Terminal differentiation of palatal medial edge epithelial cells in vitro is not necessarily dependent on palatal shelf contact and midline epithelial seam formation
Terminal differentiation of palatal medial edge epithelial cells in vitro is not necessarily dependent on palatal shelf contact and midline epithelial seam formation
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DOI：
10.1387/ijdb.041840tt
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发表时间：
2004-06-01
影响因子：
0.7
通讯作者：
Shiota, K
中科院分区：
文献类型：
--
作者：
Takigawa, T;Shiota, K
在哺乳动物次级腭裂融合过程中，腭侧缘上皮(MEE)细胞通过细胞凋亡、上皮-间充质转化(EMT)和上皮细胞迁移等方式消失。然而，人们普遍认为，除非腭架接触并形成中线上皮缝，否则MEE细胞永远不会分化。为了明确MEE细胞的分化潜能，我们采用悬浮培养和静态培养两种混合气体对ICR小鼠单个(非配对)腭架进行了培养。我们由此发现，在95%O-2/5%CO2的悬浮培养中，即使没有与对侧的MEE接触和黏附，MEE细胞也可以消失在整个内侧边缘。仔细观察MEE细胞在培养中的行为，发现在MEE细胞消失的不同阶段都发生了细胞凋亡、EMT和上皮细胞迁移，包括上皮三角和胰岛的瞬时形成和消失。相比之下，在CO2培养箱中静态培养的MEE细胞分化较差。此外，在培养的单个腭架中，尽管成对的腭架即使在羊水存在的情况下也能成功融合，但小鼠和人的羊水仍能阻止MEE细胞的分化。因此，我们得出结论，MEE细胞的终末分化不一定依赖于腭架接触和中线上皮缝的形成，但这种MEE细胞的分化在宫内似乎被羊水阻止，除非腭架紧密接触并形成中线上皮缝。
During fusion of the mammalian secondary palate, it has been suggested that palatal medial edge epithelial (MEE) cells disappear by means of apoptosis, epithelial-mesenchymal transformation (EMT) and epithelial cell migration. However, it is widely believed that MEE cells never differentiate unless palatal shelves make contact and the midline epithelial seam is formed. In order to clarify the potential of MEE cells to differentiate, we cultured single (unpaired) palatal shelves of ICR mouse fetuses by using suspension and static culture methods with two kinds of gas-mixtures. We thereby found that MEE cells can disappear throughout the medial edge even without contact and adhesion to the opposing MEE in suspension culture with 95% O-2/5% CO2. Careful examination of MEE cell behavior in the culture revealed that apoptosis, EMT, and epithelial cell migration all occurred at various stages of MEE cell disappearance, including the transient formation and disappearance of epithelial triangles and islets. In contrast, MEE cells showed poor differentiation in static culture in a CO2 incubator. Furthermore, mouse and human amniotic fluids were found to prevent MEE cell differentiation in the cultured single palatal shelf, although paired palatal shelves fused successfully even in the presence of amniotic fluid. We therefore conclude that terminal differentiation of MEE cells is not necessarily dependent on palatal shelf contact and midline epithelial seam formation, but such MEE cell differentiation appears to be prevented in utero by amniotic fluid unless palatal shelves make close contact and the midline epithelial seam is formed.