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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.
1

Pubertal changes in the expression of fertility associated antigen in Bos indicus and Bos taurus bulls

Novosad, Aaron M. 25 April 2007 (has links)
Fertility Associated Antigen (FAA) produced by the accessory sex glands and contained within the seminal fluid binds heparin and facilitates capacitation in ejaculated sperm, resulting in improved fertility in bulls capable of producing the protein. In this study, a total of 206 bulls derived from three populations were evaluated for the presence or absence of FAA through utilization of the Repro Test at three semen collections over a 60-d period. Across all collections, the percentage of FAA Negative bulls ranged from 13.64 to 36.11%. Within the three populations, 32, 33, and 67 bulls were observed at three different collections, of which 3.03, 9.09 and 4.48% were FAA Negative at all three collections, respectively. Furthermore, 27.27, 33.33, and 20.90% of bulls were observed to have variations within their FAA status after providing an initial FAA Positive result, respectively. Bull age, sperm concentration, progressive forward motility, percent normal sperm, ejaculate volume, and scrotal circumference were determined to be significantly different between FAA Negative and FAA Positive bulls in at least one collection. However, no consistent trend was observed across populations, or collections within a population, with regard to a relationship between these variables and FAA. Furthermore, of fourteen bulls that produced an ejaculate in which no sperm was detected, 78.57% (n=11) were FAA Positive despite the lack of sperm within the ejaculate. No single variable commonly measured to determine bull fertility was consistent in predicting the FAA status of bulls. The ability to produce FAA precedes puberty and the Repro Test can be used to identify FAA in prepuberal bulls. However, a large percentage of bulls, both prepuberal and peripuberal, are capable of displaying variation in their FAA status (as determined by the Repro Test) over time.
2

PATTERNS OF USING ANTIHYPERTENSIVE DRUGS IN OUTPATIENT SETTINGS / “VAISTŲ NUO HIPERTENZIJOS VARTOJIMO AMBULATORINĖMIS SĄLYGOMIS SAVYBIŲ TYRIMAS“

Feigelman, Leonid 18 June 2014 (has links)
We did not know the patterns of using antihypertensive drugs in outpatient settings in Israel that is why we raised a research aim to analyze the pattern of use of HBP in outpoint setting. In order to meet this aim we raised several research objectives:. 1) Does lifestyle modification is important for the patient for blood pressure control? 2) Do the patients need to change their medication at set of time until BP goals reached? 3) Does the use of more than one drug would help achieving better HBP results? Does the use of single doses combination would have better affect then using fixed dose combination? 4) How often noncompliance take in HBP control? 5) How many patients suffer from side effects? Methods: a questionnaire composed of 36 questions and qualitative statistical analysis. / Mes nežinojome, kad naudojant antihipertenzinių vaistinių preparatų ir ambulatorinėmis Izraelyje, kuris yra, kodėl mes iškėlė Tyrimo tikslas išanalizuoti naudojimo HBP Išėjo taško nustatymo modelį modelius. Siekiant įgyvendinti šį tikslą, mes iškėlė kelis mokslinių tyrimų tikslams:. 1) Ar gyvenimo būdo pakeitimas yra svarbus kraujospūdžio kontrolės pacientui? 2) Ar pacientai turi pakeisti savo vaistą esant rinkinį, kol pasiekė BP tikslai? 3) Ar iš daugiau nei vieno narkotiko naudojimas padėtų pasiekti geresnių HBP rezultatus? Ar vienos dozės deriniu būtų geriau veikia tada naudojant fiksuotų dozių derinys? 4) Kaip dažnai nesilaikymo imtis HBP kontrolės? 5) Kiek pacientų kenčia nuo šalutinio poveikio? Metodai: Klausimynas sudarytas iš 36 klausimų ir kokybinio statistinę analizę.
3

Dissecting the signaling pathways controlling inflammation during Gram-negative bacterial infections : the role of ALPK1, TIFA and TRAF6 during Shigella flexneri infection / Dissection des voies de signalisation contrôlant l'inflammation lors d'infections bactériennes à Gram négatif : le rôle de ALPK1, TIFA et TRAF6 lors d'une infection à Shigella flexneri

