Kloepper Jennifer Elisabeth, Tiede Stephan, Brinckmann Jürgen, Reinhardt Dieter Peter, Meyer Wilfried, Faessler Reinhard, Paus Ralf
Department of Molecular Medicine, Max-Planck-Institute for Biochemistry, Martinsried, Germany.
Exp Dermatol. 2008 Jul;17(7):592-609. doi: 10.1111/j.1600-0625.2008.00720.x.
Since the discovery of epithelial hair follicle stem cells (eHFSCs) in the bulge of human hair follicles (HFs) an important quest has started: to define useful markers. In the current study, we contribute to this by critically evaluating corresponding published immunoreactivity (IR) patterns, and by attempting to identify markers for the in situ identification of human eHFSCs and their niche. For this, human scalp skin cryosections of at least five different individuals were examined, employing standard immunohistology as well as increased sensitivity methods. Defined reference areas were compared by quantitative immunohistochemistry for the relative intensity of their specific IR. According to our experience, the most useful positive markers for human bulge cells turned out to be cytokeratin 15, cytokeratin 19 and CD200, but were not exclusive, while beta1 integrin and Lhx2 IR were not upregulated by human bulge keratinocytes. Absent IR for CD34, connexin43 and nestin on human bulge cells may be exploited as negative markers. alpha6 integrin, fibronectin, nidogen, fibrillin-1 and latent transforming growth factor (TGF)-beta-binding protein-1 were expressed throughout the connective tissue sheath of human HFs. On the other hand, tenascin-C was upregulated in the bulge and may thus constitute a component of the bulge stem cell niche of human HFs. These immunophenotyping results shed further light on the in situ expression patterns of claimed follicular 'stem cell markers' and suggest that not a single marker alone but only the use of a limited corresponding panel of positive and negative markers may offer a reasonable and pragmatic compromise for identifying human bulge stem cells in situ.
自从在人类毛囊隆突部发现上皮毛囊干细胞（eHFSCs）以来，一项重要的探索已经开始：确定有用的标志物。在当前的研究中，我们通过严格评估相应的已发表免疫反应性（IR）模式，并试图识别用于原位鉴定人类eHFSCs及其生态位的标志物，为此做出了贡献。为此，我们检查了至少五个不同个体的人类头皮皮肤冰冻切片，采用标准免疫组织学以及提高灵敏度的方法。通过定量免疫组织化学比较定义的参考区域中其特异性IR的相对强度。根据我们的经验，人类隆突细胞最有用的阳性标志物是细胞角蛋白15、细胞角蛋白19和CD200，但并非唯一，而β1整合素和Lhx2的IR在人类隆突角质形成细胞中未上调。人类隆突细胞上CD34、连接蛋白43和巢蛋白缺乏IR可作为阴性标志物。α6整合素、纤连蛋白、巢蛋白、原纤维蛋白-1和潜伏转化生长因子（TGF）-β结合蛋白-1在人类毛囊的整个结缔组织鞘中均有表达。另一方面，腱生蛋白-C在隆突部上调，因此可能构成人类毛囊隆突干细胞生态位的一个组成部分。这些免疫表型分析结果进一步揭示了所谓毛囊“干细胞标志物”的原位表达模式，并表明不是单一标志物，而是仅使用一组有限的相应阳性和阴性标志物，可能为原位鉴定人类隆突干细胞提供合理且实用的折衷方案。
