O diabetes mellitus do tipo 1 (T1D) é uma doença autoimune mediada por células T e caracterizada pela destruição seletiva das células ? pancreáticas produtoras de insulina. Células estromais mesenquimais (MSCs) e células tronco hematopoéticas (HSCs) são os principais componentes do nicho hematopoético na medula óssea. Estas células vêm sendo utilizadas nos últimos anos em transplantes autólogos para tratamento do T1D. O objetivo geral do presente trabalho foi avaliar o perfil de expressão gênica global de MSCs e HSCs de pacientes com T1D e compará-lo com células isoladas de indivíduos saudáveis através da técnica de microarray e programas específicos de bioinformática. As MSCs e HSCs foram isoladas da medula óssea de pacientes com T1D antes e após o tratamento com imunossupressão em altas doses seguida pelo transplante autólogo de células tronco hematopoéticas (AHSCT). As MSCs apresentaram valor elevado de expressão absoluta de diversas moléculas potencialmente relacionadas com suas funções de suporte à hematopoese. MSCs de pacientes diabéticos apresentaram perfil de expressão gênica global distinto das isoladas de indivíduos saudáveis, com hiper-regulação da sinalização via proteína G e hiporregulação da atividade transcricional. O receptor ?3 adrenérgico, assim como a sinalização simpática, foram hiper-expressos nas células dos pacientes. Genes que codificam moléculas que suportam a hematopoese e regulados pelo sistema nervoso simpático, VCAM1 e CXCL12, foram hiporregulados em nossa análise. Após o AHSCT, houve atenuação do perfil de expressão diferencial das MSCs dos pacientes, entretanto elas permaneceram com hiperatividade da sinalização via proteína G e déficit da atividade transcricional. As HSCs apresentaram altos níveis de expressão absoluta de diversas integrinas e receptores de citocinas e fatores de crescimento, potencialmente relacionados com funções na hematopoese. HSCs de pacientes com T1D apresentaram perfil de expressão gênica global distinto das de indivíduos saudáveis, com hiper-regulação de genes associados com a atividade transcricional. Os fatores de transcrição TCFL2 e p53, que têm papel fundamental na regulação do ciclo celular das HSCs, foram diferencialmente expressos entre as HSCs de pacientes diabéticos e controles. Assim, nossos resultados de expressão gênica global apontaram alterações intrínsecas nas HSCs e MSCs de pacientes diabéticos que podem estar relacionadas com a falha terapêutica dos transplantes autólogos. A implicação dessas alterações no desenvolvimento e patogênese do T1D permanece desconhecida e a realização de ensaios funcionais poderá esclarecer o significado biológico das mesmas. / Type 1 diabetes mellitus (T1D) is a T cell-mediated autoimmune disease, characterized by selective destruction of insulin-producing pancreatic ? cells. Mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) are the main components of hematopoietic niches. In the last years, these cells are being used in autologous transplantation settings for T1D treatment. The main goal of this study was to evaluate the global gene expression profile of MSCs and HSCs from T1D patients, by using microarrays and bioinformatics specific programs. MSCs and HSCs were isolated from bone marrow of T1D patients before and after treatment with high dose immunossupression followed by hematopoietic stem cell transplantation. MSCs showed high absolute expression values of several molecules potentially related to their function of hematopoiesis support. MSCs from T1D patients exhibited distinct gene expression profile from control MSCs and presented up-regulation of the G protein-coupled receptor signaling pathway and down-regulation of transcriptional activity. The ?3 adrenergic receptor, as well the sympathetic nervous system signaling were up-regulated on patient´s cells. Genes that codify molecules which support hematopoeisis and are regulated by the symphatic nervous system, VCAM1 and CXCL12, were downregulated on our analysis. After AHSCT, there was an attenuation of the differential expression profile of MSCs from T1D patients, however they remained with G proteincoupled receptor signaling pathway hyperactivity and transcriptional activity deficit. HSCs exhibited high absolute expression values of integrins, cytokine receptors and growth factors, molecules potencially related to hematopoietic functions. HSCs from T1D patients showed distinct expression profile from control HSCs and demonstrated up-regulation of genes related to transcriptional activity. The transcription factors TCFL2 and p53, which have important role in regulating HSC cycle, were differentially expressed between HSCs from T1D patients and controls. Thus, our global gene expression analysis has revealed intrinsic alterations on MSCs and HSCs from T1D patients that could be related to the autologous transplant therapeutic failures. The implications of these alterations on the development and pathogenesis of T1D remain unknown and functional assays could unravel their biological meaning.

