Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, Beijing, China.
Department of Endodontics, Capital Medical University School of Stomatology, Beijing, China.
BMC Oral Health. 2021 Jun 21;21(1):314. doi: 10.1186/s12903-021-01675-0.
Epiregulin (EREG) is an important component of EGF and was demonstrated to promote the osteo/dentinogenic differentiation of stem cells from dental apical papilla (SCAPs). Whether EREG can stimulate the osteo/dentinogenic differentiation of dental pulp stem cells (DPSCs) in inflammatory environment is not clear. The purpose of the present study is to investigate the role of EREG on the osteo/dentinogenic differentiation ability of DPSCs in inflammatory environment.
DPSCs were isolated from human third molars. Short hairpin RNAs (shRNAs) were used to knock down EREG expression in DPSCs. Recombinant human EREG (rhEREG) protein was used in the rescue experiment. TNF-α was employed to mimic the inflammatory environment in vitro. Alkaline phosphatase (ALP) staining, Alizarin red staining, quantitative calcium analysis, and real-time RT-PCR were performed to detect osteo/dentinogenic differentiation markers and related signalling pathways under normal and inflammatory conditions.
EREG depletion promoted the ALP activity and mineralization ability of DPSCs. The expression of BSP, DMP-1, and DSPP was also enhanced. Moreover, 50 ng/mL rhEREG treatment decreased the osteo/dentinogenic differentiation potential of DPSCs, while treatment with 10 ng/mL TNF-α for 4 h increased the expression of EREG in DPSCs. Conversely, EREG knockdown rescued the impaired osteo/dentinogenic differentiation ability caused by TNF-α treatment. Further mechanistic studies showed that EREG depletion activated the p38 MAPK and Erk signalling pathways in DPSCs under normal and inflammatory conditions.
Our results demonstrated that EREG could inhibit the osteo/dentinogenic differentiation potential of DPSCs via the p38 MAPK and Erk signalling pathways. Under inflammatory environment, EREG depletion enhanced osteo/dentinogenic differentiation potential of DPSCs by improving the expression of p-p38 MAPK and p-Erk.
表皮调节素（EREG）是表皮生长因子（EGF）的重要组成部分，被证明能促进根尖乳头干细胞（SCAP）的成骨/成牙本质分化。表皮调节素是否能刺激牙髓干细胞（DPSCs）在炎症环境中的成骨/成牙本质分化尚不清楚。本研究旨在探讨表皮调节素对炎症环境中 DPSCs 成骨/成牙本质分化能力的影响。
从人第三磨牙中分离 DPSCs。短发夹 RNA（shRNA）用于敲低 DPSCs 中的表皮调节素表达。重组人表皮调节素（rhEREG）蛋白用于挽救实验。TNF-α 用于体外模拟炎症环境。在正常和炎症条件下，通过碱性磷酸酶（ALP）染色、茜素红染色、定量钙分析和实时 RT-PCR 检测成骨/成牙本质分化标志物和相关信号通路。
表皮调节素耗竭促进了 DPSCs 的 ALP 活性和矿化能力。BSP、DMP-1 和 DSPP 的表达也增强了。此外，50ng/ml rhEREG 处理降低了 DPSCs 的成骨/成牙本质分化潜能，而用 10ng/ml TNF-α处理 4h 增加了 DPSCs 中表皮调节素的表达。相反，表皮调节素耗竭挽救了 TNF-α处理引起的 DPSCs 成骨/成牙本质分化能力受损。进一步的机制研究表明，表皮调节素耗竭在正常和炎症条件下激活了 DPSCs 中的 p38 MAPK 和 Erk 信号通路。
我们的研究结果表明，表皮调节素可以通过 p38 MAPK 和 Erk 信号通路抑制 DPSCs 的成骨/成牙本质分化潜能。在炎症环境中，表皮调节素耗竭通过提高 p-p38 MAPK 和 p-Erk 的表达增强了 DPSCs 的成骨/成牙本质分化潜能。
