Researchers identify the beneficial role of sleep that includes repair of DNA damage
Sleep allow the neurons to perform efficient DNA maintenance that repair DNA damage accumulated during waking hours. If you have been pondering why do most humans “waste” a third time of their lives sleeping and the reason why animals sleep despite the continuous threat of predators then this study has the answers.
Sleep is vital for efficient DNA maintenance to correct the DNA damage accumulated during waking hours. Researchers reveal a novel and unexpected function of sleep that they believe could explain how sleep and sleep disturbances affect brain performance, aging and various brain disorders.
Using 3D imaging techniques in live zebrafish, the researchers were able to define sleep in a single chromosome resolution and show, for the first time, that single neurons require sleep in order to perform nuclear maintenance.
DNA damage can be caused by many processes including radiation, oxidative stress, and even neuronal activity. DNA repair systems within each cell correct this damage. The role of sleep is to increase chromosome dynamics, and normalize the levels of DNA damage in each single neuron
DNA damage can be caused by many processes including radiation, oxidative stress, and even neuronal activity. DNA repair systems within each cell correct this damage. The role of sleep is to increase chromosome dynamics, and normalize the levels of DNA damage in each single neuron. Apparently, this DNA maintenance process is not efficient enough during the online wakefulness period and requires an offline sleep period with reduced input to the brain in order to occur.
Researchers hypothesized that sleep consolidates and synchronizes nuclear maintenance within individual neurons, and set out to confirm this theory.
Zebrafish, who have a brain very similar to humans was used in this study. Using a high resolution microscope, the movement of DNA and nuclear proteins within the cell – inside the fish – can be observed while the fish are awake and asleep. The researchers were particularly surprised to find that chromosomes are more active at night, when the body rests, but this increased activity enables the efficiency of the repair to DNA damage.
The results establish chromosome dynamics as a potential marker for defining single sleeping cells and propose that the restorative function of sleep is nuclear maintenance.
“We’ve found a causal link between sleep, chromosome dynamics, neuronal activity, and DNA damage and repair with direct physiological relevance to the entire organism,” said lead author Prof. Lior Appelbaum of Bar-Ilan University in Israel. “Sleep gives an opportunity to reduce DNA damage accumulated in the brain during wakefulness.”
“Despite the risk of reduced awareness to the environment, animals – ranging from jellyfish to zebrafish to humans – have to sleep to allow their neurons to perform efficient DNA maintenance, and this is possibly the reason why sleep has evolved and is so conserved in the animal kingdom,” concludes Prof. Appelbaum.
The study was published in the journal Nature Communications.
