<p>CD4+ T cells play a crucial in the adaptive immune system. They function as the central hub to orchestrate the rest of immunity: CD4+ T cells are essential governing machinery in antibacterial and antiviral responses by facilitating B cell affinity maturation and coordinating the innate and adaptive immune systems to boost the overall immune outcome; on the contrary, hyperactivation of the inflammatory lineages of CD4+ T cells, as well as the impairments of suppressive CD4+ regulatory T cells, are the etiology of various autoimmunity and inflammatory diseases. The broad role of CD4+ T cells in both physiological and pathological contexts prompted me to explore the modulation of CD4+ T cells on the molecular level.</p><p>microRNAs (miRNAs) are small RNA molecules capable of regulating gene expression post-transcriptionally. miRNAs have been shown to exert substantial regulatory effects on CD4+ T cell activation, differentiation and helper function. Specifically, my lab has previously established the function of the miR-17-92 cluster in Th1 differentiation and anti-tumor responses. Here, I further analyzed the role of this miRNA cluster in Th17 differentiation, specifically, in the context of autoimmune diseases. Using both gain- and loss-of-function approaches, I demonstrated that miRNAs in miR-17-92, specifically, miR-17 and miR-19b in this cluster, is a crucial promoter of Th17 differentiation. Consequently, loss of miR-17-92 expression in T cells mitigated the progression of experimental autoimmune encephalomyelitis and T cell-induced colitis. In combination with my previous data, the molecular dissection of this cluster establishes that miR-19b and miR-17 play a comprehensive role in promoting multiple aspects of inflammatory T cell responses, which underscore them as potential targets for oligonucleotide-based therapy in treating autoimmune diseases. </p><p>To systematically study miRNA regulation in effector CD4+ T cells, I devised a large-scale miRNAome profiling to track in vivo miRNA changes in antigen-specific CD4+ T cells activated by Listeria challenge. From this screening, I identified that miR-23a expression tightly correlates with CD4+ effector expansion. Ectopic expression and genetic deletion strategies validated that miR-23a was required for antigen-stimulated effector CD4+ T cell survival in vitro and in vivo. I further determined that miR-23a targets Ppif, a gatekeeper of mitochondrial reactive oxygen species (ROS) release that protects CD4+ T cells from necrosis. Necrosis is a type of cell death that provokes inflammation, and it is prominently triggered by ROS release and its consequent oxidative stress. My finding that miR-23a curbs ROS-mediated necrosis highlights the essential role of this miRNA in maintaining immune homeostasis. </p><p>A key feature of miRNAs is their ability to modulate different biological aspects in different cell populations. Previously, my lab found that miR-23a potently suppresses CD8+ T cell cytotoxicity by restricting BLIMP1 expression. Since BLIMP1 has been found to inhibit T follicular helper (Tfh) differentiation by antagonizing the master transcription factor BCL6, I investigated whether miR-23a is also involved in Tfh differentiation. However, I found that miR-23a does not target BLIMP1 in CD4+ T cells and loss of miR-23a even fostered Tfh differentiation. This data indicate that miR-23a may target other pathways in CD4+ T cells regarding the Tfh differentiation pathway.</p><p>Although the lineage identity and regulatory networks for Tfh cells have been defined, the differentiation path of Tfh cells remains elusive. Two models have been proposed to explain the differentiation process of Tfh cells: in the parallel differentiation model, the Tfh lineage is segregated from other effector lineages at the early stage of antigen activation; alternatively, the sequential differentiation model suggests that naïve CD4+ T cells first differentiate into various effector lineages, then further program into Tfh cells. To address this question, I developed a novel in vitro co-culture system that employed antigen-specific CD4+ T cells, naïve B cells presenting cognate T cell antigen and BAFF-producing feeder cells to mimic germinal center. Using this system, I were able to robustly generate GC-like B cells. Notably, well-differentiated Th1 or Th2 effector cells also quickly acquired Tfh phenotype and function during in vitro co-culture, which suggested a sequential differentiation path for Tfh cells. To examine this path in vivo, under conditions of classical Th1- or Th2-type immunizations, I employed a TCRβ repertoire sequencing technique to track the clonotype origin of Tfh cells. Under both Th1- and Th2- immunization conditions, I observed profound repertoire overlaps between the Teff and Tfh populations, which strongly supports the proposed sequential differentiation model. Therefore, my studies establish a new platform to conveniently study Tfh-GC B cell interactions and provide insights into Tfh differentiation processes.</p> / Dissertation

Title: Structural changes in model of hypoxic-ischemic encephalopathy in rat Objectives: The aim of the research is to develop a model of hypoxic-ischemic encephalopathy in a rat that would represent perinatal injury in a human and then histologically differentiate the most commonly damaged cerebral structures. Methods: This is an experimental study. Five laboratory rats underwent hypoxic-ischemic conditions causing encephalopathy according to the Rice-Vannucci model. The control group representing the other five rats underwent hypoxia for 1.5 hours. Subsequently, the animals were returned to their mother. 48 hours later, cerebral perfusion, paraffinisation, slicing the brain into sections and followed by applying these sections onto slides. Sections to represent morphological changes and degeneration of neurons were stained with Hematoxylin-Eosin, Fluoro Jade B and immunohistochemically. The sections were then observed and evaluated under a light microscope. Results: Following the onset of hypoxic-ischemic encephalopathy in 7-day-old rat pups, damage to the investigated structures was observed in two animals. Other animals in the experimental group exhibited only minor morphological changes in neurons observable in H&E staining. Brains of the control group were intact. Keywords: necrosis,...

