Protein interfering with brown fat causes obesity

Protein interfering with brown fat causes obesity

High levels of a protein known as ld1 may boost obesity, according to a new research.

Many people become alarmed when they hear the word ‘fat.’ But, scientists say not all fat is bad news. There are certain types of fat known as brown fat and beige fat that perform crucial metabolic functions, making energy and helping the body to adjust to cold temperatures.

The new study was conducted by researchers from Georgia Cancer Center and Medical College of Georgia at Augusta University in the U.S. Dr. Satya Ande, a molecular biologist at Georgia Cancer Center is the corresponding author of the study.  Dr. Ande and colleagues found that high levels of a certain type of protein called ld1 increases obesity by diminishing the energy-producing activity of brown and beige fat.

The researchers believe targeting the ld1 protein may help reverse obesity by boosting brown fat levels and lowering white fat, which is normally found on the belly.

Energy in our body are stored as fat. The fat, or adipose, tissue – which helps control the body’s metabolism – is commonly separated into two main types: white and brown. Also, a third type of fat known as “beige fat” can be develop from white fat.

White and brown fat perform different functions. White fat mainly stores energy in the form of triglycerides, a type of fat found in the bloodstream. High levels of triglycerides may trigger conditions such as heart disease and diabetes.

On the other hand, specialty of brown fat is to expand that energy by creating heat during exposure to cold temperatures, in a process known as thermogenesis.

There 2 types of fats also have structural differences.

Brown and beige fat have more mitochondria – known as the “powerhouses” of the cell because they turn food into energy. These types of fat are considered healthier than white fat. Past studies have shown that brown and beige fat decrease obesity and metabolic disease in mice. At the same time, human studies have found a link between leanness and these types of fats.

White fat, on the other hand, possess fewer mitochondria and blood vessels.

In previous research, the protein Id1 was found to be linked with prostate cancer.

Read more Low-calorie sweeteners promote fat formation, study indicates

For the study, Ande and colleagues used genetically modified mice that produce excessive levels of Id1 in their fat cells.

The mice were then fed high-fat diet, as well as a regular diet.

A control group comprising of normal mice were fed the same diets.

The researchers found that the mice that produced excessive levels of ld1 gained significantly more weight than the control mice. While on a regular diet, they also gained more weight than their normal counterparts.

The study showed that high levels of ld1 suppresses the fat-burning activity of brown fat by binding to it.

High amounts of ld1 also impedes the activity of the key transcription factor, PGC1 alpha. PGC1 alpha controls thermogenesis by regulating the unique protein Ucp1, which, in turn, enables brown fat cells burn energy for heat more efficiently.

In addition, Ande and colleagues found that another transcription factor, Ebf2, is also inhibited by ld1. This transcription factor helps white fat turn into beige. The researchers showed that eliminating Id1 boosts the expression of the beige gene and Ucp1 in the response of white fat to cold exposure.

Moreover, removing the Id1 protein did not seem to suggest that it is needed for normal functioning – at least not in mice. [Read more Avoid obesity: Have home-cooked meals, turn off the TV while eating]

The researchers say their findings suggest that the Id1 protein is a risk factor for obesity and diabetes, and these two conditions could be reversed by targeting this protein.

“If we can target Id1, we may able to prevent […] and ultimately reduce the risk of obesity and related disease,” says Dr. Ande.

For most of us, as we age, the body finds it increasingly difficult to produce brown fat. This explains why we tend to gain weight more easily when we get older. Targeting Id1 at a molecular level, however, may help to increase brown fat, Dr. Ande adds.

The study was published in the journal Diabetes.

18/04/2017 / by / in

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