Objetivos: Avaliar os resultados das coletas de células hematopoéticas CD34+, por aférese, em crianças portadoras de neuroblastoma tratadas no Serviço de Oncologia e Hematologia do Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; estudar os fatores (idade, peso, estimulação com quimioterapia, dose do G-CSF, uso terapêutico de 131I-MIBG e tempo entre exposição à quimioterapia prévia) que influenciaram na mobilização e no rendimento da coleta de células CD34+ no sangue periférico e associar a quantidade de células CD34+ obtidas com a evolução clínica do paciente. Métodos: Trata-se de um estudo retrospectivo de pacientes com neuroblastoma submetidos à coleta de células-tronco hematopoéticas entre janeiro de1989 e junho 2012. Resultados: Avaliados 45 prontuários de crianças com idade mediana de 3,1 anos (0-12 anos), 26 (57%) apresentavam metástase em medula óssea ao diagnóstico. O tempo entre diagnóstico e o início da mobilização foi em média 19,7 ± 12 meses (mediana de 15,8 meses). Dos pacientes estudados, 11/45 (24,4%) receberam 131I-MIBG terapêutico antes da mobilização. Somente cinco pacientes (11,1%) receberam quimioterapia associada ao G-CSF para mobilização; as demais 40 crianças (88,9%) receberam exclusivamente G-CSF na dose média 26,5 ± 5,3 ug/kg/dia (mediana 28 ug/kg/dia). Não houve correlação entre o número máximo de células CD34+ no sangue periférico com a idade (p=0,9), com o peso (p=0,63), com a dose do G-CSF (p=0,46) ou com o intervalo entre o diagnóstico e o início da mobilização (p=0,09). A mediana da quantificação de células CD34+/uL no sangue periférico foi de 36,6 células, média de 45,2 ± 42,6 (mínimo 1,7 e máximo 236,3). Pacientes que haviam recebido 131I-MIBG previamente à mobilização apresentaram menor número de células CD34+/uL no sangue periférico (p=0,04). Em 26 pacientes (57,8%) foi possível coletar mais de 2,0x106 células CD34+/Kg na primeira coleta e em 19 pacientes (42,2%) foram necessárias mais de uma coleta, sendo que, oito pacientes (17,8%) apresentaram falha de mobilização. Os pacientes que apresentaram menor quantidade de células CD34+/uL no sangue periférico (<= 12) não conseguiram número maior ou igual a 2,0x106 células CD34+/Kg em 81,8% das coletas. O número mediano de células infundidas foi de 2,66 x106 células CD34+/Kg (média 3,38 ±1,6; mínimo 1,8; máximo 8,74 x106 CD34+/Kg). Os pacientes apresentaram contagem de leucócitos maior que 1000/mm3 e de plaquetas maior 50000/mm3 por dois dias consecutivos em média, no dia 13 ± 10 e no dia 46 ± 33, respectivamente, após infusão. Conclusões: A coleta de células-tronco hematopoéticas por aférese foi factível em todos os pacientes do estudo. Não houve influência significativa da idade, do peso, da dose do G-CSF e do tempo entre diagnóstico e inicio da mobilização, no número máximo de células. O uso prévio à coleta de 131I-MIBG terapêutico parece influenciar negativamente no pico de células CD34+ no sangue periférico (p=0,04). A contagem de células CD34+ no sangue periférico é importante fator preditivo do resultado das coletas de células progenitoras hematopoéticas CD34+ por aférese / Objectives: To evaluate the results of peripheral hematopoietic CD34+ stem cells harvesting in children with neuroblastoma treated at Serviço de Oncologia e Hematologia do Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; regarding age, weight, stimulation with chemotherapy, G-CSF dose, time between diagnosis and the mobilization beginning and therapeutic 131I-MIBG use and the influence in mobilization and peripheral harvesting of autologous hematopoietic stem cells and to associate the amount of CD34+ cells obtained with the patient\'s clinical evolution. Methods: Between January 1989 and June 2012, children with neuroblastoma underwent to mobilization and peripheral hematopoietic stem cell harvesting and were retrospectively analyzed. Results: The charts of 45 children were reviewed. Median age was 3.1 years (0-12years), and 26 (57%) had metastases in bone marrow at diagnosis. Average time between diagnosis and mobilization was 19.7 ± 12 months (median, 15.8 months). 11/45 (24.4%) received therapeutic 131I-MIBG prior to mobilization. The average G-CSF dose was 26.5 ± 5.3mg/kg/day (mean 28mg/kg/day). There was no correlation between the absolute number of peripheral CD34+ cells and age (p=0.9), weight (p=0.63), G-CSF dose (p=0.46) or the range between diagnosis and early mobilization (p=0.09). The median quantification of CD34+ cells/uL in peripheral blood was 36.6, average 45.2 ±42.6 (minimum 1.7 and maximum 236.3 CD34+ cells/uL). Patients who had received therapeutic 131I-MIBG prior to mobilization, showed fewer absolute amount of CD34+/uL cells in peripheral blood (p=0.04). In 26 patients (57.8%) it was possible to harvest more than 2.0 x106 CD34+ cells/kg at first apheresis and in 19 patients (42.2%) more than one collection were necessary, and eight patients (17.8 %) failure to mobilize. Patients presenting less than 12 CD34+ cells/uL in peripheral blood on the harvesting day failed to reach more then 2.0x106 cells CD34+/kg in 81.8% of the apheresis procedures. It was infused a median number of 2.66 x106 CD34+ cells/kg (mean 1.6 ± 3.38; min 1.8; max 8.74 x106 CD34+ cells/kg). After the stem cells infusion, patients had white blood cells count greater than 1000/mm3 and platelet greater than 50,000/mm3 for two consecutive days on average after 13 ±10 and 46 ± 33 days, respectively. Conclusions: The hematopoietic stem cells harvesting was feasible in all patients included in this report. The G-CSF dose, age, weight and the period between harvesting and diagnosis showed no influence in mobilization and harvesting of autologous hematopoietic stem cells, however the absolute number of peripheral blood CD34+ cells/uL is an important predictive factor for the harvesting outcome. Additionally our findings support for the first time the notion that the use of therapeutic 131I-MIBG could have a negative impact in mobilization of peripheral blood stem cells in children with neuroblastoma

