Fat is more related to muscle than we realize, according to research published in Nature. In two related studies, scientists identify the factors that regulate fat formation. The research could help to develop new therapies to tackle obesity.
Although we all wish we had a little less of it, fat is essential for managing our energy balance and helping to regulate body temperature. There are two distinct types of fat tissue, with very different functions: white 'bad' fat acts as an energy store whereas brown 'good' fat helps in burning calories to generate body heat.
Yu-Hua Tseng and colleagues looked at the factors regulating fat tissue development and identified one factor - bone morphogenetic protein 7 (BMP7) - that uniquely promotes brown fat development. They showed that without BMP7 the stocks of brown fat in mouse embryos run low. When excess BMP7 was artificially introduced into mice, they observed a marked increase in brown fat whereas white fat remained normal.
Bruce Spiegelman and colleagues show that the two types of fat develop from distinct cell types in the early embryo. Following the fate of these cells, they observed brown fat to share a developmental pathway with muscle. PRDM16 is identified as the factor that regulates the switch between muscle and fat; in its absence, cells become muscle, but an excess pushes them to become brown, but not white, fat.
In a related News and Views article, Barbara Cannon comments that the research could "take us a step closer to the ultimate goal of promoting the brown fat lineage as a potential way of counteracting obesity".
Yu-Hua Tseng (Joslin Diabetes Center, Harvard Medical School, Boston, MA, USA) Author paper 
Bruce Spiegelman (Dana-Farber Cancer Institute, Boston, MA, USA) Author paper 
Barbara Cannon (The Wenner-Gren Institute, Stockholm University, Sweden) N&V author
(C) Nature press release.
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