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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
471

INVESTIGATING THE ROLES OF REACTIVE OXYGEN AND NITROGEN SPECIES IN PLANT PROGRAMMED CELL DEATH, CYTOSKELETAL AND MITOCHONDRIAL DYNAMICS

2012 September 1900 (has links)
Mitochondria are usually considered simply as the “powerhouses of the cell”, however in recent years it has become apparent that mitochondria are also of fundamental importance in programmed cell death (PCD), which refers to cell death resulting from a controlled, genetically defined pathway. In Arabidopsis, PCD induced by either heat shock or treatment with strong oxidants is found to be correlated with an early and irreversible change in mitochondrial morphology which manifests as an increase in the size of individual mitochondria. In addition, PCD causes a clustering of mitochondria and loss of motility. In this study, I have used two arginase negative mutant Arabidopsis lines (argah1-1 and argah2-1) which have elevated cellular NO concentrations to examine the effect of nitrosative stress on mitochondria undergoing PCD. Another three different Arabidopsis lines (mito-GFP/mTalin-mCherry, mito-GFP/MAP4-mCherry, mito- mCherry/EB1b-GFP) were used to visualize cytoskeletal elements alongside mitochondria to examine the mechanisms responsible for the mitochondrial morphology transition, clustering and motility inhibition. Results indicate that the elevated concentration of NO found in arginase negative mutants is not sufficient to induce PCD. There was no significant mitochondrial morphology or dynamic change detected between arginase negative mutants and wild type plants, with or without a heat shock. Disruption of either actin or microtubule (MT) cytoskeletal elements leads to the formation of mitochondrial clusters, although they showed different cluster morphology and sizes. Mitochondrial clusters were observed to be moving along the remaining actin cables after a mild heat treatment or cytoskeletal depolymerizing drug treatment. Intact microtubules or MT plus ends visualized with EB1b did not show any interaction with mitochondria under normal conditions. However, after a mild heat stress, EB1b appeared to be associated with clusters of enlarged, possibly swollen mitochondria.
472

The Role of Sphingosine Kinase 2 in Cell Growth and Apoptosis

Sankala, Heidi M. 01 January 2007 (has links)
Two isoforms of sphingosine kinase (SphK) catalyze the formation of sphingosine-1-phosphate (SIP). Whereas, SphKl stimulates cell growth and survival, it was found that when overexpressed in mouse NIH 3T3 fibroblasts SphK2 enhances caspase-dependent apoptosis in response to serum deprivation, independently of S1P receptors. Sequence analysis revealed that SphK2 contains a 9 amino acid motif similar to that present in BH3-only proteins. Studies showed that the BH3-only domain, catalytic activity, endoplasmic reticulum (ER) stress, and uptake of calcium by the mitochondria may all contribute to the apoptotic effects of overexpressed SphK2 in NIH 3T3 cells. Further studies in human carcinoma cells showed that overexpression of SphK2 increased the expression of the cyclin dependent kinase (cdk) inhibitor p21, but interestingly had no effect on p53 or its phosphorylation. Correspondingly, downregulation of endogenous SphK2 with small interfering RNA (siRNA) targeted to unique mRNA sequences decreased basal and doxorubicin-induced expression of p21 without affecting p53. In addition, downregulation of SphK2 decreased G2/M arrest in response to doxorubicin. Surprisingly however, siSphK2 markedly enhanced apoptosis induced by doxorubicin in MCF7 and HCT-116 cells. This result raises the question of how overexpression of SphK2 decreases cell growth and enhances apoptosis while its downregulation sensitizes cells to apoptosis. A partial answer may come from the possibility that when SphK2 is overexpressed it does not always have the same subcellular distribution as the endogenous protein. It may also be possible that proteolysis of overexpressed SphK2 might induce apoptosis due to liberation of its BH3 peptide domain, which does not occur at the levels at which endogenous SphK2 is expressed. Collectively, these results demonstrate that endogenous SphK2 is important for p53-independent induction of p21 expression by doxorubicin and suggest that SphK2 expression may influence the balance between cytostasis and apoptosis.
473

Etude des conséquences de l’activation de la voie imd au cours de la métamorphose et la vie adulte de la drosophile / Consequences of imd pathway activation during metamorphosis and adult life of drosophila

