Na gestação, a expressão das moléculas HLA-E ocorre principalmente nos trofoblastos extravilosos da placenta e estão associados com a inibição do sistema imune resultando na imunotolerância ao feto. Esta inibição da resposta imunológica pode ser benéfica em condições fisiológicas como a gestação, mas prejudicial na vigência de tumores e infecções. Nessa condição, tem sido descrito que o HIV infecta células trofoblásticas e utiliza a molécula HLA-E como mecanismo de escape, aumentando sua expressão para inibir a atuação de células citotóxicas. Entretanto, apesar da continua exposição viral, o fato de a maioria dos recém-nascidos não serem verticalmente infectados sugere a existência de barreiras naturalmente protetoras que previnem a transmissão materno-infantil (TMI) do HIV. Frente à escassez de estudos avaliando as moléculas HLA-E na interação imunológica materno-fetal, mais especificamente na infecção do HIV-1, e à importância que este tema tem perante a prevenção da TMI, este projeto teve o objetivo de avaliar a expressão de HLA-E em tecidos placentários de mulheres infectadas ou não pelo HIV-1. Trata-se de um estudo transversal, ao qual foram submetidos ao processamento imunohistoquímico tecido placentário parafinado de 106 mulheres infectadas pelo HIV-1 e de 100 mulheres não infectadas. A expressão da molécula HLA-E foi analisada por um patologista e classificada qualitativamente como leve, moderada ou intensa e quantitativamente como negativa (<5% de marcação), 1+ (6-25%), 2+ (26-50%), 3+ (51-75%) e 4+ (>75%). Os resultados sociodemográficos apontam que as gestantes infectadas pelo HIV-1 eram mulheres não vivendo em união conjugal (p<0,0001) e com baixa escolaridade (p=0,0004). Na análise imunohistoquímica, ficou evidente que a expressão do HLA-E ocorreu principalmente na região do trofoblasto extraviloso e em células endoteliais, mas não nas vilosidades da placenta. Os testes de estatísticos utilizados foram Qui-quadrado e exato de Fisher. Os resultados mostraram que em mulheres portadoras da infecção pelo HIV-1, a expressão das moléculas HLA-E estava significantemente menor entre as que apresentavam carga viral indetectável (p=0,03), e não houve associação entre a expressão das moléculas HLA-E com outras condições como presença ou não da infecção pelo HIV, ocorrência de aborto em gestações anteriores, número de células CD4+ e terapia antirretroviral utilizada. Estes resultados sugerem que o HIV-1 induz a expressão de HLA-E em células placentárias, podendo ser utilizado como mecanismo de escape do sistema imunológico. Entretanto outros trabalhos com polimorfismos genéticos e microRNAs são necessários para ampliar o conhecimento sobre a molécula, sua atuação na infecção pelo HIV- 1 e seu papel na TMI / During pregnancy, the expression of HLA -E molecules occurs mainly in extravillous trophoblasts of the placenta and are associated with the inhibition of the immune system resulting in immune tolerance to the fetus. This inhibition of the immune response may be beneficial in physiological conditions such as pregnancy, but harmful in the presence of tumors and infections. In this condition, it has been reported that HIV infects trophoblast cells and uses the HLA -E as an escape mechanism, increasing its expression to inhibit the activity of cytotoxic cells. However, despite the continued viral exposure, the fact that most newborns are not vertically infected suggests the existence of naturally protective barriers that prevent mother to child transmission (MTCT) of HIV. Due to the lack of studies evaluating HLA-E in the maternal-fetal immunological interaction, specifically in HIV-1 infection, and the importance that this topic has towards the prevention