Memoria para optar al título de Bioquímico / La industria acuícola de salmónidos, como la del salmón del Atlántico o de la trucha arcoíris, constituye una de las principales actividades económicas de Chile. Sin embargo, en su puesta en marcha enfrenta desafíos técnicos y ambientales, incluyendo la aparición de enfermedades que se transmiten rápidamente dentro de las poblaciones de cultivo. La segunda causa de pérdidas por patología infecciosa es la Necrosis Pancreática Infecciosa, causada por el virus IPNv. Se ha descrito que la citoquina IFN-I induce una potente actividad antiviral contra IPNv. Para este trabajo de investigación, se propuso clonar IFN-I de la especie Salmo salar en Bacillus megaterium, una bacteria inocua capaz de producir grandes cantidades de proteína y que ha sido utilizada exitosamente en la industria biotecnológica. Para lo anterior, se diseñó un método de clonación clásico y se logró exitosamente la transformación de Escherichia coli con el vector de B. megaterium pSSBm110 con el gen de IFN-I como inserto (pSSBm110:IFN-I). Se probaron luego dos métodos de transformación para B. megaterium, uno de electroporación que no dio resultados cuantificables y otro de creación de protoplastos libres de pared capaces de absorber ADN exógeno. Sin embargo, a pesar de lograr la transformación y la clonación exitosa del vector pSSBm110:IFN-I en B. megaterium, no se logró la detección de la expresión de IFN-I recombinante, por lo cual serán necesarios nuevos intentos para lograr su uso como sistema de expresión para esta citoquina / The salmonid aquaculture industry, such as the Atlantic salmon or the rainbow trout aquaculture, is one of the Chile’s main economic activities. However, this industry faces technical and environmental challenges, including the emergence of diseases which spread quickly through the fish populations. The infectious pancreatic necrosis, which is caused by the IPNv virus, is the second cause of fish losses related to an infectious disease. It has been described that the cytokine IFN-I induces a powerful antiviral response against IPNv. In this research, we proposed the cloning of IFN-I from Salmo salar in the harmless bacterium Bacillus megaterium, a species of high-yielding protein production, successfully used in the biotechnology industry. For this, a classic cloning method was used, obtaining transformed Escherichia coli cells with the B. megaterium pSSBm110 vector, and the IFN-I insert (pSSBm110:IFN-I). Then, two B. megaterium transformation methods were tested. The first one, an electroporation method, which did not offer quantifiable results. The second one, a method based on protoplast cells generation where foreign DNA was absorbed. Even though the transformation and cloning in B. megaterium were both successful, and verified through sequencing, the expression of the recombinant peptide was not detectable. Thus, new attempts will be necessary to use this expression system for this cytokine / FIA PYT-2012-0056

Tesis presentada a la Universidad de Chile para optar al grado de Doctora en Bioquímica / Antecedentes: El síndrome de ovario poliquístico (SOP), patología endocrinometabólica, afecta alrededor del 15% de mujeres en edad fértil, afectando principalmente la función del ovario, aunque también altera la función de otros tejidos de importancia reproductiva, como el endometrio. El 70% de las mujeres con SOP son obesas y entre el 60 – 80 % de ellas presentan resistencia a la insulina. La obesidad genera un ambiente pro-inflamatorio leve pero crónico, caracterizado por una alta producción de citoquinas pro-inflamatorias. Además, adiponectina y TNF-α, marcadores de obesidad, tienen un papel importante en la sensibilidad y la acción de insulina en los tejidos. Los niveles de adiponectina (sensibilizador de insulina) disminuyen, mientras que los de TNF-α (regulador negativo de la vía de la insulina) aumentan en mujeres obesas. Estos cambios podrían afectar el estado energético del endometrio, tejido que exhibe una anormal señalización de insulina bajo la condición SOP (ambiente hiperandrogénico / hiperinsulínico). Objetivo: Evaluar si el ambiente proinflamatorio representado por TNF-α, afecta la señalización de insulina a través de una disminución de la señalización de adiponectina o por la inactivación de IRS1, en endometrios de mujeres obesas con SOP. Metodología: En muestras de suero provenientes de cuatro grupos de estudio: Delgadas (peso normal), Delgadas-SOP, Obesas y Obesas-SOP (este último grupo es el único con hiperinsulinemia / hiperandrogenemia) (n=7 para cada grupo), se determinaron mediante ELISA los niveles de adiponectina, TNF-α e IL-6. En endometrios provenientes de los cuatro grupos de estudio, se determinó los niveles de proteína / mRNA de moléculas asociadas a las vías de señalización de TNF-α (TNF-α, TNFR1, TNFR2, NFκB (p65), IKK, IκB) y adiponectina (adiponectina, AdipoR1, AdipoR2, APPL1, AMPK) por IHQ / WB y qPCR; además, se evaluó el ambiente pro-inflamatorio a través de la proteína CD68 y los niveles de IL-6 e IL-6R, mediante IHQ. Los estudios in vitro se realizaron en cultivos de células estromales endometriales humanas (líneas T-HESC / St-T1b) bajo condiciones hiperandrogénicas / hiperinsulínicas, y se determinó el efecto de TNF-α sobre moléculas asociadas a su vía de señalización y a la vía de adiponectina. Se analizó además, la participación de NFκB, usando un inhibidor de NFκB (PDCT), en el efecto de TNF-α sobre la expresión de adiponectina en células St-T1b, por ICQ / WB; finalmente, se evaluó el efecto de TNF-α sobre los niveles de IRS1 fosforilado en tirosina (activante) o serina (inactivante) y sobre la activación de quinasas (S6K, JNK, AKT), posiblemente involucradas en la inactivación de IRS1 en una condición de resistencia a la insulina. Resultados: Se observó una menor concentración de adiponectina en sueros de Obesas-SOP (p<0,05), no