Transcriptome profiling of DPP stimulated DPSCs identifies the role of autophagy in odontogenic differentiation

Dentin phosphophoryn (DPP), synthesized and processed predominantly by the odontoblasts, serves both a structural and signaling role in dentin. In the ECM, DPP functions as an avid calcium and collagen binding protein and it also plays a crucial role as a scaffold for cell attachment and survival. The signaling function of DPP was demonstrated when undifferentiated mesenchymal cells stimulated with DPP, mediated calcium signaling through release of intracellular Ca²⁺. The objective of this study was to identify potentially novel signaling mechanisms that mediate odontoblast differentiation. Therefore, transcriptomes of DPSCs (dental pulp stem cells) with or without DPP stimulation were compared by bulk RNA-seq. Analysis of the unbiased RNA-seq data were subjected to functional enrichment analysis using Gene Ontology (GO) and KEGG pathways. Results identified several upregulated genes which were associated with autophagy, that were subsequently validated by RT-PCR. Western blotting analysis confirmed the up regulation of several autophagy markers such as ATG5, BECN1 and LC3A/B at specific time points. Autophagosome formation was also observed with DPP treatment. Additionally, autophagy supported a role for odontoblast differentiation of DPSCs. These findings suggest that DPP mediated autophagy might be a potential mechanism for the survival and terminal differentiation of DPSCs.