Rodent of the week runner-up: Lost gene blocks obesity

This article was originally on a blog post platform and may be missing photos, graphics or links. See About archive blog posts.

Mice lacking a normal immune system gene can eat virtually anything they want -- even a diet of almost pure lard -- without gaining weight, researchers reported today in the journal Cell. Instead of being converted into fat, the excess calories are simply burned up, raising the animals’ body temperature slightly, endocrinologist Alan Saltiel and his colleagues at the University of Michigan in Ann Arbor found. Researchers do not yet know if the gene works the same way in humans, however.

The gene is I kappa B kinase epsilon, or IKKε. The gene is involved in inflammation, and Saltiel was interested in it because low-level inflammation is linked to obesity and Type 2 diabetes. He speculated that eliminating the gene from mice would break the link between obesity and diabetes. To his surprise, however, he found that the absence of the gene prevented mice from getting obese, even when they were fed a diet containing 45% of its calories as a lard-like fat. The same diet caused normal mice to plump up like balloons.

‘The fact that you can disrupt all the effects of a high-fat diet by deleting this one gene in mice is pretty interesting and surprising,’ Saltiel said. The mice without the gene ‘are not exercising any more than the control mice used in the study. They’re just burning more energy.’

Saltiel is now looking for small molecules that block the activity of the enzyme produced by the gene in hopes that they could make good anti-obesity drugs.

-- Thomas H. Maugh II