10(-7)  m 17β-oestradiol enhances odonto/osteogenic potency of human dental pulp stem cells by activation of the NF-κB pathway.

Oestrogen has been proven to significantly enhance osteogenic potency, while oestrogen deficiency usually leads to impaired osteogenic differentiation of mesenchymal stem cells. However, little is known concerning direct effects of oestrogen on differentiation of human dental pulp stem cells (DPSCs). In this study, human DPSCs were isolated and treated with 10(-7)  m 17β-oestradiol (E2). Alkaline phosphatase (ALP) assay and alizarin red staining were performed. Alkaline phosphatase and alizarin red showed that E2 treatment significantly enhanced ALP activity and mineralization ability of DPSCs, but had no effect on cell proliferation. Real-time RT-PCR and western blot assay demonstrated that odonto/osteogenic markers (ALP, RUNX2/RUNX2, OSX/OSX, OCN/OCN and DSPP/DSP) were significantly upregulated in the cells after E2 treatment. Moreover, phosphorylation of cytoplasmic IκBα/P65 and expression of nuclear P65 were enhanced in a time-dependent manner following E2 treatment, suggesting activation of NF-κB signaling. Conversely, inhibition of the NF-κB pathway suppressed E2-mediated upregulation of odonto/osteogenic markers, indicating that the NF-κB pathway was pivotal for E2-mediated differentiation. These findings provide evidence that 10(-7)  m 17β-oestradiol promoted odonto/osteogenic differentiation of human DPSCs via activation of the NF-κB signaling pathway.

Wang Y ，Zheng Y ，Wang Z ，Li J ，Wang Z ，Zhang G ，Yu J ... -  《-》

Mineral trioxide aggregate enhances the odonto/osteogenic capacity of stem cells from inflammatory dental pulps via NF-κB pathway.

This study was designed to investigate the effects of mineral trioxide aggregate (MTA) on the osteo/odontogenic differentiation of inflammatory dental pulp stem cells (iDPSCs). inflammatory DPSCs were isolated from the inflammatory pulps of rat incisors and cocultured with MTA-conditioned medium. MTT assay and flow cytometry were performed to evaluate the proliferation of iDPSCs. Alkaline phosphatase (ALP) activity, alizarin red staining, real-time RT-PCR, and Western blot assay were used to investigate the differentiation capacity as well as the involvement of NF-κB pathway in iDPSCs. Mineral trioxide aggregate-treated iDPSCs demonstrated the higher ALP activity and formed more mineralized nodules than the untreated group. The odonto/osteoblastic markers (Alp, Runx2/RUNX2, Osx/OSX, Ocn/OCN, and Dspp/DSP, respectively) in MTA-treated iDPSCs were significantly upregulated as compared with untreated iDPSCs. Mechanistically, cytoplastic phos-P65 and nuclear P65 in MTA-treated iDPSCs were significantly increased in a time-dependent manner. Moreover, the inhibition of NF-κB pathway suppressed the MTA-induced odonto/osteoblastic differentiation of iDPSCs, as indicated by decreased ALP levels, weakened mineralization capacity and downregulated levels of odonto/osteoblastic genes (Osx, Ocn, and Dspp). Mineral trioxide aggregate enhances the odonto/osteogenic capacity of DPSCs from inflammatory sites via activating the NF-κB pathway.

Wang Y ，Yan M ，Fan Z ，Ma L ，Yu Y ，Yu J ... -  《-》

Dental pulp stem cells from traumatically exposed pulps exhibited an enhanced osteogenic potential and weakened odontogenic capacity.