of MTCT, this project aimed to evaluate the expression of HLA-E in placental tissues of infected women or not by HIV-1. It is a cross sectional study, which were submitted to immunohistochemical processing the paraffin- embedded placental tissue of 106 women infected with HIV-1 and 100 uninfected women. The expression of HLA-E was analyzed by a pathologist and classified qualitatively as mild, moderate or severe and quantitatively as negative (<5% markup), 1+ (6-25 %), 2+ (26-50%), 3+ (51-75%) and 4+ (>75%). The sociodemographic results indicate that pregnant women infected with HIV-1 were not women living in marital union (p<0,0001) and have lower education (p=0,0004). In immunohistochemical analysis, it became evident that the expression of HLA-E occurred mainly in the extravillous trophoblast and endothelial cells, but not in the villi of the placenta. The statistical tests used were chi-square and Fisher exact tests. The results showed that in women with the HIV-1 infection, the expression of HLA-E was significantly lower among those who had undetectable viral load (p=0,03), and there was no association between the expression of HLA- E with other conditions such as the presence or absence of HIV infection, miscarriage in previous pregnancies, number of CD4+ cells and antiretroviral therapy used. These results suggest that HIV-1 induces the expression of HLA-E placental cells, using it as a mechanism to escape the immune system. However other studies with genetic polymorphisms and microRNAs are needed to increase knowledge about the molecule, its role in HIV-1 infeccion and its role in MTCT

Pseudomonas aeruginosa é uma gamma-proteobacteria ubíqua, sendo a principal causa de infecção hospitalar dentre todos os patógenos relacionados com pneumonia em UTI. A defesa do hospedeiro se dá por vários mecanismos como a liberação, por fagócitos, de espécies reativas de oxigênio, como o ânion superóxido (O2?-), peróxido de hidrogênio (H2O2) e o radical hidroxila (OH?) para combater o patógeno. LsfA pertence à família das peroxirredoxinas (Prx) e ao sub-grupo de Prxs que contém somente uma cisteína catalítica (denominadas 1-Cys Prx). Prxs são enzimas capazes de remover peróxidos (incluindo peroxinitrito) em velocidades muito elevadas. Além disso, LsfA está relacionada a patogenicidade de P. aeruginosa. Dentro desse contexto, o objetivo do presente trabalho é a caracterização bioquímica e estrutural de LsfA; que pode possibilitar a identificação de inibidores dessa enzima antioxidante. Por outro lado, caracterizando cineticamente reações de oxido-redução de LsfA e caracterizando seus mecanismos de ação, podemos identificar seus substratos biológicos. Dessa maneira, utilizando diferentes técnicas, determinamos as constantes de segunda ordem de LsfA com H2O2 (na ordem de 107 M -1.s -1); para terc-butilhidroperóxido (na ordem de 106 M-1.s-1) e peroxinitrito (na ordem de 107 M-1.s-1). A redução de LsfA por ascorbato foi descrita previamente por nosso grupo (na ordem de 103 M-1.s-1); e aqui apresentamos dados preliminares sobre a redução dessa 1-Cys Prx por GSH. Além disso, fomos capazes de determinar a estrutura cristalográfica de LsfA em sua forma oxidada e superoxidada, com resolução de 2.6 e 2.0 ? respectivamente; que, como esperado, se apresentou no estado dimérico, em ambos os casos. Descrevemos aqui características sobre a estrutura do sítio ativo de LsfA, que apresenta mais eletronegativo, com a cisteína peroxidásica desprotonada, e mais hidrofóbico. Na estrutura de LsfA superoxidada, observamos a co-cristalização dessa enzima com uma molécula de polietileno glicol que pode estar mimetizando um substrato. Portanto, esses estudos levantaram importantes informações estruturais e bioquímicas de uma enzima antioxidante envolvida com a virulência de P. aeruginosa / Pseudomonas aeruginosa is a ubiquous gamma-proteobacteria that is the main cause of hospitalar infections among all pathogens related with pneumonia. Host defenses against pathogens are mainly by phagocytes, which releases reactive oxygen species, such as superoxide (O2?