O Epstein-Barr vírus (EBV) é a única espécie humana pertencente ao gênero Lymphocryptovirus. A transmissão ocorre através da saliva contaminada e geralmente ainda na infância. Nosso estudo analisou 165 amostras clínicas de pacientes, portadores de HIV, em tratamento com antiretrovirais, atendidos no Sistema Hospitalar do Sistema Penitenciário do Estado de São Paulo. Nosso enfoque foi pesquisar o EBV nas células mononucleares do sangue periférico, através das técnicas de PCR, Nested-PCR e seqüenciamento de nucleotídeos. Os resultados obtidos, indicaram que 11,51% (19) das amostras analisadas, apresentaram-se positivas para o EBV. Essas 19 amostras, foram seqüenciadas com primers específicos para a região da EBNA-1 (Epstein Barr Nuclear Antigen 1). As amostras foram alinhadas com o auxílio do DNASTAR. Ao alinharmos as amostras, encontramos uma troca de base (de G para A) em 7 amostras e essa troca não alterou a conformação da proteína EBNA-1. Na análise filogenética de nossas sequências com as depositadas no GenBank, foi possível observar dois grupos, que representam tipo 1 e o tipo 2 do EBV. 100% das amostras estudadas por nós foram identificadas como pertencentes ao grupo que caracteriza o tipo 2. Sendo assim, as 7 amostras que apresentaram a troca sugerem a origem um novo subtipo. / The Epstein-Barr Virus (EBV) is the only species to the genus Lymphocriptovirus that infects humans. One of the possible route for its transmission thought by contamined saliva and usually occurs in the childhood. This study analysed 165 clinical samples from HIV infected patients, treated by HARRT, attended in the Hospitalar System in the Penitentiary System from Sao Paulo State. The aim of this study was to search EBV in peripheral blood mononuclear cells by PCR, Nested-PCR and sequencing analysis. The results showed 11,51% of the analysed samples, positive for EBV. This samples, was sequenced with specifics primers from the EBNA-1 (Epstein Barr Nuclear Antigen 1) region. The samples were aligned by DNASTAR program. The aligned sequences showed the base conversion G to A in seven samples. This conversion caused no alteration in the EBNA-1 protein conformation. In the phylogenetic analysis the studied sequences with the sequences from GenBank was possible to observe two groups represented with type 1 and type 2 from EBV. 100% the samples studied was identified with the group characterized by the type 2 to EBV. So the seven samples showed the conversion, suggesting the origin of the one new subtype.

Orientadores: Laura Sterian Ward, Alfio José Tincani / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T20:17:52Z (GMT). No. of bitstreams: 1 Almeida_JacquelineFatimaMartins_M.pdf: 2198135 bytes, checksum: 94a76c347fc27e9b1fc05d077aa728a0 (MD5) Previous issue date: 2014 / Resumo: Agentes biológicos causadores de neoplasias humanas têm sido alvo de pesquisas científicas nos últimos anos, especialmente os vírus, considerados responsáveis pela causa de cerca de 20% de todos os tipos de cânceres em geral. No entanto os mecanismos pelos quais estes vírus causam tumores variam dependendo do tipo de sua espécie, da célula alvo e de fatores que concernem ao hospedeiro. Os herpes vírus, como o Herpes Simplex Virus tipo 2 (HSV-2), Epstein-Barr vírus (EBV), Citomegalovirus (CMV) e Herpesvirus Humano tipo 8 (HHV-8) têm sido associados com diversas neoplasias malignas e também com doenças autoimunes tireoidianas. O objetivo do nosso trabalho foi verificar a presença da infecção destes herpes vírus em nódulos tireoidianos benignos e malignos procurando indícios de uma possível associação com tumores tireoidianos. Foram coletadas amostras de tecido tumoral tireoidiano e soro de 153 portadores de nódulos de tireoide (136 mulheres e 17 homens, 46±15 anos) incluindo 65 tumores benignos (48 bócios, 17 adenomas foliculares e 09 portadores de doença tireoidiana autoimunes sendo 02 doenças de Graves e 07 Hashimotos) e 79 tumores malignos (78 carcinomas papilíferos e 01 carcinoma folicular). Também obtivemos 75 tecidos tireoidianos normais extraídos do lobo contralateral da lesão em 75 tumores. Foi realizada análise sorológica por ELISA para detecção de anticorpos dos herpes vírus e foi realizada análise da Carga Viral por PCR em Tempo Real. Quarenta e