Expression profile of proliferating and differentiating primary human keratinocytes in vitro

Human epidermal keratinocytes undergo tightly controlled program of cell differentiation, leading to the formation of cornified envelope. Primary keratinocytes in vitro, under calcium stimulation mimic the differentiation program observed in vivo. Analysis of the transcription profile of two cell population, such as proliferating cells and differentiating cells helps to discover new genes implicated in that process and to understand the mechanisms of regulation of the keratinocyte differentiation. Primary human keratinocytes were cultured under proliferating (Day 0, sub-confluent cells) and differentiating (seven days of high calcium medium) conditions. As a source of cells, we used normal skin from different body sites: back, foreskin, palmoplantar. RNA extracted from cultured primary human keratinocytes were isolated from five different donors. We compared the expression profiles of proliferating versus differentiating keratinocytes.