Banca de QUALIFICAÇÃO: JÉSSYCA TAMIRES DA FONSECA

Uma banca de QUALIFICAÇÃO de MESTRADO foi cadastrada pelo programa.
DISCENTE : JÉSSYCA TAMIRES DA FONSECA
DATA : 14/05/2018
HORA: 10:00
LOCAL: Sala de Reuniões do Centro de Biociências
TÍTULO:

DNA REPAIR IN HUMAN MESENCHYMAL STEM CELLS

PALAVRAS-CHAVES:

Human mesenchymal stem cells. DNA repair. Genetic stability. Cell senescence. PCR array.

PÁGINAS: 86
GRANDE ÁREA: Ciências Biológicas
ÁREA: Bioquímica
RESUMO:

Human mesenchymal stem cells (hMSC) are multipotent cells used in several cell therapy and tissue engineering research, as they have the ability to differentiate in multiple and different strains, have great capacity for self-renewal and in vitro expansion, excellent properties immunosuppressive and are able to secrete bioactive molecules that exert trophic effects. The umbilical cord is a source rich in hMSC whose extraction does not require an invasive procedure, not does it involve ethical, political and religious controversies. One of the problems that involve the use of these cells in clinical research is to ensure their in vitro expansion to obtain an ideal number of cells. However, this long-term expansion in culture may lead to loss of genetic stability, which makes it difficult to use mainly cell therapy research. In this work we investigated how the DNA repair system behaves in the hMSC when submitted to different culture conditions. The PCR-array methodology was used to evaluate the differential expression of 84 genes involved in the main mechanisms of DNA repair in the five culture conditions imposed on these cells (undifferentiated, differentiated, young, senescent and cultured with hydroxyapatite microparticles), seeking mainly to evaluate its genetic stability. The evaluation of the data showed that the permanence of the cells for a long time in culture tends to lead to a decrease in their genetic stability, mainly through the reduction of the mechanisms of DNA repair and that all the pathways are affected in this process, but the pathways of the nucleotide excision repair (NER) and repair of DNA double strand breaks (DSBr) are the most significant differential expression. When cells maintained under the different conditions were compared it was observed that both senescence and differentiation as well as culture with the microparticles trigger decreased expression of most of the genes involved in the repair and that under these conditions arise protein interactions that also culminate with genetic stability of hMSC. In conclusion, it is suggested that the culture time required for the differentiation process and the differentiation process itself lead to a decrease in DNA repair pathways, cellular senescence is a limiting factor for the performance of DNA repair in hMSC and that culture with microparticles generated the unexpected result of leading to a decrease in the expression of the repair pathways, since the trend would increase. In this context, further studies should be conducted to identify ways to maintain the genetic stability of these cells when maintained for long periods in culture to facilitate their use in clinical research.

MEMBROS DA BANCA:
Presidente - 1880243 - DANIEL CARLOS FERREIRA LANZA
Externo ao Programa - 1837354 - JULLIANE TAMARA ARAUJO DE MELO CAMPOS
Interno - 1149647 - LUCYMARA FASSARELLA AGNEZ