MØ spreading. These motor proteins are strongly phosphorylated in LPS-activated MØ. Because of their ability to simultaneously bind to actin filaments and cell membrane or other proteins, we investigated their role in phagocytosis, cytokine production and antigen presentation. Phagocytosis and killing of bacteria were not affected in Myo1e-/- macrophages. However, MYO1e plays a role in chemokine secretion and antigen presentation processes. MCP1 (CCL2) release was selectively increased in Myo1e-deficient MØ and dendritic cells (DC), while cytokine secretion was unaffected. Furthermore, macrophages and DCs lacking MYO1e showed lower levels of MHC-II on the cell surface. However, mRNA levels of CCL2 and of MHC-II were unaltered. These data suggest a role for MYO1e in the transport of selected chemokines and of MHC-II molecules to the cell surface. MHC-II-restricted antigen presentation assays revealed an impaired capacity of macrophages and DC lacking MYO1e to stimulate antigen-specific T cells, suggesting that the reduced MHC-II expression is functionally relevant.
Taken together, in this study first a quantitative image analysis method was developed which allows the unbiased, robust and efficient investigation of the macrophage spreading response. Combination of this method with siRNA knockdown of selected cytoskeleton-associated phosphoproteins led to the identification of MYO1e and MYO1f as regulators of macrophage spreading. Furthermore, we identified MYO1e in MØ and DC to be essential for the intracellular transport of CCL2 and MHC-II to the cell surface and for optimal stimulation of antigen-specific CD4 T cells. / Toll-like Rezeptoren (TLR) sind Mustererkennungsrezeptoren (PRR) durch die Makrophagen (MØ) pathogen-assoziierte molekulare Muster (PAMPs) erkennen. Die Erkennung von Lipopolysacchariden (LPS), dem PAMP gramnegativer Bakterien, durch TLR4 löst Signalkaskaden aus, die zu einer pro-inflammatorischen Aktivierung der Zellen führen. Eine quantitative und kinetische Analyse des Phosphoproteoms LPS-aktivierter primärer Makrophagen identifizierte das Zytoskelett als ein Zellkompartiment mit gesteigerter Proteinphosphorylierung. Insgesamt wurden 44 Zytoskelett-assoziierte Proteine identifiziert, die durch diese post-translationale Modifikation reguliert wurden und demzufolge an der Regulation wichtiger Zellfunktionen von Makrophagen wie Spreading, Motilität und Phagozytose beteiligt sein könnten.
Um die Kontrolle Zytoskelett-vermittelter Zellfunktionen nach TLR4 Aktivierung zu untersuchen, entwickelten wir zunächst eine Methode zur quantitativen Messung der Spreadingantwort von Knochenmarksmakrophagen nach LPS Stimulation. Die Visualisierung der Zellen sowie ihrer Kontaktfläche erfolgte hierbei mittels Fluoreszenzmikroskopie. Für eine schnelle, robuste und objektive Analyse der Fluoreszenzaufnahmen entwickelten und validierten wir in Kollaboration mit dem Fraunhofer Institut in Erlangen eine Software zur halbautomatischen Segmentierung und Quantifizierung der Kontaktfläche. Unter Verwendung dieser Methode konnte eine zeitabhängige LPS-induzierte Zunahme der Zellkontaktfläche beobachtet werden, die nach 1-2 Stunden detektierbar war und ein Maximum nach
24 Stunden erreichte. Durch den Einsatz pharmakologischer Inhibitoren sowie genetisch veränderter Zellen wurde anschließend der Einfluss bekannter TLR4-Signalwegkomponenten untersucht. Die genetische Defizienz des Adapterproteins MYD88 führte hierbei zu einer stark reduzierten Spreadingaktivität der Zellen während der späten LPS Stimulationsphase, wohingegen das initiale Spreading nicht beeinflusst wurde. Ein vergleichbarer Effekt konnte unter Verwendung eines pharmakologischen Inhibitors zur Hemmung des ERK1/2 Signalweges identifiziert werden. Diese Beobachtungen deuten darauf hin, dass ERK1/2 für die Weiterleitung des MYD88 vermittelten Spreading notwendig ist. Im Gegensatz dazu wurde in p38-defizienten Makrophagen ein beeinträchtigtes initiales Spreading beobachtet, wohingegen das späte Spreading nach 8 – 24 Stunden nicht beeinflusst war. Die genetische Deletion der MAPK Phosphatasen DUSP1 und DUSP16 resultierte ebenfalls in einer Minderung des späten Spreadings, ebenfalls ein Hinweis auf die essentielle Rolle funktioneller MAPK Signalwege.
Um die Beteiligung weiter Zytoskelett-Phosphoproteine am Zellspreading zu identifizieren, wurde die Expression ausgewählter Kandidatengene in primären Makrophagen mittels spezifischer siRNA unterdrückt und das Zellspreading mit Hilfe der entwickelten Software quantifiziert. Diese Versuche zeigten eine funktionelle Rolle der Myosine MYO1e und MYO1f. Diese Motorproteine weisen ebenfalls eine starke Phosphorylierung nach LPS Stimulation auf. Aufgrund ihrer Eigenschaft simultan mit Aktinfilamenten und Zellmembranen sowie anderen Proteinen zu interagieren, untersuchten wir ihre Rolle während der Phagozytose, Zytokinfreisetzung und Antigenpräsentation. Obwohl Myo1e defiziente Makrophagen keine Beeinträchtigung der Phagozytose oder Abtötung von Bakterien aufwiesen, spielte das Motorprotein eine wichtige Rolle in der Chemokinfreisetzung und Antigenpräsentation. Interessanterweise war die Sekretion des Chemokins MCP1 (CCL2) in Myo1e-defizienten Makrophagen und dendritischen Zellen (DC) selektiv erhöht, während die Zytokinfreisetzung unbeeinträchtigt war. Des Weiteren wiesen Myo1e KO Makrophagen und DC eine reduzierte MHC-II Oberflächen-Expression auf, obwohl die MHC-II als auch die CCL2 Transkription auf mRNA Ebene nicht beeinflusst war. Diese Daten legen nahe, dass MYO1e während des Transports bestimmter Chemokine, sowie von MHC-II zur Zelloberfläche eine wichtige Rolle spielt. Zudem zeigten Myo1e KO Makrophagen und DC in einem MHC-II-abhängigen Antigenpräsentationsassay eine abgeschwächte Fähigkeit zur Antigen-spezifischen T-Zell Aktivierung, was die funktionelle Relevanz der reduzierten Expression von MHC-II nahelegt.
Zusammenfassend wurde in dieser Studie zunächst eine Methode zur quantitativen Bildanalyse entwickelt, welche eine unvoreingenommene, robuste und effiziente Untersuchung des Spreadings von Makrophagen erlaubte. Die Kombination dieser Methode mit dem spezifischen siRNA Knockdown ausgewählter Zytoskelett-assoziierter Phosphoproteine führte zur Identifizierung von MYO1e und MYO1f als wichtige Regulatoren dieser Zellfunktion. Darüber hinaus konnte in Makrophagen und DC eine essentielle Rolle für MYO1e im intrazellulären Transport von CCL2 und MHC-II an die Zelloberfläche identifiziert werden, sowie dessen Notwendigkeit für eine vollständige Aktivierung antigen-spezifischer CD4 T Zellen.
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