Milivojevic, Milica 16 November 2017 (has links)
Les cellules épithéliales constituent la première ligne de défense face à l’infection et jouent un rôle actif dans l'immunité innée. Par la sécrétion locale de cytokines, ces cellules sont capables d'orchestrer la réponse immunitaire contre les pathogènes invasifs. L'activation des récepteurs de reconnaissance de pathogènes, qu’ils soient intracellulaires ou extracellulaires, conduit à une cascade de signalisation complexe. Cette dernière entraîne l'activation du facteur de transcription NF-kB ainsi que la production ultérieure de cytokines pro-inflammatoires. Cependant, les mécanismes moléculaires qui gouvernent ce processus n'ont pas été entièrement élucidés. La bactérie à Gram négatif Shigella flexneri est un pathogène humain majeur à l’origine de la dysenterie bacillaire. Cette maladie se caractérise par une inflammation aiguë du colon qui peut entraîner la destruction du tissu intestinal et même dans les cas les plus graves, la mort. En effet, S. flexneri peut envahir les cellules épithéliales du colon et se répliquer dans leur cytoplasme. Après la détection de bactéries intracellulaires, les cellules infectées et non infectées déclenchent des voies de signalisation inflammatoire, ce qui entraîne une production massive d'interleukine-8. En utilisant S. flexneri comme modèle d'infection, nous avons identifié une nouvelle voie de signalisation qui joue un rôle central dans l'activation de NF-kB et la production d'IL-8 qui en résulte lors des infections bactériennes à Gram négatif. Après la détection cytosolique des bactéries, les protéines TIFA forment des oligomères à travers un processus dépendant de leur thréonine en position 9, ainsi que de leur domaine « Forkhead-associated ». D’une part, ces oligomères interagissent avec TRAF6, ce qui conduit à l’oligomérisation de cette dernière et à l'activation subséquente de NF-kB. D'autre part, nous montrons que l'oligomérisation de TIFA dépend de la kinase ALPK1 et que cette voie est activée en réponse au métabolite bactérien heptose-1, 7-bisphosphate. Ces observations pourraient être étendues au pathogène entéro-invasif Salmonella typhimurium ainsi qu'à la bactérie extracellulaire Neisseria meningitidis. Nos résultats démontrent donc le rôle central de la voie de signalisation ALPK1-TIFA-TRAF6 en réponse aux pathogènes bactériens à Gram négatif intracellulaires et extracellulaires. Ainsi, ces travaux contribuent à une meilleure compréhension des mécanismes moléculaires régissant la réponse immunitaire des cellules épithéliales aux bactéries pathogènes. / Epithelial cells represent the first line of defense against pathogens and play an active role in innate immunity. Via local secretion of cytokines, they are able to orchestrate the immune response against invading pathogens. The activation of both intracellular and extracellular pathogen recognition receptors leads to a complex signaling cascade, resulting in the activation of the transcription factor nuclear factor kB(NF-kB)and the subsequent production of pro-inflammatory cytokines. However, the molecular mechanisms governing this process have not been fully elucidated. The Gram-negative bacterium Shigella flexneriis an important human pathogen and the causative agent of bacillary dysentery. This disease is characterized by acute inflammation of the colon resulting in the destruction of the intestinal tissue and, in severe cases, death. S. flexneri can invade and replicate within colonic epithelial cells. Following detection of the bacteria, both infected and uninfected bystander cells initiate inflammatory signaling pathways, which result in massive interleukin-8 (IL-8) production by the latter. Using S. flexneri as a model of infection, we have identified a novel signaling pathway, which is central to the activation of NF-kB and the subsequent production of IL-8 during Gram-negative bacterial infections. Following the cytosolic detection of bacteria, the protein TRAF-interacting factor with forkhead-associated domain (TIFA) forms oligomers, a process dependent on its threonine at position 9 and theforkhead-associated domain. These oligomers interact withTNF receptor associated factor (TRAF)6, leading to its oligomerization and the subsequent activation of NF-kB. In addition, we show that oligomerization of TIFA is dependent on the kinase alpha-kinase(ALPK)1 and that this pathway is activated in response to the detection of the bacterial metabolite heptose-1, 7-bisphosphate (HBP). These observations could be extended to the enteroinvasive pathogen Salmonella typhimurium as well as the extracellular bacteria Neisseria meningitidis. Our results therefore demonstrate the central role of the ALPK1-TIFA-TRAF6 signaling pathway in response to HBP of both intracellular and extracellular Gram-negative bacterial pathogens, and offer a better understanding of the molecular mechanisms governing the epithelial cell immune response to pathogenic bacteria.
4