Objetivos: Avaliar os resultados das coletas de células hematopoéticas CD34+, por aférese, em crianças portadoras de neuroblastoma tratadas no Serviço de Oncologia e Hematologia do Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; estudar os fatores (idade, peso, estimulação com quimioterapia, dose do G-CSF, uso terapêutico de 131I-MIBG e tempo entre exposição à quimioterapia prévia) que influenciaram na mobilização e no rendimento da coleta de células CD34+ no sangue periférico e associar a quantidade de células CD34+ obtidas com a evolução clínica do paciente. Métodos: Trata-se de um estudo retrospectivo de pacientes com neuroblastoma submetidos à coleta de células-tronco hematopoéticas entre janeiro de1989 e junho 2012. Resultados: Avaliados 45 prontuários de crianças com idade mediana de 3,1 anos (0-12 anos), 26 (57%) apresentavam metástase em medula óssea ao diagnóstico. O tempo entre diagnóstico e o início da mobilização foi em média 19,7 ± 12 meses (mediana de 15,8 meses). Dos pacientes estudados, 11/45 (24,4%) receberam 131I-MIBG terapêutico antes da mobilização. Somente cinco pacientes (11,1%) receberam quimioterapia associada ao G-CSF para mobilização; as demais 40 crianças (88,9%) receberam exclusivamente G-CSF na dose média 26,5 ± 5,3 ug/kg/dia (mediana 28 ug/kg/dia). Não houve correlação entre o número máximo de células CD34+ no sangue periférico com a idade (p=0,9), com o peso (p=0,63), com a dose do G-CSF (p=0,46) ou com o intervalo entre o diagnóstico e o início da mobilização (p=0,09). A mediana da quantificação de células CD34+/uL no sangue periférico foi de 36,6 células, média de 45,2 ± 42,6 (mínimo 1,7 e máximo 236,3). Pacientes que haviam recebido 131I-MIBG previamente à mobilização apresentaram menor número de células CD34+/uL no sangue periférico (p=0,04). Em 26 pacientes (57,8%) foi possível coletar mais de 2,0x106 células CD34+/Kg na primeira coleta e em 19 pacientes (42,2%) foram necessárias mais de uma coleta, sendo que, oito pacientes (17,8%) apresentaram falha de mobilização. Os pacientes que apresentaram menor quantidade de células CD34+/uL no sangue periférico (<= 12) não conseguiram número maior ou igual a 2,0x106 células CD34+/Kg em 81,8% das coletas. O número mediano de células infundidas foi de 2,66 x106 células CD34+/Kg (média 3,38 ±1,6; mínimo 1,8; máximo 8,74 x106 CD34+/Kg). Os pacientes apresentaram contagem de leucócitos maior que 1000/mm3 e de plaquetas maior 50000/mm3 por dois dias consecutivos em média, no dia 13 ± 10 e no dia 46 ± 33, respectivamente, após infusão. Conclusões: A coleta de células-tronco hematopoéticas por aférese foi factível em todos os pacientes do estudo. Não houve influência significativa da idade, do peso, da dose do G-CSF e do tempo entre diagnóstico e inicio da mobilização, no número máximo de células. O uso prévio à coleta de 131I-MIBG terapêutico parece influenciar negativamente no pico de células CD34+ no sangue periférico (p=0,04). A contagem de células CD34+ no sangue periférico é importante fator preditivo do resultado das coletas de células progenitoras hematopoéticas CD34+ por aférese / Objectives: To evaluate the results of peripheral hematopoietic CD34+ stem cells harvesting in children with neuroblastoma treated at Serviço de Oncologia e Hematologia do Instituto da Criança do Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo; regarding age, weight, stimulation with chemotherapy, G-CSF dose, time between diagnosis and the mobilization beginning and therapeutic 131I-MIBG use and the influence in mobilization and peripheral harvesting of autologous hematopoietic stem cells and to associate the amount of CD34+ cells obtained with the patient\'s clinical evolution. Methods: Between January 1989 and June 2012, children with neuroblastoma underwent to mobilization and peripheral hematopoietic stem cell harvesting and were retrospectively analyzed. Results: The charts of 45 children were reviewed. Median age was 3.1 years (0-12years), and 26 (57%) had metastases in bone marrow at diagnosis. Average time between diagnosis and mobilization was 19.7 ± 12 months (median, 15.8 months). 11/45 (24.4%) received therapeutic 131I-MIBG prior to mobilization. The average G-CSF dose was 26.5 ± 5.3mg/kg/day (mean 28mg/kg/day). There was no correlation between the absolute number of peripheral CD34+ cells and age (p=0.9), weight (p=0.63), G-CSF dose (p=0.46) or the range between diagnosis and early mobilization (p=0.09). The median quantification of CD34+ cells/uL in peripheral blood was 36.6, average 45.2 ±42.6 (minimum 1.7 and maximum 236.3 CD34+ cells/uL). Patients who had received therapeutic 131I-MIBG prior to mobilization, showed fewer absolute amount of CD34+/uL cells in peripheral blood (p=0.04). In 26 patients (57.8%) it was possible to harvest more than 2.0 x106 CD34+ cells/kg at first apheresis and in 19 patients (42.2%) more than one collection were necessary, and eight patients (17.8 %) failure to mobilize. Patients presenting less than 12 CD34+ cells/uL in peripheral blood on the harvesting day failed to reach more then 2.0x106 cells CD34+/kg in 81.8% of the apheresis procedures. It was infused a median number of 2.66 x106 CD34+ cells/kg (mean 1.6 ± 3.38; min 1.8; max 8.74 x106 CD34+ cells/kg). After the stem cells infusion, patients had white blood cells count greater than 1000/mm3 and platelet greater than 50,000/mm3 for two consecutive days on average after 13 ±10 and 46 ± 33 days, respectively. Conclusions: The hematopoietic stem cells harvesting was feasible in all patients included in this report. The G-CSF dose, age, weight and the period between harvesting and diagnosis showed no influence in mobilization and harvesting of autologous hematopoietic stem cells, however the absolute number of peripheral blood CD34+ cells/uL is an important predictive factor for the harvesting outcome. Additionally our findings support for the first time the notion that the use of therapeutic 131I-MIBG could have a negative impact in mobilization of peripheral blood stem cells in children with neuroblastoma