se observaron cambios en las concentraciones de TNF-α sérica, mientras que IL-6 aumenta en sueros de Delgadas-SOP y ambos grupos de Obesas versus Delgadas (p<0,05). A nivel tisular, los niveles de adiponectina disminuyen (p<0,05) y los de TNF-α aumentan (p<0,001) en endometrios de Obesas-SOP. El contenido proteico de los receptores de TNF-α son mayores en grupos Delgadas-SOP y ambos grupos de Obesas (p<0,05); sin embargo, el nivel de TNFR2 y de NFκB nuclear presenta un importante aumento en endometrios de Obesas-SOP (p<0,001). En relación a IL-6 endometrial, ésta es menor en Delgadas versus los otros grupos (p<0,05), mientras que su receptor no cambia. Además, un mayor ambiente pro-inflamatorio se observó en endometrios de Obesas-SOP versus los otros grupos (p<0,01). Los ensayos in vitro, los cuales confirman en gran medida lo observado en el modelo ex vivo, muestran que la condición hiperandrogénica / hiperinsulínica disminuye los niveles de adiponectina y moléculas asociadas a su vía (APPL1 / AMPK), al igual que el efecto observado con TNF-α a través de la activación de NFκB (p<0,05). Además, TNF-α induce la expresión de su propia vía de señalización, aumentando los niveles de TNFR1 y -2, moléculas que activan NFκB y el contenido nuclear de NFκB. Por último, TNF-α aumenta la fosforilación en serina de IRS1 y la activación de S6K, JNK y AKT. Conclusión: En consecuencia, la obesidad podría afectar la señalización de insulina en el endometrio, a través del aumento del ambiente pro-inflamatorio y la producción de TNF-α local, lo que generaría una disminución de la señalización de adiponectina a través de NFκB y/o una inactivación de IRS1 a través de S6K/JNK bajo condiciones hiperandrogénicas / hiperinsulínicas, lo que comprometería el metabolismo energético necesario para el normal funcionamiento del tejido endometrial, lo que explicaría, en parte, las fallas reproductivas observadas en endometrios de mujeres obesas e hiperinsulínicas con SOP / Background: Polycystic ovary syndrome (PCOS), an endocrine-metabolic disorder, affects about 15% of women of childbearing age, mainly affecting ovarian function, but also alters the function of other tissues of reproductive importance, such as the endometrium. Seventy percent of women with PCOS are obese and between 60 - 80% of them have insulin resistance. Obesity generates a mild but chronic pro-inflammatory environment, characterized by high production of pro-inflammatory cytokines. In addition, TNF-α and adiponectin, obesity markers, have an important role in insulin sensitivity and action in tissues. In fact, adiponectin level (insulin sensitizer) decreases, whereas those of TNF-α (negative regulator of insulin pathway) increases in obese women. These changes could affect the energy state of the endometrium, tissue exhibiting abnormal insulin signaling under the SOP condition (hyperandrogenic / hyperinsulinemic environment). Objective: To evaluate whether the proinflammatory environment represented by TNF-α, affects insulin signaling through a decrease in adiponectin signaling or inactivation of IRS1, in endometrium of obese women with PCOS. Methodology: In serum samples from the four study groups: Lean (normal-weight), Lean-PCOS, Obese and Obese-PCOS (the latter group is the only one with hyperinsulinemia / hyperandrogenaemia) (n = 7 for each group) were determined: adiponectin, TNF-α and IL-6 levels by ELISA. In endometrium from the four study groups, was determined the levels of protein / mRNA of molecules associated with the signaling pathways of TNF-α (TNF-α, TNFR1, TNFR2, NFκB (p65), IKK, IκB) and adiponectin molecules (adiponectin, AdipoR1, AdipoR2, APPL1, AMPK) by IHC / WB and qPCR; additionally, the proinflammatory environment through CD68 protein and IL-6 / IL-6R levels, was evaluated by IHC. In vitro studies were conducted in human endometrial stromal cells (lines T-HESC / St-T1b) under hyperandrogenic / hyperinsulinic conditions, and the effect of TNF-α on molecule levels associated with its signaling pathway and adiponectin pathway, was determined by WB. NFκB participation was further analyzed using a NFκB inhibitor (PDCT) of TNF-α action on adiponectin expression in St-T1b cells by ICC; finally, it was evaluated the effect of TNF-α on in tyrosine phosphorylated levels of IRS1 (activating) or serine (inactivating) and kinases activation (S6K, JNK, AKT), possibly involved in the inactivation of IRS1 in an insulin resistance condition. Results: A lower concentration of adiponectin in serum from Obese- PCOS (p <0.05) was observed, no changes were found in serum concentrations of TNF-α, whereas IL-6 increases in serum from Lean-PCOS and both Obese groups versus the Lean group (p <0.05). At tissue level, adiponectin content decreases (p <0.05) and TNF-α increases (p <0.001) in Obese-PCOS endometrium. The protein content of TNF-α receptors are higher in Lean-PCOS groups and both Obese groups (p <0.05); however, nuclear NFκB and TNFR2 levels present an important increase in endometrium from Obese-PCOS (p <0.001). Regarding endometrial IL-6, a lower level in Lean versus the other groups was observed (p <0.05), while receptor content does not change. In addition, a higher pro-inflammatory environment was observed in Obese-PCOS endometrium versus the other studied groups (p <0.01). In vitro assays, which largely confirm what was observed in the ex vivo model, show a decrease of adiponectin levels and molecules associated with their pathway (APPL1 / AMPK) under hyperandrogenic / hyperinsulinic conditions, as well as, the effect observed with TNF-α through NFκB activation (p <0.05). In addition, TNF-α induces the expression of their own signaling pathway, increasing levels of TNFR1 and -2, molecules that activate NFκB and nuclear NFκB content. Finally, TNF-α increases phosphorylated IRS1 levels in serine and activation of S6K, JNK and AKT. Conclusion: Consequently, obesity may affect insulin signaling in the endometrium, by increasing the proinflammatory environment and local production of TNF-α, generating a decrease in adiponectin signaling through NFκB and / or inactivation of IRS1 through S6K / JNK under hyperandrogenic / hyperinsulinic conditions, which compromise the energy metabolism necessary for normal functioning of endometrial tissue. These abnormalities may explain in part, reproductive failures observed in endometria from obese and hyperinsulinic women with PCOS / Conicyt; Fondecyt

