EphrinB2 signalling modulates the neural differentiation of human dental pulp stem cells

Abstract

Dental pulp stem cells (DPSCs) originate from the embryonic neural crest and have neurogenic potential. The present study investigated the roles of the forward and reverse EphrinB2 signalling pathways during DPSC neurogenesis. Treatment of DPSCs with recombinant EphrinB2-Fc protein over 7 days in a neural induction culture resulted in significant downregulation of the following neural markers: βIII-Tubulin, neural cell adhesion molecule (NCAM), nestin, neurogenin 2 (NGN2), neurofilament medium polypeptide and Musashi1. Immunocytochemistry revealed that EphrinB2-Fc-treated DPSCs exhibited more rounded morphologies with fewer neurite outgrowths as well as reduced protein expression of βIII-tubulin and NGN2. Treatment of DPSCs with a peptide inhibitor specific to the EphB4 receptor significantly upregulated expression of the neural markers microtubule-associated protein 2, Musashi1, NGN2 and neuron-specific enolase, whereas treatment with a peptide inhibitor specific to the EphB2 receptor exerted negligible effects on neurogenesis. Transgenic expression of EphrinB2 in DPSCs resulted in significant upregulation of Musashi1 and NCAM gene expression, while treatment of DPSCs with recombinant EphB4-Fc protein led to significant upregulation of only Musashi1. Thus, it may be concluded that stimulation of forward EphrinB2-EphB4 signalling markedly inhibited neurogenesis in DPSCs, whereas suppression of this forward signalling pathway with peptide inhibitor specific to EphB4 promoted neurogenesis. Meanwhile, stimulation of reverse EphB4-EphrinB2 signalling only marginally enhanced the neural differentiation of DPSCs. The present findings indicate the potential application of peptide or small molecule inhibitors of EphrinB2 forward signalling in neural tissue engineering with DPSCs.

Lentiviral-mediated ephrin B2 gene modification of rat bone marrow mesenchymal stem cells

“…25 A previous study suggested that stimulation of reverse EphB4-EphrinB2 signalling marginally enhanced the neural differentiation of dental pulp stem cells. 6 These results offer an explanation for the directional differentiation of EphrinB2/BMSCs into neuron-like cells.…”

“…5 Currently, there are limited reports on the roles of EphB4 and EphrinB2 in stem cells. 6 Similar to other tyrosine kinase receptors, signal transduction between EphB4 and EphrinB2 is bidirectional, as each can be activated by the other, producing ‘forward signals’ and ‘reverse signals’. 3 Autophosphorylation of the receptor is initiated by EphrinB2, with phosphoinositide 3-kinase, Src, mitogen-activated protein kinases, Akt and other proteins mediating the cascade reaction, thus giving rise to what is known as a forward signal.…”

Assessment of Dental Pulp Stem Cell (DPSC) Biomarkers Following Induction with Bone Morphogenic Protein 2 (BMP-2)

“…These results demonstrated that some, but not all, DPSC isolates were capable of responding to BMP-2 with corresponding changes to growth, viability, and cellular morphology. Moreover, these changes were associated with sDT DPSC isolates not expressing multiple MSC biomarkers, but rather one specific MSC marker -Nestin [30,31].…”

“…For example, many other studies of DPSC differentiation have evaluated 4, which are known transcription factors that may directly influence specific pathways related to cellular phenotypes [40,41]. However, the role of Nestin ap to have been evaluated peripherally in studies of DPSC and neural differentiation without evaluation of this biomarker among studies of osteogenic differentiation and BMP administration [42,43]. These biomarkers may be critical indicators not only of differentiation status and may also directly or indirectly affect other phenotypic behaviours observed in this study, such as doubling time.…”

Extrapolating neurogenesis of mesenchymal stem/stromal cells on electroactive and electroconductive scaffolds to dental and oral-derived stem cells

“…It is important to note that dental and oral-derived stem cells also possess a high propensity to differentiate into the osteo-odontogenic lineage, which could in turn compromise their neurogenic differentiation capacity. Hence, previous studies have investigated various strategies to enhance the neural differentiation of these adult cells, involving supplementation of various growth factors and small molecules within the culture milieu, 5 recombinant gene expression, 6 utilization of various novel scaffold materials, 7 , 8 together with the application of physical stimuli such as ultrasound. 8 …”