Researchers at Touro University Nevada have identified that extracellular vesicles (EVs), small particles found in blood and other body fluids, play a significant role in transporting hormone precursors throughout the body. The study, published in the Proceedings of the National Academy of Sciences (PNAS), focused on how physical exercise affects this process.
EVs are known to carry biological materials such as proteins, lipids, and nucleic acids between cells, facilitating communication both within tissues and across different organ systems. While previous research has established their involvement in processes like immune response and cancer progression, their interaction with hormones had not been well understood.
The team concentrated on proopiomelanocortin (POMC), a hormone precursor that is converted into various hormones including endorphins and adrenocorticotropic hormone (ACTH). Both hormones are linked to exercise responses. By studying the effects of vigorous exercise, researchers observed that POMC attached itself to EVs at four times the usual rate during intense physical activity.
"This study doesn't just show an 'exercise effect' but it reveals a new biological mechanism where stress from exercise makes EVs temporarily act as hormone transport shuttles in the bloodstream," said Mark Santos, Ph.D., assistant professor at Touro and first author of the study.
Laboratory tests also demonstrated that POMC bound to EVs was able to cross human blood vessel barriers, including the blood-brain barrier, more efficiently than POMC alone. This suggests a potential pathway for hormones to access areas like the brain that are typically difficult for many substances to reach.
However, further research is needed to determine how increased levels of POMC after exercise impact brain function since POMC must be processed into active forms before triggering any effects in the brain.
"The observation that EVs can carry POMC has so many potential directions," said Aurelio Lorico, MD, PhD, professor of pathology at Touro and co-senior author along with Cheryl Hightower. "It may have wide-ranging implications, for pain management, metabolism and obesity, inflammation, and the stress response," he added.