Tavignot, Raphaël 19 October 2018 (has links)
Au cours d’une infection, l’intensité et la durée de la réaction immunitaire doivent être étroitement contrôlées au risque de devenir délétère pour l’hôte. Chez la drosophile Drosophila Melanogaster, une infection bactérienne conduit à l’activation de voies de signalisation de type NFκ-B, conservées au cours de l'évolution, via la détection du peptidoglycane, un composant de la paroi bactérienne, par des récepteurs PGRPs (« Peptidoglycan Recognition Proteins »). Durant ma thèse, j’ai étudié les conséquences d’une activation non contrôlée d'une de ces voies, la voie IMD, sur la physiologie de la drosophile. Le premier projet auquel j’ai participé montre que l’inactivation de PGRP-LF, un régulateur négatif de la voie, conduit à l'activation de la voie IMD dans les tissus larvaires dérivés de l’ectoderme en absence d’infection. Cette activation entraine l’expression ectopique dans ces tissus de la protéines DIAP1 («Drosophila Inhibitor of Apoptosis 1»), suffisante pour induire la malformation de certains tissus de la drosophile adulte démontrant une fonction développementale jusqu'alors inconnue de la voie IMD au cours de la métamorphose de la drosophile. Dans la seconde partie de ma thèse, j’ai pu observer que durant une infection chronique, le maintien de l’activation de la voie IMD entraine l’apparition de nombreux phénotypes tels qu’une baisse de l’espérance de vie, des troubles locomoteurs, de la neurodégénérescence et l’atrophie du corps gras et des ovaires. Mes résultats montrent que l’activation de la voie IMD spécifiquement au niveau de la glie périneuriale, un composant de la barrière hématoencéphalique, participe activement à l’apparition des phénotypes observés. / Upon infection, the intensity and duration of the immune response must be tightly controlled at the risk of becoming harmful for the host. In the fruit fly Drosophila Melanogaster, a bacterial infection leads to the activation of evolutionary conserved NFk-B signalling pathways, through detection of a bacterial cell wall component, the peptidoglycan (PG), by PGRPs ("Peptidoglycan Recognition Proteins") receptors. During my thesis, I studied the consequences of uncontrolled activation of one of these NFk-B pathways, the IMD pathway, on the physiology of Drosophila. The first project I took part in shows that inactivation of PGRP-LF, a negative regulator of the pathway, leads to the activation of the IMD pathway in ectodermal derived larval tissues without any infection. This pathway activation in those tissues leads to an ectopic expression of the DIAP1 ("Drosophila Inhibitor of Apoptosis 1") protein, wich is sufficient to induce some adult Drosophila structures malformations, demonstrating a previously unknown developmental function of the IMD pathway during Drosophila metamorphosis. In the second part of my thesis, I was able to demonstrate that during chronic infection, maintenance of IMD pathway activation leads to the appearance of many deleterious phenotypes such as a decreased lifespan, locomotor disorders, neurodegeneration and atrophy of the fat body and ovaries. My results show that IMD pathway activation specifically in the perineurial glia, a component of the blood-brain barrier, actively contributes to the development of the observed phenotypes. Demonstrating for the first time that fhe fly's brain is able to detect circulating PG in the hemolymph.
474

Desenvolvimento das modificações morfofuncionais em ovários de Astyanax altiparanae Garutti e Britski 2000 (Teleostei, Characidae) / Development of morphofunctional changes in the ovaries of Astyanax altiparanae Garutti and Britski 2000 (Teleostei, Characidae).

Cassel, Mônica Caroline Pavan 31 March 2017 (has links)
Este estudo apresenta: (1) uma revisão atualizada sobre o desenvolvimento oocitário em teleósteos, as vias de involução no processo de regressão ovariana e a espécie modelo Astyanax altiparanae; (2) a descrição da morfologia ovariana e das células garminativas de A. altiparanae e a caracterização do seu ciclo reprodutivo; (3) a caracterização dos processos de involução de atresia folicular e complexos pós-ovulatórios de A. altiparanae e a localização de proteínas envolvidas nas vias de apoptose e autofagia ao longo desses processos. Foram apresentados neste estudo novos detalhes da oogênese para espécies de Astyanax, sendo que esses novos dados parecem ter aplicação na piscicultura. Além disso, A. altiparanae apresenta um período de desova longo, com pico reprodutivo de outubro a fevereiro, e desenvolvimento oocitário assíncrono. Por fim, parece haver uma interrelação entre as vias de autofagia e apoptose nos processos de involução ovarianos e as vias regulatórias desses processos parecem ser conservadas entre espécies de teleósteos com fertilização externa. / This study presents: (1) an updated review on oocyte development in teleosts, the involution pathways during the process of ovarian regression, and the model species Astyanax altiparanae; (2) the description of the ovarian and germ cell morphology of A. altiparanae and the characterization of its reproductive cycle; (3) the characterization of the involution processes of follicular atresia and post-ovulatory complexes of A. altiparanae and the localization of proteins involved in the apoptosis and autophagy pathways throughout these processes. New details of the oogenesis for Astyanax species were presented in this study, and these new data seem to be applied in fish culture. In addition, A. altiparanae presents a long spawning period, with reproductive peak from October to February, and asynchronous oocyte development. Finally, there seems to be a crosstalk between autophagy and apoptosis pathways in ovarian involution processes and the regulatory pathways of these processes seem to be conserved among species of teleosts with external fertilization.
475

