Longevity & AgingGut Bacteria Signal the Brain to Stop Eating via a Newly Discovered Neural Pathway
Scientists at Duke University have discovered a novel gut–brain sensory pathway called the 'neurobiotic sense.' In the mouse colon, the bacterial protein flagellin activates Toll-like receptor 5 (TLR5) on specialized peptide YY (PYY)-secreting neuropod cells. These cells then release PYY onto vagal neurons, signaling the brain to reduce food intake. Mice lacking TLR5 specifically in these cells ate significantly more and gained more weight than controls. Critically, this effect is independent of immune responses, metabolic changes, or the actual presence of gut microbiota, suggesting a direct, real-time neural sensing mechanism. This represents the first identified molecular circuit through which the host interprets microbial signals to regulate behavior.
