Nerve Growth Factor Promotes Differentiation of Odontoblast-Like Cells

Contemporary strategies in tooth repair markedly rely on the newest findings on the cellular and biological components of dental development. Among several identified bioactive molecules, neurotrophins were recently proposed to affect tooth germ cell proliferation, differentiation, and cell-extracellular matrix interactions. The present study attempted to explore the effect of nerve growth factor (NGF) on a spontaneously immortalized dental papilla mesenchymal cell line. NGF induced differentiation of odontoblast-lineage cells with subsequent biomineralization in vitro. Here we showed that normalized transcript levels of tissue-specific markers such as DSPP and DMP I were elevated significantly, indicating cell differentiation and maturation processes. We performed innovative gene expression analysis or TM14, a matricellular protein and novel member of the fibulin family. TM14 expression followed a pattern similar to that of DMP 1, which suggests its important role in cell-matrix and intercellular interactions during dentin calcification. Alkaline phosphatase enzyme assay confirmed the extracellular matrix calcifications in NGF-supplemented groups. Thus, NGF was characterized as a potent promoter of mineralization during dentin formation. For the first time, we included TM14 in odontoblast genotype analysis and proved that NGF also promotes in vitro odontoblast differentiation. Collectively, these results highlight the importance of NGF during tooth morphogenesis, as well as urge the elaboration of complex epithelial-mesenchymal tissue cultures, where further elucidation of the signaling factor network could be completed. J. Cell. Biochem. 106: 539-545, 2009. (C) 2009 Wiley-Liss, Inc.