Molecular characterization of entosis / Caractérisation des bases moléculaires de l’entose

Raza, Syed Qasim 26 September 2012 (has links)
L’entose est une forme de mort cellulaire non apoptotique caractérisée par l’internalisation d’une cellule cible vivante dans une cellule hôte vivante. Ce processus de cannibalisme cellulaire qui est également connu sous le nom de « cellule dans une cellule » est retrouvé dans de nombreux cancers humains. Au cours de mes travaux de thèse, nous avons développé différents modèles d’entose in vitro et avons débuté l’identification des protéines qui répriment l’entose en combinant un criblage de petits ARN interférants à une approche de microscopie confocale. Nous avons découvert que la protéine suppressive de tumeur TP53 ainsi que son isoforme Δ133TP53 bloquent le processus d’internalisation cellulaire et l’entose. La perte de l’expression de la protéine TP53 ou de Δ133TP53 entraîne une libération extracellulaire d’adénosine triphosphate ainsi que l’activation du récepteur purinergique P2Y2, deux évènements cellulaires qui aboutissent à l’internalisation d’une cellule par une autre cellule. De plus, nous avons constaté que les cellules cannibales deviennent énescentes à la suite de l’induction de la protéine p21WAF1.Mes travaux de recherche révèlent l’existence d’une nouvelle modalité d’induction de la sénescence cellulaire. De façon surprenante, nous avons également observé que l’induction de la sénescence par l’oncogène RasV12ou à la suite de stress (réplicatifouoxydatif) déclenchait le cannibalisme cellulaire, suggérant que le cannibalisme cellulaire est une caractéristique des cellules sénescentes. L’ensemble de mes travaux de recherche souligne le lien étroit qui existe entre le cannibalisme cellulaire et la senescence. / Entosis is a non-apoptotic cell death process of live internalized cell inside the host/cannibal cell. In human cancers, commonly "cell-in-cell" cytological features have been observed over the period of time. In this study we have established in vitro models of entosis and initiated the identification of entotic repressors by developing fluorescent confocal microscopy screening of small interfering RNA. We identified that TP53 and one of its isoform 133TP53 specifically inhibits the cell internalization. Loss of TP53 or 133TP53 expression increases extracellular ATP release and the consequent activation of purinergic P2Y2 receptors, which signal for engulfment. Cannibal cells activate a senescence program through p21WAF1 induction, revealing a new modality of induction of cellular senescence that can occur in the absence of TP53 or 133TP53. Senescence induced by oncogenic RasV12 and by replicative or oxidative stresses also results in cellular cannibalism, suggesting that cannibalism is a common feature of senescent cells. Altogether, our results provide evidence that cellular cannibalism and senescence are tightly linked.
476

Mécanismes de la chimiothérapie immunogène / Mechanisms of immunogenic chemotherapy

