Neurogenic differentiation of human dental pulp stem cells using different induction protocols

Abstract

An investigation on neuronal differentiation capacity of human dental pulp stem cells (DPSCs) was still lacking. In this study, two different neuronal induction protocols were investigated and compared. The neuronal differentiation was induced using chemical or growth factor induction protocol. The differentiation was confirmed by the neurogenic mRNA and protein expression using polymerase chain reaction and immunocytochemistry, respectively. Chemical-induced neuronal differentiation protocol promoted morphological change and β3-TUBULIN protein expression. Though, SOX2, SOX9, and β3-TUBULIN mRNA levels were not different compared with the control, indicating a defective differentiation. For growth factor induction protocol, the cells were exhibited neurite-like cellular process and positively stained with β3-TUBULIN. In addition, the increase in intracellular calcium was noted upon NMDA stimulation, implying the neuronal function. A dramatic increased mRNA expression of neurogenic markers [SOX2, SOX9, β3-TUBULIN, and gamma-aminobutyric acid (GABA receptors)] was noted as compared to the control. In addition, a remarkable increased expression of Notch signaling target gene, HEY1, was observed in growth factor-induced DPSCs derived neuronal-like cells compared with the control. These data indicate that growth factor induction method is a preferable protocol for neuronal differentiation by DPSCs.