Reduced enamel epithelium-derived cell niche in the junctional epithelium are maintained for a long time in mice
Reduced enamel epithelium-derived cell niche in the junctional epithelium are maintained for a long time in mice
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在小鼠中，连接上皮中釉质上皮衍生细胞生态位的减少可长期维持
DOI：
10.1002/jper.19-0269
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发表时间：
2019
期刊：
影响因子：
4.3
通讯作者：
Ohshima H
中科院分区：
文献类型：
--
作者：
Soda M;Saito K;Ida-Yonemochi H;Nakakura-Ohshima K;Kenmotsu S;Ohshima H
虽然大量报道表明，结膜上皮（JE）来源于还原的牙釉质上皮（REE），但REE来源的JE的命运仍然存在争议。本研究阐明了稀土来源的乙脑的命运和乙脑干/祖细胞在牙齿萌出后的细胞动力学。方法将B6野生型（WT）和绿色荧光蛋白（GFP）转基因小鼠的上第一磨牙提取后，将胚胎期15天至出生后1天的下颌第一磨牙胚移植到2周龄小鼠的牙槽内。经µ‐CT分析后，对石蜡切片进行免疫组化处理，检测Nestin、Ki67和GFP。我们还对BrdU给药的TetOP - H2B - GFP小鼠进行了追踪分析。结果乙脑牙体发育正常，结构与正常牙体发育相似。以GFP转基因小鼠为宿主移植的乙脑为GFP阴性，口腔上皮（OE）呈阳性反应。相比之下，在使用GFP转基因小鼠作为供体的移植实验期间，乙脑仍保持GFP阳性。追逐分析显示，随着追逐时间的增加，乙脑基底侧的H2B‐GFP‐和5‐溴‐2′‐脱氧尿苷（BrdU）‐标记的细胞转移到乙脑口腔侧。在乙脑中，一些保留标记的细胞仍然存在于基底细胞层上。结论乳牙出牙后，乙脑内稀土元素来源的细胞生态位可维持较长时间。因此，乙脑可能是牙源性上皮的来源。
BackgroundAlthough numerous reports have demonstrated that the junctional epithelium (JE) is derived from the reduced enamel epithelium (REE), the fate of the REE‐derived JE remains controversial. The present study elucidated the fate of the REE‐derived JE and the cell dynamics of stem/progenitor cells in the JE following tooth eruption.MethodsMandibular first molar germs (embryonic days 15 to postnatal 1‐day‐old) were transplanted into the socket of 2‐week‐old mice after extraction of the upper first molars of B6 wild‐type (WT) and green fluorescent protein (GFP) transgenic mice. After analysis by µ‐CT, paraffin sections were processed for immunohistochemistry for Nestin, Ki67 and GFP. We also performed chasing analysis using BrdU‐administered TetOP‐H2B‐GFP mice.ResultsAmelogenesis progressed normally in the cervical areas, and the structure of the JE was like that in normal tooth development. The JE was GFP‐negative in transplantations using GFP transgenic mice as the host, and the oral epithelium (OE) showed a positive reaction. By contrast, the JE remained GFP‐positive throughout the experimental period in transplantations using GFP transgenic mice as the donor. Chasing analysis revealed that H2B‐GFP‐ and 5‐Bromo‐2′‐deoxyuridine (BrdU)‐labeled cells in the basal side of the JE translocated to oral side of the JE as the chasing time increased. Some label‐retaining cells remained at the supra‐basal cell layer in the JE.ConclusionThese results suggest that REE‐derived cell niche in the JE is maintained for a long time following tooth eruption. Therefore, the JE may be available as the source of the odontogenic epithelium.