The epidermis provides a physical and permeability barrier which is continuously regenerated by the epidermal keratinocyte differentiation process. During this process, keratinocytes migrate from the basal lamina to the outermost layer of the epidermis and form the stratum corneum. Multiple components can impact the barrier function quality, including protein structure (claudin, desmoglein, filaggrin, etc.), lipids (ceramides) and proteases. When properly functioning, the epidermis prevents water loss and provides a barrier to epidermal invasion of allergens and bacteria.
The purpose of this in vitro assay, performed on reconstructed human epidermis (RHE), is to evaluate the effects of compounds on specific gene expression of epidermal keratinocytes.
Transcriptomic analysis is performed from a selection of 16 or 64 genes, using RT-qPCR where genes of each list are grouped according to biological function (lipid synthesis pathways, epidermal differentiation process, dermal-epidermal junction, intracellular interaction, etc.).