The difference on the osteogenic differentiation between periodontal ligament stem cells and bone marrow mesenchymal stem cells under inflammatory microenviroments

• The significant difference on the osteogenesis between PDLSCs and BMSCs was showed in inflammatory microenvironments.
• TNF-α strongly inhibited PDLSCs mineralization and ALP activity but stimulated the mineralization of BMSCs.
• TNF-α inhibited genes expression of osteogenic differentiation in PDLSCs, while, it stimulates gene expressions (BSP and Runx2) in BMSCs.
• Enhanced NF-κB activity in PDLSCs decreases expression of Runx2 but it does not impede the osteogenic differentiation of BMSCs.

Periodontitis is a major cause of tooth loss in adults and periodontal ligament stem cells (PDLSCs) is the most favorable candidate for the reconstruction of tissues destroyed by periodontal diseases. However, pathological alterations caused by inflammatory insults might impact the regenerative capacities of these cells. Bone-marrow-derived human mesenchymal stem cells (hBMSCs) would accelerate alveolar bone regeneration by transplantation, compared to PDLSCs. Therefore, a better understanding of the osteogenic differentiation between PDLSCs and BMSCs in inflammatory microenviroments is therefore warranted. In this study, human PDLSCs were investigated for their stem cell characteristics via analysis of cell surface marker expression, colony forming unit efficiency, osteogenic differentiation and adipogenic differentiation, and compared to BMSCs. To determine the impact of both inflammation and the NF-κβ signal pathway on osteogenic differentiation, cells were challenged with TNF-α under osteogenic induction conditions and investigated for mineralization, alkaline phosphatase (ALP) activity, cell proliferation and relative genes expression. Results showed that PDLSCs exhibit weaker mineralization and ALP activity compared to BMSCs. TNF-α inhibited genes expression of osteogenic differentiation in PDLSCs, while, it stimulates gene expressions (BSP and Runx2) in BMSCs. Enhanced NF-κβ activity in PDLSCs decreases expression of Runx2 but it does not impede the osteogenic differentiation of BMSCs. Taken together, these results may suggest that the BMSCs owned the stronger immunomodulation in local microenvironment via anti-inflammatory functions, compared to PDLSCs.