Researchers at the Dana-Farber Cancer Institute say they have isolated a previously unknown hormone they found in muscle cells. They sat that the protein serves as a chemical messenger triggering many of the key health benefits of exercising.
Bruce Spiegelman, PhD, a cell biologist at Dana-Farber, and senior author of the report, published in Nature worked alongside Pontus Bostroöm, MD, PhD, a postdoctoral fellow in the Spiegelman lab.
Bostroöm said :
“It’s exciting to find a natural substance connected to exercise that has such clear therapeutic potential.”
The hormone which Spiegelman named “Irisin,” after Iris, a Greek messenger goddess, could open the door for treatment for people with diabetes, obesity and possibly other disorders, including cancer. It’s the first stage in understanding how the body broadcasts the benefits of exercise into positive changes in physiology, and should with further research enable scientists to mimic that effect, both in healthy people and by way of combating disease.
Spiegelman, who is a professor of cell biology at Harvard Medical School said :
One of the most powerful effects of Irisin is to command fat cells to convert white fat stores into brown fat, which is considered a better type of fat, that burns off more excess calories than exercise alone. Irisin was also seen to improve glucose tolerance levels, which is a key measure of metabolic health. The trials were conducted in mice, but researchers are confident the observations will translate to human physiology.
Spiegelman’s team found the Irisin hormone while looking for genes and proteins that are regulated by a master metabolic regulator known as PGC1-alpha. They discovered PGC1-alpha in previous research and is activated by exercise.
Bostroöm said the search for molecular targets of increased PGC1-alpha activity ultimately pinpointed irisin, which turned out to be located within the outer membrane of muscle cells. This discovery ran against the general consensus of scientists’ that thought such a protein would reside in the cell’s nucleus.
To analyze whether increasing Irisin alone could produce similar benefits of exercise, the scientists injected the hormone into sedentary mice that were obese and pre-diabetic. After 10 days of treatment, the mice had better control of blood sugar and insulin levels, effectively preventing the onset of diabetes. They also lost a small amount of weight. Although the weight loss was small, Spiegelman postulates that the hormone should have a larger effect when given for longer periods. Additionally, there were no signs of toxicity or side effects, which was predicted since the researchers limited the increase of Irisin to levels typically caused by exercise.
But don’t cancel your gym membership just yet. Taking supplements of Isirin won’t increase muscle mass, and the buildup of the hormone is only evident after regular and prolonged exercise, but not during short term exercise.
The future for Isirin looks very positive though, because it is a natural substance and the mouse and human forms of the protein are identical. Spiegelman said it should be possible to move an irisin-based drug rapidly into clinical testing, perhaps within two years.
The discovery of Irisin has been licensed by Dana-Farber exclusively to Ember Therapeutics for drug development. Ember is a Boston-based startup co-founded by Spiegelman and scientists at the Joslin Diabetes Center and the Scripps Research Institute in Florida.
With obesity and diabetes becoming a major health problem, and more recently, physical inactivity being implicated as a cancer risk, Irisin based drugs could have a significant impact on treating a variety of diseases, including neurodegenerative problems like Parkinson’s disease.
Other authors, in addition to Spiegelman and Boström, are from Dana-Farber; Harvard Medical School; Brigham and Women’s Hospital; University of California at San Francisco; Universita Politecnica delle Marche, Ancona, Italy; Odense University Hospital, Denmark; and LakePharma, Belmont, Calif.
Written by Rupert Shepherd