cinco (29,4%) pacientes (45/153) possuíam anticorpos anti-HSV2; 83,7% anti-CMV (128/153); 98% anti-EBV (150/153) e nenhum paciente possuía anticorpos anti-HHV8, o que é compatível com as estimativas esperadas na população brasileira. As concentrações de anticorpos anti-EBV foi, em média maior do que o do HSV-2 e do que o do CMV (p<0,0001). Os herpes vírus HSV-2, CMV e HHV-8 não foram encontrados em nenhum tecido tireoidiano da população estudada. No entanto, encontramos sequências de DNA do EBV em 20 amostras de tecidos tireoidianos (04 bócios, 03 DAIT e 13 CP). Embora a carga viral média fosse de 1068 cópias/µg nos casos malignos e de 374 cópias/µg nos casos benignos, esta diferença não se mostrou estatisticamente significante. Foram encontrados também 6/75 (8%) casos positivos para a infecção por EBV nos tecidos normais. A carga viral foi, em média, maior nos tumores (126,5 cópias/µg) do que em seus respectivos tecidos normais (93 cópias/µg; p=0,0207). Não houve correlação entre a presença de EBV e as características clínicas ou de evolução dos pacientes. Embora, para melhor compreensão de seus mecanismos de ação, sejam necessários novos estudos moleculares e microbiológicos, a presença da alta carga viral do EBV nos tecidos tumorais tireoidianos em relação aos tecidos normais correspondentes sugere que este vírus pode exercer um papel no desenvolvimento de nódulos tireoidianos / Abstract: Biological agents that cause human cancers have been the subject of scientific research in recent years, especially viruses considered to be responsible for the cause of about 20% of all cancers in general. Although the mechanisms of latent infection and carcinogenesis vary depending on the particular virus, target cells, and host factors. Herpesviruses, such as Human Simplex Virus type 2 (HSV-2), Epstein - Barr virus (EBV), Cytomegalovirus (CMV) and Human Herpes Virus type 8 (HHV-8) have been associated with human malignancies and also with thyroid autoimmunity. We aimed to analyze the presence of these viruses in benign and malignant thyroid nodules looking for evidence of a possible association with thyroid tumors. Serum and thyroid specimens were prospectively collected from 153 thyroid nodule patients (136 females and 17 males, aged 46±15 years) including 78 papillary thyroid cancers (PTC), 01 follicular thyroid cancer (FTC), 17 follicular adenomas and 48 goiters. We used ELISA to screen all patients for the presence of the viruses and a real-time quantitative PCR (qPCR) technique to analyze thyroid tissues viral load on antibody-positive patients. Forty-five (29.4%) patients (45/153) presented anti-HSV2 antibodies; 83.7% anti-CMV (128/153); 98% ani-EBV (150/153) e no patient presented antibodies anti-HHV8, which would be expected to be found in Brazilian population in general. In both malignant and benign groups the medians of antibodies anti-EBV were higher than HSV-2 and CMV medians (p<0,0001). There was no evidence of the presence of HSV-2, CMV and HHV-8 in the population studied. Nevertheless we found EBV¿s DNA sequences in 20 thyroid tissue samples. Even though the average malignant viral load was 1068 copies/µg in 13 cases and 374 copies/µg in 7 benign cases, there was no statistically significant difference between groups. We also found 6 (8%) positive cases for EBV viral load out of 75 normal tissues. In paired test the viral load median was higher in tumors (126.5 copies/µg) than in their respective normal tissues (93 copies/µg; p=0.0207). We did not find any association among the presence of EBV and/or its viral load and any clinical or pathological feature. Althought molecular studies are needed to a better comprehension of the mechanisms underlying the relation between EBV and thyroid nodules, the presence of high EBV copy numbers in thyroid tumors, especially in PTC cases, in comparison with normal tissues, suggests that this virus may play a role in the development of thyroid nodules / Mestrado / Clinica Medica / Mestra em Clínica Médica

