Dental Pulp Stem Cells, proliferation/differentiation switch reveals new insights in Oct4A dynamics

Although the role played by transcription factors network, that includes c-Myc, Klf4, Nanog, and Oct4, in the maintenance of embryonic stem cell pluripotency is known, its persistence and function in adult stem cells are still debated. To verify and clarify the role played by these molecules in adult stem cell function, we investigated the expression pattern of embryonic and adult stem cell markers in proliferating and differentiated dental pulp stem cells (DPSC). A particular attention was devoted to the expression pattern and intracellular localization of Oct4A. Data demonstrate that: Oct4, Nanog, Klf4 and c-Myc are expressed in adult stem cells and, with the exception of c-Myc, they are significantly down-regulated following differentiation. Moreover, a nuclear to cytoplasm shuttling of Oct4A was identified in differentiated cells, which was associated with Oct4A phosphorylation. Last, cell differentiation was also associated with a reduction in both the Wnt/beta-catenin/Lrh-1 pathway and CD10, CD29 and CD117. Learning how to exploit the nuclear-cytoplasm translocation of Oct4A could help in maintaining stem cells in an undifferentiated state, thus increasing opportunities to use adult stem cells in therapeutic applications.