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Master's Dissertation
DOI
10.11606/D.85.2016.tde-05122016-160030
Document
Author
Full name
Patricia Marinho Sant'Ana
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
São Paulo, 2016
Supervisor
Committee
Ribela, Maria Teresa de Carvalho Pinto (President)
Augusto, Elisabeth de Fatima Pires
Peroni, Cibele Nunes
Title in Portuguese
Expressão de tireotrofina humana em células de embrião de rim humano (HEK293)
Keywords in Portuguese
expressão
HEK-293
recombinante
tireotrofina
Abstract in Portuguese
Neste trabalho foi transfectada uma linhagem de células embrionárias de rim humano (HEK293) com os genes das subunidades α e β da tireotrofina humana (hTSH), hormônio glicoproteico secretado pela hipófise. Após 5 dias de cultivo obteve-se uma concentração de hTSH no meio condicionado de 0,95μg/mL. O material foi concentrado e purificado utilizando uma estratégia envolvendo duas etapas, uma cromatografia de troca catiônica e uma cromatografia líquida de alta eficiência (HPLC) de fase reversa, que permitiu uma recuperação de 55% e uma pureza >90%. O produto purificado (hTSH-HEK) foi analisado e comparado a uma preparação comercial obtida em células CHO (hTSH-CHO) e a uma preparação hipofisária (hTSH-Pit). A identidade e a pureza do hTSH-HEK foram avaliadas por métodos físicoquímicos e imunológico (espectrometria de massa MALDI-TOF, HPLC de exclusão molecular e de fase reversa, SDS-PAGE e ensaio imunoradiométrico). A porção glicídica do hTSH-HEK foi avaliada pela análise do perfil dos N-glicanos e o comportamento biológico deste hormônio foi avaliado por bioensaio in vivo e estudo farmacocinético. As 3 preparações apresentaram pureza equivalente (97%) e a massa molecular relativa do hTSH-HEK foi 2,1% menor do que a do hTSH-CHO e 2,7% maior do que a do hTSH-Pit. A maior hidrofobicidade relativa, avaliada por RP-HPLC, foi a do hTSH-HEK. Os N-glicanos identificados no hTSH-HEK foram do tipo complexo, apresentando predominantemente estruturas tri-antenárias, enquanto no hTSH-CHO e no hTSH-Pit as estruturas bi-antenárias foram predominantes. Foram detectadas diferenças significativas relacionadas à composição dos carboidratos para estas preparações, um teor muito menor de ácido siálico e muito maior de fucose foram observados no hTSHHEK. Foi confirmada a atividade biológica das 3 preparações, sendo a bioatividade do hTSHHEK 39% e 16% inferior à do hTSH-CHO e hTSH-Pit, respectivamente. A meia-vida circulatória do hTSH-HEK foi menor (1,5 X) que a do hTSH-CHO e a do hTSH-Pit (1,2 X). De acordo com esses resultados o hTSH-HEK pode ser considerado uma alternativa viável para aplicações clínicas especialmente por sua origem humana e composição de carboidratos.
Title in English
Human tryrotropin expression in human embrionic kidney cells (HEK293)
Keywords in English
expression
HEK-293
recombinant
tryrotropin
Abstract in English
In this work a strain of embryonic human kidney cells (HEK293) was transfected with the genes of the α and β subunits of human thyrotropin (hTSH), a glycoproteic hormone secreted by the pituitary gland. After 5 days of culture, the concentration of hTSH in conditioned medium was 0.95μg/mL. The material was concentrated and purified utilizing a strategy involving two steps, a cation-exchange chromatography and a reversed phase high performance liquid chromatography (RP-HPLC), providing an overall yield of 55% and a purity level > 90%. The purified material (hTSH-HEK) was analyzed and compared to a recombinant commercial preparation obtained from CHO cells (hTSH-CHO) and to a human pituitary preparation (hTSH-Pit). Identity and purity of hTSH-HEK were evaluated through physicochemical and immunological methods (MALDI-TOF mass spectrometry, size exclusion HPLC, reversed-phase HPLC, SDS-PAGE, immunoradiometric assay). Glycidic portion of hTSHHEK was evaluated by N-glycoprofiling analysis and the biological behavior of this hormone was evaluated by an in vivo bioassay and via a pharmacokinetic study. The 3 preparations showed equivalent purity (97%) and hTSH-HEK molecular mass was 2.1% lower than hTSHCHO mass and 2.7% higher than hTSH-Pit mass. The highest relative hydrophobicity, evaluated by RP-HPLC, was shown by hTSH-HEK. Remarkable differences related to the carbohydrate moiety were found for these preparations, a much lower sialic acid content and a higher fucose content being observed in hTSH-HEK. Biological activity was confirmed for the three preparations, the hTSH-HEK bioactivity being 39% and 16% lower than hTSH-CHO and hTSH-Pit, respectively. The hTSH-HEK circulatory half-life (t1/2) was lower than that of hTSHCHO (1.5-fold) and hTSH-Pit (1.2-fold). According to these findings, HEK293-derived hTSH can be considered useful for clinical applications, also in view of its human origin and particular N-glycan composition.
 
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Publishing Date
2016-12-15
 
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