summary: Scientists have discovered “the sensation of neurobial organisms.” This is a newly identified system that helps the gut send real-time signals from microorganisms to the brain to regulate appetite. Specialized cells in the colon, known as nerves, detect bacterial protein flagellin, and signal the brain through the vagus nerve to suppress feeding.
Mice lacking receptors for this signal continued to increase appetite, gain weight, and emphasized the role of pathways in appetite control. This breakthrough suggests that microbes in our gut can directly influence behavior and open up the means to study diet, obesity and mood disorders.
Important facts:
- The nerve feet sense microorganisms in the intestine, inform the brain and regulate appetite.
- Bacterial protein flagella causes this real-time intestinal communication.
- Disruption of the pathway alters feeding behavior and weight gain in mice.
sauce: Duke University
In a breakthrough rethinking how the gut and brain communicate, researchers uncover what is called “neurobiosensory,” a newly identified system that allows the brain to respond in real time to signals from microorganisms that live in our gut.
The new research led by Dr. Diego Bojorquez, a neuroscientist at Duke University School of Medicine, and Dr. M. Maya Kaerberler, is Naturethe center of the nerve feet, the center of small sensor cells lined up in the colonic epithelium. These cells detect common microbial proteins and send a rapid message to the brain that helps to suppress appetite.
But this is just the beginning. The team believes this neurobial sensation could be a broader platform for understanding how the gut detects microorganisms. This affects everything from eating habits to mood, and even how the brain shapes the microbiota.
“We were interested in whether the body could sense microbial patterns in real time, not just as an immune or inflammatory response, but as a neural response that guides behavior in real time,” said Bojorquez, professor of medicine and neurobiology at Duke University School of Medicine and a senior author of the study.
An important player is flagellin, an ancient protein found in bacterial flagella. It is a tail-like structure used by bacteria to swim. When we eat, some intestinal bacteria release flagella. With the help of a receptor called TLR5, the nerve pod detects it and fires a message through the Vagus nerve, the main line of communication between the gut and the brain.
The team, supported by the National Institutes of Health, proposed bold ideas. This means that bacterial flagella in the colon can trigger nerve feet to send appetite signals to the brain.
The researchers tested this by fasting mice overnight, then gave them flagella directly to the colon. Those mice didn’t eat much.
When researchers tried the same experiment in mice lacking the TLR5 receptor, nothing changed. The mice continued to eat and gained weight. This is a clue that pathways can help regulate appetite.
Findings suggest that flagellin sends a “sufficient enough” signal through TLR5, telling the brain it’s time for the gut to stop eating. Without that receptor, the message cannot pass through.
This discovery was led by both graduate students in the Medical Scientist Training Program and fellow postdoc Dr. Namalacher, PhD, Winston Liu, Maryland, Winston Liu, Maryland.
Their experiments revealed that disrupting pathways altered the eating habits of mice, indicating a deeper connection between intestinal microorganisms and behavior.
“I think this work will be especially useful in explaining how our behavior is influenced by microorganisms in the future for the broader scientific community,” Bojorquez said.
“One of the next clear steps is to investigate how a particular diet changes the microbial landscape in the gut. This can be an important part of the puzzle of conditions such as obesity and mental disorders.”
About this neuroscience and microbiome research news
author: Fedor Kossakovski
sauce: Duke University
contact: Fedor Kossakovski – Duke University
image: This image is credited to Neuroscience News
Original research: Open access.
“Intestinal sensations of microbial patterns regulate feeding“Diego Bojörquez et al. Nature
Abstract
Intestinal sensations of microbial patterns regulate feeding
To coexist with the resident microorganisms, the host must have a sense of adjusting their behavior accordingly. In the intestine, the sense of nutrients introduced into the brain through neuroepithelial circuits leads to appetite choices.
However, the sensations that allow the host to respond in real time to stimuli arising from the intestinal microorganisms of the resident, have not been revealed.
Here we show that in the mouse colon, ubiquitous microbial pattern flagellin (a integrative feature of the whole phylum) stimulates the Toll-like receptor 5 (TLR5) of peptide YY (PYY)-labeled colon-binding neuromuscular cells.
This stimulus results in PYY release in NPY2R vagus nodose neurons to regulate feeding. Mice lacking TLR5 in these cells eat more and gain weight than controls. It was found that flagellin does not act directly on nerves.
Instead, flagellin stimulates nerve cells from the colonic cavity, reducing feeding through sensory neural circuits in the gut and brain. Additionally, flagellin reduces feeding independently of immune response, altered metabolism, or the presence of gut microbiota.
This sensation allows the host to adjust their behavior according to the molecular patterns from the resident microorganisms.
We call this sensation the neurobial sensation at the interface between the body and the brain.