O diabetes mellitus do tipo 1 (T1D) é uma doença autoimune mediada por células T e caracterizada pela destruição seletiva das células ? pancreáticas produtoras de insulina. Células estromais mesenquimais (MSCs) e células tronco hematopoéticas (HSCs) são os principais componentes do nicho hematopoético na medula óssea. Estas células vêm sendo utilizadas nos últimos anos em transplantes autólogos para tratamento do T1D. O objetivo geral do presente trabalho foi avaliar o perfil de expressão gênica global de MSCs e HSCs de pacientes com T1D e compará-lo com células isoladas de indivíduos saudáveis através da técnica de microarray e programas específicos de bioinformática. As MSCs e HSCs foram isoladas da medula óssea de pacientes com T1D antes e após o tratamento com imunossupressão em altas doses seguida pelo transplante autólogo de células tronco hematopoéticas (AHSCT). As MSCs apresentaram valor elevado de expressão absoluta de diversas moléculas potencialmente relacionadas com suas funções de suporte à hematopoese. MSCs de pacientes diabéticos apresentaram perfil de expressão gênica global distinto das isoladas de indivíduos saudáveis, com hiper-regulação da sinalização via proteína G e hiporregulação da atividade transcricional. O receptor ?3 adrenérgico, assim como a sinalização simpática, foram hiper-expressos nas células dos pacientes. Genes que codificam moléculas que suportam a hematopoese e regulados pelo sistema nervoso simpático, VCAM1 e CXCL12, foram hiporregulados em nossa análise. Após o AHSCT, houve atenuação do perfil de expressão diferencial das MSCs dos pacientes, entretanto elas permaneceram com hiperatividade da sinalização via proteína G e déficit da atividade transcricional. As HSCs apresentaram altos níveis de expressão absoluta de diversas integrinas e receptores de citocinas e fatores de crescimento, potencialmente relacionados com funções na hematopoese. HSCs de pacientes com T1D apresentaram perfil de expressão gênica global distinto das de indivíduos saudáveis, com hiper-regulação de genes associados com a atividade transcricional. Os fatores de transcrição TCFL2 e p53, que têm papel fundamental na regulação do ciclo celular das HSCs, foram diferencialmente expressos entre as HSCs de pacientes diabéticos e controles. Assim, nossos resultados de expressão gênica global apontaram alterações intrínsecas nas HSCs e MSCs de pacientes diabéticos que podem estar relacionadas com a falha terapêutica dos transplantes autólogos. A implicação dessas alterações no desenvolvimento e patogênese do T1D permanece desconhecida e a realização de ensaios funcionais poderá esclarecer o significado biológico das mesmas. / Type 1 diabetes mellitus (T1D) is a T cell-mediated autoimmune disease, characterized by selective destruction of insulin-producing pancreatic ? cells. Mesenchymal stromal cells (MSCs) and hematopoietic stem cells (HSCs) are the main components of hematopoietic niches. In the last years, these cells are being used in autologous transplantation settings for T1D treatment. The main goal of this study was to evaluate the global gene expression profile of MSCs and HSCs from T1D patients, by using microarrays and bioinformatics specific programs. MSCs and HSCs were isolated from bone marrow of T1D patients before and after treatment with high dose immunossupression followed by hematopoietic stem cell transplantation. MSCs showed high absolute expression values of several molecules potentially related to their function of hematopoiesis support. MSCs from T1D patients exhibited distinct gene expression profile from control MSCs and presented up-regulation of the G protein-coupled receptor signaling pathway and down-regulation of transcriptional activity. The ?3 adrenergic receptor, as well the sympathetic nervous system signaling were up-regulated on patient´s cells. Genes that codify molecules which support hematopoeisis and are regulated by the symphatic nervous system, VCAM1 and CXCL12, were downregulated on our analysis. After AHSCT, there was an attenuation of the differential expression profile of MSCs from T1D patients, however they remained with G proteincoupled receptor signaling pathway hyperactivity and transcriptional activity deficit. HSCs exhibited high absolute expression values of integrins, cytokine receptors and growth factors, molecules potencially related to hematopoietic functions. HSCs from T1D patients showed distinct expression profile from control HSCs and demonstrated up-regulation of genes related to transcriptional activity. The transcription factors TCFL2 and p53, which have important role in regulating HSC cycle, were differentially expressed between HSCs from T1D patients and controls. Thus, our global gene expression analysis has revealed intrinsic alterations on MSCs and HSCs from T1D patients that could be related to the autologous transplant therapeutic failures. The implications of these alterations on the development and pathogenesis of T1D remain unknown and functional assays could unravel their biological meaning.

