p75 neurotrophin receptor regulates differential mineralization of rat ectomesenchymal stem cells.

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.