Our gut is the largest defense barrier of our body, harboring more than 60% of immune cells in the gut mucosa. Further protection occurs by the gut-microbiome that conditions the mucosal immune response. The human microbiome is composed of resident bacteria, yeasts, eukaryotic viruses and bacteriophages. Molecular and metagenomic approaches have allowed identifying main phyla and their relationships with almost all human diseases. However, the lack of definitive culprit species, either bacterial or viral, with limited cultured isolates prevents meaningful comparison of microbiomes in health and disease. Moreover, little is known about the composition and physiological significance of the phage components of our microbiome. The question remains as to whether there are consistent microbiomarkers of disease. Our goal is to identify microbial signatures that can broadly define microbiomes to help focus isolation efforts and mechanistic studies on the best microbial candidates for further study.
For instance, the host immune system interacts with pathogens by inducing inflammation, while maintaining tolerance towards harmless microbes. This requires a careful surveillance to be able to distinguish threats. Out goal is to decipher how host cells discriminate pathogens from commensal microbes mediated by pattern recognition receptors. Receptor engagement induces several signaling cascades resulting in the production of cytokines, chemokines, and transcription factors that are essential for the maintenance of the gut homeostasis and infection control.
Dwayne Roach, Sylvie Chollet-Martin, Benoît Noël, Vanessa Granger, Laurent Debarbieux, Luc de Chaisemartin