Upper human hair follicle contains a subpopulation of keratinocytes with superior in vitro proliferative potential.
Upper human hair follicle contains a subpopulation of keratinocytes with superior in vitro proliferative potential.
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DOI：
10.1111/1523-1747.ep12371671
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发表时间：
1993-11
期刊：
影响因子：
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通讯作者：
Jing Shan Yang;R. M. Lavker;T. Sun
中科院分区：
文献类型：
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作者：
Jing Shan Yang;R. M. Lavker;T. Sun
我们和其他人之前已经证明，角膜角质形成细胞干细胞在体外的增殖能力比其子代细胞更好。在本文中，我们应用这种方法来鉴定毛囊干细胞。当将人头皮毛囊置于外植体培养物中时，凸起区域产生了最好的生长物。在另一项实验中，我们通过显微解剖分离了不同的人毛囊角质形成细胞亚群，通过胰蛋白酶/EDTA将它们分散到单细胞中，并在3T3饲养细胞存在的情况下生长它们。然后将角质形成细胞在相同条件下进行传代培养，以比较它们的体外寿命。我们的结果表明，角质形成细胞的寿命为上毛囊（主要包含峡部区域）>皮脂腺>下毛囊（在凸起和球部之间）>球部（包含基质细胞）。培养的上毛囊角质形成细胞往往较小且大小相对均匀。基质细胞的体外生长不良可能反映了它们的非干细胞性质和/或邻近真皮乳头细胞在体内满足的特殊生长要求。出乎意料的是，我们发现上层毛囊角质形成细胞比表皮角质形成细胞生长得更好。角质形成细胞亚群的存在，其体外生长潜力优于其他已知的皮肤角质形成细胞，这支持了毛囊干细胞位于上毛囊的假设。我们的数据还提出了一种可能性，即推定的毛囊干细胞不仅参与毛囊的形成，而且还参与表皮的长期维持。最后，我们讨论了角质形成细胞干细胞（根据其体内缓慢循环性质定义）在培养物中不存在的可能性。
We and others have shown previously that corneal keratinocyte stem cells can proliferate in vitro better than their progeny cells. In this paper, we applied this approach to the identification of hair follicular stem cells. When human scalp hair follicles were placed in explant culture, the bulge area yielded best outgrowths. In another experiment, we isolated different subpopulations of human follicular keratinocytes by micro-dissection, dispersed them by trypsin/EDTA into single cells, and grew them in the presence of 3T3 feeder cells. The keratinocytes were then subcultured under identical conditions to compare their in vitro life span. Our results indicate that the life span of keratinocytes of the upper follicle (containing mainly the isthmus area) > sebaceous gland > lower follicle (between the bulge and bulb) > bulb (containing the matrix cells). The cultured upper follicular keratinocytes tend to be small and relatively uniform in size. The poor in vitro growth of matrix cells may reflect their non-stem cell nature and/or special growth requirement(s) satisfied in vivo by the neighboring dermal papilla cells. Unexpectedly, we found that the upper follicular keratinocytes grow even better than epidermal keratinocytes. The existence of a subpopulation of keratinocytes with an in vitro growth potential superior than other known keratinocytes of the skin supports the hypothesis that follicular stem cells reside in the upper follicle. Our data also raise the possibility that putative follicular stem cells are involved not only in forming the follicle, but also in the long-term maintenance of the epidermis. Finally, we discuss the possibility that keratinocyte stem cells, as defined by their in vivo slow-cycling nature, are absent in culture.