title: Side population in adult murine epidermis exhibits phenotypic and functional characteristics of keratinocyte stem cells.
abstract: Based on functional studies in the bone marrow, it has been suggested that the ability to efflux Hoechst 33342 may represent a universal stem cell trait. In this phenotypic and functional characterization of the Hoechst side population (SP) in adult murine epidermis, we demonstrate that these cells are a rare subset of the keratinocyte stem cell-enriched alpha(6)(bri)CD71(dim) fraction comprising SSC(low)/K14(+)/CD34(-)/Oil red O(-)/c-kit(-)/CD45(-) keratinocytes. Epidermal SPs have the smallest cell and nuclear size but exhibit the highest nuclear-to-cytoplasmic ratio of any fraction examined, consistent with a primitive cell type. Although SPs demonstrated poor cumulative in vitro proliferative output, they exhibited sustained epidermal tissue-regenerative activity in vivo compared with unfractionated and non-SP cells. Collectively, these results indicate that the epidermal SP contains the most potent keratinocyte stem cell population in skin epithelium.
authors.affiliation: Epithelial Stem Cell Biology Laboratory, Peter MacCallum Cancer Centre, Trescowthick Research Laboratories, St. Andrew's Place, East Melbourne, Victoria 3002, Australia.
authors.forename: Richard P
authors.initials: RP
authors.lastname: Redvers
authors.forename: Amy
authors.initials: A
authors.lastname: Li
authors.forename: Pritinder
authors.initials: P
authors.lastname: Kaur
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D002467:Cell Nucleus / Q000378:metabolism; D049109:Cell Proliferation; D048429:Cell Size; D003593:Cytoplasm / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D000078404:Epidermal Cells; D005786:Gene Expression Regulation; D018398:Homeodomain Proteins / Q000235:genetics; D015603:Keratinocytes / Q000166:cytology*; D051379:Mice; D008810:Mice, Inbred C57BL; D008938:Mitosis; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics; D010641:Phenotype; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011990:Receptors, Transferrin / Q000378:metabolism; D012038:Regeneration; D013234:Stem Cells / Q000166:cytology*; D013623:Tail / Q000166:cytology; D014132:Trachea / Q000166:cytology
chemical_list: D015703:Antigens, CD; C068126:CD71 antigen; D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; D012333:RNA, Messenger; D011990:Receptors, Transferrin