US researchers have uncovered what they call a “neurobiotic sense,” a newly identified system that lets the brain respond in real time to signals from microbes living in our gut.

The research, led by Duke University School of Medicine, centres on tiny sensor cells lining the colon’s epithelium. These neuropods detect a common microbial protein and send rapid messages to the brain that help to curb appetite.

The researchers believe this neurobiotic sense may be a broader platform for understanding how gut detects microbes, influencing everything from eating habits to mood  and even how the brain might shape the microbiome in return. 

“We were curious whether the body could sense microbial patterns in real time and not just as an immune or inflammatory response, but as a neural response that guides behaviour in real time,” said Dr Diego Bohórquez, a professor of medicine and neurobiology at Duke University and senior author of the study.  

The key player is flagellin, an ancient protein found in bacterial flagella, a tail-like structure that bacteria use to swim. When we eat, some gut bacteria release flagellin. Neuropods detect it, with help from a receptor called TLR5, and fire off a message through the vagus nerve, a major communication line of communication between the gut and the brain.  

“Looking ahead, I think this work will be especially helpful for the broader scientific community to explain how our behaviour is influenced by microbes. One clear next step is to investigate how specific diets change the microbial landscape in the gut. That could be a key piece of the puzzle in conditions like obesity or psychiatric disorders,” said Dr Bohórquez