title: Mapping the expression of epithelial hair follicle stem cell-related transcription factors LHX2 and SOX9 in the human hair follicle.
abstract: In the murine hair follicle (HF), the transcription factors LHX2 and SOX9 are implicated in epithelial hair follicle stem cell (eHFSC) self-renewal and the maintenance of eHFSC niche characteristics. However, the exact expression patterns of LHX2 and SOX9 in the human HF are unclear. Therefore, we have quantitatively mapped the localisation of known human eHFSC markers keratin 15 (K15) and keratin 19 (K19) in the outer root sheath (ORS) of male occipital scalp anagen HFs and related this to the localisation of LHX2 and SOX9 protein expression. As expected, K15(+) and K19(+) cells represented two distinct progenitor cell populations in the bulge and in the proximal bulb ORS (pbORS). Interestingly, cell fluorescence for K19 was significantly stronger within the pbORS versus the bulge, and vice versa for K15, describing a hitherto unrecognised differential expression pattern. LHX2 and SOX9 expressing cells were distributed throughout the ORS, including the bulge, but were not restricted to it. SOX9 expression was most prominent in the ORS immediately below the human bulge, whereas LHX2(+) cells were similarly distributed between the sub-bulge and pbORS, that is compartments not enriched with quiescent eHFSCs. During catagen development, the intensity of LHX2 and SOX9 protein expression increased in the proximal HF epithelium. Double immunostaining showed that the majority of SOX9(+) cells in the human anagen HF epithelium did not co-express K15, K19 or LHX2. This expression profile suggests that LHX2 and SOX9 highlight distinct epithelial progenitor cell populations, in addition to K15(+) or K19(+) cells, that could play an important role in the maintenance of the human HF epithelium.
authors: Centre for Dermatology Research, Institute of Inflammation and Repair, University of Manchester, Manchester, UK.
authors: Talveen S
authors: TS
authors: Purba
authors: Centre for Dermatology Research, Institute of Inflammation and Repair, University of Manchester, Manchester, UK.
authors: Iain S
authors: IS
authors: Haslam
authors: Crown Clinic, Manchester, UK.
authors: Asim
authors: A
authors: Shahmalak
authors: Unilever R&D Colworth, Bedfordshire, MK44 1LQ, UK.
authors: Ranjit K
authors: RK
authors: Bhogal
authors: Centre for Dermatology Research, Institute of Inflammation and Repair, University of Manchester, Manchester, UK.|Department of Dermatology, University of Münster, Münster, Germany.
authors: Ralf
authors: R
authors: Paus
mesh_terms: D015415:Biomarkers / Q000378:metabolism; D002874:Chromosome Mapping; D004847:Epithelial Cells / Q000166:cytology / Q000378:metabolism*; D005786:Gene Expression Regulation; D018859:Hair Follicle / Q000166:cytology / Q000378:metabolism*; D006801:Humans; D053569:Keratin-15 / Q000235:genetics / Q000378:metabolism; D053539:Keratin-19 / Q000235:genetics / Q000378:metabolism; D060850:LIM-Homeodomain Proteins / Q000235:genetics / Q000378:metabolism*; D008297:Male; D055758:SOX9 Transcription Factor / Q000235:genetics / Q000378:metabolism*; D013234:Stem Cells / Q000166:cytology / Q000378:metabolism*; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism*
chemical_list: D015415:Biomarkers; D053569:Keratin-15; D053539:Keratin-19; C489783:LHX2 protein, human; D060850:LIM-Homeodomain Proteins; D055758:SOX9 Transcription Factor; C527932:SOX9 protein, human; D014157:Transcription Factors
keywords: K15; K19; LHX2; SOX9; eHFSCs; epithelial human hair follicle stem cells