Micro-organisms and intestinal physiopathology

This research group focused on the dialog between bacteria of the intestinal microbiota and human intestinal epithelial cells in the context of inflammatory bowel disease (IBD) namely Crohn’s disease (CD) and ulcerative colitis (UC). The exact physiopathogeny of IBD is still unknown but involves a dysregulated immune response to the gut microbiota in genetically predisposed host. For many years, our group has been involved in the description of the gut ecosystem of CD and UC patients and remained a leader in this field. We used a translational approach from basic biology to clinical practice. The clinical unit embedded in our group is internationally recognized in the field of IBD. Our database includes more than 7000 patients. This gives access to samples of well phenotyped patients in order to validate several hypotheses made in the lab regarding pathophysiology of IBD. This allowed us to describe dysbiosis (i.e. imbalance in gut microbiota composition) in IBD and to generate many works devoted to the characterization and to the consequences of this dysbiosis. For the last two years, we were able to measure some of the consequences of this dybiosis in the gut ecosystem. We took advantage of our position of team 4 in UMR 7203 to investigate small molecules involved in the dialog between host and gut microbiota. We observed changes in bile acids (BA) composition, anti-microbial peptides (AMP), and quorum sensing molecules such as N-Acyl-Homoserin Lactones (AHLs) within the lumen in case of dysbiosis. It is highly suspected that some of these molecules are implicated in the regulation of the bacterial composition of an ecosystem. Moreover, those molecules can interplay with host and particularly with inflammation pathways. ​