title: Genetic reporter analysis reveals an expandable reservoir of OCT4+ cells in adult skin.
abstract: The transcription factor Oct4 (Pou5f1) is a critical regulator of pluripotency in embryonic and induced pluripotent stem cells. Therefore, Oct4 expression might identify somatic stem cell populations with inherent multipotent potential or a propensity for facilitated reprogramming. However, analysis of Oct4 expression is confounded by Oct4 pseudogenes or non-pluripotency-related isoforms. Systematic analysis of a transgenic Oct4-EGFP reporter mouse identified testis and skin as two principle sources of Oct4 (+) cells in postnatal mice. While the prevalence of GFP(+) cells in testis rapidly declined with age, the skin-resident GFP(+) population expanded in a cyclical fashion. These cells were identified as epidermal stem cells dwelling in the stem cell niche of the hair follicle, which endogenously expressed all principle reprogramming factors at low levels. Interestingly, skin wounding or non-traumatic hair removal robustly expanded the GFP(+) epidermal cell pool not only locally, but also in uninjured skin areas, demonstrating the existence of a systemic response. Thus, the epithelial stem cell niche of the hair follicle harbors an expandable pool of Oct4+ stem cells, which might be useful for therapeutic cell transfer or facilitated reprogramming.
authors.affiliation: Research Group Regenerative Agents, Hannover, Germany ; REBIRTH Cluster of Excellence, Hannover, Germany ; Integrated Research Center Transplantation (IFB-Tx), Hannover, Germany ; Department of Plastic, Hand and Reconstructive Surgery, Hannover, Germany.
authors.forename: Anne
authors.initials: A
authors.lastname: Limbourg
authors.affiliation: Research Group Regenerative Agents, Hannover, Germany ; REBIRTH Cluster of Excellence, Hannover, Germany.
authors.forename: Sabine
authors.initials: S
authors.lastname: Schnabel
authors.affiliation: Research Group Regenerative Agents, Hannover, Germany ; REBIRTH Cluster of Excellence, Hannover, Germany ; Department of General and Transplant Surgery, University Hospital Heidelberg, Heidelberg, Germany.
authors.forename: Vladimir J
authors.initials: VJ
authors.lastname: Lozanovski
authors.affiliation: Research Group Regenerative Agents, Hannover, Germany ; Department of Cardiology and Angiology, Hannover, Germany.
authors.forename: L Christian
authors.initials: LC
authors.lastname: Napp
authors.affiliation: REBIRTH Cluster of Excellence, Hannover, Germany ; Institute of Experimental Hematology, OE6960 Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
authors.forename: Teng-Cheong
authors.initials: TC
authors.lastname: Ha
authors.affiliation: REBIRTH Cluster of Excellence, Hannover, Germany ; Institute of Experimental Hematology, OE6960 Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Maetzig
authors.affiliation: REBIRTH Cluster of Excellence, Hannover, Germany ; Department of Cardiology and Angiology, Hannover, Germany.
authors.forename: Johann
authors.initials: J
authors.lastname: Bauersachs
authors.affiliation: Department of Physiological Chemistry, Hannover Veterinary School, Hannover, Germany.
authors.forename: Hassan Y
authors.initials: HY
authors.lastname: Naim
authors.affiliation: REBIRTH Cluster of Excellence, Hannover, Germany ; Integrated Research Center Transplantation (IFB-Tx), Hannover, Germany ; Institute of Experimental Hematology, OE6960 Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany ; Division of Hematology/Oncology, Boston Children's Hospital, Harvard Medical School, Harvard, USA.
authors.forename: Axel
authors.initials: A
authors.lastname: Schambach
authors.affiliation: Research Group Regenerative Agents, Hannover, Germany ; REBIRTH Cluster of Excellence, Hannover, Germany ; Department of Nephrology and Hypertension, Hannover Medical School, Hannover, Germany ; Vascular Medicine and Transplantation Research, Dept. of Nephrology and Hypertension, OE 6841, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
authors.forename: Florian P
authors.initials: FP
authors.lastname: Limbourg
keywords: Epidermal stem cells; Oct4; Skin; Transgenic reporter mice