Citopenia é um importante sinal de falência medular, sendo um achado comum de várias doenças, dentre as quais se destacam as mielodisplasias e a anemia aplástica. As mielodisplasias correspondem a um grupo de alterações hematopoéticas de natureza clonal, cuja principal característica é a hematopoese ineficaz, clinicamente manifesta como uma medula óssea celular, porém associada a citopenias. Já a anemia aplástica apresenta uma medula hipo ou acelular sem evidência de infiltração neoplásica, sendo substituída por tecido gorduroso. O gene GATA2 é um fator regulador da hematopoese, atuando também na manutenção e proliferação do pool de células-tronco e progenitoras hematopoéticas. Recentemente, mutações constitucionais no gene GATA2 foram descritas na síndrome de monocitopenia e infecção micobacteriana (MonoMac), que eventualmente cursa com outras citopenias, medula hipocelular ou mesmo mielodisplasia. Entretanto, a contribuição de mutações no gene GATA2 para o desenvolvimento de anemia aplástica adquirida e síndrome mielodisplásica não é conhecida. Neste trabalho, propomos pesquisar mutações no gene GATA2 em pacientes com anemia aplástica adquirida e síndrome mielodisplásica, por meio de sequenciamento direto do DNA. Adicionalmente, também avaliaremos as subpopulações linfocitárias no sangue periférico e níveis de citocinas plasmáticas no intuito de correlacionar a presença de mutação do GATA2 a um perfil imunológico. / Cytopenia is an important signal of marrow failure, being commom to various diseases, among them myelodysplasia and aplastic anemia. Myelodysplasia is a group of hematopoietic clonal disorders, with inneficient hematopoiesis, cellular bone marrow with associated cytopenias. The aplastic anemia presents a hypo or even acellular bone marrow without any evidence of neoplastic infiltration with the stem cells being substituted by fat. The GATA2 gene is a key regulator of hematopoiesis, also acting on the maintenance and proliferation of stem and progenitor cells. Recently, constitutional mutations in the GATA2 gene were described in MonoMAC syndrome, which eventually presents cytopenias, hypocellular marrow or even myelodysplasia. However, the contribution of GATA2 mutations for the development of acquired aplastic anemia or myelodysplasia is not known. In this work we aim to search for GATA2 gene mutations in patients with acquired aplastic anemia and myelodysplasia through Sanger sequencing. Also, we will evaluate the levels of subpopulations of lymphocytes and the plasmatic levels of cytokines to establish a correlation between the presence of mutation in the GATA2 and a specific immune profile

Citopenia é um importante sinal de falência medular, sendo um achado comum de várias doenças, dentre as quais se destacam as mielodisplasias e a anemia aplástica. As mielodisplasias correspondem a um grupo de alterações hematopoéticas de natureza clonal, cuja principal característica é a hematopoese ineficaz, clinicamente manifesta como uma medula óssea celular, porém associada a citopenias. Já a anemia aplástica apresenta uma medula hipo ou acelular sem evidência de infiltração neoplásica, sendo substituída por tecido gorduroso. O gene GATA2 é um fator regulador da hematopoese, atuando também na manutenção e proliferação do pool de células-tronco e progenitoras hematopoéticas. Recentemente, mutações constitucionais no gene GATA2 foram descritas na síndrome de monocitopenia e infecção micobacteriana (MonoMac), que eventualmente cursa com outras citopenias, medula hipocelular ou mesmo mielodisplasia. Entretanto, a contribuição de mutações no gene GATA2 para o desenvolvimento de anemia aplástica adquirida e síndrome mielodisplásica não é conhecida. Neste trabalho, propomos pesquisar mutações no gene GATA2 em pacientes com anemia aplástica adquirida e síndrome mielodisplásica, por meio de sequenciamento direto do DNA. Adicionalmente, também avaliaremos as subpopulações linfocitárias no sangue periférico e níveis de citocinas plasmáticas no intuito de correlacionar a presença de mutação do GATA2 a um perfil imunológico. / Cytopenia is an important signal of marrow failure, being commom to various diseases, among them myelodysplasia and aplastic anemia. Myelodysplasia is a group of hematopoietic clonal disorders, with inneficient hematopoiesis, cellular bone marrow with associated cytopenias. The aplastic anemia presents a hypo or even acellular bone marrow without any evidence of neoplastic infiltration with the stem cells being substituted by fat. The GATA2 gene is a key regulator of hematopoiesis, also acting on the maintenance and proliferation of stem and progenitor cells. Recently, constitutional mutations in the GATA2 gene were described in MonoMAC syndrome, which eventually presents cytopenias, hypocellular marrow or even myelodysplasia. However, the contribution of GATA2 mutations for the development of acquired aplastic anemia or myelodysplasia is not known. In this work we aim to search for GATA2 gene mutations in patients with acquired aplastic anemia and myelodysplasia through Sanger sequencing. Also, we will evaluate the levels of subpopulations of lymphocytes and the plasmatic levels of cytokines to establish a correlation between the presence of mutation in the GATA2 and a specific immune profile