Etude du stress oxydatif dans l’hypertrophie bénigne de la prostate et mise en évidence de l’effet de la propolis contre le cancer de la prostate in vivo sur un modèle animal de rat Wistar et ex vivo sur les cellules LNCaP du cancer de la prostate hormono-sensibles / Study of the oxidative stress in benign prostatic hyperplasia and the effect of propolis against prostate cancer in vivo on an animal model of Wistar rat and ex vivo on hormone-sensitive (LNCaP) prostate cancer cell lines

Zabaiou, Nada 23 October 2017 (has links)
L’HBP et le cancer de la prostate constituent les deux maladies prostatiques les plus répandues chez l’homme âgé. La compréhension de leur étiologie et de leur pathogenèse est nécessaire afin de permettre la prévention mais aussi la recherche et le développement de nouveaux agents thérapeutiques. Notre but est d’étudier l’implication du stress oxydatif dans l’HBP et d’étudier l’effet de l’extrait de propolis sur le cancer de la prostate in vivo chez le rat Wistar et in vitro sur les cellules LNCaP. Nous avons montré que : 1) Le stress oxydatif joue le rôle de promoteur dans le développement de l’HBP, 2) Le benzo(a)pyrène administré aux rats Wistar induit le développement du cancer de la prostate, 3) La propolis induit la diminution de la prolifération, de l’expression du Ki-67 (-49 %) et de l’expression de AhR chez le rat Wistar, 4) La propolis possède un effet antiprolifératif sur les cellules LNCaP via le blocage de la signalisation de AR. / BPH and prostate cancer are the two most prevalent prostatic diseases in elders. Understanding their etiology and pathogenesis is necessary in order to prevent them and to enhance both research and development of new therapeutic agents. Our goal is to study the implication of oxidative stress in BPH and to study the effect of propolis extract on prostate cancer in vivo in Wistar rats and in vitro on LNCaP cells. We have shown that: 1) Oxidative stress acts as a promoter in the development of BPH, 2) Benzo(a)pyrene administered to Wistar rats induces the development of prostate cancer, 3) Propolis induces a decrease in proliferation, Ki-67 expression (-49%) and AhR expression in the Wistar rat, (4) Propolis has an antiproliferative effect on LNCaP cells via AR signaling blockade.
5

Exploring Interoception

Kearney, Hannah January 2018 (has links)
Body ownership is a complicated and multifaceted percept. Although we subjectively perceive body ownership to be a stable component of our identity, recent work has illustrated that body ownership is a dynamic construct that is constantly updated by the integration of current endogenous and exogenous body-related information. The goal of this study was to explore the relation between these endogenous (interoceptive) and exogenous (exteroceptive) channels of information. We investigated this by using a heartbeat perception (HBP) task to measure interoceptive accuracy, and the Rubber Hand Illusion (RHI) to measure malleability of body ownership. Based on prior findings, we hypothesized that the less accurate you are at counting your heartbeats, the more susceptible you will be to the RHI (i.e. the more malleable your sense of body ownership will be). In addition, we were also interested in exploring the relationship between interoception and emotion recognition ability (ERA). In this experiment, we failed to induce the RHI, and thus could not investigate the relationship between endogenous and exogenous body-related information. However, we successfully demonstrated the reliability of the interoceptive accuracy HBP task, as well as demonstrated that interoceptive accuracy is not related to ERA. / Thesis / Master of Science (MSc)
6

Exploring underlying mechanisms driving the onset of stress-induced insulin resistance

