Protein Linked to Endurance Exercise Promotes Brain Health

Researchers have identified a protein tied to endurance exercise that appears to promote brain health even in the absence of exercise.

Called FNDC5, the protein was first reported in a previous study by the team of scientists led by Bruce Spiegelman of Harvard Medical School.

Writing in the journal Cell Metabolism, the researchers report the protein increased brain health and triggered the growth of new nerves in learning and memory when given to non-exercising mice. The results clearly outline why endurance exercise improves cognitive function, especially in the elderly.

"What is exciting is that a natural substance can be given in the bloodstream that can mimic some of the effects of endurance exercise on the brain," Spiegelman said in a statement. According to the team, if the protein can be made in a stable form, it could possibly be used to produce a drug to help stave off cognitive decline and even slow the effects of diseases such as Alzheimer's and Parkinson's.

In the past, the group found that the protein is produced by muscular exertion and released into the bloodstream as a variant called irisin. In the new study, the researchers found that endurance exercise in mice led to an increase in FNDC5, which boosted the expression of the brain-health protein BDNF in the hippocampus, a part of the brain involved in learning and memory.

Finding that FNDC5 represents a molecular link between exercise and increased BDNF, the scientists used a harmless virus to deliver the former to sedentary mice through the bloodstream. A week later, they found significant increases in BDNF in the mice's hippocampus.

"Perhaps the most exciting result overall is that peripheral [delivery] of FNDC5 with adenoviral vectors is sufficient to induce central expression of BDNF and other genes with potential neuroprotective functions or those involved in learning and memory," the authors said.