Traumatic pulp exposure can bring about some permanent damages to tooth tissues including dental pulps. This study was designed to evaluate the effects of traumatic pulp exposure on the osteo/odontogenic capacity of dental pulp stem cells (DPSCs). Rat incisors were artificially fractured and dental pulps were exposed to the oral environment for 48 h. Then, multi-colony-derived DPSCs from the injured pulps (iDPSCs) were isolated. Their osteo/odontogenic differentiation and the involvement of NF-κB pathway were subsequently investigated. iDPSCs presented a lower proliferative capacity than normal DPSCs (nDPSCs), as indicated by MTT and FCM assay. ALP levels in iDPSCs were significantly higher (P<0.01) than those in nDPSCs. Alizarin red staining revealed that iDPSCs exhibited an increased capacity of calcium deposition. Moreover, iDPSCs expressed stronger osteogenic markers (Runx2/RUNX2 and Ocn/OCN) and less odontogenic gene/protein (Dspp/DSP) than nDPSCs in vitro. In vivo transplantation showed that nDPSCs implants generated the typical dentine-pulp complex while all iDPSCs pellets formed the osteodentin-like tissues which were immunopositive for OCN. Mechanistically, iDPSCs expressed the higher levels of cytoplasmic phosphorylated IκBα/P65 and nuclear P65 than nDPSCs, indicating an active cellular NF-κB pathway in iDPSCs. After the inhibition of NF-κB pathway, the osteogenic potential in iDPSCs was significantly down-regulated while odontogenic differentiation was up-regulated, as indicated by the decreased Alp/Runx2/Ocn and uprised Dspp expression. Pulp exposure for 48 h decreased the odontogenic capacity and enhanced the osteogenic potential of DPSCs via the NF-κB signalling pathway.

Wang Y ，Yan M ，Wang Z ，Wu J ，Wang Z ，Zheng Y ，Yu J ... -  《-》

Potassium dihydrogen phosphate promotes the proliferation and differentiation of human periodontal ligament stem cells via nuclear factor kappa B pathway.

Periodontal ligament stem cells (PDLSCs) are vital for the regeneration of periodontal tissues. Potassium dihydrogen phosphate (KH2PO4) has recently been applied as a component of the mineralization inducing medium (MM), which can be used to induce osteogenic differentiation of dental stem cells. However, whether KH2PO4 has effects on PDLSCs has not been studied. PDLSCs were isolated by magnetic activated cell sorting and cultured. Alkaline phosphatase (ALP) activity and ALP protein expression of PDLSCs treated with different concentrations of KH2PO4 were examined to make sure the optimal concentration of KH2PO4 for the following experiments. The effects of KH2PO4 on the proliferation and differentiation of PDLSCs were investigated by flow cytometry, cell counting kit-8 assay, alizarin red staining, real-time RT-PCR, and Western blot. The involvement of nuclear factor kappa B (NF-κB) pathway in KH2PO4-treated PDLSCs was analyzed by Western blot and alizarin red staining. ALP activity assay and ALP protein expression examination revealed that 1.8 mmol/L KH2PO4 was the optimal concentration for the induction of hPDLSCs by KH2PO4. The proliferation and mineralization capacity of PDLSCs treated with KH2PO4 were enhanced as compared with the control group. PDLSCs treated with KH2PO4 showed an improved proliferation capacity in logarithmic growth phase at day 7. As PDLSCs were treated with KH2PO4, the expression of odonto/osteogenic markers (OCN/OCN, DSP/DSPP, OSX/OSX, RUNX2/RUNX2, and ALP/ALP) in cells were up-regulated at day 3 or 7. Moreover, the expression of IκBα in cytoplasm was down-regulated, along with an increased expression of p-P65 in cytoplasm and an up-regulated expression of P65 in nucleus. When treated with BMS345541 (the specific NF-κB inhibitor), the odonto/osteogenic differentiation of KH2PO4-treated PDLSCs was significantly attenuated. KH2PO4 can improve the proliferation and odonto/osteogenic differentiation capacity of PDLSCs via NF-κB pathway, and thus represents a potential target involved in the regeneration of periodontium for clinical treatments.

Xu Y ，Wang Y ，Pang X ，Li Z ，Wu J ，Zhou Z ，Xu T ，Gobin Beharee R ，Jin L ，Yu J ... -  《-》

17beta-estradiol promotes the odonto/osteogenic differentiation of stem cells from apical papilla via mitogen-activated protein kinase pathway.

Li Y ，Yan M ，Wang Z ，Zheng Y ，Li J ，Ma S ，Liu G ，Yu J ... -  《Stem Cell Research & Therapy》