O tratamento do câncer e de lesões pré-malignas é uma importante aplicação da terapia fotodinâmica. A base da técnica é o uso da luz associada a um fotossensibilizador, na presença de oxigênio, de forma a promover a formação de espécies reativas de oxigênio que culminam na morte celular. Esta técnica é altamente seletiva, e apresenta poucos efeitos colaterais. A efetividade da terapia pode ser avaliada com base na emissão de fluorescência do fotossensibilizador, uma vez que o grau de fotodegradação deste indica uma terapia mais ou menos efetiva. No caso de tumores, a reincidência de lesões, causada por células malignas remanescentes, é um problema importante e que pode piorar as condições clínicas de um paciente. Este estudo propõe, portanto, um modelo matemático baseado na aferição da fluorescência do fotossensibilizador in situ para previsão da extensão do dano promovido pela terapia fotodinâmica em tempo real. Esta aferição é feita em comparação com o parâmetro experimental de profundidade de necrose, de modo a avaliar se uma lesão pode ser completamente eliminada numa dada aplicação. O estudo utilizou fígados de ratos Wistar machos, saudáveis, como modelo inicial dada sua relativa homogeneidade óptica com relação a lesões tumorais, visando minimizar variáveis. Os fígados foram irradiados com diferentes intensidades (150, 250 e 350 mW/cm2) e com diferentes fluências (50-450 J/cm2) de luz com comprimento de onda de 630 nm, CW, para avaliação das necroses e da fluorescência (avaliada usando 532 nm para excitação). A primeira versão do modelo utilizou o conjunto de dados de 250 mW/cm2 para obtenção de um modelo inicial baseado na fotodegradação avaliada por fluorescência. Este modelo foi alterado com base em modificações biológicas observadas na literatura durante a terapia. Tais alterações estão relacionadas à modificação de aporte de oxigênio causada por vasoconstricção, pela farmacocinética do fotossensibilizador e pelas modificações nas propriedades ópticas intrínsecas ao tecido. Foi possível encontrar equivalência entre modelo e experimentação ao final das modificações propostas ao modelo inicial, embora tenha sido evidente o efeito da variação no fracionamento da fluência entregue sobre os resultados da previsão. Como forma de mostrar a capacidade do modelo não apenas para previsão da profundidade de necrose (e, portanto, da extensão do dano), mas também para avaliações de dosimetria, foi proposta uma situação hipotética onde se entrega a mesma fluência de luz com intensidades diferentes (variando linearmente). Este teste mostrou o potencial do modelo não apenas para avaliar a extensão do dano causado pela terapia em tempo real, mas também para estimar os resultados de protocolos clínicos não-testados e, portanto, para a proposta de melhorias a protocolos de terapia fotodinâmica. / Malignant and pre-malignant cancer lesions treatment is an important application of photodynamic therapy. It is based on the use of light associated to a photosensitizer, in the presence of oxygen, so that reactive oxygen species may be formed, resulting in cell death. This is a highly selective technique, and few side effects are reported. The therapy efficacy may be evaluated through the photosensitizer fluorescence emission, since its level of bleaching indicates a more or less effective therapy application. Concerning cancer, recurrent lesions, caused by remaining malignant cells, is an important problem which may cause the worsening of patient´s clinical condition. Therefore, this study proposes a mathematical model based on the assessment of photosensitizer fluorescence in situ for prediction of the damage extent caused by photodynamic therapy. This evaluation is performed by comparison with the experimental parameter of depth of necrosis, as to evaluate if a lesion can be completely eliminated during an application. This study used male Wistar rats healthy livers as an initial model due to its relative optical homogeneity when compared to tumor lesions, hence minimizing variables. Livers were irradiated using different light fluence rates (150, 250 and 350 mW/cm2) and fluences (50-450 J/cm2) with 630 nm wavelength, CW, to perform evaluation of fluorescence (wit 532 nm excitation) and depth of necrosis. A first model was obtained from the 250 mW/cm2 dataset, based on fluorescence-assessed photobleaching. Such model was modified according to literature observations on biological changes during therapy. Those changes are related to the oxygen arrival, promoted by vessels shutdown, by the photosensitizer pharmacokinetics and by the changes in the intrinsic optical properties of liver tissue. Correspondence between model and experimentation was achieved after the changes proposed to the initial model, although the effect of different fractioning of light fluences on prediction has become evident. To show the model ability not only to predict depth of necrosis (and, hence, damage extent), but also for dosimetry studies, an hypothetical situation in which the same fluence has been delivered in different (linearly varying) fluence rates. This test result showed the potential of the model not only to evaluate the damage extension by the therapy in real-time, but also to investigate untested clinical protocols results and, therefore, to allow proposals of improvement to photodynamic therapy protocols.

