Joslin study identifies protein that produces ‘good’ fat; finding may lead to ways to treat, prevent obesity

A study by researchers at the Joslin Diabetes Center has shown that a protein known for its role in inducing bone growth can also help promote the development of brown fat, a “good” fat that helps in the expenditure of energy and plays a role in fighting obesity.

“Obesity is occurring at epidemic rates in the U.S. and worldwide and that impacts the risk and prognosis of many diseases,” said Yu-Hua Tseng, Ph.D. an Assistant Investigator in the Joslin Section on Obesity and Hormone Action and lead author of the paper published in the August 21 issue of Nature. “We hope this study can be translated into applications to help treat or prevent obesity.”

Tseng noted that obesity is a major risk factor for type 2 diabetes and is closely linked to the metabolic syndrome, a collection of medical problems associated with insulin resistance that can lead to an increased risk of atherosclerosis, the buildup of plaque in coronary arteries that leads to heart attack and stroke.

In laboratory studies of mouse cells, Tseng and her colleagues identified that a bone-inducing protein called BMP-7 drives precursor cells that give rise to mature brown fat cells. According to Tseng, there are two main types of fat cells in the body – white and brown.

“White fat cells are the ‘conventional’ form of fat designed to store energy. By contrast, the main role of brown fat is to burn calories by generating heat. Brown fat cells largely disappear by adulthood in humans, but their precursors still remain in the body,” Tseng explained.

A 2005 Joslin study by Dr. Tseng and colleagues discovered genes that control the creation of the precursor cells of brown fat. Another more recent 2007 Joslin study led by C. Ronald Kahn, M.D., head of the Joslin Section on Obesity and Hormone Action and also a co-author of the current Nature study, found clusters of brown fat cells dispersed between bundles of muscle fibers in an obesity-resistant strain of mice.

Now, this latest study identified BMP-7 as the protein capable of inducing the formation and function of brown fat cells. According to the paper, delivery of BMP-7 into mice