A protein that is increased by endurance exercise has been isolated and given to non-exercising mice, in which it turned on genes that promote brain health and encourage the growth of new nerves involved in learning and memory.
It has been found that exercise stimulates BDNF (brain-derived neurotrophic protein) in the hippocampus, one of only two areas of the adult brain that can generate new nerve cells. BDNF promotes development of new nerves and synapses – connections between nerves that allow learning and memory to be stored – and helps preserve the survival of brain cells.
How exercise raises BDNF activity in the brain wasn’t known; the new findings linking exercise and BDNF provide a molecular pathway for the effect, although Spiegelman, PhD, of Dana-Farber and his colleagues suggest there are probably others.
The findings, reported in the journal Cell Metabolism, help explain the well-known capacity of endurance exercise to improve cognitive function, particularly in older people. If the protein can be made in a stable form and developed into a drug, it might lead to improved therapies for cognitive decline in older people and slow the toll of neurodegenerative diseases such Alzheimer’s and Parkinson’s, according to the investigators.
The Spiegelman group previously reported that the protein, called FNDC5, is produced by muscular exertion and is released into the bloodstream as a variant called irisin. In the new research, endurance exercise – mice voluntarily running on a wheel for 30 days – increased the activity of a metabolic regulatory molecule, PGC-1a, in muscles, which spurred a rise in FNDC5 protein. The increase of FNDC5 in turn boosted the expression of a brain-health protein, BDNF (brain-derived neurotrophic protein) in the dentate gyrus of the hippocampus, a part of the brain involved in learning and memory.
Spiegelman said that development of irisin as a drug will require creating a more stable form of the protein.
Source: Dana-Farber Cancer Institute, USA