O adenocarcinoma de ducto pancreático (PDAC) é a quarta causa de morte em decorrência de neoplasias nos países ocidentais. Atualmente, a cirurgia ressectiva é a única possibilidade de cura para a doença, porém, a recidiva tumoral acontece em menos de um ano após a intervenção cirúrgica, mesmo com a quimioterapia adjuvante. A terapia fotodinâmica (PDT) é uma alternativa promissora no tratamento do câncer. No entanto, pouco se sabe sobre o uso da PDT em tumores pancreáticos. Portanto, o objetivo deste trabalho foi avaliar a eficiência da PDT com o azul de metileno (MB) como fotossensibilizador (MB-PDT) em induzir a morte de linhagens de PDAC humanas (AsPC-1, Panc-1, MIAPaCa-2 e BxPC-3) e estudar a contribuição de vias de necrose regulada nos efeitos citotóxicos da terapia sobre estes modelos. Os resultados obtidos mostraram que a MB-PDT foi capaz de induzir a morte massiva das células de PDAC. Além disso, eles indicaram que há dois perfis de susceptibilidade entre as quatro linhagens estudadas quando submetidas a MBPDT com 4,5 J/cm2 de energia e 6min de irradiação. De acordo com os dados apresentados, a diferença nas sensibilidades das linhagens à terapia não está associada à diferenças na capacidade de incorporação do MB ou na localização sub-celular do fotossensibilizador nas diferentes células, uma vez que a localização é, predominantemente, lisossomal em todas elas. Adicionalmente, mostrou-se que as linhagens menos susceptíveis ao tratamento, MIAPaCa-2 e Panc-1, apresentam níveis significativamente menores de RIPK3 e MLKL, dois dos componentes do necrossomo, essenciais para a execução da necroptose. Além disso, foi visto que a MB-PDT induz um aumento de fosforilação de MLKL em AsPC-1, demonstrando a ativação da necroptose após a terapia nestas células, mas não em MIAPaCa-2 (menos responsiva à terapia com 4,5 J/cm2 deenergia e 6min de tempo de irradiação). Ainda, a inibição da via de sinalização necroptótica diminuiu significativamente as porcentagens de morte das células mais susceptíveis (BxPC-3 e AsPC-1), não alterando a resposta de Panc-1 e MIAPaCa-2, corroborando a ativação e importância da necroptose para a citotoxicidade da MB-PDT. Finalmente, neste trabalho foi mostrado que o aumento do tempo de irradiação, mantendo-se a quantidade total de energia aplicada no tratamento, melhora a eficiência da MB-PDT em induzir a morte das células que apresentam limitações para executar a necroptose, sugerindo que mais de uma via de morte esteja sendo ativada após a terapia e que o tempo de irradiação atuaria modulando esta ativação. Complementarmente, foi mostrado que os tempos maiores de irradiação aumentam o estresse oxidativo intracelular que é acompanhado por uma diminuição significativa do conteúdo intracelular de glutationa reduzida (GSH), indicando, preliminarmente, que a ferroptose pode estar sendo acionada após os protocolos mais longos de irradiação. Coletivamente, os resultados apresentados neste trabalho confirmam a eficiência da MB-PDT no tratamento de diferentes linhagens de PDAC, indicando que a necroptose está sendo ativada e contribuindo para a citotoxicidade da terapia sobre as células que não apresentam resistência à esta via de morte. Ainda, eles demonstram que o aumento do tempo de irradiação pode transpor a barreira de resistência de algumas linhagens à terapia, provavelmente por induzir a ativação de outras vias de necrose regulada, mostrando a importância da otimização do protocolo de tratamento no aumento da eficiência da MB-PDT sobre os tumores de pâncreas. Finalmente, os resultados confirmam a MB-PDT como alternativa eficaz no tratamento do PDAC, apresentando um amplo espectro de atuação sobre subtipos tumorais resistentes à vias clássicas de morte celular, uma característica importante no contexto de uma terapia anti-cancer. / Pancreatic ductal adenocarcinoma (PDAC) is the fourth leading cause of death due to neoplasms in western countries. Currently, resective surgery is the only therapetical approach to cure this disease, but tumor´s recurrence occurs less than one year after the surgery, even with adjuvant chemotherapy. Photodynamic therapy (PDT) is a promising alternative for the cancer treatment. However, the efficacy of PDT to treat pancreatic tumors as well as the mechanisms involved in the induction of tumorigenic cell death remain unclear. For this purpose, in this study, we set out to evaluate the efficacy of PDT using methylene blue (MB) as a photosensitizer (MB-PDT), in inducing death of human PDAC derived cell lines (AsPC-1, Panc-1, MIAPaCa-2 and BxPC-3) and to deeper investigate the contribution of necroptosis to the cytotoxic effects of the therapy. We observed that MB-PDT was able to induce massive death of PDAC cells. Moreover, our results indicated that upon MB-PDT (4.5 J/cm2 energy and 6min of irradiation time), there were two susceptibility profiles among the four cell lines studied. Data also showed that this differential profile of cell response was neither associated with the differences in the MB incorporation capacity nor with the subcellular location of the photosensitizer, since the localization was predominantly lysosomal in all of tested cell lines. In addition, less susceptible cells, MIAPaCa-2 and Panc-1, showed significantly lower levels of RIPK3 and MLKL, two of the necrosome components, essential for triggering necroptosis. Furthermore, while MB-PDT (4.5 J/cm2 and 6min of irradiation) has been able to increase MLKL´s phosphorylation levels, an essential step in necroptosis induction, in AsPC-1cells, less responsive MIAPaCa-2 cells presented no variations on the phosphorylation state of this pseudokinase. Moreover, pharmacological inhibition of the necroptotic signaling pathway significantly decreased cell death percentages of the most susceptible cells (BxPC-3 andAsPC-1), without altering the response of Panc-1 and MIAPaCa-2, corroborating that activation of necroptosis was strongly involved in the cytotoxicity of MB-PDT. Finally, this work showed that increasing the irradiation time improved the efficacy of MB-PDT in killing cells which display limitations to perform necroptosis, suggesting that the irradiation time would be modulating the degree of oxidative stress generated and this stimuli would in turn, be responsible for triggering other regulated cell death pathways in a RIKP3 and MLKL independent way. Indeed, this increase in oxidative stress was accompanied by a significant decrease in GSH, a global indicatior of less antioxidant cell capacity, preliminarily pointing at the induction of ferroptosis by longer irradiation protocols. In summary, we demonstrated that MB-PDT is able to induce cell death in different PDAC cell lines and that different regulated cell death mechanisms are being activated upon MB-PDT induction. Furthermore, it was demonstrated that increased irradiation time may overcome the resistance barrier of some cell lines, probably inducing the activation of other regulated cell death pathways, showing the importance of optimizing the irradiation protocol in order to maximize the efficacy of the therapy. Finally, our observations point MB-PDT as an alternative and effective therapy for pancreatic cancer treatment, displaying a broad-spectrum action on tumors displaying different resistance mechanisms to classic cell death pathways, a desired property for improving an anticancer therapy.

