Immunophenotyping of the human bulge region: The quest to define useful in situ markers for human epithelial hair follicle stem cells and their niche

Research output: Contribution to journalArticle

  • External authors:
  • Jennifer Elisabeth Kloepper
  • Stephan Tiede
  • Jürgen Brinckmann
  • Dieter Peter Reinhardt
  • Wilfried Meyer
  • Reinhard Faessler

Abstract

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 β1 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. α6 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. © Journal compilation © 2008 Blackwell Munksgaard.

Bibliographical metadata

Original languageEnglish
Pages (from-to)592-609
Number of pages17
JournalExperimental Dermatology
Volume17
Issue number7
DOIs
Publication statusPublished - Jul 2008