A two-step strategy for neuronal differentiation in vitro of human dental follicle cells

Human dental follicle cells (DFCs) derived from wisdom teeth are precursor cells for cementoblasts. In this study, we recognized that naïve DFCs express constitutively the early neural cell marker β-III-tubulin. Interestingly, DFCs formed β-III-tubulin-positive neurosphere-like cell clusters (NLCCs) on low-attachment cell culture dishes in serum-replacement medium (SRM). For a detailed examination of the neural differentiation potential, DFCs were cultivated in different compositions of SRM containing supplements such as N2, B27, G5 and the neural stem cell supplement. Moreover, these cell culture media were combined with different cell culture substrates such as gelatin, laminin, poly-l-ornithine or poly-l-lysine. After cultivation in SRM, DFCs differentiated into cells with small cell bodies and long cellular extrusions. The expression of nestin, β-III-tubulin, neuron-specific enolase (NSE) and neurofilament was up-regulated in SRM supplemented with G5, a cell culture supplement for glial cells, and the neural stem cell supplement. DFCs formed NLCCs and demonstrated an increased gene expression of neural cell markers β-III-tubulin, NSE, nestin and for small neuron markers such as neuropeptides galanin (GAL) and tachykinin (TAC1) after cultivation on poly-l-lysine. For a further neural differentiation NLCC-derived cells were sub-cultivated on laminin and poly-l-ornithine cell culture substrate. After 2 weeks of differentiation, DFCs exposed neural-like cell morphology with small neurite-like cell extrusions. These cells differentially express neurofilament and NSE, but only low levels of β-III-tubulin and nestin. In conclusion, we demonstrated the differentiation of human DFCs into neuron-like cells after a two-step strategy for neuronal differentiation.