Otto, Delita 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2012. / ENGLISH ABSTRACT: Physical and psychological stressors trigger activation of the hypothalamo-pituitary-adrenocortical (HPA) axis that leads to enhanced secretion of glucocorticoids e.g. cortisol. Moreover, chronic activation of this pathway may elevate oxidative stress that is linked to the onset of insulin resistance and cardiovascular diseases (CVD). Our laboratory previously found that oxidative stress increases flux through metabolic circuits such as the hexosamine biosynthetic pathway (HBP), in effect increasing its modification of target proteins post-transcriptionally with O-GlcNAc moeities. This in turn may alter protein function and contribute to the onset of myocardial insulin resistance and impaired contractile function. Since the underlying mechanisms linking chronic stress to cardiometabolic pathophysiology are poorly understood, we hypothesised that cortisol elicits myocardial oxidative stress, HBP activation, and decreased glucose uptake (due to attenuated glucose transport functionality) with detrimental outcomes, i.e. insulin resistance and apoptosis. To investigate this hypothesis we established an in vitro model using HL-1 cardiomyocytes, with which we evaluated the degree of O-GlcNAcylation and oxidative stress in response to a range of time-dose treatments with dexamethasone (synthetic glucocorticoid). Glucose transporter 4 (GLUT4) translocation to the sarcolemma was also assessed. In agreement with the literature, results suggest that GLUT4 translocation is significantly decreased subsequent to dexamethasone treatment. Although no significant differences were observed with regards to oxidative stress or O-GlcNAcylation, the data show that dexamethasone increased the latter with a maximal effect after two hours exposure to the 10-6 M dose. Although our results were not conclusive, the data suggest a potential novel link between dexamethasone exposure, HBP activation and decreased GLUT4 translocation. Based on our findings we propose that detrimental effects of chronic stress on the heart may be mediated by increased HBP flux. Given that glucocorticoid excess and GLUT4 dysregulation have been associated with insulin resistance (and related metabolic derangements and diseases), these results provide new targets for potential therapeutic agents. / AFRIKAANSE OPSOMMING: Fisiese sowel as psigologiese stressors veroorsaak die aktivering van die hipotalamiese-hipo seale-bynier (HHB) pad wat lei tot die verhoogde sekresie van glukokortikoïede soos kortisol. Kroniese aktivering van hierdie pad kan ook oksidatiewe stres verhoog wat weer tot insulienweerstandigheid en kardiovaskulêre siektes (KVS) kan lei. Navorsing uit ons laboratorium het voorheen bewys dat oksidatiewe stres 'n toename in vloei deur metaboliese paaie soos die heksoamine biosintetiese pad (HBP) kan veroorsaak deur die modi sering van teikenproteïene met O-GlcNAc motiewe. Dit kan weer proteïen funksie verander en bydra tot die ontstaan van miokardiale insulienweerstandigheid en verswakte kontraktiele funksie. Die onderliggende meganismes wat kroniese stres aan kardiometaboliese pato siologie verbind word nog nie goed verstaan nie, daarom is ons hipotese dat kortisol miokardiale oksidatiewe stres veroorsaak, die HBP pad aktiveer, en glukose opname verminder (deur die funksionele onderdrukking van glukose transport), wat nadelige uitkomste soos insulienweerstandigheid en apoptose tot gevolg kan hê. Om hierdie hipotese te ondersoek, is 'n in vitro model van HL-1 kardiomiosiete gebruik waarmee die graad van O-GlcNAsilering en oksidatiewe stres in reaksie op 'n reeks tyd-konsentrasie behandelings met deksametasoon (sintetiese glukokortikoïed), bepaal is. Glukose transporter 4 (GLUT4) translokasie na die sarkolemma is ook geasseseer. In ooreenstemming met die literatuur, is GLUT4 translokasie insiggewend onderdruk tydens deksometasoon behandeling. Alhoewel geen insiggewende verskille rakende oksidatiewe stres en O-GlcNAsilering gevind is nie, het ons data aangedui dat laasgenoemde deur deksametasoon vermeerder het na twee ure van blootstelling aan die 10-6 M konsentrasie. Alhoewel ons resultate geen afdoende bewys lewer nie, stel dit wel voor dat daar 'n potensiële verbintenis tussen deksametasoon behandeling en 'n afname in GLUT4 translokasie is. Gebasseer op ons bevindings, stel ons voor dat die nadelige e ekte van kroniese stres op die hart bemiddel kan word deur 'n toename in vloei deur die HBP. Gegewe dat 'n oormaat glukokortikoïede en GLUT4 wanregulering geassosieer is met insulien weerstandigheid (en verbandhoudende metaboliese veranderinge en siektes), verskaf hierdie resultate nuwe teikens vir potensiële terapeutiese ingrepe.
7

Function of granulocytes after burns and trauma, associations with pulmonary vascular permeability, acute respiratory distress syndrome, and immunomodulation