Schlemmer, Frédéric 25 November 2013 (has links)
L’amélioration constante du pronostic des pathologies cancéreuses est le fruit des progrès réalisés dans leur prévention, leur dépistage, leur diagnostic et leur traitement. Malgré l’avènement récent des thérapies ciblées, la chimiothérapie conventionnelle reste souvent le seul recours pour des patients atteints de cancer non opérable ou non éligibles pour ces thérapeutiques novatrices. Certaines chimiothérapies conventionnelles (anthracyclines et oxaliplatine notamment) ont la capacité d’entrainer une mort des cellules tumorales dont les caractéristiques permettent d’induire une réponse immunitaire antitumorale efficace. Cette réponse immunitaire antitumorale spécifique agirait en synergie avec l’effet cytotoxique direct de ces drogues, participant ainsi à leur efficacité. La réponse immunitaire antitumorale induite par la chimiothérapie dépend de plusieurs mécanismes moléculaires et cellulaires clefs identifiés récemment. L’induction d’un stress du réticulum endoplasmique (RE) est à l’origine de l’exposition d’une protéine chaperonne résidente du RE, la calréticuline (CRT), à la surface des cellules mourantes, servant alors de signal de phagocytose pour les cellules dendritiques. La libération dans le milieu extracellulaire de signaux de danger est également essentielle : la protéine nucléaire High Mobility Group Box 1 (HMGB1) sert ainsi de ligand pour le Toll-like récepteur 4 (TLR4), présent à la surface des cellules dendritiques et son activation favorise l’apprêtement et la présentation des antigènes tumoraux aux lymphocytes T cytotoxiques. L’adénosine-5'-triphosphate (ATP) est également libéré par les cellules tumorales, entrainant l’activation des récepteurs purinergiques P2RX7 présents à la surface des cellules dendritiques, activant l’inflammasome NLRP3 et entrainant la libération d’IL-1 par les cellules dendritiques, favorisant alors l’orientation de la réponse immunitaire vers une réponse de type TH1 et la production d’interféron  par les lymphocytes T cytotoxiques. Dans ce travail, nous avons cherché à comparer la capacité de deux drogues issues d’une même classe de chimiothérapie, les sels de platine, à induire une mort cellulaire immunogène des cellules tumorales. Grace à des expériences in vitro et in vivo (modèles murins de vaccination antitumorale et de chimiothérapie sur tumeurs établies), nous avons pu montrer que l’oxaliplatine (OXP), contrairement au cisplatine (CDDP), avait la capacité d’induire une mort immunogène des cellules de cancer colique et que cette différence intra-classe dépendait de la capacité respective de ces deux drogues à entrainer un des phénomènes clés de l’induction d’une mort cellulaire immunogène, l’exposition de la CRT à la surface des cellules tumorales mourantes. Nous avons également pu montrer que l’induction d’une mort cellulaire immunogène des cellules de cancer colique par l’oxaliplatine avait une relevance clinique chez l’homme, l’existence d’un polymorphisme perte-de-fonction du gène tlr4 affectant le pronostic (survie sans progression) de patients traités par chimiothérapie pour un cancer colique métastatique. Par la suite, nous avons mis au point des biosondes permettant d’étudier à grande échelle, à l’aide d’une plateforme de vidéo-microscopie automatisée, la capacité de différentes drogues à induire les différents phénomènes clefs de la mort cellulaire immunogène des cellules tumorales (exposition de la CRT, libération d’HMGB1 et d’ATP). Nous avons ainsi pu montrer que la correction pharmaceutique du défaut d’activation d’un stress du réticulum endoplasmique par le cisplatine permettait de restaurer l’immunogénicité de la mort cellulaire induite par cette chimiothérapie. Ces résultats ouvrent la voie à la découverte de nouvelles molécules susceptibles, à elles seules ou en association à d’autres thérapies connues, d’améliorer le pronostic des néoplasies. / The steady improvement of cancer prognosis is the result of progress in cancer prevention, screening, diagnosis and treatment. Despite the recent advent of targeted therapies, conventional chemotherapy often remains the only solution for patients with non-operable cancer or not eligible for these novel therapies.Some conventional chemotherapy (including anthracyclines and oxaliplatin) has the ability to cause tumor cells death with characteristics able to induce an effective antitumor immune response. This specific antitumor immune response would be synergistic with the direct cytotoxic effect of these drugs and contribute to their efficacy. The antitumor immune response induced by chemotherapy depends on several key cellular and molecular mechanisms recently identified. The induction of an endoplasmic reticulum (ER) stress is necessary for the exposure of calreticulin (CRT), an ER-resident chaperone protein, on the surface of dying cells, then acting as a phagocytosis signal for dendritic cells. Release of danger signals into the extracellular medium is also essential. The nuclear protein High Mobility Group Box 1 (HMGB1) is a ligand of the Toll-like receptor 4 (TLR4) on the surface of dendritic cells. TLR4 activation promotes the processing of tumor antigens and their presentation to cytotoxic T lymphocytes. Adenosine-5'-triphosphate (ATP) is also released by tumor cells, leading to the activation of the purinergic receptors P2RX7 expressed on the surface of dendritic cells, activating the NLRP3 inflammasome and causing the release of IL-1β by dendritic cells, while promoting the orientation of the immune response towards a TH1 response and the production of γ-interferon by cytotoxic T lymphocytes.In this work, we aimed to compare the ability of two drugs of a same class of chemotherapy, the platinum derivates oxaliplatin (OXP) and cisplatin (CDDP), to induce immunogenic death of tumor cells. Thanks to in vitro and in vivo experiments (models of tumor vaccination and chemotherapy on established tumors in mice), we showed that OXP, in contrast to CDDP, has the ability to induce immunogenic death of colon cancer cells. This intra-class difference depends on the ability of each drug to cause one of the key phenomena of immunogenic cell death: the induction of the exposure of the CRT to the surface of dying tumor cells. We could also show that the induction of immunogenic death of colon cancer cells by OXP had clinical relevance in humans. Indeed, the existence of a loss-of-function polymorphism of tlr4 affects the prognosis (PFS) of patients treated with OXP-based chemotherapy regimen for a metastatic colorectal cancer. Subsequently, we developed biosensors to study the ability of different drugs to induce key phenomena of cell death immunogen tumor cells (CRT exposure, HMGB1 and ATP release) using high-content screening by an automated video-microscopy platform. We showed that a pharmaceutical correction of the inability of cisplatin to induce an endoplasmic reticulum stress could restore the immunogenicity of cisplatin-induced tumor cell death. These results open the way to the discovery of new molecules that, alone or in combination with other known therapies, could improve the prognosis of cancer.
477

