Molekulare Mechanismen der Degradierung von humanem elastischem Gewebe in älteren Individuen

To identify molecular mechanisms of degradation of cutaneous elastic tissue in ageing individuals, skin models of intrinsic ageing will be used, such as human skin cell cultures (dermal fibroblasts and sebocytes) maintained at defined age-corresponding hormone-substituted conditions. Expression profiling using total RNA derived from the cell cultures will be performed on a whole genome cDNA chip. Array data will be analyzed utilizing data quality control procedures and robust statistical tests for detection of differentially expressed genes. Candidate genes identified will be verified by real-time PCR and their significance will be corroborated by expression analysis in biopsies from light-protected skin of females and males of 20 and 60 years of age. Subsequent identification of potential downstream targets and regulatory pathways will be addressed by gene regulatory networks, correlation analysis, western blotting, immunohistochemistry and ELISA, enzyme activity by gelatin zymography, and glycosaminoglycans will be characterized chemically, biochemically and enzymologically. Preliminary experiments using human fibroblasts and sebocytes ageing in vitro identified several metalloproteinases, tissue inhibitors of metalloproteinases, and hyaluronan synthases to be regulated at the mRNA level.