RESUMO
OBJECTIVE: The aim of this study was to investigate the spatiotemporal expression and potential role of p75NTR in tooth morphogenesis and tissue mineralization. MATERIALS AND METHODS: The dynamic morphology of the four stages (from the beginning of E12.5 d, then E13.5 d and E15.5 d, to the end of E18.5 d) was observed, and the expressions of p75NTR and Runx2 were traced. The ectomesenchymal stem cells (EMSCs) were harvested in vitro, and the biological characteristics were observed. Moreover, the mineralization capability of EMSCs was evaluated. The relations between p75NTR and ALP, Col-1 and Runx2 were investigated. RESULTS: The morphologic results showed that the dental lamina appeared at E12.5 d, the bud stage at E13.5 d, the cap stage at E15.5 d and the bell stage at E18.5 d. p75NTR and Runx2 showed the similar expression pattern. EMSCs from the four stages showed no significant difference in proliferation. But the positive rate of p75NTR in the E12.5 d cells was significantly lower than that in the other three stages (P < 0.05). Moreover, the higher positive rate of p75NTR the cells were, the stronger mineralization capability they showed. p75NTR was well positively correlated with the mineralization-related markers ALP, Col-1 and Runx2, which increased gradually with the mature of dental germs. CONCLUSION: p75NTR might play an important role in the regulation of tooth morphogenesis, especially dental hard tissue formation.
Assuntos
Subunidade alfa 1 de Fator de Ligação ao Core/metabolismo , Células-Tronco Mesenquimais/citologia , Proteínas do Tecido Nervoso/metabolismo , Odontogênese/fisiologia , Receptores de Fatores de Crescimento/metabolismo , Calcificação de Dente/fisiologia , Dente/crescimento & desenvolvimento , Animais , Proliferação de Células/fisiologia , Células Cultivadas , Colágeno Tipo I/genética , Colágeno Tipo I/metabolismo , Cadeia alfa 1 do Colágeno Tipo I , Subunidade alfa 1 de Fator de Ligação ao Core/genética , Desenvolvimento Embrionário , Transição Epitelial-Mesenquimal/fisiologia , Dente Molar/citologia , Morfogênese/genética , Proteínas do Tecido Nervoso/genética , Ratos , Ratos Sprague-Dawley , Receptores de Fatores de Crescimento/genética , Inibidor Secretado de Peptidases Leucocitárias/genética , Inibidor Secretado de Peptidases Leucocitárias/metabolismo , Dente/citologiaRESUMO
OBJECTIVES: The aim of this study was to investigate whether p75NTR (p75 neurotrophin receptor) regulates differential mineralization capacity of rEMSCs (rat ectomesenchymal stem cells) and underlying mechanisms associated with Mage-D1 (melanoma-associated antigens-D1). MATERIALS AND METHODS: Immunohistochemical staining of p75NTR in developing tooth germs was performed on E12.5d (embryonic 12.5 days) and E19.5d (embryonic 19.5 days). E12.5d EMSCs and E19.5d EMSCs were isolated in the same pregnant Sprague-Dawley rats from embryonic maxillofacial processes and tooth germs. p75NTR small-interfering RNA, p75NTR overexpression plasmid, Mage-D1 small-interfering RNA and recombined rat NGF were used to transfect cells. RESULTS: p75NTR was expressed in epithelial-mesenchymal interaction areas at E12.5d and E19.5d tooth germ development stages. E19.5d EMSCs had higher p75NTR expression levels and differential mineralization capacity but lower levels of cell proliferation. Under induction by mineralized culture medium, the potential of differential mineralization had identical trends in regulation of p75NTR in EMSCs; Mage-D1 did not fluctuate and TrkA was not expressed. Binding of p75NTR and Mage-D1 were detected. Mage-D1 knockdown significantly down-regulated expression of related genes, which NGF could not rescue. CONCLUSION: p75NTR participated in tooth germ development stages and mediated differential mineralization of EMSCs. p75NTR played a critical role in regulating the potential of differential mineralization of EMSCs. Mage-D1 seemed to act as a bridge in the underlying mechanism of effects of p75NTR.