Autophagy gene atg-18 regulates C. elegans lifespan cell nonautonomously by neuropeptide signaling

Unknown Date (has links)
In the round worm C. elegans, it has recently been shown that autophagy, a highly conserved lysosomal degradation pathway that is present in all eukaryotic cells, is required for maintaining healthspan and for increasing the adult lifespan of worms fed under dietary restriction conditions or with reduced IGF signaling. It is currently unknown how extracellular signals regulate autophagy activity within different tissues during these processes and whether autophagy functions cell-autonomously or nonautonomously. We have data that for the first time shows autophagy activity in the neurons and intestinal cells plays a major role in regulating adult lifespan and the longevity conferred by altered IGF signaling and dietary restriction, suggesting autophagy can control these phenotypes cell non-autonomously. We hypothesize that autophagy in the neurons and intestinal cells is an essential cellular process regulated by different signaling pathways to control wild type adult lifespan, IGF mediated longevity and dietary restriction induced longevity. Excitingly we also have found that in animals with reduced IGF signaling autophagy can control longevity in only a small subset of neurons alone. Autophagy in either specific individual chemosensory neurons or a small group of them is completely sufficient to control IGF mediated longevity. This work provides novel insight to the function and regulation of autophagy which will help shed light on understanding this essential process in higher organisms, including mammals. / Includes bibliography. / Dissertation (Ph.D.)--Florida Atlantic University, 2017. / FAU Electronic Theses and Dissertations Collection
478

Imunomarcação de proteínas relacionadas à apoptose em mastocitomas cutâneos caninos e seu valor como indicador prognóstico / Immunostaining of apoptosis-related proteins in canine cutaneous mast cell tumors and its value as prognostic indicators

