Found a way to turn white fat into brown
The possibility of converting white fat cells into cells of the so-called brown fat, which is a source of "fast energy" in the body of newborns and is practically not contained in the adult body, has long worried the minds of many researchers. Scientists at the University of Bonn, working under the guidance of Professor Alexander Pfeifer, believe that they have managed to get one step closer to solving this problem.
Together with colleagues from the Federal Institute of Medicines and Medical Equipment, as well as the University of Regensburg, they conducted experiments on transgenic mice that did not have a functional copy of the gene encoding microRNA-155, or were characterized by its increased expression.
The functions of microRNAs in a cell are to regulate gene expression very quickly and efficiently. The microRNA-155 studied by the authors suppresses the synthesis of a certain transcription factor – a protein that controls the functioning of brown fat cells. Unexpectedly for scientists, it turned out that the transcription factor itself also regulates the level of microRNA-155, turning this pair of molecules into a feedback loop. The high expression of microRNA-155 blocks the differentiation of brown fat cells and, on the contrary, an increase in the expression of the transcription factor stimulates the production of brown fat, which, in turn, triggers the active burning of fat deposits in the body.
According to the authors, this mechanism was triggered when the expression of microRNA-155 in mouse cells decreased by 50%. The body of such animals contained much more brown fat cells than in the body of animals of the control group, while part of their white fat cells turned into brown fat cells.
The researchers believe that their results can be used as a basis for the development of new drugs for the treatment of obesity. This is supported by some data obtained by other groups. For example, scientists from Leipzig found elevated levels of microRNA-155 in the cells of patients with severe forms of obesity. These observations do not contradict the data obtained when working with animal models, according to which high levels of microRNA-155 are associated with low activity of fat splitting processes. However, according to Professor Pfeifer, today the work is at a very early stage and it is too early to talk about the practical application of his results.
The article by Yong Chen et al. miR-155 regulates the differentiation of brown and beige adipocytes via a bistable circuit is published in the journal Nature Communications.
Evgeniya Ryabtseva
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