Jin Luyuan, Cao Yu, Yu Guoxia, Wang Jinsong, Lin Xiao, Ge Lihua, Du Juan, Wang Liping, Diao Shu, Lian Xiaomeng, Wang Songlin, Dong Rui, Shan Zhaochen
Laboratory of Molecular Signaling and Stem Cells Therapy, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, No. 4 Tiantanxili, Dongcheng District, Beijing, 100050 China.
Molecular Laboratory for Gene Therapy and Tooth Regeneration, Beijing Key Laboratory of Tooth Regeneration and Function Reconstruction, Capital Medical University School of Stomatology, No. 4 Tiantanxili, Dongcheng District, Beijing, 100050 China.
Cell Mol Biol Lett. 2017 Aug 8;22:14. doi: 10.1186/s11658-017-0044-2. eCollection 2017.
Exploring the molecular mechanisms underlying directed differentiation is helpful in the development of clinical applications of mesenchymal stem cells (MSCs). Our previous study on dental tissue-derived MSCs demonstrated that secreted frizzled-related protein 2 (SFRP2), a Wnt inhibitor, could enhance osteogenic differentiation in stem cells from the apical papilla (SCAPs). However, how SFRP2 promotes osteogenic differentiation of dental tissue-derived MSCs remains unclear. In this study, we used SCAPs to investigate the underlying mechanisms.
SCAPs were isolated from the apical papilla of immature third molars. Western blot and real-time RT-PCR were applied to detect the expression of β-catenin and Wnt target genes. Alizarin Red staining, quantitative calcium analysis, transwell cultures and in vivo transplantation experiments were used to study the osteogenic differentiation potential of SCAPs.
inhibited canonical Wnt signaling by enhancing phosphorylation and decreasing the expression of nuclear β-catenin in vitro and in vivo In addition, the target genes of the Wnt signaling pathway, (axin-related protein 2) and (matrix metalloproteinase-7), were downregulated by . inhibited the osteogenic differentiation potential of SCAPs. could rescue this -impaired osteogenic differentiation potential.
The results suggest that SFRP2 could bind to locally present Wnt ligands and alter the balance of intracellular Wnt signaling to antagonize the canonical Wnt pathway in SCAPs. This elucidates the molecular mechanism underlying the SFRP2-mediated directed differentiation of SCAPs and indicates potential target genes for improving dental tissue regeneration.
探索定向分化背后的分子机制有助于间充质干细胞（MSCs）临床应用的发展。我们之前对牙组织来源的MSCs的研究表明，分泌型卷曲相关蛋白2（SFRP2），一种Wnt抑制剂，可增强根尖乳头干细胞（SCAPs）的成骨分化。然而，SFRP2如何促进牙组织来源的MSCs的成骨分化仍不清楚。在本研究中，我们使用SCAPs来研究其潜在机制。
从未成熟第三磨牙的根尖乳头分离出SCAPs。应用蛋白质免疫印迹法和实时逆转录-聚合酶链反应检测β-连环蛋白和Wnt靶基因的表达。采用茜素红染色、定量钙分析、Transwell培养和体内移植实验研究SCAPs的成骨分化潜能。
在体外和体内通过增强磷酸化并降低核β-连环蛋白的表达来抑制经典Wnt信号通路。此外，Wnt信号通路的靶基因，axin相关蛋白2和基质金属蛋白酶-7，被SFRP2下调。SFRP2抑制了SCAPs的成骨分化潜能。重组人Wnt3a可挽救这种被SFRP2损害的成骨分化潜能。
结果表明，SFRP2可与局部存在的Wnt配体结合，改变细胞内Wnt信号的平衡，从而拮抗SCAPs中的经典Wnt通路。这阐明了SFRP2介导的SCAPs定向分化的分子机制，并指出了改善牙组织再生的潜在靶基因。