Barra, Camila Neri 18 August 2015 (has links)
A desregulação da apoptose, principalmente da via mitocondrial, exerce papel na progressão tumoral, resistência à quimioterapia, além de favorecer a formação de metástases por permitir a sobrevivência de células tumorais na circulação e outros microambientes teciduais. No presente estudo, foram avaliados 58 mastocitomas cutâneos caninos, provenientes de 50 animais submetidos à cirurgia excisional como única forma de tratamento. Os tumores foram graduados de acordo com o sistemas de estabelecidos por Patnaik, Ehler e MacEwen (1984) e Kiupel et al. (2011). As expressões das proteínas relacionadas à via intrínseca da apoptose, BCL2, BAX, APAF1, Caspase 9 e Caspase 3, foram caracterizadas por meio de imuno-histoquímica. Os resultados obtidos das imunomarcações foram comparados às graduações histopatológicas, bem como à mortalidade em função do tumor e ao tempo de sobrevida pós-cirúrgico. Observamos maior expressão de BAX em mastocitomas de grau III, bem como menor expressão de BCL2 em tumores de alto grau. A detecção imuno-histoquímica de BAX foi considerada um indicador prognóstico para sobrevida e mortalidade em função da doença, enquanto que as de APAF1 e BCL2 adicionaram valor prognóstico às graduações histopatológicas melhorando a previsão da sobrevida pós-cirurgia / Deregulation of apoptosis, especially in the mitochondrial pathway, plays a role in tumor progression, resistance to chemotherapy, and favor the formation of metastases by allowing the survival of tumor cells in the blood stream and other tissue microenvironments. In the present study, we evaluated 58 canine cutaneous mast cell tumors, from 50 dogs, which were submitted to excisional surgery alone. The tumors were graded according to the systems proposed by Patnaik, Ehler and MacEwen (1984) and Kiupel et al. (2011). The expression of the apoptosis-related proteins BCL2, BAX, APAF1, caspase 9 and caspase 3 was characterized by immunohistochemistry. Immunohistochemical results were compared with the histopathological grades, mortality due to the tumor and post-surgical survival time. We observed increased expression of BAX in grade III mast cell tumors and lower expression of BCL2 in high-grade tumors. Immunohistochemical detection of BAX was considered an independent indicator of prognosis for survival and mortality due to the disease, whereas APAF1 and BCL2 added prognostic value to the histopathological grading systems improving the prediction of survival post surgery
479

Estudo da via de sinalização da apoptose de neutrófilos em atletas praticantes de meia maratona suplementados ou não com óleo de peixe. / Apoptosis signaling pathway study in the neutrophils of marathon runners supplemented or not supplemented with fish oil.