Feminist Science Fiction: Cherie Priest's The Clockwork Century Diploma Thesis Petra Nováková Abstract Marleen S. Barr, one of the pioneers of feminist science fiction criticism, is an outspoken commentator on gender inequality in this genre. In Feminist Fabulation: Space/Postmodern Fiction and Future Females: A Critical Anthology, Barr defines feminist science fiction as metafiction about patriarchal fiction. She speaks out against both authors and critics who recycle narratives restricted by a patriarchal view of the world in which women are silenced and/or relegated to the position of an accessory of the male hero, made to behave in a stereotypically feminine manner. While Barr does not include steampunk fiction but focuses on science fiction oriented towards the future and space exploration, her analysis of the female character's plight is nonetheless applicable to the steampunk genre. In this respect, feminist steampunk fiction can be read as a meditation on established gender norms. Cherie Priest's work is a prime example of such an innovative re-examination of gender stereotypes that Barr calls for in her critical work. As both a woman and a writer of science fiction, the author has adopted a feminist approach in her steampunk series The Clockwork Century. Among other things, Priest examines the role...

Le virus d'Epstein-Barr (EBV), est un gamma herpes virus exclusivement humain qui infecte près de 95% de la population adulte. EBV établit un cycle de latence dans les cellules B mémoires et les cellules épithéliales. EBV entre périodiquement dans une réplication lytique avec sécrétion des virions dans la salive. L’infection EBV est associée à l’apparition de lymphomes, de cancers et de maladies auto-immunes. Les conditions favorisant le développement de ces pathologies restent mal connues mais l’immunodépression et potentiellement l’activation des lymphocytes B nécessaire à la réplication d’EBV jouent un rôle clé.Nous avons examiné l’association entre activation des cellules B dans le compartiment systémique et le contrôle sur le réservoir de l’EBV. Deux situations cliniques d’activation chronique des cellules B ont été explorées ; le syndrome de Gougerot-Sjögren et la mastite subclinique dans le contexte de l’infection par le VIH.Dans ce travail de thèse, nous avons tout d’abord développé une PCR en temps réel pour la quantification de l'ADN de EBV ciblant la région répétée BamHI-W du génome. Le travail de validation de la technique a permis d’évaluer précisément le gain de sensibilité comparativement à une qPCR LMP2 (cible unique). L’impact des variations de répétition de la séquence BamHI-W suivant les souches et isolats EBV a également été analyse.Dans un deuxième travail, nous avons montré que, la mastite subclinique était fréquente au cours de l’allaitement et qu’elle était un facteur indépendant associé à une augmentation de l'excrétion EBV par le lait maternel. Cette sécrétion est associée localement à l’inflammation et à l’excrétion du VIH ce qui témoigne de phénomène de synergie entre les deux virus. Nous avons également démontré que l'ADN EBV dans le lait maternel peut être résistant à la DNase et que le virus était est probablement encapsidé dans le lait, donc potentiellement infectieux.Enfin, bénéficiant d’un accès aux prélèvements de la cohorte ASSESS nous avons recherché de possible anomalie du contrôle de l’infection EBV dans le compartiment sanguin au cours du syndrome de Gougerot-Sjögren primaire dans lequel les lésions glandulaires salivaires et lacrymales sont associées à la présence d’EBV. Nous avons démontré que le réservoir EBV et la réplication EBV dans le compartiment systémique sont bien contrôlées au cours du syndrome de Gougerot-Sjögren primaire. La réponse anticorps contre l’antigène précoce d’EBV (EA) n'était pas associée à une augmentation de l'ADN de EBV.Ce travail de thèse, souligne le lien entre l'activation des lymphocytes B, l'inflammation chronique et le contrôle sur le réservoir d’EBV. Dans la glande mammaire le contrôle de l’infection EBV est perturbé en cas de mastite subclinique. Au contraire dans le syndrome de Gougerot-Sjögren l’infection reste bien contrôlée dans le compartiment sanguin malgré l’activation des lymphocytes B et la présence renforcée du virus dans les lésions glandulaires. / TEpstein-Barr virus (EBV), an ubiquitous human gammaherpesvirus affects 95% of adult human population and establishes a lifelong latency in memory B cells periodically entering into lytic replication with further propagation in oropharyngeal