Deng Zilong, Yan Wenjuan, Dai Xingzhu, Chen Ming, Qu Qian, Wu Buling, Zhao Wanghong
Department of Stomatology, Nanfang Hospital, Southern Medical University, Guangzhou, China.
Stomatological Hospital, Southern Medical University, Guangzhou, China.
Front Cell Dev Biol. 2021 Mar 30;9:661116. doi: 10.3389/fcell.2021.661116. eCollection 2021.
Dental pulp stem cell (DPSC) transplantation has shown new prospects in dental pulp regeneration, and is of great significance in the treatment of pulpitis and pulp necrosis. The fate and regenerative potential of stem cells are dependent, to a great extent, on their microenvironment, which is composed of various tissue components, cell populations, and soluble factors. N-cadherin-mediated cell-cell interaction has been implicated as an important factor in controlling the cell-fate commitment of mesenchymal stem cells. In this study, the effect of N-cadherin on odontogenic differentiation of DPSCs and the potential underlying mechanisms, both and , was investigated using a cell culture model and a subcutaneous transplantation mouse model. It was found that the expression of N-cadherin was reversely related to the expression of odontogenic markers (dentin sialophosphoprotein, DSPP, and runt-related transcription factor 2, Runx2) during the differentiation process of DPSCs. Specific shRNA-mediated knockdown of N-cadherin expression in DPSCs significantly increased the expression of DSPP and Runx2, alkaline phosphatase (ALP) activity, and the formation of mineralized nodules. Notably, N-cadherin silencing promoted nucleus translocation and accumulation of β-catenin. Inhibition of β-catenin by a specific inhibitor XAV939, reversed the facilitating effects of N-cadherin downregulation on odontogenic differentiation of DPSCs. In addition, knockdown of N-cadherin promoted the formation of odontoblast-like cells and collagenous matrix in β-tricalcium phosphate/DPSCs composites transplanted into mice. In conclusion, N-cadherin acted as a negative regulator via regulating β-catenin activity during odontogenic differentiation of DPSCs. These data may help to guide DPSC behavior by tuning the N-cadherin-mediated cell-cell interactions, with implications for pulp regeneration.
牙髓干细胞（DPSC）移植在牙髓再生方面展现出了新的前景，对牙髓炎和牙髓坏死的治疗具有重要意义。干细胞的命运和再生潜能在很大程度上取决于其微环境，该微环境由各种组织成分、细胞群体和可溶性因子组成。N-钙黏蛋白介导的细胞间相互作用被认为是控制间充质干细胞细胞命运决定的一个重要因素。在本研究中，利用细胞培养模型和皮下移植小鼠模型，研究了N-钙黏蛋白对DPSCs成牙分化的影响及其潜在机制。研究发现，在DPSCs分化过程中，N-钙黏蛋白的表达与成牙标记物（牙本质涎磷蛋白，DSPP，和 runt相关转录因子2，Runx2）的表达呈负相关。特异性shRNA介导的DPSCs中N-钙黏蛋白表达的敲低显著增加了DSPP和Runx2的表达、碱性磷酸酶（ALP）活性以及矿化结节的形成。值得注意的是，N-钙黏蛋白沉默促进了β-连环蛋白的核转位和积累。用特异性抑制剂XAV939抑制β-连环蛋白，逆转了N-钙黏蛋白下调对DPSCs成牙分化的促进作用。此外，敲低N-钙黏蛋白促进了移植到小鼠体内的β-磷酸三钙/DPSCs复合材料中成牙本质样细胞和胶原基质的形成。总之，在DPSCs成牙分化过程中，N-钙黏蛋白通过调节β-连环蛋白活性发挥负调节作用。这些数据可能有助于通过调节N-钙黏蛋白介导的细胞间相互作用来指导DPSC的行为，对牙髓再生具有重要意义。
