The establishment of a method to derive dental epithelial cells seems to be an important challenge toward realizing the whole tooth regeneration. In order to obtain a source of dental epithelial-like cells, a new methodology has been previously developed by our research group. In the method, induced pluripotent stem cells are cultured in suspension in the presence of neurotrophin-4 to form embryoid bodies followed by further adherent culture of the embryoid bodies in DMEM basal nutrient medium. The present study was directed to improve the efficiency of dental epithelial-like cell production, by focusing on the optimization of initial cell number for the formation of embryoid bodies and the addition of epidermal growth factor as well as its timing. Our results demonstrated that an initial cell number of 1000 cells/drop gives the highest efficiency of dental epithelial-like cell production. It appears that, under this condition, medium deterioration is moderated, and that cell-cell interactions are optimized within embryoid bodies. On the other hand, epidermal growth factor serves to increase the abundance of dental epithelial-like cells when added to the medium together with neurotrophin-4 during embryoid body formation. The promotive effect of epidermal growth factor may involve the transactivation of TrkB, mediated by the effectors of epidermal growth factor receptor signaling.

建立一种获得牙上皮细胞的方法似乎是实现全牙再生的重要挑战。为了获得牙上皮样细胞的来源，我们的研究小组先前开发了一种新方法。在该方法中，诱导多能干细胞在neurotrophin-4存在下悬浮培养以形成拟胚体，然后在DMEM基础营养培养基中进一步贴壁培养拟胚体。本研究旨在通过优化用于形成胚体的初始细胞数量和添加表皮生长因子及其时间来提高牙齿上皮样细胞的生产效率。我们的结果表明，1000 个细胞/滴的初始细胞数可提供最高的牙齿上皮样细胞生产效率。似乎在这种情况下，培养基变质得到缓和，并且胚状体内的细胞-细胞相互作用得到优化。另一方面，在胚状体形成过程中，表皮生长因子与神经营养因子-4 一起添加到培养基中时，可增加牙齿上皮样细胞的丰度。表皮生长因子的促进作用可能涉及 TrkB 的反式激活，由表皮生长因子受体信号传导的效应子介导。在胚状体形成过程中，表皮生长因子与神经营养因子 4 一起添加到培养基中时，可增加牙齿上皮样细胞的丰度。表皮生长因子的促进作用可能涉及 TrkB 的反式激活，由表皮生长因子受体信号传导的效应子介导。在胚状体形成过程中，表皮生长因子与神经营养因子 4 一起添加到培养基中时，可增加牙齿上皮样细胞的丰度。表皮生长因子的促进作用可能涉及 TrkB 的反式激活，由表皮生长因子受体信号传导的效应子介导。