Fat cells were reduced after the 'obesity' gene was silenced (left vs. right).
Image credit: Gareth Lim, UBC
Obesity remains a global health issue, particularly in the US. Earlier this year, Medical News Today reported how the rate of obesity in the country has grown, and it is now estimated more than two thirds of Americans are either overweight or obese.
According to the Centers for Disease Control and Prevention (CDC), the estimated annual medical cost to deal with obesity is between $147-210 billion a year.The possible causes of obesity are vast, and there is still much debate regarding the nature versus nurture influences of the condition.
Results from the largest ever genome-wide study on obesity were published this year, strengthening the genetic link to the condition.
A consortium of scientists discovered that over 100 regions of the human genome had an influence on the development of obesity, such as the regulation of the feeling of hunger and the distribution of fat in the body.
Researchers at the University of British Columbia (UBC) in Canada began investigating the 14-3-3 family of proteins because it is a common component in the unhealthy fat tissue of obese patients.
One particular gene encodes a protein called 14-3-3zeta, which is found in every cell of the body. Scientists discovered that when this gene was silenced in mice, it resulted in a dramatic reduction in white fat.
White fat, or white adipose tissue, is traditionally linked to the development of obesity, heart disease and diabetes because it stores up calories, in contrast to brown fat that burns calories to generate heat.
Study author Gareth Lim, a postdoctoral fellow at UBC's Life Sciences Institute, explains the importance of the 14-3-3zeta protein:
"People gain fat in two ways: through the multiplication of their fat cells and through the expansion of individual fat cells. This protein affects both the number of cells and how big they are, by playing a role in the growth cycle of these cells."
50% reduction of white fat in mice with silenced gene
The amount of white fat in mice with the silenced gene was reduced by 50%, despite the fact these mice were eating the same amount of food.Furthermore, mice that were bred to have higher levels of the 14-3-3zeta protein were found to be noticeably bigger, rounder and averaged 22% more white fat when fed a high-calorie diet.
The research was published in Nature Communications and brings an end to a 4-year study. By discovering the link between a protein and fat production, new drug therapies could be explored as a possible treatment for obesity.
Scientists theorize that by suppressing the gene or blocking the protein, akin to the mice in the study, excess fat accumulation in people who are at risk of obesity can be prevented.
Study author Prof. James Johnson believes the study to be an important step to tackling obesity:
"Until now, we did not know how this gene affected obesity. This study shows how fundamental research can address major health problems and open up new avenues for drug discovery."
Although drug therapy is currently available for obesity, effectiveness for the medication does vary as comprehensive weight management and regular exercise are still vital.
Meanwhile, MNT recently reported how a new genetic form of obesity has been discovered - a new twist to the current obesity crisis, which the World Health Organization (WHO) describe as "one of today's most blatantly visible - yet most neglected - public health problems."