-), hydrogen peroxide (H2O2) and hydroxyl radical (OH?) to fight against pathogen. LsfA belongs to peroxiredoxins (Prx) family; and to the 1-Cys Prx sub-group (Prx6 sub-family) that possess only one catalytic cysteine. Prx are enzymes can remove peroxides with extremely high efficiency. LsfA was already related with P. aeruginosa virulence. So, the aim of the present work is the structural and biochemical characterization of LsfA, which may enable the discovery of inhibitors. Furthermore, the investigation of the kinetics and the mechanism of catalysis of LsfA may give insights on the chemical nature of its biological substrates. Therefore, using different techniques; the second order rate constants of LsfA with H2O2 (107 M -1.s -1), tert-butylhydroperoxide (106 M -1.s -1) and peroxynitrite (107 M -1.s -1) were determined. Our group has already determined the rate constant between ascorbate and LsfA (103 M -1.s -1) and preliminary data on the reduction of this 1-Cys Prx by glutathione is described. Furthermore, two crystallographic structures of LsfA were elucidated in distinct oxidative states (sulfenic and sulfonic acid in the CP), both in the dimeric state; at 2.6 and 2.0 ? resolution respectively. Features in the LsfA active site are also described here, such as poor exposure to the solvent. In the LsfA crystal structure where Cp is hyperoxidized to sulfinic acid, we observed the presence of an electronic density compatible with a PEG molecule that might be mimicking one of the possible substrates. Therefore, relevant structural and biochemical information were gained with our studies about an antioxidant enzyme involved with P aeruginosa virulence

I föreliggande uppsats undersöks IKT (informations- och kommunikationsteknik) i gymnasieskolans svenskundervisning. Studien har utförts bland annat genom kvalitativa intervjuer av 5 svensklärare på fyra olika gymnasieskolor i Småland. Författarna försöker ge svar på vilka motiv som ligger bakom den pågående förändringen mot ett mer digitaliserat svenskämne, vad och hur dessa förändringar rent konkret ser ut samt om svensk-undervisningen blir bättre eller sämre av IKT. Dessutom har vi försökt ta reda på och besvara hur svensklärares attityder till förändringen ser ut samt huruvida skolornas 1:1-satsning med en dator per elev har betydelse för förändringen mot en IKT-baserad svenskundervisning. De huvudsakliga resultaten visar att det finns olika motiv till integrerandet av IKT i svenskämnet på gymnasiet. Vi ser tendenser till något som kan sägas vara ett slags socialiserat behov hos dagens unga där de nya digitala, visuella medierna ser ut att påverka och förändra den unga generationens sätt att hantera sitt lärande. Användandet av IKT i svenskundervisningen verkar leda till lite mer aktiva och motiverade elever och en anledning kan vara ett hos läraren elevcentrerat, individanpassat förhållningssätt gentemot sina elever. En annan orsak kan vara att teknikens hjälp bland annat ger mer tid för lärarstöd under lektionerna. Dessutom kan vi i studien urskilja att skolledningens inställning är direkt avgörande för hur IKT-utvecklingen på skolan fortlöper och att deras inställning speglas i svenskläraren, samt att 1:1-satsningar i initialskeenden ofta är problematiska men att ledningsgruppen är avgörande för vilken riktning den framtida utvecklingen tar.