Introdução: A terapêutica da psoríase foi modificada pela introdução dos imunobiológicos, que permitem melhor controle da doença e melhor qualidade de vida aos pacientes, mas promovem aumento do risco de tuberculose latente, exigindo diagnóstico antecedendo seu início. Objetivo: Avaliar o desempenho do teste T-SPOT.TB no diagnóstico de infecção tuberculosa latente em pacientes com psoríase. Métodos: Em estudo experimental, prospectivo, analítico, com comparação de grupos,de prevenção primária, para validade de teste diagnóstico, 33 pacientes com psoríase (grupo psoríase) e 30 pacientes com outras doenças dermatológicas (grupo base), atendidos nos Ambulatório de Dermatologia Geral ou de Psoríase do Centro de Estudos Dermatológicos do Recife, da Santa Casa de Misericórdia, entre fevereiro e novembro de 2009, foram submetidos aos testes do PPD e T-SPOT.TB. Para ambos os grupos, admitiu-se inclusão com idade mínima de 18 anos e critérios de exclusão doenças ou condições fisiológicas que comprometessem a competência imunológica, exceto psoríase, para o grupo psoríase. Adotou-se a técnica de Mantoux para o teste do PPD e uma variante simplificada da técnica Enzyme-Linked Immunospot para a determinação de células T efetoras, secretoras de IFN-g em resposta à estimulação pelos antígenos específicos do M. tuberculosis para o teste T-SPOT.TB. As variáveis dependentes foram os resultados do teste T-SPOT.TB contra antígenos ESAT-6, CFP-10, e os resultados do teste do PPD, considerando enduração de 0-4 mm: não reator; 5-9 mm: reator fraco; &#8805; 10 mm: reator forte. As variáveis independentes foram: idade, sexo, cor da pele, tempo de evolução da psoríase, ocupação, história de contato intradomiciliar e renda, alcoolismo e gravidade da doença. Foram submetidos a teste Qui quadrado ou exato de Fisher, em nível de significância de 0, 05, assim como ao teste de Mantel-Haenszel, três modelos comparando o teste T-SPOT.TB com teste do PPD, contato intradomiciliar e associação teste do PPD e contato intradomiciliar. A pesquisa foi aprovada pelos Comitês de Ética da Universidade Federal de Pernambuco e Universidade de São Paulo. Resultados: O grupo psoríase diferiu do grupo base quanto a razão de sexo com predomino do masculino (razão=0,7:1; p=0,047); maior idade média 42,1±1,9 anos (contra 34,1±1,4 anos no grupo base, p=0,023); fototipos I e II (p=0,020); menor nível de instrução e renda média mensal e contato intradomiciliar com tuberculose menos freqüente (p=0,001). Os grupos também diferiram quanto à positividade do teste do PPD (maior no grupo base; p=0,001). O teste T-SPOT.TB apresentou sensibilidade e especificidade de 9,1% e 95,5%, no modelo 1, 27,3% e 60%, no modelo 2, e valores de 60% e 53,3%, respectivamente no modelo 3. Foi no modelo 1 do grupo psoríase que o teste TSPOT. TB mostrou a maior concordância e o maior valor de Odds Ratio ponderado pelo teste de Mantel-Haenszel, tendo esses dois parâmetros significância estatística, quando comparados aos outros dois modelos. Conclusões: O teste T-SPOT.TB apresentou maior capacidade de diagnosticar casos negativos para tuberculose latente, constituindo-se numa opção para triagem de pacientes na instituição de terapêutica com imunobiológicos. / Introduction: The therapy for psoriasis was modified by the introduction of immunebiological products that allow better disease control and better quality of life for patients, but promotes increased risk forf latent tuberculosis, requiring diagnosis shortly before its establishment. Purpose: To assess the performance of T-SPOT.TB test for the diagnosis of latent tuberculosis infection in patients with psoriasis. Methods: Within a experimental, prospective, analytic, clinical assay type study, with comparison of groups, to validate a diagnostic test, 33 patients with psoriasis (psoriasis group) and 30 patients with other dermatological diseases (basis group), attempted at General Dermatology and Psoriasis Out-patients Departments of Recife\'s Dermatological Studies Center of Santa Casa de Misericórdia, from February to November 2009, were submitted to PPD and TSPOT. TB tests. For both groups, we admitted 18 years as minimal age for inclusion. The exclusion criteria included disease ou physiological conditions that compromised immunological competence, except psoriasis to psoriasis group. We used Mantoux technique for PPD test and a simplified variant of Enzyme-Linked Immunospot technique to determine effector T cells, secretors of IFN-g in response to M. tuberculosis specific antigens, to T-SPOT.TB test. Dependent variables were the results of T-SPOT.TB test against ESAT-6 and CPF-10 antigens, and the results to PPD test, considering enduration of 0-4 mm as non reactor; 5-10 mm weak reactor and &#8805; 10 mm, strong reactor. Independent variables were age, sex, skin color, psoriasis evolution time, occupation, history of intradomiciliar contact and income, alcoolism and disease grade. Three models, comparing T-SPOT.TB test to PPD test, intradomiciliar contact and both, were submitted to Qui Squared test or Exact Fisher Test, at significance level of 0.05, as well as to Mantel- Haenszel test. The research has been approved by Ethics Committee of Universidade Federal de Pernambuco e Universidade de São Paulo. Results: Psoriasis group differed from base group on sex ratio with predominance of male gender (rate=0.7:1; p=0,047), major mean age (42,1 ± 1.9 years against 34,1 ± 1.4 years in basic group, p = 0,023) phototypes I and II (p = 0,020); lower scholarship, income and less frequent intradomiciliar contact with tuberculosis (p = 0,001). The groups also differed on the positivity of PPD test (greater in base group; p = 0,001). T-SPOT.TB test had sensibility and specificity of 9,1% and 95.5%, in model 1; 27,3% and 60%, in model 2, and values of 60% and 53,3% respectively in model 3. Model 1 showed greater concordance and highest value of Odds Ratio test weighted by Mantel-Haenszel test, having these two parameters statistical significance when compared to the other two models. Conclusions: T-SPOT.TB test had great ability to diagnose negative cases for latent tuberculosis, and constitutes an option for screening patients to immunobiological therapy administration.