Diss. (sammanfattning) Stockholm : Karol. inst., 2004. / Härtill 4 uppsatser.

Background: Receptor tyrosine kinase, c-Kit (CD117) plays a pivotal role in the maintenance and expansion of hematopoietic stem/progenitor cells (HSPCs). Additionally, over-expression and/or mutational activation of c-Kit have been implicated in numerous malignant diseases including acute myeloid leukemia. However, the translational regulation of c-Kit expression remains largely unknown. Methods and results: We demonstrated that loss of Pim1 led to specific down-regulation of c-Kit expression in HSPCs of Pim1(-/-)mice and Pim1(-/-)2(-/-)3(-/-) triple knockout (TKO) mice, and resulted in attenuated ERK and STAT3 signaling in response to stimulation with stem cell factor. Transduction of c-Kit restored the defects in colony forming capacity seen in HSPCs from Pim1 (-/-) and TKO mice. Pharmacologic inhibition and genetic modification studies using human megakaryoblastic leukemia cells confirmed the regulation of c-Kit expression by Pim1 kinase: i.e., Pim1-specific shRNA knockdown down-regulated the expression of c-Kit whereas overexpression of Pim1 up-regulated the expression of c-Kit. Mechanistically, inhibition or knockout of Pim1 kinase did not affect the transcription of c-Kit gene. Pim1 kinase enhanced c-Kit S-35 methionine labeling and increased the incorporation of c-Kit mRNAs into the polysomes and monosomes, demonstrating that Pim1 kinase regulates c-Kit expression at the translational level. Conclusions: Our study provides the first evidence that Pim1 regulates c-Kit gene translation and has important implications in hematopoietic stem cell transplantation and cancer treatment.

Les cellules souches hématopoïétiques (CSH) sont rares, mais indispensables pour soutenir la production des cellules matures du sang, un tissu en constant renouvellement. Deux caractéristiques principales les définissent; la propriété d’auto-renouvellement (AR), ou la capacité de préserver leur identité cellulaire suivant une division, et la multipotence, ce potentiel de différentiation leur permettant de générer toutes les lignée hématopoïétiques. De par leurs attributs, les CSH sont utilisée en thérapie cellulaire dans le domaine de la transplantation. Une organisation tissulaire hiérarchique est aussi préservée dans la leucémie, ou cancer du sang, une masse tumorale hétérogène devant être maintenue par une fraction de cellules au potentiel prolifératif illimité, les cellules souches leucémiques (CSL). Les travaux présentés dans ce manuscrit visent à explorer les bases moléculaires de l’AR, encore mal définies. Certains membres de la famille des facteurs de transcription à homéodomaine HOX sont impliqués dans la régulation de l’hématopoïèse normale, et leur dérégulation peut contribuer à la transformation leucémique. En particulier, la surexpression du gène Hoxb4 dans les CSH influence leur destin cellulaire, favorisant des divisions d’auto-renouvellement et leur expansion en culture et in vivo. En général, les CSH s’épuisent rapidement lorsque maintenue hors de leur niche ex vivo. Différents facteurs interagissent avec les HOX et modulent leur liaison à l’ADN, dont la famille des protéines TALE (Three Amino acid Loop Extension), comme MEIS1 et PBX1. En utilisant une stratégie de surexpression combinée de Hoxb4 et d’un anti-sens de Pbx1 dans les CSH, générant ainsi des cellules Hoxb4hiPbx1lo, il est possible de majorer encore d’avantage leur potentiel d’AR et leur expansion in vitro. Les CSH Hoxb4hiPbx1lo demeurent fonctionnellement intactes malgré une modulation extrême de leur destin cellulaire en culture. Les niveaux d’expressions de facteurs nucléaires, seules ou en combinaison, peuvent donc s’avérer des déterminants majeurs du destin des CSH. Afin d’identifier d’autres facteurs nucléaires potentiellement impliqués dans le processus d’AR des CSH, une stratégie permettant d’évaluer simultanément plusieurs gènes candidats a été élaborée. Les progrès réalisés en termes de purification des CSH et de leur culture en micro-puits ont facilité la mise au point d’un crible en RNAi (interférence de l’ARN), mesurant l’impact fonctionnel d’une diminution des niveaux de transcrits d’un gène cible sur l’activité des CSH. Les candidats sélectionnés pour cette étude font partie du grand groupe des modificateurs de la chromatine, plus précisément la famille des histones déméthylases (HDM) contenant un domaine catalytique Jumonji. Ce choix repose sur la fonction régulatrice de plusieurs membres de complexes méthyl-transférases sur l’AR des CSH, dont l’histone méthyl-transférases MLL (Mixed Lineage Leukemia). Cette stratégie a aussi été utilisée dans le laboratoire pour étudier le rôle de facteurs d’asymétrie