Transgenic mice show us our future.

In recent years, obesity has taken on epidemic proportions in developed nations, contributing significantly to major medical problems, early death and rising health care costs. According to Centers for Disease Control and Prevention estimates, at least a quarter of all American adults and more than 15 percent of children and adolescents are obese.

While recent research advances and treatment methods have had little effect in reducing obesity levels, researchers at the UCLA Henry Samueli School of Engineering and Applied Science, in collaboration with the David Geffen School of Medicine at UCLA, may have discovered a completely new way to approach the problem.

In a study to be published in the June 3 issue of the journal Cell Metabolism, chemical and biomolecular engineering professor James Liao, associate professor of human genetics and pediatrics Katrina Dipple and their research team demonstrate how they successfully constructed a non-native pathway in mice that increased fatty acid metabolism and resulted in resistance to diet-induced obesity.

Humans are going to need to re-engineer our metabolisms to better fit into our niches in industrialized societies with plentiful food. Mice are leading the way into our transgenic future.

The researchers transferred genes from bacteria into the mice to alter their fatty acid metabolism.

To investigate the effects of the glyoxylate shunt on fatty acid metabolism in mammals, Liao's team cloned bacteria genes from Escherichia coli that would enable the shunt, then introduced the cloned E. coli genes into the mitochondria of liver cells in mice; mitochondria are where fatty acids are burned in cells.

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.

We might adjust to our altered environments by altering our taste buds to derive more enjoyment from vegetables or perhaps by tweaking our brains to lower our appetites. But the ability to turn up our metabolisms to burn off excess fat would certainly be handy.