1. ¹Faculty of Life Sciences, University of Manchester, Manchester, UK
2. ²School of Medicine, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK

Correspondence: Dr Denis J. Headon, Faculty of Life Sciences, University of Manchester, Oxford Road, Manchester M13 9PT, UK. E-mail: denis.headon@manchester.ac.uk

Received 23 July 2007; Revised 4 September 2007; Accepted 26 September 2007; Published online 22 November 2007.

Abstract

Hair follicles have been observed to provide a major cellular contribution to epidermal healing, with emigration of stem-derived cells from the follicles aiding in wound reepithelialization. However, the functional requirements for this hair follicle input are unknown. Here we have characterized the keratinocyte stem cell status of mutant mice that lack all hair follicle development on their tail, and analyzed the consequent alterations in epidermal wound healing rate and mechanisms. In analyzing stem cell behavior in embryonic skin we found that clonogenic keratinocytes are relatively frequent in the ectoderm prior to hair follicle formation. However, their frequency in the interfollicular epidermis drops sharply by birth, at which time the majority of stem cells are present within the hair follicles. We find that in the absence of hair follicles cutaneous wounds heal with an acute delay in reepithelialization. This delay is followed by expansion of the region of activated epidermis, beyond that seen in normal haired skin, followed by appropriate wound closure.

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