Overview: Certain groups of fungi in the intestine can protect against intestinal damage and affect social behavior.
Source: Weil Cornell Medicine
According to a new preclinical study by Weill Cornell Medicine scientists, certain fungal swarms present in the intestine may protect against intestinal damage and affect social behavior.
The findings identify the “cerebral intestinal immune brain axis,” a signaling system that is influenced not only by the body’s own cells but also by its inhabitants and can have wide-ranging effects on physiology in both health and illness. We are expanding a series of studies. Microorganisms.
Study published on February 16 cellReveals a new set of molecular signals that connect fungi in the intestine to host cells throughout the body, including immune cells and neurons.
“We have directly linked the major immune pathways induced by fungi on the inner wall of the intestine to the signals of the nervous system that affect animal behavior,” said an associate professor of immunology in the department. Said senior author Dr. Ilyan Iliev. He is a member of the Department of Gastroenterology and Liver Medicine and a member of the Jill Roberts Institute for Inflammatory Bowel Disease in Weil Cornell Medicine.
Dr. Weill Cornell Medicine’s Dilek Colak, Melanie Johncilla, Megan Allen, Weill Cornell Medicine and New York-Presbyterian’s Dr. Rhonda K. Yantiss also contributed to this study.
The inner wall of the intestine needs to absorb water and nutrients from food and balance conflicting needs, while acting as a barrier to prevent the invasion of large numbers of microorganisms in the intestine into the bloodstream.
Examining this system in a mouse model, scientists have mapped the location of various fungi in the intestine and found that a unique consortium of fungi tends to accumulate in specific areas near the intestinal epithelium or inner layer. did. It interacts closely with nearby epithelial cells.
Mice carrying some of these fungi enjoyed better protection against events that could disrupt the intestinal barrier, such as intestinal damage and bacterial infections. “When we added certain fungal communities to mice, these barrier functions were enhanced,” said Dr. Iriev.
Improving the integrity of the intestinal barrier was not the only effect of the fungus. In another experiment, the team found that mice with fungal communities in the gut exhibited more social behavior than animals without these fungi.
Both effects appear to be derived from the animal’s own T cells, a type of immune cell. The fungus causes T cells to secrete two immune signaling proteins, the cytokines IL-22 and IL-17. Fungal-induced IL-22 acts locally within the epithelium and enhances its barrier function. IL-17, on the other hand, enters the bloodstream and eventually reaches neurons that have receptors for it. Mice lacking the IL-17 receptor in neurons do not show the social effects of fungal colonization.
“There is this harmony. It’s a kind of communication between different kinds of organisms or between organisms,” said Dr. Iriev.
Currently, researchers want to investigate the communication network further. “We are looking at signals involved at the neuronal level in different brain regions to dig deeper into the mechanism of this interaction,” said Dr. Irina, a medical immunology instructor. Lead author Dr. Irina Leonardi said. At IBD’s Jill Roberts Institute.
One of the intriguing potentials is that different microbial communities in the gut can stimulate different regions of the brain and immune system, with a definite impact on the host’s biology.
“This opens up a whole new territory for exploration,” said Dr. Iriev.
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“”Mucosal fungi promote intestinal barrier function and social behavior through type 17 immunityIliyan Iliev et al. cell
Mucosal fungi promote intestinal barrier function and social behavior through type 17 immunity
- A specific community of fungi is present in the intestinal mucosa of humans and mice
- Mucosa-related fungus (MAF) induces type 17 immunity via T helper cells
- MAF protects mice from intestinal damage and infection through IL-22-dependent mechanisms
- MAF promotes mouse social behavior through IL-17-mediated signaling in neurons
Fungal communities (mycobiota) are an integral part of the intestinal flora, and their integrity disruption contributes to local and distal intestinal pathologies. Nevertheless, the mechanism by which intestinal fungi promote homeostasis remains unclear.
We characterized the biogeography of fungi along the gastrointestinal tract and identified a subset of fungi associated with the intestinal mucosa of mice and humans. Mucosa-related fungi (MAFs) enhance intestinal epithelial function and protect mice from intestinal damage and bacterial infections.
In particular, intestinal colonization by a consortium defined by MAF promoted social behavior in mice.Local intestinal effects on barrier function depended on IL-22 production by CD4+ The effects on social behavior are mediated by IL-17R-dependent signaling in neurons, whereas helper T cells.
Therefore, the spatial composition of intestinal mycoviota is associated with host-protective immunity and epithelial barrier function and may be a driver of neuroimmunoregulation of mouse behavior through complementary type 17 immune mechanisms.