The study, conducted by researchers from the University of Copenhagen and Nanyang Technological University in Singapore, was published in the journal Molecular Cell in late November 2024.

Notably, both mice and human skin cells demonstrated similar responses to UV radiation, underscoring the relevance of these findings across species.

Traditionally, sunburn symptoms were attributed to DNA damage caused by ultraviolet B radiation, which was thought to lead to cell death and inflammation.

Recent research reveals that the acute effects of sunburn, such as inflammation and cell death, are primarily triggered by RNA damage instead of the traditionally emphasized DNA damage.

This shift in understanding, as highlighted by co-author Dr. Franklin Zhong, could pave the way for innovative treatments for chronic skin conditions worsened by sun exposure.

Sunburn results from prolonged exposure to shorter-wavelength ultraviolet B radiation, which induces various cellular stresses that activate the immune response.

The research indicates that RNA damage triggers a response mediated by a protein known as ZAK-alpha, which is responsible for inflammatory signaling and the recruitment of immune cells.

This ribotoxic stress response, initiated by messenger RNA (mRNA) damage, serves as a surveillance mechanism that registers RNA damage, ultimately leading to skin inflammation and cell death.

To further validate their findings, the study utilized genetically engineered mice lacking the stress response protein ZAK-alpha, demonstrating the critical role of RNA damage in sunburn symptoms.

Mice that did not have ZAK-alpha did not exhibit the typical responses associated with sunburn when exposed to ultraviolet B radiation, reinforcing the significance of RNA damage in sunlight sensitivity.

Messenger RNA (mRNA) is a transient molecule that conveys information from DNA for protein synthesis, contrasting with the long-lived nature of DNA.

Overall, these results suggest a significant paradigm shift in our understanding of skin responses to UV radiation, indicating that existing textbooks may need to be revised regarding sunburn and skin defenses.