The researchers found that the glyoxylate shunt cut the energy-generating pathway of the cell in half, allowing the cell to digest the fatty acid much faster than normal. They also found that by cutting through this pathway, they created an additional pathway for converting fatty acid into carbon dioxide. This new cycle allowed the cell to digest fatty acid more effectively.
"The significance of this is great. It is a unique approach to understanding metabolism. Perturbing metabolic pathways, such as introducing the glyoxylate shunt and seeing how it affects overall metabolism, is a novel way to understand the control of metabolism," Dipple said.
The team also found that the new pathway decreased the regulatory signal malonyl-CoA. When malonyl-CoA levels are high, a signal is released that tells the body it is too full and that it needs to stop using fat and begin making it. Malonyl-CoA is high after eating a meal, blocking fatty acid metabolism. The new pathway, however, allowed for fat degradation even when the body was full.
Ultimately, the research team found that mice with the glyoxylate shunt that were fed the same high-fat diet 60 percent of calories from fat for six weeks remained skinny, compared with mice without the shunt.
"One exciting aspect of this study is that it provides a proof-of-principle for how engineering a specific metabolic pathway in the liver can affect the whole body adiposity and response to a high-fat diet," said Karen Reue, a UCLA professor of human genetics and an author of the study. "This could have relevance in understanding, and potentially treating, human obesity and as
|Contact: Wileen Wong Kromhout|
University of California - Los Angeles