Comparison of the Expression of Periodontal Markers in Dental and Bone Marrow-derived Mesenchymal Stem Cells.

Periodontal ligament stem cells are a source of mesenchymal stem cells, but it is unclear whether their phenotype is distinct from mesenchymal stem cells derived from different tissues, such as those derived from bone marrow.

To investigate the expression of the putative PDL markers asporin, periostin, nestin and cementum protein 1, by periodontal ligament stem cells both constitutively and during osteogenic differentiation when compared to bone marrow-derived mesenchymal stem cells, and dental pulp stem cells.

The primary human periodontal ligament, bone marrow, and dental pulp stem cells, and osteoblasts from different donors were cultured in vitro. The expression of periodontal marker associated genes during osteogenic induction was tested by qRT-PCR and immunofluorescence staining.

Asporin expression was detected in periodontal ligament stem cells and increased markedly during the time in culture (upregulated x53 fold at 21 days post-induction). During osteogenic differentiation, asporin expression significantly decreased in periodontal ligament cells whereas periostin significantly decreased in dental pulp cells. Periostin expression was absent in osteoblasts, but expression gradually increased in all other cells with time in culture. Nestin expression was mainly seen in the periodontal ligament and dental pulp cells and was largely absent in osteoblasts and bone marrow cells. Cementum protein-1 was most highly expressed in bone marrow cells and osteoblasts following osteogenic induction.

The results provide further evidence that periodontal ligament-derived and bone marrow derived mesenchymal stem cells are phenotypically distinct. Periodontal markers are also expressed in dental pulp stem cells.