Summary:

In just a few years, the study of the intestinal microbiota and its impact on human health has become a major area of research. This vast microbial community, housed in the intestine, performs numerous biological and metabolic functions and confers many benefits on the host. In recent years, imbalances between different intestinal bacterial populations, or dysbiosis, have been described in various human pathologies and metabolic disorders, underlining the importance of the intestinal microbiota for human health.

For several years now, our team has been investigating the interactions between commensal microbiota and digestive physiopathology, focusing in particular on intestinal epithelial cells. We have shown that primocolonising bacteria, in particular a commensal strain of Escherichia coli, play a major role in the maturation and remodelling of the colonic epithelium during initial exposure to bacteria. This remodelling leads to the development of deeper crypts, a dynamic equilibrium between the different cell lineages studied and the implementation of innate defence mechanisms (mucus secretion, ionic movements). The data obtained in mono-associated models show a dynamic transcriptional response of the ileum and colon to commensal strains of E coli, affecting the expression of key genes in intestinal homeostasis. These effects are accompanied by a beneficial effect in a mouse model of predisposition to develop intestinal inflammation.

Taken together, our data represents a significant contribution to our understanding of the relationship between the microbiota and intestinal cells. We are now developing work to study 1/ the impact of diet (high-fat diet, prebiotics) in modulating these interactions and 2/ the mechanisms involved, in particular through the contribution of intestinal organoids.

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