The integrity of the intestinal epithelial and blood-brain barriers is critical for maintaining homeostasis along the gut-brain axis as these interfaces regulate the passage of inflammatory mediators into systemic circulation and their access to the brain. Disruption of these barriers can lead to neuroinflammatory processes implicated in mood disturbances. Lacticaseibacillus rhamnosus HN001 has been associated with improved mood outcomes in clinical and preclinical studies, however the mechanist