http://stream.publicbroadcasting.net/production/mp3/wamc/local-wamc-1000871.mp3
Albany, NY – In today's Academic Minute, Dr. Elena Oancea of Brown University explains the similarity in how our eyes and skin respond to UV light.
Elena Oancea is an assistant professor of medical science at Brown University where her researched is focused on understanding signal transduction events using fluorescent microscopy in living cells. She holds a Ph.D. from Duke University.
Dr. Elena Oancea - UV Light and the Skin
Being out in the sun gives us a suntan a day or two later. The darkening of the skin is due to melanin production by skin cells named melanocytes. And it is caused by the break of DNA strands by long-wavelength UV light, or UVB. Breaking DNA is an unfortunate event that, when, when not repaired properly could result in cancer. Melanin protects skin cells against further DNA damage caused by UV.
We wondered whether there is more to the way our skin cells respond to UV light. Using a UV lamp resembling sunlight spectrum and a fluorescent microscope we asked whether skin is able to respond directly to the short wavelength UV, or UVA, which amounts for almost 95% of the solar UV radiation. We were also intrigued by how long it takes for the skin's melanin-mediated protection mechanism to kick in.
With these questions in mind, we exposed human melanocytes to doses of UV that correspond to seconds in the bright sun. To our surprise the cells elicited a robust calcium signaling response, but only when we added retinal. Retinal suggested to us that the UV response is likely to be mediated by receptors related to those that detect light in the eye. Indeed, we found that rhodopsin is present in skin cells and required for the UV-induced signaling response. Moreover, UV worth a few minutes in the sun led to melanin production within 1 hour, much faster than the suntan we get after a day at the beach. Interestingly both the calcium response and the early melanin production were caused by UVA.
Our finding suggests that the skin uses same of the same receptors as the eyes to detect UVA light within seconds of exposure and that it elicits a protective response within an hour.