Microbes, Intestin, Inflammation and Susceptibility of the Host

A permanent cross talk exists in the gut between microbiota and host cells. With the molecular characterization of bacterial pathobionts and the data generated by genome-wide association studies concerning various pathologies, it has become evident that there is a parallel evolution of pathobionts and hosts. Over the last twenty years, the M2iSH unit has been studying the interaction between host cells and bacteria, particularly Escherichia coli pathobionts associated with inflammatory bowel diseases (IBD) notably Crohn’s Disease (CD), a chronic inflammation of the intestine characterized by hyperactivation of the immune system, and colorectal cancer (CRC).


It is now well established that abnormal inflammatory responses require an interplay between host genetic susceptibility and the intestinal microbiota. Several lines of evidence support the notion that CD results from an excessive immune response to gut commensal or pathobiont organisms. We was pioneer in reporting that the ileal mucosa of CD patients is abnormally colonized by adherent-invasive E. coli (AIEC). We have investigated how these bacteria can be involved in the onset or the recurrence of CD in genetically predisposed patients. In addition, as a possible link between chronic inflammation and cancer could exist, we opened up a new field of investigation concerning the role of E. coli pathobionts in CRC development. In this context, our previous research projects have focused on (i) characterization of the CD- and CRC-associated E. coli strains, (ii) host-bacteria cross-talk at the intestinal mucosa, and (iii) development of innovative diagnostic tools and therapies.


Our current research projects are structured around three interactive research axes:

Axis 1: Investigation of the virulence and antibiotic resistance of Escherichia coli pathobionts involved in chronic intestinal diseases, such as Crohn's disease and colorectal cancer (Thematic Leader: Richard Bonnet). (Research Axis 1)

Axis 2: Study of host responses to infection by E. coli pathobionts involved in chronic intestinal pathologies (Thematic Leaders: Hang Nguyen and Jérémy Denizot). (Research Axis 2)

Axis 3: Development of new biomarkers and innovative personalized therapies (Thematic Leaders: Mathilde Bonnet and Anthony Buisson). (Research Axis 3)