Body’s circadian rhythms affect skin stem cell regulation

New research suggests that the body’s internal clock and its circadian rhythms adjust the modulation of skin stem cells based on the time of day - and that disruption to this cycle can cause tissue aging and lead to predisposition to skin cancer.

According to researchers from the Centre for Genomic Regulation (CRG) in Barcelona, during long exposure to pathogens or ultraviolet light, the skin’s stem cells will protect themselves. When not exposed to light, the cells produce new keratinocytes - dead cells rich in keratin - that provide a protective layer against harmful agents, according to the study.

“Stem cells have some genes that control their biological clock and that determine peaks of activity and intervals of inactivity over 24-hour periods,” study leader Salvador Aznar Benitah, Ph.D., said in a news release. “In this study, we describe how the cells manage to perceive what time of the day it is. This precision allows the stem cells to adapt their activity to the time of day and to its environmental conditions.”

In a 2011 study, Dr. Benitah and colleagues described the link between circadian rhythms and the skin’s stem cell regulation. That study found that the cells could distinguish between night and day. The new study, funded by the European Research Council and the European Union, monitored the activity of the stem cells - adult stem cells in particular - by the minute to ascertain exactly how they determine the time and use that information to self-regulate and regenerate.

Dr. Benitah’s latest study also found that disruptions to the circadian rhythms had serious effects on the proper functioning of skin stem cells, which can lead to tissue aging and possible predisposition to skin cancer.

The study appears in the journal Cell Stem Cell.