Researchers at the University of California, San Diego School of Medicine and elsewhere published their new report in the July 8, 2012 Advance Online Publication of Nature Medicine, and say that the findings could open the way to eventually blocking the inflammatory process, with implications for a range of treatments and applications.
RNA, which is similar but not identical to DNA, is part of a group of molecules known as the nucleic acids, which are one of the four major macromolecules (along with lipids, carbohydrates and proteins) essential for all known forms of life.
The researchers state that this discovery could lead to a number of further investigations into medical conditions and the treatments used.
"For example, diseases like psoriasis are treated by UV light, but a big side effect is that this treatment increases the risk of skin cancer," said principal investigator Richard L. Gallo, professor of medicine at UC San Diego School of Medicine and Veterans Affairs San Diego Healthcare System.
"Our discovery suggests a way to get the beneficial effects of UV therapy without actually exposing our patients to the harmful UV light. We are exploring if we can help them by blocking the pathway we discovered."
Findings and effects
Using both human skin cells and a mouse model, Gallo, first author Jamie J. Bernard, and colleagues found that UVB radiation fractures and tangles elements of non-coding micro-RNA; which they explain as a special type of RNA inside the cell that does not directly make proteins.
Irradiated cells release this altered RNA, provoking healthy, neighboring cells to start a process that results in an inflammatory response intended to remove sun-damaged cells.
"The inflammatory response is important to start the process of healing after cell death," said Gallo.
"We also believe the inflammatory process may clean up cells with genetic damage before they can become cancer. Of course, this process is imperfect and with more UV exposure, there is more chance of cells becoming cancerous."
The lead investigator continues to state that it is not known how gender, skin pigmentation and individual genetics may affect the mechanism of sunburn.
"Genetics is closely linked to the ability to defend against UV damage and develop skin cancers. We know in our mouse genetic models that specific genes will change how the mice get sunburn.”
“Humans have similar genes, but it is not known if people have mutations in these genes that affect their sun response,” he said.