PTEN regulates proliferation and osteogenesis of dental pulp cells and adipogenesis of human adipose‑derived stem cells

Objective To investigate the role of phosphatase and tensin homolog (PTEN) in dental pulp cells (hDPs) and adipose‐derived mesenchymal stem cells (hADSCs). Materials and Methods Genetic variant was identified with exome sequencing. The hDPs isolated from a patient with Cowden syndrome were investigated for their proliferation, osteogenesis, adipogenesis, and gene expression compared with controls. The normal hDPs and hADSCs were treated with the PTEN inhibitor, VO‐OHpic trihydrate (VOT), to investigate the effect of PTEN inhibition. Results A heterozygous nonsense PTEN variant, c.289C>T (p.Gln97*), was identified in the Cowden patient's blood and intraoral lipomas. The mutated hDPs showed significantly decreased proliferation, but significantly upregulated RUNX2 and OSX expression and mineralization, indicating enhanced osteogenic ability in mutated cells. The normal hDPs treated with VOT showed the decreases in proliferation, colony formation, osteogenic marker genes, alkaline phosphatase activity, and mineral deposition, suggesting that PTEN inhibition diminishes proliferation and osteogenic potential of hDPs. Regarding adipogenesis, the VOT‐treated hADSCs showed a reduced number of cells containing lipid droplets, suggesting that PTEN inhibition might compromise adipogenic ability of hADSCs. Conclusions PTEN regulates proliferation, enhances osteogenesis of hDPs, and induces adipogenesis of hADSCs. The gain‐of‐function PTEN variant, p.Gln97*, enhances osteogenic ability of PTEN in hDPs.