Expression of CD90 on keratinocyte stem/progenitor cells

Y Nakamura, Y Muguruma, T Yahata… - British Journal of …, 2006 - academic.oup.com
Y Nakamura, Y Muguruma, T Yahata, H Miyatake, D Sakai, J Mochida, T Hotta, K Ando
British Journal of Dermatology, 2006academic.oup.com
Background The identification and purification of keratinocyte stem cells (KSCs) that are
capable of self‐renewal and maintenance of differentiating cell populations could contribute
both to our understanding of the biology of these cells, and to significant clinical
applications, such as the culturing of keratinocytes for transplantation to severe burn
wounds. Here, we report the detection of CD90+ cells in cultured normal human epidermal
keratinocytes and adult skin. Objectives To investigate the biological function of CD90+ and …
Summary
Background The identification and purification of keratinocyte stem cells (KSCs) that are capable of self‐renewal and maintenance of differentiating cell populations could contribute both to our understanding of the biology of these cells, and to significant clinical applications, such as the culturing of keratinocytes for transplantation to severe burn wounds. Here, we report the detection of CD90+ cells in cultured normal human epidermal keratinocytes and adult skin.
Objectives To investigate the biological function of CD90+ and CD90 keratinocytes.
Methods CD90+ and CD90 keratinocytes were purified from adult skin and cultured keratinocytes using fluorescent activated cell sorting, and their biological abilities were analysed using both in vitro and in vivo assays.
Results Flow cytometry (FCM) analysis identified approximately 18% of post‐primary neonatal keratinocytes as CD90+. However, during expansion of the culture, the expression level of CD90 rapidly decreased to about 2·5% at passage 10, while most of the keratinocytes maintained expression of α6 integrin. Purified CD90+ keratinocytes demonstrated a sixfold higher cell growth rate than CD90 cells and the ability to form large (over 3 mm in diameter) colonies. We then quantitatively evaluated both populations using a previously described in vivo human epidermal cyst formation assay. Enhanced green fluorescent protein (EGFP)‐labelled CD90+ or CD90 keratinocytes were subcutaneously injected into nonobese diabetic/severe combined immunodeficient (NOD/SCID) mice. Six weeks after transplantation, EGFP+ cell clusters in human epidermal cysts were evaluated using image analysis software. EGFP+ cell cluster areas in the basal layer, derived from EGFP+ CD90+ cells, were eightfold larger than clusters of EGFP+ CD90 cells. Furthermore, immunohistochemical staining and FCM analysis indicated that CD90 was expressed in most of the basal layer of the normal human epidermis.
Conclusions These results indicated that CD90 is a useful marker for the detection of human KSC‐enriched populations in cultured human keratinocytes.
Oxford University Press