509 Using the human iPSCs-derived sensory neurons re-innervated skin ex vivo model to investigate mast cell-nerve fiber cross-talk in solar elastosis

Prolonged sun exposure can cause solar elastosis, characterized by the degeneration and abnormal accumulation of elastic fibers. This study used skin samples from 4 healthy donors, cultured with human iPSC-derived sensory neurons, to explore the interaction between mast cells and nerve fibers during UV irradiation. The findings revealed that UVB exposure significantly increased mast cell degranulation, particularly in the presence of cutaneous innervation, and led to increased elastin and fibrillin-I in the dermis, resulting in disorganized fiber architecture. These results suggest that nerve fibers may exacerbate mast cell activity, promoting dysfunctional elastic fiber accumulation, and highlight a potential targetable mechanism in solar elastosis and extrinsic aging.