Some genes controlled by the body’s circadian clock are more active in older fruit flies compared to younger ones. And oxidative stress can induce the expression of these genes in young flies, according to a study published today (February 21) in Nature Communications. Disruption of the 24-hour circadian clock has previously been shown to be deleterious, exacerbating aging-related health issues. These latest results add to a body of evidence suggesting an anti-aging role of the circadian clock.
“The finding that the circadian transcriptional program changes with age is totally novel,” Amita Sehgal, who studies sleep and circadian rhythms in fruit flies at the University of Pennsylvania but was not involved in the work, wrote in an email to The Scientist.
“The study’s results “are surprising, because the conventional wisdom in the field based on studies of mammals and human subjects is that circadian rhythms weaken with aging,” Michael Nitabach, who studies the genetic basis of behavior of fruit flies at Yale University, and who also was not involved in the work, wrote in an email to The Scientist. “This adds an interesting wrinkle that there is induction of rhythmicity of some transcripts with aging, not just weakening or loss of rhythmicity.”
The circadian clock, well-studied in the fruit fly Drosophila melanogaster and in mammalian organisms, imposes a 24-hour oscillating rhythm onto cells of the body. The clock regulates many important processes, from metabolism to sleep/wake cycles, memory consolidation, and neuronal remodeling. While the master transcription factors that regulate the clock are well known, the genes and processes they control and how perturbations of the clock can negatively affect lifespan are not fully understood. “It is unknown why disruption of the circadian clock can lead to neurodegenerative phenotypes in mammals and flies and a higher susceptibility to oxidative stress,” explained study coauthor David Hendrix, a computational biologist who studies gene regulation at Oregon State University in Corvallis.