Molecular Biological Comparison of Dental Pulp- and Apical Papilla-Derived Stem Cells

Martyna Smeda,Wolfgang Buchalla,Kerstin M. Galler,Andreas Rosendahl,Christoph Moehle,Beate Lenhardt,Melanie Woelflick,Matthias Widbiller

doi:10.3390/ijms23052615

Abstract

Both the dental pulp and the apical papilla represent a promising source of mesenchymal stem cells for regenerative endodontic protocols. The aim of this study was to outline molecular biological conformities and differences between dental pulp stem cells (DPSC) and stem cells from the apical papilla (SCAP). Thus, cells were isolated from the pulp and the apical papilla of an extracted molar and analyzed for mesenchymal stem cell markers as well as multi-lineage differentiation. During induced osteogenic differentiation, viability, proliferation, and wound healing assays were performed, and secreted signaling molecules were quantified by enzyme-linked immunosorbent assays (ELISA). Transcriptome-wide gene expression was profiled by microarrays and validated by quantitative reverse transcription PCR (qRT-PCR). Gene regulation was evaluated in the context of culture parameters and functionality. Both cell types expressed mesenchymal stem cell markers and were able to enter various lineages. DPSC and SCAP showed no significant differences in cell viability, proliferation, or migration; however, variations were observed in the profile of secreted molecules. Transcriptome analysis revealed the most significant gene regulation during the differentiation period, and 13 biomarkers were identified whose regulation was essential for both cell types. DPSC and SCAP share many features and their differentiation follows similar patterns. From a molecular biological perspective, both seem to be equally suitable for dental pulp tissue engineering.

Highlights

Regenerative endodontic procedures aim to replace an irreversibly inflamed or necrotic dental pulp
In accordance with previous studies, our analysis revealed both cell types to be positive for the mesenchymal stem cell markers CD73, CD90, and CD105, as well as a multi-lineage differentiation potential [10,22–24], both of which characterize mesenchymal stem cells according to Dominici et al [25]
The findings of this study suggest that dental pulp stem cells (DPSC) and stem cells from the apical papilla (SCAP) have similar viability and capacity for cell proliferation and migration, they both fulfil the requirements for tissue engineering techniques

Summary

Introduction

Regenerative endodontic procedures aim to replace an irreversibly inflamed or necrotic dental pulp. Stem cells and growth factors are inserted into a suitable scaffold and injected directly into the root canal. This requires storage and laboratory processing of stem cells beforehand, which is afflicted with high costs. A primarily cell-free approach based on cell-homing seems to be more practical for use in dental offices. In this case, no cells have to be transplanted but local stem cells are attracted from periapical tissues by recombinant signaling molecules or endogenous, dentin-derived growth factors and migrate into the root canal. Cell-homing can be used to restore the whole pulp and parts of the tissue that are lost due to local inflammatory or necrotic processes [3,6,7]

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