Two distinct steps of immigration of hematopoietic progenitors into the early thymus anlage
Two distinct steps of immigration of hematopoietic progenitors into the early thymus anlage
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DOI：
10.1093/intimm/13.9.1203
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发表时间：
2001-09-01
影响因子：
4.4
通讯作者：
Amagai, T
中科院分区：
文献类型：
--
作者：
Itoi, M;Kawamoto, H;Amagai, T
胸腺上皮细胞形成胸腺特有的三维有组织的网状结构，在器官发生过程中从第三咽囊和裂隙的简单上皮发育而来。我们用免疫组织化学方法比较了正常和裸鼠胸腺在器官形成早期的造血祖细胞的上皮组织和分布。结果表明，小鼠胸腺原基的早期发育至少可分为两个阶段，即胚胎第11天的层状上皮期和第12天的簇状上皮期。在前一阶段，造血祖细胞聚集在胸腺原始的间充质层，在后一阶段，造血祖细胞进入上皮簇并增殖。在裸鼠体内，在ED11.5的间质层可见造血祖细胞，而在ED12的上皮细胞中未见造血祖细胞，尽管上皮细胞形成簇状结构。结果提示，裸鼠胸腺原基发育异常发生在聚集上皮期，裸鼠胸腺原基上皮细胞缺乏诱导造血祖细胞进入上皮簇的能力。
Thymic epithelial cells, which create a three-dimensionally organized meshwork structure peculiar to the thymus, develop from simple epithelia of the third pharyngeal pouch and cleft during organogenesis. We comparatively investigated the thymus anlages of normal and nude mice by immunohistochemical analysis with regard to epithelial organization and distribution of hematopoietic progenitor cells at early stages of organogenesis. Our results show that development of the mouse thymus anlage at early stages can be subdivided into at least two stages by the differences in epithelial organization, i.e. stratified epithelial stage on embryonic day (Ed) 11 and clustered epithelial stage on Ed12. At the former stage, hematopoietic progenitor cells are accumulated in the mesenchymal layer of the thymus anlage, and at the latter stage progenitor cells enter the epithelial cluster and proliferate. In nude mice, hematopoietic progenitor cells are found in the mesenchymal layer on Ed11.5, but they are not observed among epithelial cells on Ed12, even though epithelial cells form a cluster structure. The present results suggest that aberrant development of the nude mouse thymus anlage occurs at the clustered epithelial stage and that epithelial cells of the nude anlage lack the ability to induce the entrance of hematopoietic progenitor cells into the epithelial cluster.