Characterization of putative amelogenic cells and mesenchymal cells isolated from human dental follicle and dental papilla

在这项研究中，我们分离了在基因表达谱和增殖能力方面与牙周上皮(GE)细胞不同的人牙囊上皮(DFE)细胞。此外，根据成釉细胞标志成釉细胞标志物成釉蛋白的基因表达，DFE细胞被认为是成釉细胞。我们发现，DFE与牙乳头间充质(DPM)细胞的直接接触增加了DFE细胞中釉原蛋白的表达，提示DPM细胞的跨膜信号在DFE细胞进入成釉细胞谱系中起着关键作用。更重要的是，当DFE细胞与DPM细胞一起培养时，这种增加比DFM细胞显著。我们证实DPM细胞表达成牙本质细胞标志物之一--牙本质涎磷蛋白(DSPP)，而DFM细胞不表达。因此，这种DPM细胞驱动的DFE细胞分化可能是一种上皮-间充质相互作用的复制，在牙齿生成中发现。然而，这种诱导DFE细胞分化的潜在机制尚不清楚。需要更多的信号工作来阐明人类牙齿生成中上皮-间充质的相互作用。新的人类成釉细胞，DFE细胞，可能是这类信号工作的有用工具。

In this study, we isolated human dental follicle epithelial (DFE) cells that were different from gingival epithelial (GE) cells in terms of their gene expression profiles and proliferative capacity. Furthermore, DFE cells were revealed to be putative amelogenic cells based on their gene expression of an ameloblast marker, amelogenin. We found that a direct contact between DFE and dental papilla mesenchymal (DPM) cells increased an amelogenin expression in DFE cells, suggesting transmembrane signaling from the DPM cells played some pivotal roles for DFE cells to enter into the ameloblast lineage. More importantly, this increase was remarkable when DFE cells were cultured with DPM cells in comparison to DFM cells. We confirmed that DPM cells expressed dentin sialophosphoprotein (DSPP), one of odontoblast markers, but DFM cells did not. Therefore, this DPM cells-driven DFE cells differentiation might be a reproduction of epithelial - mesenchymal interaction, found in tooth generation. However, the underlying mechanisms of this induced differentiation of DFE cells were not cleared. Much more signaling works are required to elucidate epithelial - mesenchymal interaction in human tooth generation. Novel human amelogenic cells, DFE cells, might be useful tool for such kind of signaling works.