The correct polarity of a neuron underlies its ability to integrate precise circuitries in the nervous system. The goal of my thesis was to investigate the pathways that establish and maintain neuron polarity/orientation in vivo. To accomplish this, I used bipolar VC4/5 motor neurons, which innervate the C. elegans egg-laying musculature, as a model system. Vulval proximal VC4/5 neurons extend axons in the left-right (LR) orientation, around the vulva; whereas vulval distal VC1-3,6 neurons extend axons along the anterior-posterior (AP) axis. A previous study showed that vang-1, a core planar cell polarity (PCP) gene, suppresses AP axon growth in VC4/5 neurons. In order to identify new components of this pathway we performed genetic screens for mutants with abnormal VC4/5 polarity/morphology. We isolated and mapped alleles of farnesyl transferase b (fntb-1) and of core PCP genes, prickle- 1 (prkl-1) and dishevelled-1 (dsh-1); all of which display tripolar VC4/5 neurons, similar to vang-1 lof. In prkl-1 and dsh-1 mutants, primary LR and ectopic AP VC4/5 axons are born simultaneously, suggesting an early role in establishing polarity. In addition, prkl-1 and dsh-1 act persistently to maintain neuron morphology/orientation. Genetic analysis of double mutants suggests that prkl-1 interacts with vang-1 in a common PCP pathway to prevent AP axon growth, while dsh-1 also acts in a parallel pathway. Furthermore, prkl-1 functions cell autonomously in neurons, whereas dsh-1 acts both cell autonomously and cell nonautonomously in epithelial cells. Notably, prkl-1 overexpression results in unipolar VC4/5 neurons, in a dose-dependent manner. In contrast, dsh-1 overexpression in VC4/5 neurons results in a lof phenotype, similar to vang-1 lof and overexpression phenotype. Remarkably, prkl-1 overexpression restores normal VC4/5 polarity in dsh-1 and vang-1 mutants, which is suggestive of a downstream role for prkl-1. Both PRKL-1 and DSH-1 are expressed in iii uniformly distributed puncta at the plasma membrane of VC4/5, similar to VANG-1; suggesting that their asymmetric distribution is not critical for neuron polarity. Furthermore, we found that the vulva epithelium induces prkl-1 expression in VC4/5; indicating a functional relationship between the egg-laying organ and neuron morphology. Moreover, a structure-function analysis of PRKL-1 revealed that the conserved PET domain and the Cterminal region are crucial to prevent AP axon growth, whereas the three LIM domains are dispensable for this role. In addition, we showed that dsh-1 also regulates the morphology of AP-oriented PDE neurons. dsh-1 promotes the formation of PDE posterior axons, contrary to its function in VC5 neurons; which indicates a context-dependent role for dsh-1 in neuronal polarity. Altogether, this thesis implicates the PCP signalling pathway in a previously unknown role, in establishing and maintaining neuronal polarity, by controlling AP axon growth in response to organ-derived polarizing cues.

KCN-1 is known to reduce tumor growth 6-fold in mice implanted with LN229 glioma cells. Although this inhibitor is effective, the mechanism of action for KCN-1 is not well understood. Based on preliminary studies, KCN-1 reduces tumor growth by disrupting the HIF 1 (hypoxia-induced factor-1) pathway. The binding target of KCN-1 needs to be investigated in order to develop KCN-1 or its analogs for therapeutic applications. In this research, a molecule was designed and synthesized for the identification of the binding target of KCN-1. Specifically, this molecule contains the inhibitor (KCN-1), a photocleavable linker, beads, and the affinity label (L DOPA). When UV light shines on the linker, the trans-alkene isomerizes to cis-alkene and undergoes intramolecular ring-closing reaction, which helps cleave the immobilized bead from the linker. The immobilized bead is used to separate the binding fragment attached to the photocleavable linker from the solution after enzyme digestion. The affinity label (L-DOPA) reacts with a nucleophile from the binding target and creates a covalent bond. If the design is successful, this method is able to analyze the mass of the peptide sequence and determine the binding target of KCN-1.

