Exposure to ultraviolet B (UVB) radiation from the sun can result in sunburn, premature aging, and carcinogenesis. The mechanism responsible for acute inflammation of the skin is not well understood.

Jamie J. Bernard, University of California San Diego, USA, and colleagues treated human skin cells with acute UVB radiation. They show that RNA is released from keratinocytes after UVB exposure. Keratinocyte is the predominant cell type in the epidermis, the outermost layer of the skin. This stimulates an inflammatory response from the surrounding cells, intended to remove sun-damaged cells.

The findings open the way to perhaps eventually blocking the inflammatory process and have implications for a range of medical conditions and treatments.

• Ultraviolet radiation damages self noncoding RNA and is detected by TLR3,
  Jamie J Bernard, Christopher Cowing-Zitron, Teruaki Nakatsuji, Beda Muehleisen, Jun Muto, Andrew W Borkowski, Laisel Martinez, Eric L Greidinger, Benjamin D Yu, Richard L. Gallo,
  Nature Medicine 2012.
  DOI:10.1038/nm.2861