Santos, Vinicius Coneglian 22 May 2015 (has links)
O exercício físico intenso está associado à mudanças na quantidade, na função e na morte de neutrófilos. Tem sido proposto que a suplementação com óleo de peixe minimiza os efeitos imunossupressivos do exercício físico e que a fosfatidilcolina também poderia exercer importantes efeitos sobre a função de leucócitos. O objetivo do estudo foi o de investigar os efeitos da meia maratona e da suplementação com lecitina de soja ou óleos de peixe ricos em EPA ou DHA na apoptose de neutrófilos de atletas amadores. Quarenta e seis atletas amadores, foram avaliados antes e após duas competições de meia maratona. Na primeira meia maratona, os atletas não foram suplementados. As coletas de sangue dos atletas foram realizadas nas seguintes condições: Em repouso e imediatamente após a competição. No primeiro dia, após a primeira meia maratona, iniciou-se a suplementação. Os indivíduos foram suplementados diariamente com 3g de óleo de peixe ou lecitina de soja, por 60 dias, e divididos em 3 grupos: 1) Lecitina, 2) DHA e 3) EPA. Os atletas foram reavaliados 8 semanas após o início da suplementação. Já na segunda meia maratona, com todos os atletas suplementados, as coletas de sangue foram realizadas nas mesmas condições da primeira corrida. Neste estudo avaliamos os receptores da apoptose de neutrófilos (Fas e TRAIL), as moléculas de adesão (L-selectina e ICAM-1), a fragmentação de DNA e a externalização de fosfatidilserina. Além disso, foi avaliada a concentração plasmática das citocinas TNF-alfa, IL-8, IL-6, IL-4, IL-10 e IL-1beta. As enzimas creatina quinase e lactato desidrogenase, a concentração de mioglobina, proteína C reativa e o número de leucócitos e neutrófilos também foi determinada. A meia maratona aumentou a atividade das enzimas CK e LDH e a concentração de mioglobina em todos os grupos estudados, sendo que a suplementação não apresentou nenhum efeito sobre estes parâmetros. Já o número de neutrófilos e leucócitos, aumentaram após a meia maratona em todos os grupos, e a suplementação provocou este aumento somente nos grupos EPA e Lecitina. Em neutrófilos de atletas, a meia maratona diminuiu a expressão dos receptores Fas e TRAIL e das móleculas de adesão ICAM-1 e L-selectina em todos os grupos, por outro lado, aumentou a fragmentação de DNA (somente no grupo DHA) e a externalização de FS (DHA, EPA e Lectina). A meia maratona também elevou a concentração das citocinas IL-8, IL-6 e IL-10 em todos os grupos. Já a suplementação (DHA, EPA ou lecitina de soja) diminuiu a fragmentação de DNA e a expressão do receptor Fas em neutrófilos. Além disso, aumentou a expressão de TRAIL, ICAM-1, L-selectina e a externalização de fosfatidilserina. Em relação a concentração plasmática de citocinas a suplementação reduziu a concentração de TNF-alfa e aumentou a de IL-10 em todos os grupos. Enquanto que, a concentração de IL-4 aumentou somente nos grupos DHA e EPA. Concluímos que a suplementação com lecitina de soja apresenta efeitos semelhantes aos dos óleos de peixe ricos em EPA ou DHA sobre a função de leucócitos em atletas amadores. / Intense physical exercise is associated with changes in the number, function and death of neutrophils. It has been proposed that supplementation with fish oil rich minimizes the immunosuppressive effects induced by intense physical exercise and phosphatidylcholine could also have significant effects on leukocytes function. The aim of this study was to investigate the effects of a half-marathon and fish oil suplemmentation rich in EPA or DHA or soy lecithin suplemmentation on neutrophils apoptosis of amateur athletes. Forty-six recreational athletes were evaluated before and after two half marathons. In the first competition the athletes did not receive supplementation. Blood samples were collected in the following conditions: In rest and immediately after competition. On the first day, after the first half-marathon, supplementation began. The subjects were supplemented with 3 g of fish oil or soy lecithin daily for 60 days and divided into 3 groups: 1) Lecithin 2) DHA 3) EPA. The athletes were assessed 8 weeks after the start of supplementation. In the second half-marathon, with all the supplemented athletes, blood samples were collected under the same conditions of the first competition. In this study were evaluated the receptors of neutrophils apoptosis (Fas and TRAIL), adhesion molecules (L-selectin and ICAM-1), DNA fragmentation and phosphatidylserine externalization. Moreover, the plasma concentration of TNF-alpha, IL-8, IL-6, IL-4, IL-10 and IL-1beta cytokines was evaluated. The enzymatic activity of creatine kinase and lactate dehydrogenase, plasma concentration of myoglobin, and C-reactive protein and blood counts was also determined. The half-marathon increased the enzymatic activity of CK and LDH and the myoglobin concentration in all groups studied, and the supplementation had no effect on these parameters. The number of neutrophils and leucocytes increased in all groups after half marathon, and the supplementation caused this increase only in the EPA and Lecithin groups. In athletes neutrophils, the half-marathon decreased the expression of Fas and TRAIL receptors and of ICAM-1 and L-selectin adhesion molecules. On the other hand, it increased DNA fragmentation (only in the DHA group) and phosphatidylserine externalization (DHA, EPA and Lecithin groups). The half-marathon also increased concentrations of IL-8, IL-6 and IL-10 cytokines in all groups. The Supplementation (DHA or EPA or soy lecithin) decreased DNA fragmentation and Fas receptor expression in neutrophils. Moreover, increased expression of TRAIL, ICAM-1, L-selectin and phosphatidylserine externalization. In relation to cytokines plasma concentration the supplementation decreased TNF-alfa and increased the concentration of IL-10 in all groups. Whereas, IL-4 concentration increased only DHA and EPA groups. In conclusion, supplementation with soy lecithin has similar effects to the fish oils rich in EPA or DHA on leukocyte function amateur athletes.
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Caracterização da via de ativação de neurotoxicidade induzida pela Anidroegconina Metil Éster (AEME) in vitro / Activation pathways characterization related to the Anhydroegconin Methyl Ester (AEME)-induced neurotoxicity in vitro.