Peptídeos intracelulares são constantemente produzidos pelo sistema ubiquitina proteassomo e muitos são provavelmente funcionais. Aqui, um nonapeptídio derivado da ciclina-D2, específica da transição G1/S, chamado \"pep5\" mostrou um aumento específico durante a fase S do ciclo celular em células HeLa. O pep5 (50-100 &mu;M) induziu a morte celular em células HeLa e em várias outras células tumorais, mas isso só ocorreu quando o pep5 foi sintetizado acoplado ao peptídeo penetrador de células (pep5-cpp). In vivo, o pep5-cpp reduziu o volume do glioblastoma C6 de ratos Wistar em cerca de 50%. A acetilação reduziu a potência do pep5-cpp, enquanto substituições Leu-Ala aboliram totalmente a atividade deste peptídeo. Os resultados de caracterização inicial do mecanismo de morte celular indizida pelo pep5 incluem ativação de caspases 3/7 e 9, inibição da fosforilação Akt2 e inibição da atividade do proteassomo. Esses dados colaboram com a hipótese da função de peptídeos intracelulares na sinalização. / Intracellular peptides are constantly produced by the ubiquitinproteasome system and many are probably functional. Here, a nonapeptide of G1/S-specific cyclin-D2 named pep5 showed a specific increase during the S phase of HeLa cell cycle. Pep5 (50-100 &mu;M) induced cell death in HeLa and in several other tumor cells, only when it was fused to a cell penetrating peptide (pep5-cpp). In vivo, the pep5-cpp reduced the volume of the rat C6 glioblastoma by almost 50%. Acetylation reduced the potency of the pep5-cpp while Leu-Ala substitutions totally abolished the pep5 activity. Findings from the initial characterization of the cell death mechanism of pep5 include caspase 3/7 and 9 activation, inhibition of Akt2 phosphorylation and inhibition of proteasome activity. These data further support the intracellular function of peptides.

A influência da obesidade induzida por glutamato monossódico em ratos sobre o desenvolvimento do tumor de Walker-256 e os efeitos da metformina (300mg/kg, v.o., 15 dias) foram investigados. Na 16ª semana de vida, inocularam-se as células tumorais e iniciou-se o tratamento. Após 15 dias, analisou-se o crescimento tumoral. A viabilidade de células tumorais, MCF-7, tratadas com meformina foi avaliada. A obesidade contribuiu para maior desenvolvimento tumoral e reduziu a sobrevida dos ratos. A metformina foi eficaz em impedir o aumento do tumor e aumentou a sobrevida dos ratos. Teve efeito antiproliferativo sobre as células MCF-7, efeito esse relacionado ao bloqueio do ciclo celular, estresse oxidativo, aumento na apoptose e necrose celulares, e aumento na atividade da AMPK e do FOXO3a. Conclui-se que a obesidade contribui de maneira significativa para o desenvolvimento tumoral e que a metformina é eficaz em diminuí-lo. / The influence of obesity induced by monossodium glutamate in rats on Walker-256 tumor development and the metformin (300/kg, b.w., 15 days) effect were analyzed. At the 16th week, 1x107 Walker-256 tumor cells were inoculated and the treatment with metformin was started. Following this treatment, the tumor growth was analyzed. The cell viability of MCF-7 cells treated with metformin was analyzed. Obesity positively contributed for tumor development and it reduced life span of the rats. Metformin reduced the tumor development and increased the life span of the rats. It presented an antiproliferative effect in MCF-7 cells. Effect associated with an increase in oxidative stress, apoptosis, necrosis and cell cycle arrest in G0-G1 phase. Furthermore, its effect is associated with an increased in AMPK and FOXO3a activities. In conclusion, obesity contributed significantly to tumor development and metformin is effective in reduced it.

