Layer by layer: Scientists decipher how skin layers are formed

Cologne scientists present a new two-phase model of skin formation The data provide insights into the balance of tissues and diseases associated with greatly increased cell division rates The complex layering (stratification) of skin arises form one layer of cells during embryonic development. How stratification is stimulated and driven is still largely unknown. Together with his team, Dr Hisham Bazzi, research group leader at the Cluster of Excellence in Aging Research CECAD and the Center for Molecular Medicine Cologne (CMMC), has published a new two-phase model of physiological epidermal development. Using time-lapse imaging and measurements of tissue growth dynamics in mouse models, the research team suggests that the first phase is the major phase of stratification, which is characterized by particularly high cell divisions or high proliferation rates. This applies both to basal progenitor cells, the later stem cells of the skin, and to overlying skin cells, the suprabasally-commited skin cells. In addition, the so-called delamination, the detachment and movement of the basal cells to the suprabasal layers, contributes to the stratification. The article 'High proliferation and delamination during skin epidermal stratification' has now appeared.