A gut-to-brain pathway that limits protein intake

Area of Science:

• Neuroscience
• Gastroenterology
• Metabolic pathways

Background:

• Dietary intake regulation is crucial for homeostasis.
• Gut-to-brain signaling influences feeding behavior and nutrient selection.
• Recovery from fasting involves complex metabolic and behavioral adaptations.

Purpose of the Study:

• To uncover the signaling mechanism linking gut metabolism to protein intake regulation after fasting.
• To identify the molecular players involved in sensing metabolic byproducts in the gut.
• To elucidate how gut signals influence aversion to specific macronutrients.

Main Methods:

• Investigated gut-to-brain signaling in mouse models during fasting-refeeding cycles.
• Utilized molecular biology techniques to identify ammonia-sensing cells in the intestine.
• Employed electrophysiology and behavioral assays to assess pathway activation and aversion responses.

Main Results:

• Identified ammonia, a byproduct of amino acid metabolism, as a key signal.
• Demonstrated that Trpa1-expressing intestinal epithelial cells detect ammonia.
• Showcased the activation of a neural pathway leading to protein aversion during fasting recovery.

Conclusions:

• A novel gut-to-brain signaling axis regulates protein intake based on metabolic state.
• Ammonia detection by intestinal Trpa1+ cells initiates a learned aversion to protein.
• This mechanism dynamically shapes dietary choices to optimize nutrient recovery.