CD146 positive human dental pulp stem cells promote regeneration of dentin/pulp-like structures.

CD146 and STRO-1 are endothelial biomarkers that are co-expressed on the cellular membranes of blood vessels within human dental pulp tissue. This study characterized the percentage of dentin-like structures produced by CD146-positive (CD146) human dental pulp stem cells (DPSCs), compared with their CD146-negative (CD146) counterparts. DPSC populations were enriched using magnetic-activated cell sorting (MACS), yielding CD146 and CD146 cells, as well as mixtures composed of 25% CD146 cells and 75% CD146 cells (CD146). Cell growth assays indicated that CD146 cells exhibit an approximate 3-4 h difference in doubling time, compared with CD146 cells. Cell cycle distributions were determined by flow cytometry analysis. The low percentage of CD146 cells' DNA content in G/G phase were compared with CD146 and non-separated cells. In contrast to CD146 and non-separated cells, prompt mineralization was observed in CD146 cells. Subsequently, qRT-PCR revealed high mRNA expression of CD146 and Alkaline phosphatase in mineralization-induced CD146 cells. CD146 cells were also observed high adipogenic ability by Oil red O staining. Histological examinations revealed an increased area of dentin/pulp-like structures in transplanted CD146 cells, compared with CD146 and CD146 cells. Immunohistochemical studies detected dentin matrix protein-1 (DMP1) and dentin sialophosphoprotein (DSPP), as well as human mitochondria, in transplanted DPSCs. Co-expression of CD146 and GFP indicated that CD146 was expressed in transplanted CD146 cells. CD146 cells may promote mineralization and generate dentin/pulp-like structures, suggesting a role in self-renewal of stem cells and dental pulp regenerative therapy.