| Popis: |
The skin is the largest organ of the body and dysregulation of normal skin regeneration and homeostasis results in debilitating skin diseases such as psoriasis and non-melanoma skin cancer (NMSC). Oncoprotein Yes-associated protein (YAP) plays a critical role in organ size control by regulating stem/progenitor cell proliferation. However, the mechanisms downstream of YAP activation are largely unclear due to the lack of suitable models to investigate these. In this project, I have generated YAP inducible keratinocyte cell lines and used these in cell culture and organotypic culture assays to investigate the downstream effects of epidermal YAP activation in skin. I detected that in 2D in vitro culture assays, YAP activation led to an increase in cell size but not in an increase in cell proliferation (Chapter 3). In epidermal organotypic culture assays, YAP activation resulted in tissue hyperplasia and keratinocyte enlargement, with no increased proliferation (Chapter 4). In skin organotypic culture assays, YAP activation led to epidermal hyperplasia, keratinocyte enlargement, increased cell proliferation, and an accumulation of large Lamp1-positive vesicles (Chapter 5). I also generated artificial human skin xenografts with YAP inducible keratinocytes on immunocompromised mice, but not with high efficacy (Chapter 6). Together, this project demonstrated that YAP activation leads to tissue enlargement due to increased stem/progenitor cell proliferation and cell enlargement. Furthermore, my results show that YAP requires an intact 3D skin microenvironment to control skin regeneration. My findings have important implications for our understanding of tissue regeneration and other diseases displaying increased YAP activity. |
