Glowing tags allow real-time visualization of fat metabolism in zebrafish

The Carnegie Institute team used fluorescent tags to track what lipids were assembled from broken-down fats in zebrafish. (Bob Jenkins CC BY 2.0)

Looking at how the body processes fats can help us understand a range of diseases, but doing so has proved challenging. A team from the Carnegie Institution for Science has visualized, for the first time, how fats are metabolized in zebrafish.

The team used fluorescent tagging to mark a variety of lipids before feeding them to zebrafish, according to a statement. Viewed under a microscope, the glowing tags allowed the researchers watch these lipids get broken down and then reassembled into different molecules in the fish’s organs.

Unlike proteins, which are reassembled from amino acids and encoded by DNA sequences, lipids can be made from any number of combinations of components. Many factors play a role in how a lipid is synthesized, including a person’s diet and the type of cell in which the lipid is being assembled.

"Understanding the balancing act in what makes up our bodies' lipids—between availability based on what we're eating and genetic guidance—is very important to cell biologists," said Steven Farber, who works on lipid metabolism and signaling at the Carnegie Institution. "There is growing evidence that these differences can affect wide arrays of cellular processes."

The research, published in the Journal of Lipid Research, allowed Farber and his team to investigate relationships between specific fats and human health. The team hopes that fluorescent tagging will lead to “further breakthroughs” in lipid biochemistry.

"Lipids play a vital role in cellular function, because they form the membranes that surround each cell and many of the structures inside of it," said Vanessa Quinlivan, a graduate student in Farber’s lab. "They are also part of the crucial makeup of hormones such as estrogen and testosterone, which transmit messages between cells."

Zebrafish, a member of the minnow family, are commonly used for scientific research. Their bodies are transparent, they reproduce easily and, according to Derek Stemple, of the Sanger Institute Wellcome Trust, 84% of the genes that cause human disease have analogues in zebrafish.

For example, a University of Queensland team studying lymphatic cells—which absorbs waste products leaking from cells so they don’t damage organs—found lymphlike cells in zebrafish brains, an area where this type of cell is not usually present. And last year, researchers at the University of Oregon found a protein in the zebrafish gut that can improve insulin production, while a Boston Children’s Hospital team visualized the spread of melanoma in zebrafish from a single cell.