Nature
PUBLISHED
Ever ruined a night out by acting out in the throes of hanger? It seems that you may not be alone as researchers at the Salk Institute have uncovered that even worms make questionable decisions when they’re hungry, and the findings reveal molecular underpinnings behind the way our stomach talks to our brain.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.“Animals, whether it’s a humble worm or a complex human, all make choices to feed themselves to survive,” said Sreekanth Chalasani, associate professor in Salk’s Molecular Neurobiology Laboratory and senior author on a paper published in PLOS Genetics, in a statement.
“The sub-cellular movement of molecules could be driving these decisions and is maybe fundamental to all animal species.”
The mini worm Caenorhabditis elegans was employed as a model for the study that hoped to uncover how the gut sends out hunger signals to alter an organisms’ behavior. To do so, they separate the worms from a food source with a wall of worm repellent in the form of copper sulfate. Any worm that dared to cross the toxic obstacle would suffer, so would they risk it for a meal?
The results revealed that yes, they would, with a starvation period of around two-to-three hours being enough to drive C. elegans to make the rash decision to cross the barrier. They then took a closer look at the worms to see what was driving this behavior.
As nematodes, C. elegans are significantly anatomically simpler than human beings, but, as luck would have it, we share many similarities on a molecular level. This makes them a good model organism as researchers can glean applicable insights from their much more study-friendly body plans.
Inspection of the hangry worms’ gut molecules showed activity in two transcription factor proteins: MML-1 and HLH-30. When the researchers deleted them, hungry worms were no longer willing to throw themselves across the toxic copper sulfate line for a meal.
It’s possible that these same proteins may be behind humans’ behavioral response to hunger, and by that we mean you shouting when you need a little snacky snack.
“C. elegans are more sophisticated than we give them credit for,” said co-first author Molly Matty, a postdoctoral fellow in Chalasani’s lab. “Their intestines sense a lack of food and report this to the brain. We believe these transcription factor movements are what guide the animal into making a risk-reward decision, like traversing an unpleasant barrier to get to food.”
The researchers’ next step is to look into the way these transcription factor proteins flip between active and inactive states, and how this informs our understanding of why humans will sometimes risk it all for a sandwich.
