Source: “A PGC1-α dependent myokine that drives brown-fat-like development of white fat and thermogenesis”
Bruce Spiegelman et al.
Nature 481: 463–468
Results: Researchers discovered a hormone that is produced when both mice and humans exercise. Increasing the levels of the hormone in mice resulted in some of the same benefits as exercise. It caused white fat, which stores energy, to turn into brown fat, which burns stored energy to generate heat. Mice that were given the hormone lost weight and showed a decrease in diet-induced insulin resistance, which is connected to diabetes.
Why it matters: The hormone may prove useful for treating diabetes and obesity. The discovery also sheds light on how exercise changes the way the body responds to sugar and utilizes fat.
Methods: Earlier research had shown that the protein PGC1-α is involved in regulating the expression of other proteins and is connected with exercise. The researchers identified five proteins controlled by PGC1-α. They discovered that one of these, FNDC5, is connected to the browning of fat cells and that FNDC5, in turn, is modified in cells and secreted as a hormone, which the researchers named irisin. They put mice and humans on a multiweek exercise regimen, after which they measured increased levels of irisin in both. They fed mice a diet high in fat to make them obese and insulin resistant. Then they introduced a gene into these mice that increased their production of the hormone. They measured the physical changes that resulted.
Next Steps: Ember Therapeutics, a company that the researchers founded before undertaking the study, is looking for ways to deliver the hormone therapeutically.
Changing proteins expressed in muscle allows mice to run farther
Source: “NCoR1 Is a Conserved Physiological Modulator of Muscle Mass Function and Oxidative Function”
Johan Auwerx et al.
Cell 147: 827–839
Results: By modifying proteins in muscle tissue, researchers increased muscle mass in mice and triggered other changes that improved the muscles’ ability to use oxygen. This allowed the mice to run longer: 80 minutes before they were exhausted, versus 60 minutes for control mice.
Why it matters: The finding could lead to treatments for muscular dystrophy and age-related muscle loss.
Methods: Researchers genetically engineered mice lacking in a protein, NCoR1, that works as something like a dimmer switch for other molecules in a cell, slowing the production of transcription factors that regulate the expression of genes. The protein seems to have different effects in different tissues. The researchers used a method that blocked the production of the protein only in muscle tissue and then measured changes in that tissue and in the animals’ behavior.
Next Steps: The researchers are searching for drugs that can selectively modulate the levels of NCoR1.
Meet Altos Labs, Silicon Valley’s latest wild bet on living forever
Funders of a deep-pocketed new "rejuvenation" startup are said to include Jeff Bezos and Yuri Milner.
Meta’s new learning algorithm can teach AI to multi-task
The single technique for teaching neural networks multiple skills is a step towards general-purpose AI.
All charges against China Initiative defendant Gang Chen have been dismissed
MIT professor Gang Chen was one of the most prominent scientists charged under the China Initiative, a Justice Department effort meant to counter economic espionage and national security threats.
A horrifying new AI app swaps women into porn videos with a click
Deepfake researchers have long feared the day this would arrive.
Get the latest updates from
MIT Technology Review
Discover special offers, top stories, upcoming events, and more.