Regulation of miRNA during direct reprogramming of dental pulp cells to insulin-producing cells

• Dental pulp cells (DPCs) have potential for direct reprogramming.
• Ectopic expression induces conversion of DPCs to insulin-producing cells.
• Direct conversion of DPCs is regulated by miRNAs including miR-183.
• Upregulation of Foxo1 may contribute to the direct conversion of DPCs.

To further evaluate the multipotency of dental pulp cells, and to investigate the possible direct reprogramming of these cells, we examined their in vitro induction of direct conversion to an endocrine cell lineage. In vitro induction was carried out using similar conditions to those reported for regulating the differentiation of undifferentiated intestinal cells into endocrine progenitor cells. Specifically, the transcription factors Pdx1 and Neurog3 were transfected into rat dental pulp cells to induce their direct conversion to endocrine lineage cells. The degree of induction was evaluated by detecting insulin-producing cells. Using a miRCURY LNA microRNA Array (Exiqon), the miRNA expression profiles were comprehensively analyzed. At 10 days after induction, insulin-producing cells were detected. Based on the expression profiles, eight miRNA probes showing significant differences at 10 days after induction compared with their pre-induction baseline values were extracted after filtering. Notably, miR-183 was downregulated by less than 40% after induction. Following a target scan of miR-183, we identified 242 conserved targets, including molecules crucial for the development of pancreatic beta-cells such as Foxo1. These findings indicate that dental pulp cells have potential for direct reprogramming to insulin-producing cells. This potential ability for direct reprogramming of dental pulp cells shows promise for clinically relevant tissue engineering materials.