| Recent genetic studies on common inflammatory disorders such as eczema, psoriasis, asthma and Crohn's disease suggest that perturbance of epithelial barrier function in skin, lung and gut plays a role in their disease mechanisms. Clearly, the translation of these insights to understand the pathogenesis of skin diseases, or to develop new therapies, requires a detailed knowledge of epidermal differentiation and stratum corneum homeostasis. Using genetic models in mice, we have recently uncovered a biochemical pathway that involves the protease inhibitor cystatin M/E as a central regulator of stratum corneum homeostasis. Biochemical evidence indicates that cystatin M/E controls the activity of several proteases and may indirectly regulate activity of epidermal transglutaminases, which are key enzymes in skin cornification. In the current project we aim to provide a comprehensive analysis of this pathway in human skin where the role of cystatin M/E appears to be much more complex than in mice. We will elucidate the role of proteases and protease inhibitors, and downstream activation of transglutaminases in reconstructed human skin, using lentiviral vectors for knockdown or overexpression of the relevant genes. Secondly, using a recently obtained mouse model, we will study the consequences of cystatin M/E deficiency on the physiology and maintenance of adult, non-epidermal tissues. Finally, based on our recent findings, we will investigate if the cystatin M/E dependent pathway is dependent of epigenetic regulation. This project will lead to novel insights in development, maintenance and senescence of skin barrier function. |
