Innate immunity and the regulation and mobilization of keratinocyte stem cells: are the old players playing a new game?
The skin provides an anatomical barrier to physical, chemical and biological agents. Hence, it is not surprising that it has well-developed innate immunity. What we find surprising is that the CD49f(+) /CD34(+)  hair follicle stem cells should have an enriched expression profile of so many genes involved in innate immunity. Do these stem cells require extra protection from environmental insults? Or, could there be a new role for these genes? To probe these questions, we first summarize the roles of some key players in epidermal innate immunity. We next focus on their expression in CD49f(+) /CD34(+)  hair follicle stem cells. Then, we consider recent data suggesting a new role for these 'old players' in the regulation and mobilization of haematopoietic and mesenchymal stem cells. Finally, we hypothesize that the 'old players' in these hair follicle stem cells may be playing a 'new game'.
Laboratory of Stem Cells and Cancer, The Hormel Institute, University of Minnesota, Austin, MN55912, USA.
Ashok
A
Singh
Rebecca J
RJ
Morris
D018952:Antigens, CD34 / Q000378:metabolism; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D004731:Endotoxins / Q000276:immunology; D018859:Hair Follicle / Q000276:immunology* / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000276:immunology; D006801:Humans; D007113:Immunity, Innate / Q000235:genetics* / Q000276:immunology; D039503:Integrin alpha6 / Q000378:metabolism; D015603:Keratinocytes / Q000276:immunology* / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000276:immunology; D015398:Signal Transduction / Q000276:immunology; D013234:Stem Cells / Q000276:immunology* / Q000378:metabolism; D051193:Toll-Like Receptors / Q000235:genetics / Q000378:metabolism
D018952:Antigens, CD34; D016207:Cytokines; D004731:Endotoxins; D039503:Integrin alpha6; D051193:Toll-Like Receptors