Udo, Mariana Sayuri Berto 07 December 2017 (has links)
O consumo mundial de cocaína vem crescendo e no Brasil já são estimados mais de 2 milhões de usuários, destes 370 mil usam regularmente o crack. A cocaína, em suas diversas formas, é um psicoestimulante com alto potencial de abuso e a forma fumada causa à seus usuários mais complicações de saúde do que as demais formas. Muitas dessas complicações estão relacionadas às funções cognitivas, como comprometimento da atenção e memória. O usuário de crack, no ato de fumar, está sujeito tanto à ação da cocaína volatilizada quanto a dos seus produtos de pirólise, principalmente da anidroecgnonina metil éster (AEME). Considerando que pouco se conhece a respeito da AEME, ou de sua associação com cocaína, que os distúrbios cognitivos podem estar relacionados à morte neuronal e que o hipocampo é uma das principais estruturas encefálicas relacionada com cognição e memória, este trabalho visou investigar as vias de ativação de morte celular decorrente das exposições à 1 mM de AEME, 2 mM de cocaína, bem como da associação de ambas (C + A), por 3, 6 e 12 h. Para tanto, utilizamos neurônios hipocampais de embriões de rato no 18º dia embrionário (E18) que foram mantidos em cultura por até 7 dias (DIV7), quando foram feitas as exposições. Nossos resultados mostraram que em 3 h a cocaína e a AEME promoveram aumento de atividade enzimática (pelo teste de MTT) que se reverteu ao longo de 12 h. Além disso, AEME aumentou na permeabilidade da membrana plasmática em 6 h que se manteve em 12 h. Embora essas alterações tenham ocorrido em 3 h e 6 h, caspase-8 se ativou apenas em 12 h, ativando também a sinalização apoptótica com a externalização de FS. A cocaína ativou o processo autofágico a partir de 3 h aumentando a quantificação de LC3 II, mas apresentou redução de células com vesículas ácidas em 6 h e 12 h, sugerindo que esta promova morte neuronal por causar falha no fluxo autofágico. A AEME apresentou somente aumento de células com vesículas ácidas em 3 h, revertendo-se já em 6 h, indicando que o processo autofágico só se fez presente no primeiro horário, dando vez à programação de apoptose celular, por ativação da via extrínseca. A associação dessas substâncias apresentou-se mais neurotóxica do que as substâncias isoladas, com redução de células íntegras a partir de 3 h de exposição, ativação de caspase-8 e externalização de FS em 6 h, sem envolver o sistema autofágico. Além disso, as características morfológicas observadas em 6 h, como o aumento do tamanho do núcleo e do corpo celular que se tornaram picnóticos em 12 h, podem sugerir que a neurotoxicidade induzida por C + A seja por necroptose, onde a ativação de caspases resulta em um processo tipo necrótico. Assim, concluímos que, embora a literatura mostre morte neuronal por apoptose a partir de 24 h de exposição para cocaína e para AEME, as respostas celulares que levam à este fim iniciam-se já em 12 h, por ativação da via extrínseca e a associação destas substâncias é ainda mais neurotóxica, iniciando a sinalização de morte já em 6 h e induzindo uma morfologia tipo necrótica. / Cocaine market is increasing all around the world. In Brazil it is estimated that almost 2 million people make usage of this substance which 370 thousand people use the crack form. Cocaine is a psychostimulant with large potential for abuse and the smokable form produces more health problems than the other routes of use, mainly in the cognitive field related to compromising attention, memory and decision take. The crack users are exposed to both volatized cocaine and their pyrolysis products, which the main product is the anhydroecgonine methyl ester (AEME). Considering that the cognitive disturbs could be related to neurons death, the memory functions are also related to the hippocampal functions, and little is known about the AEME neurotoxicity or even the combination of cocaine and AEME in cell fate, our study aims to characterize the time and pathways related to the hippocampal neurotoxicity induced by 2 mM of cocaine, 1 mM of AEME and the association (C + A) of both substances during 3 h, 6 h and 12 h of exposure. Our results showed that cocaine and AEME increased enzymatic activity (MTT test) in 3 h but it reversed during 12 h of exposure. Moreover, AEME increased cell permeability in 6 h keeping it until 12 h. Although theses early alterations, both substances activated caspase -8 after 12 h when early apoptosis was also observed by the FS externalization. Cocaine activated the autophagic process at 3 h increasing the LC3 II quantification, but decreased the number of cell with acid vesicle at 6 h and 12 h, suggesting neuronal death due to failure in the autophagic flux. AEME showed increased in cell number with acid vesicle only in 3 h which returned after 6 h suggesting that the autophagic process gave place to the apoptotic program starting from the extrinsic pathway. The association of cocaine and AEME was shown more neurotoxic than them alone, decreasing the number of integral cells after 3 h, activating caspase -8 and promoting FS externalization after 6 h without involving the autophagy. In addition, taking the C + A morphology in 6 h, where it was observed increasing of nucleus and soma size that became pyknotic at 12 h, we suggest that the neuronal death could occur by necroptosis because this composition activated caspase -8 and resulted in necrotic like morphology. Thus, we conclude that cocaine- and AEME-induced apoptosis neuronal death starts in 12 h of exposure by the extrinsic pathway and the association of both substances is more neurotoxic than they alone, starting earlier after 6 h and resulting in a necrotic-like morphology.

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