Background:

The dental pulp plays a crucial role in the long-term maintenance of teeth function. The progress of endodontic treatment and pulp tissue regeneration engineering has therapeutic potential. But regulation mechanisms of tooth development or regeneration dependent on dental stem cells were still not fully understood. So, it is urgently needed bridge the gaps between basic and clinical research. With single cell sequencing technology being applied in medical research, landscapes of human dental pulp cells had been initially outlined. However, the specific cellular heterogeneity of dental pulp cells, especially dental stem cells in different spatial and temporal levels are remain unclear.

Methods:

Gene expression profiles of human dental pulp cells from four teeth with different developmental periods analyzed by 10x Genomics single-cell RNA sequencing were studied and cluster analysis. Multiple spatial and temporal characteristics of subpopulation of cells were further studied by signal pathway analysis, trajectory analysis stemness analysis.

Results:

In this study, transcriptomic expression-based clustering analysis showed that dental pulp cells at different developmental points exist differences in number, not cell types. Pathway analysis revealed that early in development, the pulp may perform more developmentally relevant functions such as synthetic translation, while later it begins to differentiate into specific directions or retains functional characteristics for homeostasis maintenance. The importance of the stem cell microenvironment in human tooth development was evident. Subpopulations in early development stage were clearly identified in fibroblasts, odontoblasts and mesenchymal stem cells. Particularly, differentially expressed gene analysis and stemness analysis defined three subpopulations of dental pulp stem cells with greater stemness and potential for multiple differentiation. Combining the expression characteristics of the three cell subpopulations, some genes such as MIA, DGKI and so on that may contribute to the developmental differentiation of dental pulp stem cells were also uncovered

Conclusion:

For the first time, the specific cellular heterogeneity of dental pulp cells, especially dental stem cells in different spatial and temporal level was proviede. Gene expression profile of early developing cells may help in cell screening for regenerative engineering and improve the success of dental pulp regeneration.