Extensive tissue-regenerative capacity of neonatal human keratinocyte stem cells and their progeny
Amy Li, … , Richard Redvers, Pritinder Kaur
Amy Li, … , Richard Redvers, Pritinder Kaur
Published February 1, 2004
Citation Information: J Clin Invest. 2004;113(3):390-400. https://doi.org/10.1172/JCI19140.
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Article

Extensive tissue-regenerative capacity of neonatal human keratinocyte stem cells and their progeny

Abstract

Given our recent discovery that it is possible to separate human epidermal stem cells of the skin from their more committed progeny (i.e., transit-amplifying cells and early differentiating cells) using FACS techniques, we sought to determine the comparative tissue regeneration ability of these keratinocyte progenitors. We demonstrate that the ability to regenerate a fully stratified epidermis with appropriate spatial and temporal expression of differentiation markers in a short-term in vitro organotypic culture system is an intrinsic characteristic of both epidermal stem and transit-amplifying cells, although the stem cell fraction is most capable of achieving homeostasis. Early differentiating keratinocytes exhibited limited short-term tissue regeneration under specific experimental conditions in this assay, although significant improvement was obtained by manipulating microenvironmental factors, that is, coculture with minimally passaged dermal cells or exogenous supply of the ECM protein laminin-10/11. Importantly, transplantation of all classes of keratinocyte progenitors into an in vivo setting demonstrated that tissue regeneration can be elicited from stem, transit-amplifying, and early differentiating keratinocytes for up to 10 weeks. These data illustrate that significant proliferative and tissue-regenerative capacity resides not only in keratinocyte stem cells as expected, but also in their more committed progeny, including early differentiating cells.

Authors

Amy Li, Normand Pouliot, Richard Redvers, Pritinder Kaur

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LN-10/11 is a potent proliferative substrate for α6dim differentiating k...
LN-10/11 is a potent proliferative substrate for α6dim differentiating keratinocytes, delays terminal differentiation in vitro, and promotes epidermal tissue regeneration, particularly from α6dim cells. Keratinocyte cultures derived from α6bri (a) and α6dim (b) fractions stained for keratins (AE1/AE3) after 12 days in culture plated on BSA-coated (2% wt/vol), human collagen IV–coated (Coll-IV; 20 μg/ml), or human LN-10/11–coated (5 μg/ml) wells. While α6bri cells were stimulated to grow on both collagen IV and LN-10/11, the poor proliferative capacity of α6dim cells was significantly improved on a LN-10/11 substrate (b). Western blot analysis showing decreased involucrin expression (c) in UF cultured keratinocytes seeded on LN-10/11 (LN; 5 μg/ml) compared with controls (on plastic; P) at day 2 and day 6 following plating. Equivalent numbers of keratinocytes (104) were loaded per lane. (d–g) Organotypic cultures (day 14) of 104 α6bri (d and e) and α6dim (f and g) keratinocytes cultured either on p7 DEs alone (d and f) or on p7 DE with exogenous LN-10/11 (e and g). H&E-stained sections show that the exogenous supply of LN-10/11 known to be absent in α6dim cocultures on p7 DEs (f) enhanced the epithelial regeneration ability of these cells significantly (g). Greater epidermal regeneration was also evident with α6bri cells with the inclusion of LN-10/11 (e), although the effects on α6dim cells are more dramatic. Scale bar: 50 μm.