Syndecans and CD44 in Normal Human Keratinocyte Cultures: Modulation with Medium Composition and All-trans Retinoic Acid

Abstract

We investigated chosen epidermal proteoglycans in different culture models to explore their expression by keratinocytes at various states of differentiation. Fully defined conditions of our epidermal reconstructions allowed for evaluation of the proteoglycans in “normal” or “ageing”-like epidermal tissues in vitro. The “ageing”-like epidermis was characterized by the viable layers’ atrophy, low proliferation rate and premature keratinisation. Expression of all studied proteoglycan genes could be detected with quantitative real-time PCR but the syndecan-4 protein wasn’t observed in the reconstructed epidermis using immunohistochemistry. Treatment with all-trans retinoic acid resulted in epithelial acanthosis, combined with up-regulation of proteoglycans in the “ageing”-like culture conditions. In “normal” reconstructed epidermis, retinoids increased the syndecan-4 gene expression but down-regulated that of syndecan-1. The observed complex changes are compatible with the presumed but still poorly understood roles of various proteoglycans in epidermal differentiation. Our defined culture models are suitable for screening of pharmacological agents modulating epidermal proteoglycan expression.