In vitro growth and differentiation of rabbit bulbar, fornix, and palpebral conjunctival epithelia. Implications on conjunctival epithelial transdifferentiation and stem cells.
In vitro growth and differentiation of rabbit bulbar, fornix, and palpebral conjunctival epithelia. Implications on conjunctival epithelial transdifferentiation and stem cells.
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发表时间：
1993-04
影响因子：
4.4
通讯作者：
Z. Wei;R. Wu;R. Lavker;T. Sun
中科院分区：
文献类型：
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作者：
Z. Wei;R. Wu;R. Lavker;T. Sun
眼睛的前表面由几个物理上连续但组织学上可区分的上皮覆盖，这些上皮覆盖在角膜、利姆布斯、球结膜、穹窿结膜和睑结膜上。重要的是要确定这些上皮细胞的不同表型是否是内在分歧，外在调节，或两者的组合的结果。基于角蛋白表达和细胞动力学标准，作者先前认为角膜上皮干细胞可能实际上存在于角膜缘基底层。方法通过比较角膜缘上皮细胞和结膜上皮细胞在相同细胞培养环境中的生长和分化特性，分析角膜缘上皮细胞和结膜上皮细胞之间的关系。结果用Dispase代替胰蛋白酶分离细胞，作者能够在3 T3饲养细胞存在下生长所有5个兔眼表上皮细胞。他们发现角膜和角膜缘细胞合成相同的角蛋白，包括大量的角膜型分化的K3和K12标记物。相比之下，所有三个结膜上皮共享另一种角蛋白模式，具有大量的简单上皮角蛋白，但只有微量的K3/K12角蛋白。结论这一观察结果，加上先前的研究结果，即结膜上皮细胞向角膜上皮的“转分化”似乎是不完全的和可逆的，提供了强有力的证据，即（1）角膜缘-角膜上皮细胞形成了不同于结膜谱系的谱系，（2）结膜转分化实际上代表了一个环境调节的过程。此外，三种类型的结膜上皮细胞，穹窿细胞被发现有一个更大的增殖潜力比球和眼睑细胞。这一观察结果，再加上最近发现穹窿富含慢循环（标记保留）细胞，提高了结膜上皮干细胞可能优先驻留在穹窿的可能性。
PURPOSE The anterior surface of the eye is covered by several physically contiguous but histologically distinguishable epithelial overlying the cornea, limbus, bulbar conjunctiva, fornix conjunctiva, and palpebral conjunctiva. It is important to determine whether the different phenotypes of these epithelia are the result of intrinsic divergence, extrinsic modulation, or a combination of both. Based on keratin expression and cell kinetic criteria, the authors previously suggested that corneal epithelial stem cells may actually reside in the limbal basal layer. METHODS In this article, the relationship between the corneal-limbal epithelial cells and conjunctival epithelial cells was analyzed by comparing their growth and differentiation properties in an identical cell culture environment. RESULTS Using Dispase instead of trypsin to dissociate the cells, the authors were able to grow all five rabbit ocular surface epithelia in the presence of 3T3 feeder cells. They found that corneal and limbal cells synthesize identical keratins, including large amounts of the K3 and K12 markers of corneal-type differentiation. By contrast, all three conjunctival epithelia shared another keratin pattern, with large amounts of simple epithelial keratins but only minute amounts of K3/K12 keratins. CONCLUSIONS This observation, coupled with previous findings that the "transdifferentiation" of conjunctival epithelial cells to corneal epithelium appears to be both incomplete and reversible, provides strong evidence that (1) the limbal-corneal epithelial cells form a lineage distinct from the conjunctival lineage and (2) conjunctival transdifferentiation actually represents a process of environmental modulation. In addition, of the three types of conjunctival epithelial cells, fornix cells were found to have a much greater proliferative potential than bulbar and palpebral cells. This observation, coupled with recent finding that fornix is enriched in slow-cycling (label-retaining) cells, raises the possibility that conjunctival epithelial stem cells may preferentially reside in the fornix.