UVB radiation suppresses Dicer expression through β-catenin.

Ultraviolet (UV) rays prompt a natural response in epidermal cells, particularly within melanocytes. The changes in gene expression and related signaling pathways in melanocytes following exposure to UVR are still not entirely understood. Our findings reveal that UVB irradiation suppresses the expression of Dicer. This repression is intricately linked to the activation of the PI3K, RSK, and WNT/β-catenin signaling pathways and is directly associated with transcriptional repression by β-catenin. Notably, we have identified specific binding sites for the LEF/β-catenin complex in the Dicer promoter. Collectively, these results emphasize the significance of the UV-induced pathway involving LEF/β-catenin, which impacts Dicer expression. UV radiation also reduced the levels of specific miRNAs known to be important in the biology of melanocytes. This pathway holds potential importance in governing melanocyte physiology.