Multitasking molecules: Healthy body, healthy brain

Anna Zhou
28 December 2013

Above: Structure of the BDNF protein (Emw)

Did you know? Growth factors trigger a chain reaction called a “signal cascade”, allowing cells to divide, send messages to each other, and begin producing proteins.You often hear about the benefits of exercise for the brain: improved memory, stress relief, and protection against different forms of dementia, including Alzheimer’s disease. But how exactly do fun activities like swimming and playing soccer cause such wonderful and even life-changing effects? Interestingly, the molecules that make your body healthier when you exercise may be the same ones that make your brain healthier as well.

Researchers have identified several growth factors (protein molecules) that help improve your brain health when you exercise: BDNF, IGF-1 and VEGF. They may not have very interesting names, but each of them plays a key role in the relationship between exercise and brain health.

BDNF keeps your neurons (a type pf brain cell) healthy and stimulates the production of new neurons. Exercise increases BDNF levels in the hippocampus, improving both your ability to learn new things and to remember what you’ve learned.

Location of the Hippocampus in the Human Brain (Washington irving)

Scientists have recently discovered how exercise actually increases BDNF. During exercise, your muscles release a protein called PGC-1alpha, which causes the release of another protein called FNDC5. Next, FNDC5 is broken down into a smaller protein called irisin, which turns beige (bad) fat into brown (good) fat, protecting you from obesity and diabetes.

Did you know? The hippocampus is the part of your brain involved in learning, memory storage and formation, and emotions. Mammals, including humans, actually have two hippocampi, which are located on opposite sides of the brain.The latest research shows that when you exercise, PGC-1alpha and FNDC5 are not just released in your muscles. They are also released in the hippocampus, where they cause a highly beneficial increase in BDNF. Amazingly, the same molecules that keep you fit help you learn more efficiently too!

Exercise also increases IGF-1 and VEGF levels in both the body and the brain. These two growth factors stimulate cell growth and increase blood flow in muscles, making them stronger. At the same time, they stimulate the production of new neurons and help create blood vessels in the hippocampus, boosting learning and memory. So like FNDC5, these proteins improve both your physical and mental fitness.

Did you know? Mitochondria are responsible for producing energy in cells. They also play a role in cell growth, division, and death. For example, BDNF and IGF-1 act together to fight depression. PGC-1alpha increases the amount of energy-producing mitochondria in the brain. This defends the brain against age-related damage that can cause dementia.

We still don’t fully understand the relationship between brain function and exercise. But research into what happens at the molecular level makes one thing clear: Exercise doesn’t just keep your body fit. It keeps your brain in top shape too!

References

General information

Cascades and Cell Signalling (Theresa Phillips, About.com) Hippocampus (Regina Bailey, About.com) How Exercise Beefs Up the Brain (Kelly Servick, Science Now) Mitochondria (Regina Bailey, About.com Biology)

Scholarly publication

Berchtold, NC et al. 2005. Exercise primes a molecular memory for brain-derived neurotrophic factor protein induction in the rat hippocampus. Neuroscience. 133:853-861. Bostrm P et al. 2012. A PGC1-α-dependent myokine that drives brown-fat-like development of white fat and thermogenesis. Nature. 481:463-468. Clemmons DR. Physiology of insulin-like growth factor I. UpToDate, Waltham, MA. Cotman CW et al. 2007 Exercise builds brain health: key roles of growth factor cascades and inflammation. Trends in Neurosciences. 30:462-472. Hoshaw, BA et al. 2005. Central administration of IGF-1 and BDNF leads to long-lasting antidepressant-like effects. Brain Research. 1037:204-208. Kuipers SD, Bramham CR. 2006. Brain-derived neurotrophic factor mechanisms and function in adult synaptic plasticity: new insights and implications for therapy. Current opinion in drug discovery & development. 9:580-586. Neufeld G. 1999. Vascular endothelial growth factor (VEGF) and its receptors. The Journal of the Federation of American Societies for Experimental Biology. 13:9-22. Steiner, JL et al. 2011. Exercise increases mitochondrial biogenesis in the brain. Journal of Applied Physiology. 111:1066-1071. Wrann CD et al. 2013. Exercise induces Hippocampal BDNF through a PGC-1alpha/FNDC5 Pathway. Cell Metabolism. 18:1-11.

Anna Zhou

I completed my BSc at McMaster University in Biochemistry and am now pursuing my MSc in Medical Biophysics at the University of Toronto. I am located at the SickKids research building in downtown Toronto and am researching the structure of the ATP synthase using electron microscopy. In my spare time, I love to dance, read and explore the city.

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