Objective Genes and signaling of the teeth are conserved during evolution and this similar gene networks regulate the development of other organs. The tooth has been an excellent model to study molecular mechanisms of organs, signaling networks, cellular heterogeneity, and adult tissue renewal. Human dental pulp cells (hDPCs) are pluripotent with a high capacity for differentiation and regeneration of a dentin/pulp-like complex and extraoral tissues. To discover molecular characteristics of adult hDPSC, we performed a transcriptome analysis of hDPCs obtained from the premolar teeth to reveal gene expression profile, signaling pathways, and expression of odontogenesis genes.

Methods hDPCs of mandibular second premolar from two adult donors were isolated, cultured, and subjected for RNA sequencing. RNA-Seq Alignment, RNA-Seq Differential Expression, and Reactome program was used to analyze gene expression profile and pathways.

Results The RNA sequencing demonstrated that 17,968 genes out of 27,914 in total were expressed in adult premolar teeth.  The FN1, COL1A2, ACTB, COL1A1, EEF1A1 were the top expression genes. Extracellular matrix pathway was the most involving pathway. The important genes for odontogenesis such as BMP2, BMP4, MSX1, MSX2, TBX2 were still expressed in mature adult human teeth while FGF3, FGF8, LHX7, ALX3, FOXI3 were not observed.

Conclusion We showed that the mature permanent teeth expressed tooth developmental genes especially those related to extracellular matrix. Our findings provide new knowledge about RNA profiles and signaling networks in the permanent mandibular second premolar teeth.