Human skin cells fend off fluctuating threats by carrying out different functions depending on the time of day, according to a new study.
Researchers found that the cells protect themselves against radiation-induced DNA damage, for example, by activating genes involved in UV protection during the day.
The findings, the researchers argue, could have widespread implications for strategies designed to prevent premature aging and cancer.
"Our study shows that human skin stem cells possess an internal clock that allows them to very accurately know the time of day and helps them know when it is best to perform the correct function," study author Salvador Aznar Benitah said in a statement. "This is important because it seems that tissues need an accurate internal clock to remain healthy."
Previously, Benitah, who developed the project at the Center for Genomic Regulation (CRG) in Barcelona, found that animals lacking normal circadian rhythms in skin stem cells age prematurely. Realizing this, Benitah teamed up with CRG researchers Luis Serrano and Ben Lehner to examine why`.
Together they found that distinct sets of genes in human skin stem cells show peak activity depending on the time of day, with those involved in UV protection proving to be most active during the daytime.
"We know that the clock is gradually disrupted in aged mice and humans, and we know that preventing stem cells from accurately knowing the time of the day reduces their regenerative capacity," Benitah said. "Our current efforts lie in trying to identify the causes underlying the disruption of the clock of human skin stem cells and hopefully find means to prevent or delay it."