Significant discovery into role of fat in metabolism could impact diabetes research

Fat’s role in regulating metabolism could be more significant than previously thought, potentially indicating new treatment options for obesity and type 2 diabetes.
US scientists have identified that fat tissue can communicate with other organs at a distance, sending out small molecules that regulate gene activity.
“This finding will provide not only insights into new pathways of tissue communicatio, but also pathways that can be altered in disease states,” said C. Ronald Kah, co-study author and diabetes researcher and physician at Harvard University.
Scientists have long known that certain hormones made by fat signal the brain to regulate eating, but until this study the mechanism behind how fat tissue affects distant organs and their functions has been unknown.
Lead researcher Thomas Thomou, from the Joslin Diabetes Center, and colleagues set out to investigate a potential messenger of this signal: microRNAs.
MicroRNAs are small snippets of genetic material that help control the expression of genes. But some can flow freely through the bloodstream in tiny packets known as exomes. In previous studies high levels microRNAs in these exomes have been associated with obesity, diabetes, cancer and cardiovascular disease.
The researchers studied a genetically engineered strain of mice in which fat cells lacked a critical microRNA-possessing enzyme. These mice couldn’t produce glucose as effectively as non-engineered mice, and had lower circulating microRNA levels.
After discovering these lower levels, the researchers observed that most of the microRNAs in exomes come from fat tissue. Through additional research, they then confirmed that fat tissue can communicate with the liver and regulate gene expression.
“This is a big deal,” said Thomou. “We’re just beginning to scratch the surface of exosomes and how they regulate processes in the body.”
Thomou’s team will now explore how to engineer exomes to target specific cell types, a discovery which could one day lead to drug delivery and other treatments.
The findings appear online in the journal Nature.