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Evaluation of large scale gene expression profile of undifferentiated pulp cells and odontoblastic cells using cDNA microarray

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Author(s):
Maidy Rehder Wimmers Ferreira
Total Authors: 1
Document type: Master's Dissertation
Press: Ribeirão Preto.
Institution: Universidade de São Paulo (USP). Faculdade de Odontologia de Ribeirão Preto (PCARP/BC)
Defense date:
Examining board members:
Karina Fittipaldi Bombonato Prado; Carlos Alberto de Souza Costa; Geraldo Aleixo da Silva Passos Junior
Advisor: Karina Fittipaldi Bombonato Prado
Abstract

The extraordinary regenerative potential of pulp-dentin complex leads to the importance of the characterization of cell and molecular processes involved in regeneration of dentin. The advancement of stem cell research sparked great interest in cultivating them in the presence of signs of odontogenic induction. The purpose of the present investigation was to evaluate comparatively undifferentiated pulp cells (OD-21) and odontoblastic cells (MDPC-23) through the assessment of cell stimulation and gene expression profiling. OD-21 and MDPC-23 cells were grown in culture flasks until subconfluence, and then cultured in 24-well plates at a concentration of 104 cells/well (n=5). The parameters analyzed were: (1) proliferation, cell viability and alkaline phosphatase activity after 3, 7 and 10 days, in addition to detection and quantification of mineralized matrix after 17 days (the statistical test used was the Mann-Whitney p≤0.05), (2) immunofluorescence for non-collagen proteins (DSPP and osteopontin) at 1, 3 and 7 days, (3) transcriptional expression analysis using cDNA microarray technology and real-time PCR. The microarray data were analyzed with the aid of specialized bioinformatics programs such as SAM (significance analysis of microarrays), Cluster, TreeView and GeneNetwork. Gene expression was avalided by real-time polymerase chain reaction (PCR). The results showed that cell viability was above 80% in both cells, and cell proliferation and alkaline phosphatase activity were higher in MDPC-23 cells. Mineralization nodules were observed only in the odontoblastic cell cultures. Osteopontin was present equally in both cells, whereas dentin sialophosphoprotein was higher expressed in MDPC-23 cells. The results showed genes with similar behavior in two cell types, such as Bad (cell death), Erf and Btg1 (cell proliferation), Il13 and Cxcl10 (immune response) and Arfgef1 (cell communication). Moreover, regions of the heatmap showed differences in induction and repression of genes, such C1qb (immune response), Jak2 (death, communication and cell proliferation), Col4a1 (cell adhesion), Rpl26 and Rpl6 (cellular metabolic process). We conclude that the OD-21 cells, although undifferentiated, share many genes with similar behavior to the odontoblastic MDPC-23 cells, suggesting their potential to differentiate into odontoblasts. (AU)

FAPESP's process: 09/01888-0 - Evaluation of large scale gene expression profile of pulp stem cells and odontoblastic cells using cDNA microarrays
Grantee:Maidy Rehder Wimmers Ferreira
Support Opportunities: Scholarships in Brazil - Master