How our body’s internal clocks communicate may impact our overall health

Nearly every cell in the body has its own 24-hour clock, and new research from the Perelman School of Medicine shows the way those clocks interact with each other plays a critical role in the health of a person’s metabolism. It’s widely reported that shift workers suffer from high rates of obesity and diabetes when their internal clocks do not coordinate with each other, as well as due to irregular eating times. However, little is known about the interaction between internal clocks and eating schedules, and specifically, the impact on overall health.

Old-fashioned alarm clock on top of an empty plate with a table setting

Now, in a new study published in Science, a team of researchers led by Mitchell Lazar, the Willard and Rhoda Ware Professor in Diabetes and Metabolic Diseases and director of Penn’s Institute for Diabetes, Obesity, and Metabolism, sheds new light on the question.

“The internal clocks in the brain synchronize clocks in peripheral tissues, and misalignment of this system is associated with metabolic dysfunction,” says Lazar, the senior author of the study. “But how the environment and genetic factors control the clocks in peripheral tissue and whether communication exists between clocks in different cell types are largely unknown.”

Lazar’s team, led by postdoctoral fellow Dongyin Guan, established a new mouse model that can specifically disrupt the internal clock in hepatocytes, the major cell type in the liver, which is the body’s metabolic hub. As a result of this disruption, researchers observed an accumulation of triglycerides in the blood that increase the risk of heart disease, diabetes, and stroke. These results indicate the importance of the internal clocks in peripheral tissue of the liver in maintaining metabolic homeostasis.

Surprisingly, the metabolism of other cell types in the liver were also reprogrammed when the internal clock of hepatocytes was disrupted.

“Our discovery of clock communication between different cell types is very exciting as it suggests a previously unappreciated way that the body’s rhythms are coordinated,” says Guan.

This story is by Abbey Hunton. Read more at Penn Medicine News.