epithelia and shedding through saliva. Latent EBV infection is associated with lymphomas, carcinomas and autoimmune diseases. Although the conditions favoring the development of these pathologies are not completely understood, the immunosuppression and B cell activations play an important role in EBV-associated diseases.We examined the control over the EBV reservoir in a diseases associated with B cell activation. Two clinical situations associated with altered B cell activation were explored: primary Sjogren’s syndrome and subclinical mastitis in HIV-infected mothers.Primarily, we developed an in-house real-time PCR for EBV DNA quantification targeting the repetitive BamHI-W region of EBV DNA. The validation analyses enabled to evaluate the gain in sensitivity of the BamHI-W test relative to single repeat LMP2 qPCR. The impact of the variations in BamHI-W reiteration on EBV DNA quantification was further assessed on different EBV strains and clinical samples.In a second study, we showed that subclinical mastitis was common during breastfeeding, and it was an independent factor associated with increased EBV breast milk shedding. This secretion was associated with local inflammation and HIV shedding, reflecting synergy between the two viruses. We have also demonstrated that breast milk EBV DNA may be resistant to DNase, and the virus was probably encapsidated in the breast milk and thus potentially infectious.Finally, with an access to ASSESS cohort we looked for possible abnormal control over EBV infection in the blood compartment in primary Sjögren's syndrome, where salivary and lacrimal gland lesions were shown to be associated with the local activation of EBV. We have demonstrated that in primary Sjogren's syndrome EBV reservoir and replication in the systemic compartment are well controlled. The antibody response against EBV early antigen (EA) was not associated with increased DNA EBV.This thesis points out the link between the activation of B cells, chronic inflammation and control over the reservoir of EBV. In the mammary gland disturbed control of EBV infection is linked with subclinical mastitis. In contrast, in primary Sjogren’s syndrome EBV infection remains well controlled in the blood compartment despite the activation of B cells and the increased presence of the virus in glandular lesions.

Le virus d’Epstein-Barr (EBV) est un herpesvirus dont la séroprévalence est d’environ 90 % de la population adulte mondiale. EBV est associé à de nombreuses pathologies tumorales. La primo infection conduit à l’établissement du virus sous forme latente dans les lymphocytes B mémoires. Au sein de ces cellules B, le génome viral est sous la forme d’un épisome, un ADN circulaire double brin, et une fraction restreinte de gènes viraux est exprimée. Afin de se maintenir aux cours des divisions cellulaires, le génome viral est répliqué en phase S par la machinerie cellulaire et ségrégé lors de la mitose dans chaque cellules filles. La réplication et la ségrégation du génome viral nécessitent 2 facteurs viraux que sont la protéine virale EBNA1 (Epstein-Barr Nuclear Antigen 1) et la région oriP sur le génome viral. En phase S, EBNA1 interagit directement avec l’oriP et y recrute le complexe de pré-réplication de l’ADN. En mitose, EBNA1 ancre l’épisome à la chromatine ce qui permet une ségrégation efficace. Les mécanismes d’interaction entre EBNA1 et la chromatine reste encore flou. Au cours de notre travail, nous avons identifié la protéine RCC1 comme un partenaire potentiel pour la protéine EBNA1 pouvant être impliqué dans l’ancrage d’EBNA1 à la chromatine. Nous avons validé cette interaction et caractérisé les régions d’interactions pour ces deux protéines. Par ailleurs nous avons démontré que RCC1 est recrutée sur l’oriP en présence d’EBNA1 et que ces deux protéines interagissent en mitose. À la lumière de nos résultats et des données de la littérature, nous proposons que l’interaction d’EBNA1 avec la chromatine est dynamique et implique à la fois des interactions directes (AT-Hook, interaction avec les nucléosomes) mais aussi des facteurs cellulaires (RCC1, EBP2 et HMGB2). / Epstein-Barr virus (EBV) is a ubiquitous herpesvirus associated with several human cancers. In proliferating latently-infected cells, the