sur le destin des CSH, en collaboration. Ces études ont permis d’identifier à la fois des régulateurs positifs et négatifs de l’activité des CSH. Entre autre, une diminution de l’expression du gène codant pour JARID1B, une HDM de la lysine 4 de l’histone H3 (H3K4), augmente l’activité des CSH et s’accompagne d’une activation des gènes Hox. En conclusion, divers déterminants nucléaires, dont les facteurs de transcription et les modificateurs de la chromatine peuvent influencer le destin des CSH. Les mécanismes sous-jacents et l’identification d’autres modulateurs de l’AR demeurent des voies à explorer, pouvant contribuer éventuellement aux stratégies d’expansion des CSH ex vivo, et l’identification de cibles thérapeutiques contre les CSL. Mots-clés : cellules souches hématopoïétiques, Hoxb4, Pbx1, auto-renouvellement, histone déméthylases, RNAi / Hematopoietic stem cells (HSC) are rare, but essential to sustain the constant production of all mature blood cells, a constantly renewing tissue. They are defined by two main characteristics; namely self-renewal (SR), or the capacity to preserve cell identity following division, and multipotency, the differentiation potential that allows them to generate all hematopoietic lineages. Given their attributes, HSC are used for cellular therapy in the transplantation field. A hierarchy in tissue organisation is also preserved in leukemia, or blood cancer, a heterogeneous tumor mass that is sustained by a subset of cells with unlimited SR potential, the leukemia stem cells (LSC). Studies presented in this manuscript aim to explore the molecular basis underlying SR, which are still poorly defined. Certain members of the HOX family of homeodomain transcription factors are involved in the regulation of normal hematopoiesis, and their deregulation can contribute to leukemia development. In particular, Hoxb4 overexpression in HSC influences cells fate, favouring SR divisions and their subsequent expansion in culture and in vivo. In general, HSC exhaust rapidly when maintained ex vivo, outside of their niche. Several factors interact with HOX and modulate their binding to DNA, including members of the TALE (Three Amino acid Loop Extension) protein family, such as MEIS1 and PBX1. Using a strategy of combined overexpression of Hoxb4 and an anti-sense to Pbx1in HSC, generating Hoxb4hiPbx1lo cells, it is possible to further impact on their SR potential and expansion in vitro. These Hoxb4hiPbx1lo cells remain functionally intact despite extreme modulation of their cell fate in culture. Levels of expression of nuclear factors, alone or in combination, can thus impact significantly on HSC fate. In order to identify other nuclear factors potentially involved in the process of HSC self-renewal, a strategy enabling simultaneous assessment several gene candidates was elaborated. To this end, progress made in terms of HSC purification and their culture in micro-wells facilitated the setup of an RNAi (RNA interference) screen, measuring the functional impact of lowering gene candidate transcript levels on HSC activity. Gene candidates selected for this study belong to the greater group of chromatin modifiers, more specifically the family of histone demethylases (HDM) containing a Jumonji catalytic domain. This choice stems from the regulatory function of several members of histone methyl-transferase complexes on HSC self-renewal, including the histone methyl-transferase MLL (Mixed Lineage Leukemia). This strategy was also used in the laboratory to study the role of asymmetry factors on HSC fate, in a collaborative study. These studies enabled identification of both positive and negative regulators of HSC activity. Among these, reduced expression of the gene coding for JARID1B, a histone 3 lysine 4 (H3K4) HDM, increased HSC activity was associated with Hox genes activation. In conclusion, several nuclear determinants, including transcription factors and chromatin modifiers, can influence HSC fate. Underlying mechanisms and identification of additional modulators of SR remain areas to explore, which could eventually contribute to HSC expansion strategies ex vivo, and identification of therapeutic targets against LSC. Keywords: hematopoietic stem cells, Hoxb4, Pbx1, self-renewal, histone demethylases, RNAi

