New findings in mice reveal a key role of intestinal trial cells in normalizing behavior after initial microbial colonization

Disorders of intestinal brain interaction (DGBI) influence more than 40% of children and adults and include both gastrointestinal symptoms and changed brain function, including anxiety and depression and the most common psychiatric comorbidities. Although the intestinal microbioma is associated with their beginning and development, the mechanisms that stimulate abnormal brain function are not fully understood in patients with DGBI, so that the design of treatments that aim the causes are impeded. It is generally known that disruption of intestinal microbiota in pregnant mothers or offspring after birth can be prone to dysfunction of the intestine and brain, which leads to the development of anxiety, depression, as well as digestive problems, later in life.

New pre -clinical research McMaster University thought so Intestinal tritical cells can migrate to the brain and influence behavior. The findings shed light on how changes in intestinal bacteria can change brain function and behavior and suggest that a changed host-microbial overview during the initial phase of microbial colonization can have consequences.

To overcome the complexity of microbiota brain communication and great intervarability in bacterial profiles in humans, the authors used gnotobiotic mouse models (ie mice born and increased in sterile circumstances in which a defined microbial community is deliberately introduced) and a reduction the brain functionist approach is intended to examine) influences. They colonized germ -free mice and studied their behavior before and after colonization with a single bacterial tribe of They showed chillA simplified microbial community (changed Schaedler -Flora, consisting of 9 bacterial strains) and complex microbiota from conventional healthy mice.

Germ -free mice behaved differently than conventional mice (ie, born and raised in the presence of normal microbiota), To show more exploratory behavior and be less careful. Nevertheless, the behavior of germ -free mice and brain chemistry within 2 weeks of bacterial colonization. It is interesting that this happened when the mice were colonized with complex or simplified microbiota, or even a single bacterial tribe. Het veranderde gedrag aangedreven door tijdelijke of persistente bacteriële kolonisatie ging gepaard met veranderingen in de hersenen, waaronder expressie van neurotrofine BDNF (van de hersenen afgeleide neurotrofe factor)-het is een marker voor neurale plasticiteit- en neurale activiteit C-fos-IT wordt vaak gebruikt als een marker van neuronale activatie-in de buurt van Emotions en leren.

The researchers discovered that Intestinal cells, activated by the cell membrane located toll -like receptor (TLR) or intracellular nucleotide -binding oligomerization domain (NOD) signaling, are crucial for determining normal behavior after initial bacterial colonization. They also discovered that these specialized immune cells migrate from the intestine, some of which transport bacterial fragments in the brain. Blocking the activation and/or migration of the intestinal trial cells prevented changes in behavior after bacterial colonization. Interestingly, the use of genetically modified bacteria that the Muriene Bowel have only colonized temporarily, the study showed that intestinal bacteria are no longer necessary to maintain the changed behavior once the immune system is activated and behavioral changes occur.

These pre-clinical findings show that the congenital immune system, but not T and B lymphocytes, is associated with activation of neuro-immune networks in the intestine and the brain after bacterial colonization. They can also reveal why there is an increase in psychiatric diseases and disorders of intestinal brain communication, such as IBS, which lay the foundation for new therapeutic goals. The mechanisms of microbiome brain communication with activation and migration of intestinal immune cells to the brain can also occur in adulthood during infectious gastroenteritis, which could explain the development of psychiatric comorbidity in many of these patients.

Reference:

Philip V, Kraimi n, Zhang H, et al. Congenital Immune System Signaling and BenmeDritic cells migration to the brain are based on behavioral changes after microbial colonization in adult mice. Brain behavior Immun. 2025; 127: 238-250. DOI: 10.1016/J.BBI.2025.03.012.