EBV genome persists as a circular plasmid that is replicated once per cell cycle and partitioned at mitosis. Both of these processes require a single viral protein, Epstein Barr nuclear antigen 1 (EBNA1), which binds to two clusters of cognate binding sites within the origin of plasmid replication (oriP). EBNA1 plays an essential role both in viral episome replication, by recruiting the cellular complex of DNA replication onto the oriP, and in the efficient segregation of the viral episomes, by tethering the viral DNA onto the mitotic chromosomes. Whereas the mechanisms of viral DNA replication have been well documented, the mechanisms involved in tethering EBNA1 to the cellular chromatin are far from being understood. Here we have identified Regulator of Chromosome Condensation 1 (RCC1) as a novel EBNA1 cellular partner. RCC1 is the only known nuclear guanine nucleotide exchange factor (RanGEF) for the small GTPase Ran enzyme. RCC1, associated with chromatin, is involved in the formation of RanGTP gradients critical for nucleo-cytoplasmic transport, mitotic spindle formation, and nuclear envelope reassembly after mitosis. We have used several approaches to demonstrate a direct interaction between these two proteins and to identify the regions. involved Moreover, by using Chromatin ImmunoPrecipitation assay (ChIP) we have shown that RCC1 is enriched in the oriP region of mini viral replicons in a manner dependent on EBNA1. Finally, by using a combination of confocal microscopy and FRET analysis to follow the dynamics of interaction between the two proteins throughout the cell cycle, we have demonstrated that EBNA1 and RCC1 closely associate on the chromosomes during metaphase. Taken together, our data strongly suggest an essential role for RCC1 in tethering EBNA1 - linked to the viral episome - to the metaphasic chromosomes. Our results and those of others lead us to the idea that the interaction between EBNA1 with the cellular chromosomes requires several factors such as direct interactions or cellular proteins and these interactions are complementary and / or redundant.

Orientadores: Sandra Cecília Botelho Costa, Sandra Helena Alves Bonon / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-24T11:43:36Z (GMT). No. of bitstreams: 1 Peigo_MurilodeFreitas_M.pdf: 1466925 bytes, checksum: 094e2cd00645843fd5fa2c56ca66c2d5 (MD5) Previous issue date: 2012 / Resumo: O Lúpus Eritematoso Sistêmico (LES) é uma patologia sistêmica do tecido conjuntivo, que se apresenta de maneira variada na dependência do órgão afetado, da gravidade de seu acometimento e da idade do paciente, tendo influência de fatores raciais, de padrões imunológicos e ambientais. Pacientes lúpicos têm grande predisposição para desenvolver infecções graças à imunossupressão induzida pela própria doença como pelo uso de vários medicamentos em seu tratamento. Infecções causadas por herpesvírus, principalmente o Citomegalovírus Humano (CMV) e o Epstein-Barr (EBV), têm sido implicadas em várias doenças autoimunes graves, incluindo o LES. A reativação dos herpesvírus 6 e 7 (HHV-6 e HHV-7) geralmente ocorre em pacientes imunodeprimidos, mas seus papéis ainda são pouco estudados. As infecções por herpesvírus têm influência tanto no início do processo autoimune quanto na exacerbação da progressão da doença. A identificação de pacientes com alto risco de desenvolver doença pelos herpesvírus pode ser realizada utilizando técnicas de detecção de infecção ativa, como a Reação em Cadeia da Polimerase (Nested-PCR) e a detecção do antígeno pp65 do CMV (Antigenemia). Dependendo do caso, estes pacientes podem receber tratamento com antivirais. Diante do exposto, os objetivos deste estudo foram: monitorizar os pacientes com LES em relação à infecção ativa por CMV, EBV, HHV-6 e HHV-7, utilizando as técnicas de Nested-PCR e de antigenemia, bem como avaliar o impacto clínico dessas infecções. Foram incluídos neste trabalho, amostras de sangue de 71 pacientes em seguimento no Departamento de Reumatologia da Faculdade de Ciências Médicas ¿ UNICAMP, com diagnóstico de LES confirmado, sendo que 20/71 (28%) estavam com o lúpus ativo (SLEDAI ? 