Berlin: Scientists have discovered a new signalling molecule capable of activating brown fat cells, paving the way for new therapies to help people lose weight.
An international team of researchers led by Professor Alexander Pfeifer from the Institute of Pharmacology and Toxicology of the University Hospital Bonn, have discovered a new way to stimulate brown fat and thus burn energy from food.
Humans have two different types of fat: undesirable white fat cells which form bothersome "love handles", for example, as well as brown fat cells, which act like a desirable heater to convert excess energy into heat.
"If we are able to activate brown fat cells or to convert white fat cells into brown ones, it might be possible to simply melt excess fat away," Pfeifer said.
Pfeifer's team together with an international team from Sweden, Denmark, Finland, as well as from the Helmholtz-Center Dresden-Rossendorf and the University of Dusseldorf have discovered a new signalling molecule capable of activating brown fat cells: adenosine.
Adenosine is typically released during stress. Crucial for transmitting the adenosine signal is the adenosine receptor A2A.
"If adenosine binds to this receptor in brown fat cells, fat burning is significantly stimulated," said Dr Thorsten Gnad from Pfeifer's team.
It was previously thought not possible for adenosine to activate brown fat. Several studies with rats and hamsters demonstrated that adenosine blocks brown fat.
The new study used brown fat cells removed from humans during surgery and investigated the signalling pathway for fat activation using adenosine.
The results showed that rats and hamsters react differently than humans in this regard.
"The brown fat in mice on the other hand behaves just as in humans," said Pfeifer.
In addition, the research team investigated the possibility that adenosine transforms white fat cells into brown fat cells - a process termed "browning".
White fat cells normally cannot be induced to burn excess fat by adenosine, as they simply lack the A2A receptor.
For this reason, the team of scientists transferred the A2A receptor gene from brown fat cells to white fat cells in mice. Consequently, the white fat cells also had A2A receptors and started browning and burning energy.
The study is published in the journal Nature.