Johansson, Joakim January 2013 (has links)
Background: Our innate immunesystem protects us from infections but, since its methods is not all specific for microorganisms, may also induce collateral damage. Severe physical injury often proved deadly throughout evolution. Such injuries may induce massive collateral damage. Nowadays we can initiate advanced critical care for affected patients and save them from imminent trauma-related death. We are therefore faced with the fact that the collateral damage from the immune system may pose a major threat to the patient, the pathophysiology of which is not amenable to direct medical treatment and which leaves us with only passive supportive measures. In this thesis we investigated the role of leucocytes under such circumstances. Our main aim was to understand better the role of leucocytes in the development of increased vascular permeability after burns and trauma. More specifically we investigated the impact of an injury on the function of leucocytes such as the dynamic change of certain cell-surface receptors on the leucocytes and in their numbers and immature forms. We wanted to find out if the increased pulmonary vascular permeability after a burn could be mediated through heparin binding protein (HBP) released from granuloctes, and whether HBP could be used as a biomarker for respiratory failure after trauma. We also wanted to confirm the possible role of histamine as a mediator of the systemic increase in vascular permeability after burns. Methods: The dynamic change of cell-surface receptors was measured by flow-acquired cytometer scanning (FACS) on blood samples taken after burns. The concentrations of HBP after a burn and mechanical trauma were analysed in plasma. Pulmonary vascular permeability after a burn was assessed using transpulmonary thermodilution. The histamine turnover after a burn was assessed with high performance liquid chromatography (HPLC) for concentrations of histamine and methylhistamine in urine. Results: We confirmed earlier investigations showing altered expression of receptors on leucocytes after a burn, receptors intimately associated with leucocyte functions (study I). In a pilot study of 10 patients we measured plasma concentrations of HBP and found them to be increased soon after a burn (study II). This finding was not confirmed in a larger, more extensive and specific study of 20 patients. We did, however, find an association between alterations in the number of leucocytes soon after a burn and pulmonary vascular permeability, indicating that they had a role in this process (study III). In another study of trauma (non burn) we found an association between the concentration of HBP in early plasma-samples after injury and the development of ARDS, indicating that granulocytes and HBP have a role in its aetiology (study IV). We found a small increase in urinary histamine and normal urinary methylhistamine concentrations but had anticipated a distinct increase followed by a decrease after reading the current papers on the subject. This indicates that the role of histamine as a mediator of increased vascular permeability after burns may have been exaggerated (study V). Conclusions: We conclude that leucocytes are affected by burns and trauma, and it is likely that they contribute to the development of respiratory failure and acute respiratory distress syndrome (ARDS). HBP is a candidate biomarker for the early detection of ARDS after trauma, and the white blood count (WBC) is a useful biomarker for the detection of decreased oxygenation soon after a burn.
8

Étude de la maturation de l'extrémité 3' non traduite et de la traduction de l'ARN messager codant pour l'histone H4.

Jaeger, Sophie 25 November 2005 (has links) (PDF)
Les recherches présentées dans ce mémoire ont porté sur l'expression des gènes d'histones de type réplication-dépendants. Ces gènes sont particuliers car leurs ARNm sont dépourvus d'introns et de queue poly A en 3', l'extrémité 3' étant générée par coupure endonucléolytique au cours d'un processus de maturation original impliquant plusieurs protéines et la snRNP U7.<br /> Lors d'une première étude, nous avons étudié l'étape initiale de la réaction de maturation qui consiste en la fixation de la protéine HBP sur une structure de l'ARN pré-messager. À partir de mutants de HBP abolissant la fixation sur l'ARN nous avons sélectionné par la technique du triple hybride dans la levure des suppresseurs intragéniques permettant de restaurer cette fixation. La plupart des mutations isolées se situaient dans les domaines N- et C-terminaux de la protéine, en dehors du domaine central impliqué dans l'interaction avec l'ARN. Cette restauration s'effectuait sans perte de spécificité pour la séquence de fixation à l'ARN, suggérant que les domaines N- et C-terminaux sont impliqués dans le processus de reconnaissance de l'ARN.<br /> Dans un second volet de notre étude portant sur la réaction de maturation de l'extrémité 3' de l'ARNm d'histone, nous avons examiné l'impact structural induit par la protéine HBP lors de sa fixation sur les extrémités 3' non traduites des ARNs pré-messagers des histones H4-12, H1t et H2a-614. En utilisant les techniques de sondage en solution nous avons montré que ces extrémités présentent de fortes structures secondaires qui pourraient empêcher l'accès à la particule snRNP U7. Puis, nous avons montré que la fixation de la protéine HBP engendrait des changements de conformation de l'ARN au niveau de la séquence d'hybridation au snRNA U7. Enfin, nous avons pu montrer que ces changements de conformation étaient associés à une amélioration de l'ancrage du snRNA U7 à l'ARN pré-messager. Cependant, ce mécanisme n'est pas généralisable à l'ensemble des gènes d'histones puisque aucune modification importante n'a pu être détectée à l'extrémité 3' non traduite du gène d'histone H2a-614.<br />Enfin, nous avons étudié la traduction in vitro de l'ARNm H4-12 et montré qu'elle s'effectuait de façon très efficace en l'absence des régions 5' et 3' non codantes, suggérant que l'initiation de la traduction s'effectuerait par recrutement des ribosomes à l'intérieur de la phase codante. Par sondage en solution de l'ARNm entier, nous avons proposé un modèle de repliement secondaire dans lequel la séquence codante est circularisée par l'hybridation de ses extrémités. À l'aide d'ARNs anti-sens nous avons identifié un certain nombre de nucléotides essentiels pour le maintien d'une haute efficacité de traduction. L'ensemble des résultats obtenus lors des expériences de sondage en solution associés à ceux issus des études de traduction in vitro, de « toe print » et de microscopie électronique, ont conduit à l'établissement d'un modèle original permettant d'expliquer la traduction atypique de l'ARNm H4-12. La phase codante recruterait directement deux ribosomes à la manière de 2 sites d'entrée interne du ribosome ou « IRES ». Le premier ribosome serait recruté au niveau du codon d'initiation, le second près de la fin de la phase codante. Par le jeu de changements de conformation et grâce à la circularisation de l'ARNm, le deuxième ribosome pourrait être dirigé très efficacement sur le codon d'initiation. Cet enchaînement des deux ribosomes sur la phase codante permettrait d'expliquer d'une part, la grande efficacité de traduction observée dans le cas de notre modèle H4-12 et d'autre part, le rôle accessoire des séquences non traduites.
9