8) e 51/71 (72%) dos pacientes não tinham atividade lúpica (SLEDAI < 8). Das amostras de sangue pesquisadas, 10/71 (14%) foram positivas para os herpesvírus estudados, sendo que 90% destes pacientes com infecção ativa apresentavam o lúpus em atividade (p?0,006). Infecção ativa pelo CMV ocorreu em 4 pacientes (5,6%). HHV-7 foi detectado em 4 amostras (5,6%). Dois outros pacientes apresentaram dupla infecção por CMV e HHV-7 (2,8%). Infecção ativa pelo EBV e HHV-6 não foi detectada em nenhuma das amostras analisadas. Dois pacientes foram a óbito, sendo que um deles evoluiu com sepse de foco pulmonar (provável doença por CMV) e o outro com sepse por Psedomonas aeruginosa. Diante dos resultados obtidos, podemos observar que a infecção ativa pode ocorrer nos pacientes com LES, principalmente naqueles com a doença em atividade. Poucos estudos têm avaliado o impacto destas infecções no cuidado diário dos pacientes com LES. Acreditamos que este trabalho seja pioneiro e será de fundamental importância, contribuindo com este grupo de pacientes. Entretanto, futuros estudos deverão ser implementados com um número maior de pacientes e de coletas/paciente, principalmente naqueles com LES em atividade, que foram demonstrados com aqueles com fator de risco aumentado / Abstract: Systemic lupus erythematosus (SLE) is a connective tissue systemic pathology that presents itself in several ways, depending on the organ affected, the seriousness of the disease and patient¿s age, being influenced by racial factors, immunologic and environmental patterns. SLE patients have great predisposition to develop infections due to the immunosuppression induced by the disease itself and by the use of medicine in the treatment. Infections caused by herpesvirus, especially Human Cytomegalovirus (CMV) and Epstein-Barr (EBV), have been developed into several serious autoimmune diseases, including SLE. Herpesvirus 6 and 7 (HHV-6 and HHV-7) reactivation generally occurs in immunodepressed patients, but their roles are unclear. Herpesvirus infections have influence both on the beginning of the autoimmune process and on the aggravation of the disease progression. The patients that present high risks of developing herpesvirus related diseases can be identified using active infection detection techniques, such as the Nested polymerase chain reaction (Nested-PCR) and the CMV pp65 antigen detection (antigenemia). Depending on the case, the patients can receive treatment with antivirals. Face to the exposed, the objectives of this study were: to monitor the patients with SLE with regard to active infection by CMV using Nested-PCR and antigenemia techniques, and EBV, HHV-6, HHV-7 in serum, as well as to evaluate the clinic impact to these infections. There were included in this work blood samples of 71 patients that are being treated at the Department of Rheumatology, Faculty of Medical Sciences ¿ University of Campinas - UNICAMP, with a confirmed SLE diagnosis, given that 20/71 (28%) had active lupus (SLEDAI ? 8) and 51/71 (72%) of the patients didn¿t present lupic activity (SLEDAI < 8). Considering the blood samples researched, 10/71 (14%) were positive for the studied herpesvirus, and 90% of the patients with active infection presented lupus in activity (p ? 0,006). Active infection by CMV was observed in 4 patients (5,6%). HHV-7 was detected in 4 samples (5,6%). Two other patients presented double infection by CMV and HHV-7 (2,8%). Active infection by EBV and HHV-6 was not detected in any of the analyzed samples. Two patients have deceased, whose conditions developed into pulmonary sepsis (probable disease by CMV) and into Psedomonas aeruginosa sepsis, respectively. After analyzing the achieved results, we observe that active infection can appear in patients with SLE, especially in those with the disease in activity. Few studies have evaluated the impact of these infections on the daily care of patients with SLE. In this sense, we believe that this work is pioneer and that it will be of fundamental importance, contributing to this group of patients. However, future studies should be implemented, with a larger number of patients and samples, especially those with SLE in activity, which are the ones with increased risk factor as shown / Mestrado / Clinica Medica / Mestre em Clinica Medica