京都大学 / 新制・課程博士 / 博士(医学) / 甲第23372号 / 医博第4741号 / 新制||医||1051(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 滝田 順子, 教授 髙折 晃史, 教授 江藤 浩之 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第19269号 / 医博第4033号 / 新制||医||1011(附属図書館) / 32271 / 京都大学大学院医学研究科医学専攻 / (主査)教授 岩井 一宏, 教授 髙折 晃史, 教授 山田 亮 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

L'objectif principal de chaque forme de vie à transmettent fidèlement aux descendants ainsi que les renseignements génétiques auto - survie. Agents endogènes et environnementales en attaque ce processus. Pour résister à ces menaces et protéger le génome intégré, les cellules ont développé des systèmes permettant de détecter leur présence et l'adn de signalisation des dommages - intérêts, la médiation leur réparation. Notre étude porte sur un patient nés de parents consanguins présentant une insuffisance médullaire précoce, les anomalies de développement (microcéphalie et longueur des télomères caractéristiques dimorphes) EBV-B fibroblastes et lignées cellulaires ont été peu sensible à la MMC, mais a montré une forte sensibilité à la phléomycine et IR, plaidant pour un défaut de réparation de l'adn dans ce patient. Cela a également été confirmé par la persistance de foyers 53BP1 après ça. L'ensemble des études et exome genome - wide association a révélé un séquençage exon 13 mutations homozygotes est hérité de l'adn codant pour la ERCC6l2 putatif du poids RAD26l hélicase. La forme de ERCC6l2 décrits dans les bases de données n'a pas compléter le phénotype cellulaire in vitro. Une analyse a révélé une alternative possible in silico isoforme de ERCC6l2 850aa contenant un complément 6 - exons codant la réalité qui était assuré par le clonage moléculaire. On appelle cette autre isoforme hebo. La sensibilité des cellules à hebo maintenant complété la phléomycine, validant ainsi les identifié la mutation. Les deux ercc6l2 courte et hebo est exprimée de façon ubiquiste, mais seulement hebo est localisée dans le noyau. Des expériences ont démontré que les micro - irradiation hebo est recruté pour des lésions de l'adn. Ni le ercc6l2 court, ni ce formulaire auquel était annexé un signal - localiser d'adn SV40 sna dommages dans ces expériences. Nous avons exploré davantage que le recrutement de hebo dépend de nbs 1. / The main objective of every life form is to faithfully transmit genetic information to offspring as well as self-survival. Various endogenous and environmental agents constantly assault this process. To resist these threats and to protect the genome integrality, cells have evolved systems capable of detecting DNA damages, signaling their presence and mediating their repair. Our study focuses on a patient born from consanguineous parents presenting with early bone marrow failure (BMF), developmental anomalies (microcephaly and dimorphic features) but normal telomere length. Fibroblasts and EBV-B cell lines were slightly sensitive to MMC but showed a marked sensitivity to phleomycin and IR, arguing for a DNA repair defect in this patient. This was also confirmed by the persistence of 53BP1 foci following IR. Genome wide association studies and whole exome sequencing revealed an inherited homozygous nonsense mutation in exon 13 of ERCC6L2 coding for the putative DNA helicase Rad26L. Unexpectedly, the wt. form of ERCC6L2 described in the databases did not complement the cellular phenotype in vitro. An in silico analysis revealed a possible alternative isoform of ERCC6L2 containing additional 6 C-terminus exons encoding 850aa, the reality of which was ascertained by molecular cloning. We named this alternative isoform Hebo. The Hebo now complemented the cellular sensitivity to phleomycin, thus validating the identified mutation. Both ERCC6L2-short and Hebo are ubiquitously expressed, but only Hebo is localized into the nucleus. Micro irradiation experiments demonstrated that Hebo is recruited to DNA lesions. Neither the ERCC6L2-short, nor this form to which was appended an SV40 nls signal did localize to DNA damages in these experiments. We further explored that the recruitment of Hebo is dependent on NBS1 manner.

RAD51 is an indispensable homologous recombination protein, necessary for strand invasion and crossing over. It has recently been designated as a Fanconi anaemia (FA) gene, following the discovery of two patients carrying dominant negative mutations. FA is a hereditary DNA repair disorder characterised by various congenital abnormalities, progressive bone marrow failure and cancer predisposition. The cellular and molecular pathology of FA is poorly understood, resulting in a severe lack of effective treatment options. In this thesis, I describe the first viable vertebrate model of RAD51 loss. Phenotypic characterisation of zebrafish rad51 loss-of-function mutants showed that they develop key features of FA, including hypocellular kidney marrow, sensitivity to crosslinking agents and decreased size. Taking advantage of the unique properties of the zebrafish model, I show that some of these symptoms stem from both decreased proliferation, as well as increased apoptosis of embryonic haematopoietic stem and progenitor cells. Co-mutation of p$L was able to rescue the haematopoietic defects seen in the single mutants, but led to tumour development, underscoring the role of rad51 as a tumour suppressor. I further demonstrate that prolonged inflammatory stress can exacerbate the haematological impairment, leading to an additional decrease in kidney marrow cell numbers. In contrast, prolonged aldehyde-derived stress did not induce symptoms in the mutant fish. These findings strengthen the assignment of RAD51 as a Fanconi gene and provide more evidence for the notion that aberrant p53 signalling during embryogenesis leads to the haematological defects seen later in life in FA. It also strengthens the evidence for the involvement of haematopoietic stress, such as inflammation, in the development of bone marrow failure. Further research on this novel zebrafish FA model will lead to a deeper understanding of the molecular basis of bone marrow failure in FA and the cellular role of RAD51.

