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Human skin must cope with UV radiation from the sun and other harmful environmental factors that fluctuate in a circadian manner. A study published by Cell Press on October 10th in the journal Cell Stem Cell has revealed that human skin stem cells deal with these cyclical threats by carrying out different functions depending on the time of day. By activating genes involved in UV protection during the day, these cells protect themselves against radiation-induced DNA damage. The findings could pave the way for new strategies to prevent premature aging and cancer in humans.
Disurbance in skin circadian rhythm produces an increase of latent cells and a low number of proliferating cells (already differentiated). On the left, many proliferating cells (red arrow) in a sample with active Bmal1 gene and on the right, very few proliferating cells from a suppressed gene sample. (Credit: Image courtesy of Centre for Genomic Regulation)
Janich et al. Human epidermal stem cell function is regulated by circadian oscillations. Cell Stem Cell, October 2013