A Stable Niche Supports Long-Term Maintenance of Human Epidermal Stem Cells in Organotypic Cultures
A Stable Niche Supports Long-Term Maintenance of Human Epidermal Stem Cells in Organotypic Cultures
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DOI：
10.1634/stemcells.2007-0991
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发表时间：
2008-01-01
期刊：
影响因子：
5.2
通讯作者：
Boukamp, Petra
中科院分区：
文献类型：
--
作者：
Muffler, Sonja;Stark, Hans-Juergen;Boukamp, Petra
人类滤泡间表皮中的干细胞仍然难以识别，主要是因为缺乏明确的标记以及无法标记人类的标记保留细胞（LRC）。在这里，我们报告可以在用人类细胞制成的器官型培养物（OTC）中识别和定位LRC。用碘脱氧尿苷 (IdU) 标记培养物 2 周，然后追踪 6-10 周，留下保留 IdU 标记的基底细胞 < 1%。整体安装表明LRCs单独分散在表皮基底层中。一些 LRC（但不是全部）与表达黑色素瘤硫酸软骨素蛋白多糖（一种假定的干细胞标记物）的细胞共定位。尽管我们在基于胶原蛋白和基于支架的 OTC 中都发现了 LRC，但只有支架 OTC 支持长期存活和再生。 LRC 在胶原-OTC 中的短暂存活并不是由于成纤维细胞失去适当的生长因子。相反，这是由于金属蛋白酶，特别是基质金属蛋白酶（MMP）-2和MMP-14的表达，导致胶原蛋白断裂、基质降解以及与表皮整合素结合的特定基底膜成分的错位。阻断 MMP 激活不仅消除了 MMP 依赖性基质降解，而且还延长了这些培养物中表皮和 LRC 的寿命。这些发现表明，干细胞生态位，即周围和影响干细胞的微环境，对于干细胞的生存和功能（包括长期组织再生）至关重要。干细胞2008； 26：2506-2515
Stem cells in human interfollicular epidermis are still difficult to identify, mainly because of a lack of definitive markers and the inability to label human beings for label-retaining cells (LRCs). Here, we report that LRCs could be identified and localized in organotypic cultures (OTCs) made with human cells. Labeling cultures for 2 weeks with iododeoxyuridine (IdU) and then chasing for 6-10 weeks left < 1% of basal cells retaining IdU label. Whole mounts demonstrated that LRCs were individually dispersed in the epidermal basal layer. Some LRCs, but not all, colocalized with cells expressing melanoma chondroitin sulfate proteoglycan, a putative stem cell marker. Although we found LRCs in both collagen- and scaffold-based OTCs, only the scaffold- OTCs supported long-term survival and regeneration. LRCs' short survival in collagen- OTCs was not due to loss of appropriate growth factors from fibroblasts. Instead, it was due to expression of metalloproteinases, especially matrix metalloproteinase (MMP)-2 and MMP-14, which caused collagen fragmentation, matrix degradation, and dislocation of specific basement membrane components bound to epidermal integrins. Blocking MMP activation not only abrogated MMP-dependent matrix degradation but also increased longevity of the epidermis and the LRCs in these cultures. Such findings indicate that the stem cell niche, the microenvironment surrounding and influencing the stem cell, is essential for stem cell survival and function, including long-term tissue regeneration. STEM CELLS 2008; 26: 2506-2515