Neuroscientist Richard Huganir had no intention of studying obesity. His team at Johns Hopkins wanted to understand how an enzyme called OGT influenced learning and memory, so they genetically engineered mice whose brains didn’t produce the chemical. But a grad student noticed that the OGT-less mice quickly became unbelievably fat — and, as reported on Thursday in Science, their unexpected findings could provide new drug targets for obesity.

What they found:

The mice that were missing OGT in certain areas of the brain quickly grew to be obese.

“They were hyperactive, so they weren’t couch potatoes. Their metabolism was normal, but they ate twice as much per day,” said Huganir, the lead author of the paper. “Interestingly, they ate the same number of meals, but the meals were bigger.”

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He suggested that OGT could regulate how full the mice felt. His team also pinpointed certain neurons that, when stimulated, immediately stopped mice from eating.

Why it matters:

While there are some anti-obesity drugs out there, they aren’t perfect, and the new research could provide new methods to tackle the disease: An increase in OGT levels, or the stimulation of those satiety-related neurons, could help reduce people’s appetites.

“We might be able to modulate the activity of those cells, and make people stop eating earlier than they would normally,” said Huganir, though he added that more testing is needed to confirm that idea.

The mouse on the left, engineered not to have OGT, was substantially heftier than its littermate, which was injected with a control virus. Olof Lagerlof

 

But keep in mind:

This research was done on mice, and it is unclear how well it will translate to humans. Even just the idea of stimulating those particular neurons in people is hard to imagine at this point: The mice were genetically engineered so that those cells were activated when hit with a blue light.

“Although people have talked about using this technique of optogenetics in humans, that’s sort of a dream right now,” said Huganir.

And some nutrition experts are doubtful about the whole endeavor of finding anti-obesity drugs. “We are drowning in calories and labor-saving technology. Drugs have a very limited role in fixing that,” noted Dr. David Katz, a nutritionist and the director of the Yale Prevention Research Center.

The bottom line:

These researchers may have stumbled across new possible targets for obesity drugs. But it’s hard to predict whether they will actually prove effective in humans.

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