Keratinocytes enriched for epidermal stem cells differ in their response to IFN-gamma from other proliferative keratinocytes

Exp Dermatol. 2008 Dec;17(12):998-1003. doi: 10.1111/j.1600-0625.2008.00735.x. Epub 2008 Jun 14.

Abstract

The epidermis has a pool of adult stem cells [epidermal stem cells (ESC)]. Although the localization of ESC is well described, we lack a clear understanding of their role in perturbed conditions such as inflammation. One of the most important mediators in inflammatory skin diseases acting on keratinocytes (KCs) is interferon gamma (IFN-gamma). The assumption that ESC might generate a protected niche prompted us to investigate their response to the pro-inflammatory cytokine IFN-gamma. In this study, we isolated two populations of KCs according to their adherence ability. ESC enriched by adherence showed a higher CD29 and CD49f expression compared with other KCs. Surprisingly, surface expression of CD54 was more inducible upon IFN-gamma stimulation in short-term cultures of the ESC subpopulation. In contrary to that, a markedly lower induction of IL-18 and reduced basal production of CCL2 were observable in ESC. No differences in IFN-gamma-induced interleukin (IL)-10, CXCL10, CCL22 or transforming growth factor (TGF)beta1 secretion were detectable between the two keratinocyte subpopulations. These results suggest that ESC respond to IFN-gamma with a 'restricted' pattern of pro-inflammatory cytokines, and do not build up an anti-inflammatory microenvironment by means of TGF-beta or IL-10. Activated ESC possess the capability to interact with infiltrating lymphocytes via CD54. In conclusion, the ESC compartment might actively contribute to the immunological properties of the skin organ.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult Stem Cells / cytology
  • Adult Stem Cells / drug effects*
  • Adult Stem Cells / metabolism
  • Cell Adhesion / drug effects
  • Cells, Cultured
  • Chemokine CCL2 / genetics
  • Chemokine CCL2 / metabolism
  • Chemokine CCL22 / genetics
  • Chemokine CCL22 / metabolism
  • Chemokine CXCL10 / genetics
  • Chemokine CXCL10 / metabolism
  • Epidermal Cells*
  • Flow Cytometry
  • Gene Expression / drug effects
  • Humans
  • Integrin alpha6 / metabolism
  • Integrin beta1 / metabolism
  • Intercellular Adhesion Molecule-1 / metabolism
  • Interferon-gamma / pharmacology*
  • Interleukin-10 / genetics
  • Interleukin-10 / metabolism
  • Interleukin-18 / genetics
  • Interleukin-18 / metabolism
  • Keratinocytes / cytology
  • Keratinocytes / drug effects*
  • Keratinocytes / metabolism
  • Male
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transforming Growth Factor beta1 / genetics
  • Transforming Growth Factor beta1 / metabolism

Substances

  • CCL2 protein, human
  • CCL22 protein, human
  • CXCL10 protein, human
  • Chemokine CCL2
  • Chemokine CCL22
  • Chemokine CXCL10
  • IL10 protein, human
  • Integrin alpha6
  • Integrin beta1
  • Interleukin-18
  • Transforming Growth Factor beta1
  • Intercellular Adhesion Molecule-1
  • Interleukin-10
  • Interferon-gamma