Approximately 68 percent of U.S. adults are overweight or obese, according to the National Cancer Institute, which puts them at greater risk for developing cancer, cardiovascular disease, diabetes and a host of other chronic illnesses. But an international team of scientists led by Virginia Commonwealth University Massey Cancer Center researcher Andrew Larner, M.D., Ph.D., has successfully reversed obesity in mice by manipulating the production of an enzyme known as tyrosine-protein kinase-2 (Tyk2). In their experiments, the scientists discovered that Tyk2 helps regulate obesity in mice and humans through the differentiation of a type of fat tissue known as brown adipose tissue (BAT).
Published today in the online edition of the journal Cell Metabolism, the study is the first to provide evidence of the relationship between Tyk2 and BAT. Previous studies by Larner and his team discovered that Tyk2 helps suppress the growth and metastasis of breast cancer, and now the current study suggests this same enzyme could help protect against and even reverse obesity.
The scientists were able to reverse obesity in mice that do not express Tyk2 by expressing a protein known as signal transducer and activator of transcription-3 (Stat3). Stat3 mediates the expression of a variety of genes that regulate a host of cellular processes. The researchers found that Stat3 formed a complex with a protein known as PR domain containing 16 (PRDM16) to restore the development of BAT and decrease obesity.
"We discovered that Tyk2 levels in mice are regulated by diet. We then tested tissue samples from humans and found that levels of Tyk2 were more than 50 percent lower in obese humans," said Larner, Martha Anne Hatcher Distinguished Professor in Oncology and co-leader of the Cancer Cell Signaling program at VCU Massey Cancer Center. "Our findings open new potential avenues for research and development of new pharmacological and nutritional treatments for obesity."
There are two different types of fat – white adipose tissue (WAT) and BAT. WAT is the primary site of energy storage. BAT is responsible for energy expenditure in order to maintain body temperature. BAT deposits are present in all mammals, but until recently, scientists thought BAT was only active in infants and not in adult humans. Only in the last four years have scientists realized that BAT is present in adults and helps to regulate energy expenditure. Additionally, research has shown that diminished BAT activity is associated with metabolic syndrome, a combination of medical disorders that increase the risk of developing cardiovascular disease and diabetes. Researchers estimate metabolic syndrome could affect as much as 25 percent of the U.S. population.
"We have made some very interesting observations in this study, but there are many questions left unanswered," said Larner. "We plan to further investigate the actions of Tyk2 and Stat3 in order to better understand the mechanisms involved in the development of brown adipose tissue. We're hopeful this research will help lead to new targets to treat a variety of obesity-related diseases such as cancer, cardiovascular disease and diabetes."
Virginia Commonwealth University: http://www.vcu.edu
This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.
In the 1950s a group of pioneering psychiatrists showed that hallucinogenic drugs had therapeutic potential, but the research was halted as part of the backlash against the hippy counterculture.
Five years ago cognitive scientist Rafael Núñez found himself in the Upper Yupno Valley, a remote, mountainous region of Papua New Guinea. The area is home to some 8,000 indigenous people, and Núñez and his graduate student, Kensy Cooperrider, were studying their conceptions of time.
With the Ebola outbreak in West Africa doubling by the month, the World Health Organization is pushing more extreme measures to contain the virus
For the first time, researchers have tracked the spread of Ebola, almost in real time, during an outbreak. The virus is quickly changing its DNA. But it's still unclear what these mutations mean.
Think of all the adults you know. Think of your parents and grandparents. Think of the teachers you had at school, your doctors and dentists, the people who collect your rubbish, and the actors you see on TV. All of these people probably have little mites crawling, eating, sleeping, and having sex on their faces.
A trial vaccine against Ebola could be tested on healthy volunteers in the UK in September, says an international health consortium.
The ALS Association has raised more than $94 million in recent weeks via its online ice bucket challenge — compared with $2.7 million this time last year. Now what?
Implant attached to bone in pioneering technique that helps prevent infection and discomfort
A new method for removing allergens from peanuts means help could soon be on the way for the roughly 2.8 million Americans with a potentially life-threatening allergy to the popular food, the U.S. Department of Agriculture said on Tuesday.
Survey finds many social media users hesitate to express opinions unless they know their followers will agree with them