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Doctoral Thesis
DOI
https://doi.org/10.11606/T.17.2020.tde-19082020-094004
Document
Author
Full name
Marcos Roberto Pedron Oltramari
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Ribeirão Preto, 2020
Supervisor
Committee
Rodrigues, Rodrigo do Tocantins Calado de Saloma (President)
Pieroni, Fabiano
Rego, Eduardo Magalhães
Scheinberg, Phillip
Title in Portuguese
Efeito do derivativo de purina SR1 e do derivativo pirimidoindólico UM171 na expansão de células-tronco e progenitoras hematopoéticas na anemia aplástica adquirida
Keywords in Portuguese
Anemia aplástica
Célula-tronco hematopoética
SR1
UM171
Abstract in Portuguese
A anemia aplástica adquirida (AAa) corresponde a uma doença caracterizada por falência da medula óssea devido à destruição imune das células-tronco e progenitoras hematopoéticas (CTPH). O tratamento de pacientes com esta enfermidade persiste desafiador devido tanto às complicações agudas da pancitopenia, quanto à história natural da doença e efeitos adversos das terapias vigentes. O transplante autólogo de células-tronco e progenitoras hematopoéticas (TCTH autólogo) expandidas in vitro poderia melhorar a resposta ao tratamento imunossupressor, adicionando baixa toxicidade ao mesmo. As condições usuais de cultivo para a expansão de CTPH in vitro promovem proliferação expressiva, porém acompanhada por aumento significativo da diferenciação celular. Destacam-se duas drogas (derivativo de purina SR1 e derivativo pirimidoindólico UM171) capazes de expandir células CD34+ humanas in vitro, com preservação das características de célula-tronco e indução mínima de diferenciação. Este estudo objetivou avaliar os efeitos de SR1 e UM171 em células CD34+ expandidas in vitro provenientes de amostras de aspirado de medula óssea de pacientes com AAa sobre a expressão imunofenotípica, potencial de formação de colônias, comprimento telomérico, desenvolvimento de alterações citogenéticas e perfil de expressão gênica. Para isso, utilizaramse 22 amostras de aspirado de medula óssea: cinco, provenientes de indivíduos saudáveis (grupo controle); e dezessete, provenientes de pacientes portadores de AAa grave (grupo AA). Ao contrário de SR1, UM171 mostrou-se capaz, em ambos os grupos, de expandir as células CD34+, conter a diferenciação celular e, em especial, reter a expressão dos fenótipos mais primitivos Thy-CD49f+ e Thy+CD49f+, embora com maior potencial proliferativo em células do grupo controle. Alterações citogenéticas clonais, da expressão de genes relacionados ao desenvolvimento de neoplasias hematológicas e encurtamento telomérico excessivo não foram observados com exposição a SR1 nem UM171. Este estudo demonstrou a propriedade de UM171 conter a diferenciação de células CD34+ expandidas in vitro de indivíduos com AAa sem acarretar transformação aberrante, conferindo segurança à translação destes resultados à pesquisa clínica.
Title in English
Effect of purine derivative SR1 and pyrimido-indole derivative UM171 in the expansion of hematopoietic stem and progenitor cells in acquired aplastic anemia
Keywords in English
Aplastic anemia
Hematopoietic stem cell
SR1
UM171
Abstract in English
Acquired aplastic anemia (aAA) is a disease characterized by bone marrow failure due to an immune destruction of hematopoietic stem and progenitor cells (HSPC). The treatment continues to be a challenge, not only because of the acute complications of pancytopenia but also to the natural history of the disease and adverse effects of the existing therapies. Autologous transplantation of in vitro-expanded hematopoietic stem and progenitor cells (autologous HSCT) may improve the response to immunosuppressive treatment, making it less toxic. The usual culture conditions for in vitro HSPC expansion promotes substantial proliferation, but accompanied by a significant increase in cell differentiation. Two small molecules, SR1 and UM171, stand out as being capable of expanding human CD34+ cells in vitro, preserving stemness with minimal differentiation. The aim of this study was to evaluate the effects of SR1 and UM171 in in vitro-expanded CD34+ cells from aAA-patient bone marrow aspirates, on immunophenotypic expression, colony forming potential, telomere length, cytogenetic and gene expression profile. To this end, 22 bone marrow aspirate specimens were used: five from healthy individuals (control group); and seventeen from severe aAA patients (group AA). In contrast to SR1, UM171 was capable, in both groups, of expanding CD34+ cells, suppressing cell differentiation and, in particular, retaining the expression of the more primitive phenotypes CD90-CD49f+ and CD90+CD49f+, although expansion effects were more pronounced in the control group. Excessive telomere shortening, clonal cytogenetic abnormalities, or altered transcriptomic profile of genes related to hematologic neoplasm development were not observed when cells were exposed to SR1 nor UM171. This study demonstrates UM171's property to suppress in vitro-expanded CD34+ cell differentiation from aAA patients, without inducing clonal transformation, thereby providing assurance to the translation of these results into clinical research.
 
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Publishing Date
2020-10-21
 
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