Les déficits lymphocytaires T peuvent être corrigés par l'administration en intraveineuse (IV) de cellules souches hématopoiétiques (CSH) provenant d'un donneur. Dans un modèle d'immunodéficience lié à l'absence de la protéine kinase ZAP-70, notre équipe avait précédemment montré que l'injection intrathymique (IT) de CSH histocompatibles conduit à une reconstitution du compartiment T plus robuste et plus rapide que dans le cas où les CSH sont administrées par voie IV. Au cours de ma thèse, je me suis intéressée à l'approche IT dans un contexte non-histocompatible, où j'ai montré que l'injection de CSH semi-allogéniques directement dans le thymus permet le développement d'une thymopoièse à long-terme, même en absence de conditionnement. De plus, j'ai également montré la persistence de progéniteurs thymiques précoces (ETP) provenant du donneur dans le thymus des souris transplantées. De façon remarquable, ces ETP retiennent un potentiel de différenciation plus divers que ceux rencontrés dans le thymus d'une souris sauvage, et leur fréquence est significativement élévée après IT, ce dernier suggérant une disponibilité accrue des niches thymiques. De façon intéressante, j'ai également montré que les progéniteurs déficients en ZAP-70 pouvaient se différencier de façon importante vers le lignage CD8 lors d'une activation constante de la voie de signalisation Notch couplée à la présence d'interleukine 7 (IL-7). Après la greffe de CSH par voie IV de souris ZAP-70-/-, en absence de conditionnemt, j'ai également identifié l'accumulation d'une population de CSH présentant un phénotype particulier (Lin- Sca 1+ c-kit-), nommée LSAPT. Ces cellules LSAPT présentent un biais de différenciation vers le lignage T γδ ainsi qu'une production élevée d'IL-17, ce qui suggère que les fonctions effectrices d'une cellule T γδ sont dépendantes de leur origine progénitrices. L'ensemble de mes résultats apporte à la fois de nouveaux éléments concernant l'identification de progéniteurs T et démontrent de l'influence/coopération entre voies de signalisation et facteurs environnementaux dans la modulation de la différenciation T et de leur fonctions effectrices. / T cell deficiencies can be corrected by the intravenous (IV) injection of donor hematopoietic stem cells (HSCs). Using a murine model of ZAP-70-/- deficiency, our group previously showed that the intrathymic (IT) administration of histocompatible HSCs leads to a more robust and long-term thymopoiesis as compared to that achieved by the classical IV route. During my PhD, I found that the direct IT administration of semiallogeneic HSCs results in a sustained donor-derived thymopoiesis, overcoming histocompatibility barriers, even in the absence of conditioning. Furthermore, I found that donor-derived early thymic progenitors (ETPs) persist in the thymi of ZAP-70-/- transplanted mice, and present increased multi-lineage potential as compared to wild-type ETPs. Importantly, the frequency of donor-derived ETPs was augmented following IT transplantation, indicative of an increased progenitor niche. Interestingly, ZAP-70-deficient HSC could themselves be driven to a CD8 lineage fate in an environment where IL-7 potentiates continuous activation of the Notch pathway. Following IV transplantation of donor HSC into non-conditioned ZAP-70-/- mice, I determined that there is an accumulation of lineage-/Sca1+ donor progenitors lacking expression of the stem cell marker c-kit, termed LSAPT. These LSAPT show a biased differentiation towards the γδ T cell lineage with high IL-17-producing effector function, suggesting that progenitor origin regulates γδ T cell fate. The ensemble of my experiments provide new insights into the identity of T lineage progenitors and demonstrate how signaling pathways as well as environmental factors modulate T cell differentiation and effector function.

Objectives: Hematopoietic stem cell transplantation (HSCT) is a widely used method for treatment of hematological disorders and some other diseases. However, sometimes a suitable donor of hematopoietic stem cells (HSC) is not found for a patient. Because HSC have been described as cells with low proliferative and metabolic activity, their tolerance to the lack of oxygen or metabolic substrates may be assumed. In this study, we explored cadaveric bone marrow as an alternative source of HSC for HSCT, using a mouse experimental model. In addition, the effect of in vitro metabolic inhibition and short-term in vitro storage (1 - 4 days) on functional properties of mouse HSC was investigated. Methods: C57Bl/6 mice (wild-type or p53-/- ) were used in the experiments. To explore cadaveric HSC, bone marrow (BM) was left in intact femurs at 37řC, 20řC and 4řC under the conditions of ischemia. The bone marrow cells were harvested after defined time periods ranging 0 - 48 hours. For metabolic inhibition, the electron transport chain inhibitor potassium cyanide (KCN) and inhibitor of glycolysis 2-deoxy-D-glucose (2-DG) were used in vitro. To determine the impact of ischemia, metabolic inhibition, or in vitro storage on transplantability of HSC, the competitive repopulation assay using Ly5.1/Ly5.2 congenic model...

