Poster presentation, P80

Official XXIst International Pigment Cell Conference website - 21-24 Sept 2011, Bordeaux - France | updated: September 04 2011

Novel aspects of melanocyte - keratinocyte interactions in vitro as a clue towards repigmentation in vitiligo

BACKGROUND AND OBJECTIVES: Repigmentation of skin hypopigmentary disorders such as vitiligo is thought to involve the activation and migration of melanocyte precursors resident in the epidermal or hair follicle niches, into the denuded areas. The mechanism and mode of this migration is not well understood and may occur trans-epidermally, and/or along the basement membrane and/or in the dermis. METHODS: In order to explore possible mechanisms of human melanocyte migration, primary human melanocytes and keratinocytes were co-cultured and the migration of melanocytes into the keratinocytes using lateral migration and transmembrane assays.. Melanocytes were visualised by immunofluorescent detection and scanning electron microscopy and gene expression changes were quantified using qPCR. RESULTS: These assays demonstrated that human melanocytes were stimulated to actively migrate through intercellular spaces between keratinocytes both laterally and from the basolateral surfaces, suggesting that reciprocal signals stimulated both melanocyte migration and de-adhesion of intercellular connections between keratinocytes. Immunofluorescent and scanning electron microscopy analyses demonstrated that the melanocyte dendrites play a pivotal role by extending ahead of the melanocyte nucleus to explore the substrate and act as anchorage points. In addition, melanocyte migration through a 0.45 µm Millipore membrane demonstrated that the melanocyte nucleus is a highly malleable structure that aids in its migration through the intercellular spaces between the keratinocytes. Analysis of gene expression in these migrating cells using qRT-PCR indicated that c-Kit expression was increased in migrating melanocytes, suggesting that SCF/c-Kit signalling provided chemotactic and chemokinetic signals for melanocyte migration. CONCLUSION: This study provides further insight into the mechanism of melanocyte migration and potentially contributes towards improving therapies for hypopigmentary disorders such as vitiligo as well as providing further clues towards healing skin wounds.

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