La familia de tumores del sarcoma de Ewing (ESFT) incluye un grupo heterogéneo de neoplasias caracterizadas por la presencia de células redondas de pequeño tamaño con mínima evidencia morfológica de diferenciación. ESFT es el segundo tumor óseo más frecuente, afectando fundamentalmente a niños y adolescentes. A pesar del uso de terapias agresivas combinando quimioterapia, radioterapia y cirugía, la supervivencia de pacientes con metástasis es aproximadamente del 30%, mientras que en ausencia de enfermedad metastásica alcanza valores del 70 %. Debido a esto, son necesarias nuevas aproximaciones terapéuticas dirigidas a reducir la morbilidad relacionada con el tratamiento y a mejorar el índice de supervivencia. Afortunadamente, los ESFT presentan una diana molecular perfecta que resulta de la translocación cromosómica t(11;22)(q24;q12), que ocurre en aproximadamente un 95% de los casos, e involucra al gen EWS y a un miembro de la familia de factores de transcripción ETS, fundamentalmente FLI-1 o ERG. La translocación más común genera la formación de la oncoproteína de fusión EWS/FLI-1 que actúa como factor de transcripción y regula de forma aberrante la expresión de genes diana, favoreciendo el proceso tumorigénico. De esta forma la inactivación de la proteína de fusión EWS/FLI-1 se convierte en una estrategia atractiva, no sólo debido su papel fundamental en la tumorigénesis de ESFT, sino también por su especificidad en células transformadas. En este estudio se evaluaron diferentes estrategias dirigidas a reducir los niveles expresión de EWS/FLI-1 in vitro e in vivo. La primera estrategia utilizada para inhibir los niveles de expresión de la proteína de fusión EWS/FLI-1 se basó en el uso de la rapamicina, un antifúngico e inmunosupresor con propiedades anticancerígenas. La rapamicina inhibió la vía de señalización de mTOR/p70s6K y la proliferación de células de ESFT. Estos resultados sugirieron el uso de esta droga como agente citostático en el tratamiento de este tipo de tumores. La segunda aproximación terapéutica se basó en la inhibición simultánea de EWS/FLI-1 a nivel transcripcional y post-transcripcional. El tratamiento combinado de oligonucleótidos antisentido y rapamicina resultó en un incremento en la muerte de células de ESFT, a través de un proceso que involucra la restauración de la vía de señalización pro-apoptótica del TGF?1/TGF?-RII. In vivo, la administración del tratamiento combinado causó un retraso en el crecimiento de los tumores. Estos datos aportan la base para una mayor exploración del potencial del tratamiento combinado como una nueva estrategia en el tratamiento de este tipo de tumores. Los análisis moleculares mostraron que ESFT presentan alteraciones en proteínas reguladoras del ciclo celular, incluyendo la sobreexpresión de proteínas quinasas ciclina-dependientes (CDK2) y la pérdida o baja expresión de sus inhibidores. Basándonos en ésto, la tercera estrategia se basó en la reversión de alguna de estas alteraciones, mediante el uso de la roscovitina, un potente inhibidor de la actividad quinasa de las CDKs. El tratamiento con roscovitina resultó en un incremento de los niveles de apoptosis en células de ESFT in vitro e in vivo, por un mecanismo dependiente de la activación de caspasas. Estos resultados sugieren que la roscovitina puede ser un agente terapéutico efectivo en el tratamiento de ESFT, sola o en combinación con otras drogas potencialmente sinérgicas. Con el objetivo de identificar y evaluar nuevas proteínas que interactúan con EWS/FLI-1 y contribuir de esta forma a la comprensión de los mecanismos de transformación, identificamos como una diana transcripcional directa de EWS/FLI-1 a la caveolina-1, proteína involucrada en gran variedad de procesos celulares, tales como endocitosis, homeostasis del colesterol, transducción de señales y tumorigénesis. Los resultados de este trabajo mostraron que caveolina-1 juega un papel determinante en la tumorigénesis de células de ESFT y su inhibición podría permitir el desarrollo de nuevas estrategias terapéuticas moleculares dirigidas a mejorar el tratamiento de los pacientes de ESFT.

L'angiogenèse, soit la formation de nouveaux vaisseaux sanguins à partir de capillaires préexistants, est un processus essentiel au développement et à la croissance des tumeurs. Bon nombre de protéines ont été étudiées afin d'élucider les voies de signalisation impliquées dans l'angiogenèse, dont la métalloprotéase membranaire de type 1 (MT1-MMP). Cette protéine est reconnue pour jouer un rôle crucial dans la migration cellulaire, détruisant la matrice extracellulaire pour permettre aux cellules de migrer et ce, dans différents types cellulaires. Cependant, les mécanismes impliqués dans le contrôle de son activité demeurent incompris. Dans la présente étude, nous avons observé, en utilisant des procédures d'immunoprécipitation et de microscopie confocale, que la stimulation des cellules endothéliales de veines ombilicales humaines (HUVECs) avec la sphingosine-1-phosphate (S1P), un lipide qui induit la migration des cellules endothéliales (CEs), provoque le transfert de la MT1-MMP à la périphérie cellulaire et son association avec p130Cas (Crk-associated substrate). p130Cas est une protéine d'arrimage impliquée dans les voies de signalisation de la motilité cellulaire et est également reconnue pour se relocaliser dans des replis membranaires suite à une stimulation à la S1P. Ces résultats suggèrent fortement que l'identification du complexe MT1-MMP/p130Cas au front principal des CEs migrantes pourrait être un mécanisme efficace par lequel la protéolyse péricellulaire est reliée à l'activation des voies de signalisation, permettant la migration coordonnée des CEs au cours de l'angiogenèse. ______________________________________________________________________________ MOTS-CLÉS DE L’AUTEUR : Angiogenèse, MT1-MMP, p130Cas, Migration, Sphingosine 1-phosphate.

