Ocular surface epithelial and stem cell development.
Ocular surface epithelial and stem cell development.
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DOI：
10.1387/ijdb.041876jw
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发表时间：
2004-11
期刊：
影响因子：
--
通讯作者：
J. Wolosin;M. Budak;M. Akinci
中科院分区：
文献类型：
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作者：
J. Wolosin;M. Budak;M. Akinci
描述了涉及边缘角膜和结膜上皮细胞发生的表型特征和发育事件。这两个上皮细胞一起定义了眼表面。它们源自一小群视囊泡诱导的 PAX6+ 头部外胚层细胞，这些细胞在主要 PAX6+ 细胞群形成晶状体囊泡后保留在表面。两种上皮都是分层的，并表现出湿润的、非角化的表型。角膜缘上皮最显着的空间特征是其支持干细胞和早期前体细胞与角膜缘的分离，血管化的外缘将角膜与结膜分开。这些干细胞表达 ABCG2，这是一种存在于其他器官干细胞中的异生物质转运蛋白。 ABCG2 转运活性排除了 DNA 染料 Hoechst 33342，从而可以通过流式细胞术分离眼干细胞，作为称为侧“侧群”的独特群体。角膜缘干细胞不形成间隙连接，并作为代谢分离的实体存在。 Cx43是在上皮前外胚层和成熟中央角膜上皮中表达的主要间隙连接蛋白，对Cx43表达变化的跟踪表明，在任何可识别的解剖上皮下角膜缘特征出现之前，角膜缘干细胞表型在晶状体囊泡内陷后很快就开始发育。 Cx43 表达的差异也揭示了边缘角膜和结膜谱系差异的早期性质。回顾了几个早期基因的假定参与，包括 PAX6 的梯度以及 Id 或 msh 基因表达调节因子成员表达模式的差异。
Phenotypic features and developmental events involved in the genesis of the limbo-corneal and conjunctival epithelia are described. Together, these two epithelia define the ocular surface. They derive from a small cohort of optic vesicle-induced PAX6+ head ectodermal cells that remain on the surface following lens vesicle formation by the main PAX6+ cell cohort. Both epithelia are stratified, and display wet, non-keratinizing phenotypes. The most significant spatial feature of the limbo-corneal epithelium is the segregation of its supporting stem and early precursor cells to the limbus, the outer vascularized rim separating the cornea from the conjunctiva. These stem cells express ABCG2, a xenobiotic transporter present in stem cells from other organs. ABCG2 transport activity excludes the DNA dye Hoechst 33342, allowing the isolation of the ocular stem cells by flow cytometry, as a unique cohort known as a side 'side population'. Limbal stem cells do not form gap junctions and exist as metabolically isolated entities. Tracking of expression changes in Cx43, the main gap junction protein expressed in both the pre-epithelial ectoderm and in the mature central corneal epithelium, indicates that a limbal stem cell phenotype starts developing very soon after lens vesicle invagination, in advance of the appearance of any recognizable anatomical sub-epithelial limbal feature. Differences in Cx43 expression also reveal the very early nature of the divergence in limbo-corneal and conjunctival lineages. The putative involvement of several early genes, including gradients of PAX6 and differences in expression patterns for members of the Id or msh gene expression regulators are reviewed.