January 6, 2013
Protein’s Role In Fat Metabolism Could Lead To New Obesity Treatments
redOrbit Staff & Wire Reports - Your Universe Online
While experts have long touted proper diet and exercise as ways to stay slim and trim, an international team of researchers have discovered a biological trigger that could pave the way for new way to help overweight individuals overcome their obesity.
"In many cases, obesity is caused by more than just overeating and a lack of exercise. Something in the body goes haywire, causing it to store more fat and burn less energy," researchers from the Sanford-Burnham Medical Research Institute explained in a recent statement.
They believe the culprit is a protein called ps62. When ps62 is missing in fat tissue, the metabolic balance of a person's system changes, causing the body to block the so-called "good" brown adipose tissue (BAT) while favoring "bad" white adipose tissue (WAT), the researchers said.
“Without p62 you´re making lots of fat but not burning energy, and the body thinks it needs to store energy,” said Dr. Jorge Moscat, a professor at the Institute. Moscat, along with colleagues from the German Research Center for Environmental Health and the University of Cincinnati, who had previously tested their theory by producing mice that lacked the protein.
Those that did not have ps62 anywhere in their bodies were obese, diabetic, expended less energy, and had metabolic syndrome, they discovered. Their findings, which were published last month the Journal of Clinical Investigation (JCI), demonstrate the absence of the protein can lead to obesity, though since the rats lacked it throughout their bodies, the specific system responsible for those results remains unclear.
"Some researchers believe that muscle tissue, where energy is expended, controls obesity. Others suspect the liver is a key player, or that the brain´s appetite control center is most responsible for obesity," the Institute said. "But then there´s fat itself -- both white fat and brown fat. White fat is the type we think of as unwanted body fat. Brown fat, on the other hand, is beneficial because it burns calories."
"Many researchers now believe that brown fat somehow malfunctions in obesity, but the details are unclear," they added. "In their latest study, Moscat and colleagues set out to pinpoint the specific tissue responsible for obesity when p62 is missing. They made several different mouse models, each missing p62 in just one specific organ system, such as the central nervous system, the liver, or muscle. In every case, the mice were normal. They weren´t obese like the mice lacking p62 everywhere."
Moscat and his team then created a mouse model that only lacked p62 in their fat tissue, and like those lacking the protein throughout their entire body, these rodents became obese. Further research revealed that p62 blocks one enzyme (ERK, which is more active in white fat) while triggering a second (p38, which is less active in brown fat). As a result, they believe p62 governs the normal fat metabolic process.
"According to Moscat, the discovery of p62´s role in brown fat tissue is encouraging, because fat tissue is much more accessible than other parts of the body“¦ for potential drug therapies," the research center noted. "New methods for preventing or treating obesity, a major epidemic in the United States, are urgently needed. Drug therapies designed to minimize the intake of food have had limited success and also produce considerable side effects."