No description available.

Pseudomonas aeruginosa-induced pneumonia is serious problem that results in severe inflammation response and high mortality in the host. Interleukin-1£] (IL-1£]) is one of the major extracellular proinflammatory cytokines thought to be involved in many acute and chronic lung diseases. To investigate the role of caspase-1, IL-1£] and macrophage inflammatory protein-2 (MIP-2) in P. aeruginosa pneumonia induced lung damage, C57BL/6 (WT) and CASP-1-/- mice were subjected to pneumonia induced by intratracheal injection of P. aeruginosa. The lung permeability, bacterial content in blood and lung, lung myeloperoxidase (MPO) activity, total cell counts and protein in bronchoalveolar lavage fluid (BALF), NF-£eB activation as well as expression of IL-1£] and MIP-2 were assayed at 8 hr after P. aeruginosa injection. The IL-1£] inhibitor, anakinra, was also used to evaluate the role of IL-1£]. P. aeruginosa injection increased the lung permeability, lung MPO activity, bacterial counts in blood, total cell counts and protein in BALF, NF-£eB activation and expression of IL-1£] and MIP-2 in WT mice; and these increases were all decreased by administration of anakinra in WT mice or in CASP-1-/- mice. Furthermore, the lung MPO activity, total protein in BALF and expression of IL-1£] and MIP-2 were decreased in CASP-1-/- ¡÷ WT but not in WT ¡÷ CASP-1-/- chimeric mice, suggesting that pneumonia induced lung damage and IL-1£] and MIP-2 expressions depend on caspase-1 signaling of the resident cells.

IL-1 is an essential pro-inflammatory factor in inflammation response. The effect of IL-1 is through binding to the IL-1 receptor that triggers the following signal transduction pathway. To study the role of IL-1 receptor-mediated signal pathway in inflammatory response, injecting P. aeruginosa into trachea of wild-type (WT) and type-1 IL-1 receptor knock-out (IL-1R1-/-) mice was used as the experimental model. Injecting bacterium into trachea of mice will induce pneumonia which increases accumulation of neutrophils, production of nitric oxide, expression of intercellular adhesion molecule-1 as well as many kinds of cytokines and causes the lung damage. The pneumonia-induced lung damage and inflammation at 24 hr after injecting P. aeruginosa into trachea were more severe in knock-out than in WT mice, as demonstrated by increases in extravasations of Evans blue dye (EBD), myeloperoxidase (MPO) activity, expression of iNOS, IL-1 beta and ICAM-1, and higher mortality of knock-out mice. The cause of the high mortality in knock-out mice was further investigated by culturing the lung and blood samples for bacterial counts. The bacterial counts of lung and blood of IL-1R1-/- mice were all higher than that of WT mice in 8 to 24 hr after injection of bacterium. Finally, chimeric mice (WT ¡÷ WT, IL1R1-/- ¡÷IL1R1-/-, WT ¡÷ IL1R1-/-, IL1R1-/- ¡÷ WT) were generated and used to determine the role of PMN cells of blood. Suggesting that increased amounts of bacteria in lung and blood is related to the higher mortality in knock-out mice and the type-1 IL-1 receptor is essential for mice to against pneumonia in this model.