Aberrations in Cytokine Signaling in Leukemia: Variations in Phosphorylation and O-GlcNAcylation

Tomic, Jelena 31 August 2012 (has links)
Tumor-induced immunosuppression can occur by multiple mechanisms, each posing a significant obstacle to immunotherapy. Evidence presented in this dissertation suggests that aberrant cytokine signaling, as a result of altered metabolism of Chronic Lymphocytic Leukemia (CLL) cells, confers a selective advantage for tumor survival and growth. Cells from CLL patients with aggressive disease (as indicated by high-risk cytogenetics) were found to exhibit prolongation in Interferon (IFN)-induced STAT3 phosphorylation, and increased levels of reactive oxygen species (ROS) in these cells reflected these signaling processes. Changes in the relative balance of phospho-STAT3 and phospho-STAT1 levels, in response to combinations of IL-2 + Toll-like receptor (TLR)-7 agonist + phorbol esters, as well as IFN, were associated with the immunosuppressive and immunogenic states of CLL cells. In addition, immunosuppressive leukemic cells were found to express high levels of proteins with O-linked N-acetylglucosamine (O-GlcNAc) modifications, due to increased metabolic activity through the Hexosamine Biosynthetic Pathway (HBP), which caused impaired intracellular signaling responses and affected disease progression. A conclusion of the studies presented here is that the intrinsic immunosuppressive properties of leukemic cells may be overcome by agents such as Resveratrol that target metabolic pathways of these cells.
10

Aberrations in Cytokine Signaling in Leukemia: Variations in Phosphorylation and O-GlcNAcylation

Tomic, Jelena 31 August 2012 (has links)
Tumor-induced immunosuppression can occur by multiple mechanisms, each posing a significant obstacle to immunotherapy. Evidence presented in this dissertation suggests that aberrant cytokine signaling, as a result of altered metabolism of Chronic Lymphocytic Leukemia (CLL) cells, confers a selective advantage for tumor survival and growth. Cells from CLL patients with aggressive disease (as indicated by high-risk cytogenetics) were found to exhibit prolongation in Interferon (IFN)-induced STAT3 phosphorylation, and increased levels of reactive oxygen species (ROS) in these cells reflected these signaling processes. Changes in the relative balance of phospho-STAT3 and phospho-STAT1 levels, in response to combinations of IL-2 + Toll-like receptor (TLR)-7 agonist + phorbol esters, as well as IFN, were associated with the immunosuppressive and immunogenic states of CLL cells. In addition, immunosuppressive leukemic cells were found to express high levels of proteins with O-linked N-acetylglucosamine (O-GlcNAc) modifications, due to increased metabolic activity through the Hexosamine Biosynthetic Pathway (HBP), which caused impaired intracellular signaling responses and affected disease progression. A conclusion of the studies presented here is that the intrinsic immunosuppressive properties of leukemic cells may be overcome by agents such as Resveratrol that target metabolic pathways of these cells.

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