074 Bioinformatic interaction network of the genes implicated in skin senescence coupled to in vitro testing models

Cellular senescence is an irreversible state of cell cycle arrest that is induced during cellular aging. In the skin, senescence is associated with phenotypic changes in cutaneous structure and cells, lowered resistance to oxidative stress and DNA damage, decreased epidermal cell renewal, decreased synthesis of extracellular matrix protein and the appearance of markers of aging (senescence-associated beta-galactosidase, etc.). Many genes have been reported to be involved in the regulation of senescence: tumor suppressor genes (e.g., p53), senescence genes (e.g., p16, p21) and senescence suppressor genes (e.g., telomerase), oncogenes (e.g., MYC), stemness genes (e.g., SOX2), genes related with epigenetics (e.g., SIRT1), inflammation-related genes, genes implicated in DNA damage repair, cytoskeletal remodeling (e.g., TGF, WNT), and also various transcription factors. All these genes participate in a network of interactions regulating senescence, ending with the highly regulated p53–p21 and p16–pRB pathways. In this study we developed a bioinformatic network model of the relationships between the main genes involved in skin senescence. This network facilitated the categorization of subsets of genes and the prediction of potential modulating microRNAs. In parallel, we developed several in vitro models to study senescence, based on the silencing of specific genes, allowing us to obtain skin cells in culture with a senescent phenotype. Characterization of the cellular phenotype by immunodetection of proteic markers and qPCR was undertaken in order to identify specific features according to the gene silenced. This complementary in silico and in vitro testing approach will foster study of the modulating potential of biofunctional ingredients or other chemicals on cellular senescence in vitro.