MicroRNAs balance good fat and muscle differentiation

Small noncoding RNAs of the microRNA family promote the formation of brown fat tissue reports a paper in Nature Cell Biology this week. As brown fat burns lipids to produce heat and may also prevent obesity in mammals, these findings could be used to develop therapeutic strategies against obesity and related disorders.

Brown fat cells, known as adipocytes, are thought to arise from the differentiation of progenitors that can become part of either muscle or fat. Harvey Lodish and colleagues find that the expression of microRNAs miR-193b and miR-365 is upregulated during the development of brown fat. They show that blocking the function of these microRNAs impairs brown fat development while inducing the expression of muscle-associated markers. Conversely, inducing high expression of the microRNA blocked the muscle differentiation programme in cells and enhanced the formation of brown adipocytes.

The microRNAs will need to be further characterized in animal models to identify therapeutic targets against obesity.