Multiple sclerosis is a complex immune mediated condition of the central nervous system characterized by myelin loss and progressive neurodegeneration. The risk of developing MS is influenced by both genetic and environmental agents and, among them, several lines of evidence support a role for vitamin D deficiency, Epstein-Barr virus (EBV) infection and smoking in the aetiology of this disease. The aim of this work was to further elucidate how nature and nurture act in the causal cascade leading to MS. In chapter 1, I show that the main genetic factor in adult MS (the HLA-DRB1*1501 allele) plays an equally important role in paediatric cases of MS (PMS) and that EBV negative PMS patients represent a separate entity characterized by lower age at disease onset, lower female to male ratio and a trend towards a lower frequency of the HLA-DRB1*1501 allele. In chapter 2, I provide evidence in support of month of birth having a role on MS risk and T cell production and that vitamin D may underlie this effect. In chapter 3 I demonstrate the presence of a link between vitamin D deficiency and the immune response against EBV, whereby the proportion of EBV seropositive MS patients and controls increases with increasing latitude and high dose vitamin D supplementation appears to reduce the level of antibodies against this virus. In chapter 4, I show that MS associated genetic variants are located in genomic regions that exert a regulatory function and are active in immune cell types. In chapter 5, I illustrate how vitamin D receptor binding is also located within active regulatory regions in immune cells and that this is particularly evident near MS associated genes. Finally, in chapter 6, I use chromatin data on more than 100 different cell types and conclude that MS associated genetic variants are particularly active in T helper, T cytotoxic and B cells. Further work is needed to elucidate how genetic and environmental agents play a role in the cause of MS and to develop effective strategies for disease treatment and prevention.

Le virus Epstein-Barr est un des virus dotés de propriétés oncogéniques. Ceci est inquiétant car le virus est présent sous forme d’infection latente dans 95% de la population adulte au niveau mondial. Bien que ce virus soit associé surtout aux lymphomes, d’autres types de cancer sont aussi connus par leur association à cette infection tels que le carcinome gastrique. En fait, 10% de tous les cas de carcinome gastrique sont associés à la présence du virus Epstein-Barr. Plusieurs protéines du virus ont été étudiées individuellement afin d’établir leurs propriétés oncogéniques. Parmi celles-ci, la protéine virale EBNA1 joue un rôle important au niveau de la carcinogénèse et son expression est détectée au niveau des tissus gastriques cancéreux associés à l’infection par le virus Epstein-Barr. Des études réalisées au cours de ces dernières années montrent la relation entre un patron aberrant de l’épissage alternatif des ARN messagers et différents types de cancer, comme le cancer du sein et de la prostate. Les travaux de recherche présentés dans ce mémoire visent à établir si le virus Epstein-Barr est capable de changer le patron d’épissage alternatif au niveau des tissus cancéreux de l’estomac. L’utilisation de données de séquençage à haut débit fait sur des tissus cancéreux et tissus sains d’estomac (infectés ou non par le virus Epstein-Barr) permettra d’estimer les changements au niveau du patron d’épissage alternatif en relation à l’état des tissus et de la présence du virus Epstein-Barr. Les résultats obtenus nous montrent que l’épissage alternatif de plus de 500 gènes est altéré lorsque le virus est présent. Parmi ces gènes plusieurs codent pour des facteurs d’épissage, des facteurs de transcription, et des suppresseurs de tumeurs qui pourraient être impliqués dans le processus de développement du cancer. Finalement, nos résultats montrent que le patron d’épissage alternatif d’une cellule est modifié lorsque celle-ci est infectée par le virus Epstein-Barr ou qu’elle exprime une de ses protéines virales EBNA1, et ces altérations touchent plusieurs gènes impliqués dans des processus biologiques et qui semblent favoriser le développement du cancer.

published_or_final_version / abstract / Anatomy / Doctoral / Doctor of Philosophy

published_or_final_version / Medicine / Master / Master of Philosophy