The Pattern Recognition Receptor Toll-Like Receptor 3 Regulates Skin Barrier Homeostasis

The study explored the role of Toll-like receptor 3 (TLR3) in skin barrier repair following UV damage. It was found that non-coding double-stranded RNA (dsRNA) from damaged keratinocytes activated TLR3, leading to increased expression of genes involved in skin barrier repair, such as ABCA12 and glucocerebrosidase. TLR3 activation also enhanced tight junction function and lipid production in keratinocytes. Tlr3-/- mice showed delayed skin barrier repair after UVB damage, highlighting TLR3's role in this process. Additionally, scavenger receptors were found to facilitate dsRNA entry into keratinocytes, influencing gene expression related to barrier repair. Msr1-/- mice exhibited defects in skin barrier repair, indicating the importance of scavenger receptors. The study also revealed that IL-1R signaling is crucial for skin homeostasis post-UVB exposure, as Il1r-/- mice developed dermal hair cysts and had fewer macrophages. Overall, the research provided insights into the cellular mechanisms involved in skin response to UVB damage.