京都大学 / 0048 / 新制・課程博士 / 博士(医学) / 甲第22002号 / 医博第4516号 / 新制||医||1038(附属図書館) / 京都大学大学院医学研究科医学専攻 / (主査)教授 滝田 順子, 教授 松田 文彦, 教授 山田 亮 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

京都大学 / 0048 / 新制・課程博士 / 博士(医科学) / 甲第18906号 / 医科博第62号 / 新制||医科||4(附属図書館) / 31857 / 京都大学大学院医学研究科医科学専攻 / (主査)教授 山下 潤, 教授 野田 亮, 教授 髙折 晃史 / 学位規則第4条第1項該当 / Doctor of Medical Science / Kyoto University / DFAM

No description available.

Introdução: A anemia aplástica (AA) adquirida é uma doença grave, caracterizada por pancitopenia e medula óssea hipocelular sem que haja associação com aumento de reticulina ou infiltração anormal na medula. Embora o mecanismo fisiopatológico não esteja totalmente elucidado, atribui-se a uma resposta imunomediada dos linfócitos T no ambiente medular. A trombopoetina (codificada pelo gene THPO) é um hormônio glicoproteico produzido pelo fígado e responsável pelo estímulo de crescimento de megacariócitos, desenvolvimento plaquetário e de demais linhagens e, quando disfuncional, contribui para o desenvolvimento da AA adquirida. Objetivos: Investigar a presença de variantes genéticas no THPO em amostras de sangue periférico e medula óssea de pacientes com AA adquirida (grupo caso) e de indivíduos saudáveis (grupo controle) e verificar a presença de alterações no número de plaquetas durante o seguimento dos pacientes com AA adquirida. Métodos: O gene THPO foi sequenciado em amostras de DNA de medula óssea de 92 pacientes com AA adquirida e no DNA de sangue periférico de 92 controles, cujas amostras haviam sido previamente armazenado no Laboratório de Hematologia da Faculdade de Medicina de Ribeirão Preto da Universidade de São Paulo (FMRP-USP). O sequenciamento foi realizado pelo método de Sanger. Realizou-se também a associação entre a presença (ou ausência) de variantes em THPO e o número de plaquetas em 83 pacientes utilizando o teste ANOVA Para outras análises estatísticas, foram utilizados os testes t e qui-quadrado com nível de significância de 5%. Resultados: Foram encontrados três polimorfismos de nucleotídeo único (SNPs) nos pacientes com AA adquirida (rs956732, rs6141 e rs3804618). Os mesmos três SNPs foram observados nos indivíduos do grupo controle (p>0,05). Não houve associação entre o número de plaquetas e a presença de SNPs nos pacientes (p>0,05). Conclusões: Três SNPs foram encontrados em frequências alélicas semelhantes tanto no grupo de pacientes quanto nos controles, sugerindo que a trombopoetina não apresenta alterações genéticas que possam ser associadas à fisiopatologia da AA adquirida nessa coorte. / Introduction: Acquired aplastic anemia (AA) is a severe illness, characterized by pancytopenia and hypocellular bone marrow without increased reticulin or abnormal infiltration of the bone marrow. Although the physiopathological mechanism has not been completely understood, an immune-mediated T-lymphocyte response has been attributed to the bone marrow environment. Thrombopoietin (encoded by THPO), a glycoprotein hormone produced by the liver and responsible for stimulating the growth of megakaryocytes, development of platelets and other lineages that when dysfunctional, contributes to the progress of acquired AA. Objectives: To screen the THPO gene for genetic variants in bone marrow of acquired AA patients and in the peripheral blood of controls, and to verify the correlation between the THPO status and platelet counts in the patients during the treatment. Method: Sanger sequencing of the THPO gene was carried out in 92 acquired AA patients (case group) and 92 controls, in DNA samples previously stored in the Hematology Laboratory of the Ribeirão Preto School of Medicine at the University of São Paulo. The association between the THPO status and the platelet counts was performed in 83 patients through the ANOVA test. The Chi-squared test and t-test were also applied for statistical analysis with a 5% significance level. Results: Three single nucleotide polymorphisms (SNPs) were found in the AA patients (rs956732, rs6141, and rs3804618), as well as in the healthy subjects (p>0,05). No association was verified between the platelet counts and the presence of SNPs in the AA patients (p>0,05). Conclusion: Three SNPs were found in both groups, suggesting that thrombopoietin does not harbor genetic variants that could be etiological for the acquired AA in our cohort.