Introdução: No paciente submetido ao transplante de células tronco-hematopoiéticas (TCTH), os eventos adversos (EA) representam ocorrência relevante, porém inerente ao procedimento. Tais EA interferem no status clínico do paciente e, possivelmente, na carga de trabalho de enfermagem. Objetivo: Avaliar a relação entre ocorrência de EA e a carga de trabalho de enfermagem demandada por pacientes submetidos ao TCTH. Método: Coorte prospectiva realizada com pacientes internados na unidade de TCTH do Hospital de Clínicas da Universidade Estadual de Campinas. A amostra foi composta por 62 pacientes; os dados foram obtidos pela análise diária dos prontuários. A variável dependente foi carga de trabalho de enfermagem, mensurada pelo Nursing Activities Score (NAS), e as variáveis independentes foram as demográfico-clínicas, dentre as quais a ocorrência e gravidade de EA, que foram identificados e classificados de acordo com Common Terminology Criteria for Adverse Events. Na análise dos dados utilizaram-se os testes Qui-quadrado ou Exato de Fisher, os não-paramétricos Mann-Whitney e Kruskal-Wallis e o coeficiente de correlação de Spearman. Para estudar as relações entre a variável NAS e as variáveis independentes foram construídos modelos de regressão linear múltipla. Resultados: Verificou-se incidência de 100% de EA relativos a investigações laboratoriais, trato-gastrointestinal e sistema sanguíneo e linfático nos grupos de TCTH autólogo e alogênico. A incidência dos EA vasculares foi de 100% no grupo de alogênicos e, no de autólogos, estiveram presentes desde o início do tratamento, o que implicou em inexistência de casos novos. Os pacientes de TCTH alogênico apresentaram em média, na fase do condicionamento (CT) e infusão (IF), maior número de EA nas seguintes categorias: gerais e sítio de administração (p=0,0047), investigações laboratoriais (p=0,0061), nutrição e metabolismo (p=0,0280), sistema nervoso (p=0,0080), vasculares (p=0,0442) e no sistema sanguíneo e linfático (CT: p=0,0062; IF: p=0,0020). Na IF pacientes de TCTH autólogo apresentaram maior número médio de EA relacionados ao sistema renal e vias urinárias (p=0,0003). Na fase pós-TCTH (PT) não houve diferença estatística significante entre os grupos quanto ao número médio de EA. Em relação à gravidade dos EA, nas fases de CT e IF os pacientes de TCTH alogênico apresentaram EA de maior gravidade relacionados às investigações laboratoriais (CT: p=0,0091; IF: p=0,0427) e ao sistema sanguíneo e linfático (CT: p=0,0088; IF: p=0,0100). Na fase PT o grupo de pacientes de TCTH autólogo apresentou maior gravidade nos EA relativos a: investigações laboratoriais (p=0,0156), nutrição e metabolismo (p=0,0118), sistema nervoso (p=0,0491); no período PT os pacientes de TCTH autólogo apresentaram maior gravidade (SAPS II p=0,0004). A média da carga de trabalho de enfermagem foi de 67,3% (DP 8,2) para os pacientes de TCTH autólogo e de 72,4% (DP 13,0) para os de TCTH alogênico (p=0,1380). Foram considerados fatores associados à carga de trabalho de enfermagem a condição de saída do paciente (p=0,0005; R2=0,19) e a gravidade dos EA relativos a investigações laboratoriais (p=0,0008) e vasculares (p=0,0002), gerando, em conjunto, um R2=0,37. Conclusão: EA contribuem para o aumento da carga de trabalho de enfermagem em TCTH, que precisa ser reavaliada para garantir uma assistência segura ao paciente. / Introduction: In the patient submitted to hematopoietic stem cells transplantation (HSTC) the adverse events (AE) represent relevant occurrence, though inherent to the procedure. Such AE interfere on the clinical status of the patient and, possibly, on nursing workload. Objective: To evaluate the relation between AE occurrence and nursing workload demanded by patients submitted to HSCT. Methodology: Prospective cohort study conducted with patients in the HSTC unit of the Clinical Hospital of State University of Campinas. The sample was composed by 62 patients; the data was obtained by daily analysis of medical records. The dependent variable was nursing workload, measured by the Nursing Activities Score (NAS) and the independent variables were demographic and clinical, among which the occurrence and severity of AE, that were identified according to Common Terminology Criteria for Adverse Events. In the data analysis were used the Chi-square or Fishers exact tests, the non-parametric Mann-Whitney and Kruskal-Wallis tests and Spearmans correlation coefficient. To study the relations between the NAS variable and the independent variables were built multiple linear regression models. Results: There was incidence 100% of AE related to laboratorial investigations, gastrointestinal tract and blood and lymphatic system in the groups of autologous and allogeneic HSCT. The incidence of vascular AE was 100% in allogeneic group and in the autologous they were present since the treatment beginning, which resulted on the inexistence of new cases. The allogeneic HSCT patients presented on average, in conditioning (CT) and infusion (IF) phases, a higher number of AE in the following categories: general and administration site (p=0,0047), laboratorial investigations (p=0,0061), nutrition and metabolism (p=0,0280), nervous system (p=0,0080), vascular (p=0,0442) and blood and lymphatic system (CT: p=0,0062; IF: p=0,0020). In IF autologous HSCT the patients presented a higher number of AE related to renal system and urinary tract (p=0,0003). In post-HSCT phase (PT) there were no significant statistical differences between the groups, regarding the average number of AE. Regarding the AE severity in CT and IF phases, the allogeneic HSCT patients presented higher severity of AE related to laboratorial investigations (CT: p=0,0091; IF: p=0,0427) and to blood and lymphatic system (CT: p=0,0088; IF: p=0,0100). In PT phase, the group of autologous HSCT patients showed higher severity of AE related to: laboratorial investigations (p=0,0156), nutrition and metabolism (p=0,0118), nervous system (p=0,0491); in PT period the autologous HSCT patients presented higher severity of AE. The average of nursing workload was 76,3% (DP 8,2) for autologous HSCT patients and 72,4% (DP 13,0) for allogeneic HSCT patients (p=0,1380). Were considered factors associated to nursing workload, the output condition of the patient (p=0,0005; R2=0,19) and the severity of AE related to laboratorial investigations (p=0,0008) and vascular (p=0,0002) creating together a R2=0,37. Conclusion: AE contribute to the increase of nursing workload in HSCT, which needs to be reviewed to ensure safe patient care.