O objetivo desse estudo de coorte histórico foi avaliar o traumatismo dental em incisivos superiores decíduos e fatores associados à ocorrência de necrose pulpar em incisivos centrais superiores decíduos traumatizados. Os dados foram coletados por um único examinador através de exame de fotografias, radiografias e informações presentes nos prontuários dos pacientes atendidos no Centro de Pesquisa e Atendimento de Traumatismo em Dentes Decíduos da Disciplina de Odontopediatria da Faculdade de Odontologia da Universidade de São Paulo entre os anos de 1998 e 2009. O critério utilizado para a inclusão do prontuário no estudo foi a existência de fotografias e/ou radiografias que comprovassem a presença de incisivos centrais permanentes erupcionados, em processo de erupção ou com incisivos superiores decíduos próximos a esfoliação. Foram avaliados 521 prontuários e em relação aos dados de traumatismo, a maioria dos pacientes pertencia ao gênero masculino, com história de trauma dental antes dos três anos de idade e 23% das crianças possuíam alterações oclusais anteriores predisponentes ao traumatismo dental. A queda da própria altura seguida de traumatismo dental contra o chão foi a etiologia dominante; os incisivos centrais foram os dentes mais acometidos; os traumas periodontais os mais prevalentes e 57% dos pacientes procuraram o atendimento no Centro de Trauma em Dentes Decíduos no mínimo 30 dias após o traumatismo. Para o estudo da necrose pulpar foram avaliados 727 incisivos centrais superiores decíduos traumatizados. Os sinais considerados na classificação do dente necrosado foram: presença de alteração no tecido gengival (fístula ou abscesso) e presença de lesão periapical. A incidência de necrose pulpar foi de 22,6%; 10% do total de dentes da amostra necrosaram no intervalo de 6 meses, correspondendo 45% do total de dentes necrosados. A análise de regressão de Poisson multivariada indicou como fatores de risco para a necrose pulpar o relato de dor (RR = 1,73; 1,22 2,45), trauma do tecido duro envolvendo dentina (RR = 1,74; 1,15 2,62), trauma do tecido duro com exposição pulpar (RR =4,55; 2,80 7,40), trauma ósseo (RR = 2,56; 1,08 6,08), alteração de cor marrom (RR = 1,82; 1,27 2,61), alteração de cor cinza (RR = 2,24; 1,48 3,41), reabsorção externa com infecção apical (RR = 4,89; 3,36 7,18), reabsorção externa com infecção apical e lateral e/ou cervical (RR = 5,05; 3,53 7,22) e reabsorção externa com infecção lateral e/ou cervical (RR = 5,66; 3,59 8,90). A presença de calcificação pulpar (RR = 0,45; 0,28 0,73) e reabsorção externa com formação óssea (RR =0,62; 0,47 0,83) foram fatores de proteção para a necrose pulpar. Conclui-se que trauma ósseo concomitante ao traumatismo dental, trauma dos tecidos duros dos dentes envolvendo dentina ou com exposição pulpar, relato de dor pela criança durante o período de acompanhamento clínico, alteração de cor cinza ou marrom reabsorção externa com infecção da raiz são fatores que aumentam o risco de necrose pulpar. Além disso, presença de calcificação pulpar e reabsorção externa com formação óssea podem ser fatores de proteção para a ocorrência de necrose pulpar. / The purpose of this historical cohort study was to assess dental trauma in primary upper incisors and factors associated with the occurrence of pulp necrosis in traumatized primary upper central incisors. Data was collected by a single examiner through the analysis of photographs, radiographs, and information contained in the clinical files of patients who attended the Center for Research and Treatment of Dental Trauma in Primary Teeth of the School of Dentistry of the University of São Paulo between the years of 1998 and 2009. The inclusion criteria used was that the clinical file had to have photographs and radiographs which could confirm the presence of exfoliating primary incisors, erupting or erupted permanent upper central incisors. Five hundred and one clinical files were assessed to analyze dental trauma data, the majority of the patients was male and presented with a history of dental trauma that had occurred before they were 3 years old. Twenty three percent of the children had occlusal alterations which might have predisposed them to dental trauma. Dental trauma as a consequence of falling down (from their own height) on the floor was the main etiological factor found; central incisors were the most commonly affected teeth, periodontal trauma was the most prevalent and 57% of the patients sought treatment at the Center for Dental Trauma in Primary Teeth at least 30 days after the trauma had occurred. For the pulp necrosis study, 727 traumatized primary upper central incisors were assessed. The signs considered as indicators of necrosis were: presence of alteration in gingival tissue (fistula or abscess) and presence of periapical lesion. The incidence of pulp necrosis was of 22.6%; 10% of the total of teeth in the sample had suffered necrosis within an interval of 6 months after trauma, corresponding to 45% of the total of necrosed teeth. Poisson multivariate regression analysis indicated the following risk factors for pulp necrosis: reported pain (RR = 1.73; 1.22 2.45), dental hard tissue trauma involving dentin (RR = 1.74; 1.15 2.62), dental hard tissue trauma causing pulp exposure (RR = 4.55; 2.80 7.40), bone trauma (RR = 2.56; 1.08 6.08), brown color alteration (RR= 1.82; 1.27 2.61), grey color alteration (RR= 2.24; 1.48 3.41), external root resorption with apical infection (RR = 4.89; 3.36 7.18), external root resorption with apical infection and lateral and/or cervical (RR = 5.05; 3.53 7.22), and external root resorption with lateral and/or cervical infection (RR = 5.66; 3.59 8.90). The presence of pulp calcification (RR = 0.45; 0.28 0.73) and external root resorption with bone formation (RR =0.62; 0.47 0.83) were protective factors against pulp necrosis. It was concluded that bone trauma occurring simultaneously to dental trauma, dental hard tissue trauma involving dentin or with pulp exposure, pain report from the children during the period of clinical follow-up, brown or grey color alteration, and external root resorption with apical infection are factors which increase the risk for pulp necrosis. Moreover, the presence of pulp calcification and external root resorption with bone formation could be protective factors against the occurrence of pulp necrosis.