“Time heals all wounds” is a popular phrase that means that grief and sorrow lessen over time. A new study takes this phrase in a literal sense and may lead to new avenues of research for traumatic brain injury (TBI). Researchers from the Children’s National Hospital discovered how a type of brain cell that can renew itself is regulated by circadian rhythms, providing insights into how the body’s internal clock may promote healing after TBI.

The findings are published in the journal eNeuro in an article titled, “Endogenous circadian clock machinery in cortical NG2-glia regulates cellular proliferation.”

“The molecular circadian clock can be found throughout the body and is essential for the synchronizing cellular physiology with the 24-hour day,” wrote the researchers. “However, the role of the clock in regulating the brain’s regenerative potential has not been explored. We report here that murine NG2-glia, the largest population of proliferative cells in the mature central nervous system, rhythmically express circadian clock genes in a 24-hour period, including the critical clock component Bmal1 RNA and BMAL1 protein.”

The brain cell, known as NG2-glia, or oligodendrocyte precursor cells, is one of the few that continually self-renews throughout adulthood and is notably proliferative in the first week after brain injuries.

“We have found evidence for the role of this well-known molecular pathway—the molecular circadian clock—in regulating the ability for these NG2-glia to proliferate, both at rest and after injury,” said Terry Dean, MD, PhD, critical care specialist at Children’s National and the lead author of the paper. “This will serve as a starting point to further investigate the pathways to controlling cellular regeneration and optimize recovery after injury.”

“It is essential for researchers to know that cell renewal is coordinated with the time of day,” said Vittorio Gallo, PhD, interim chief academic officer and interim director of the Children’s National Research Institute. “With this knowledge, we can dig deeper into the body’s genetic healing process to understand how cells regulate and regenerate themselves.”

“Because circadian rhythm disturbances are common in neurologic disorders across the lifespan, including in TBI, these findings bear significant implications for cellular regeneration in brain injuries and disease,” concluded the researchers.