TNF-α triggers osteogenic differentiation of human dental pulp stem cells via the NF-κB signalling pathway

Dental pulp stem cells (DPSCs) are a type of mesenchymal stem cells (MSCs) characterised by self-renewal and multi-lineage differentiation, including chondrocytes, adipocytes, neural cells and osteoblasts, which make it an attractive choice for tissue engineering purposes. Tumour necrosis factor (TNF-) had the positive effect on the mineralisation of bone marrow MSCs and stromal cells derived from human adipose tissue. However, the effect of TNF- on DPSCs is unclear. We found that TNF- activated the NF-B pathway during the osteogenic differentiation of DPSCs. TNF- also increased mineralisation and the expression of bone morphogenetic protein 2 (BMP2), alkaline phosphatase (ALP), runt-related transcription factor 2 (RUNX2) and collagen type I (COL I) during this process. PDTC, an NF-B inhibitor, blocked the osteogenic differentiation induced by TNF-. No effect of TNF- on proliferation of DPSCs or cell cycle was detected. In summary, TNF- promotes mineralisation and mineralisation-related gene expression through the NF-B signalling pathway in DPSCs, which may provide a foundation for autologous transplantation of DPSCs.