Can microbial molecules and particles help diagnose or treat chronic inflammatory diseases?

Coordinators: M. Poyet (CAU), M. Groussin (CAU)

The microbiome contains not only living microorganisms, but also non-cellular microbial components (NCMCs) that can influence human physiology. These include proteins and metabolites released by microbes (secretome), viruses that infect bacteria, known as bacteriophages (phageome), and tiny packages called extracellular vesicles that transport molecules between cells (vesiculome). Together, they can reshape microbial communities and influence the immune system.

Their therapeutic potential is already emerging. Sterile faecal filtrates, from which all intact microorganisms have been removed while many microbial components remain, have shown efficacy against recurrent intestinal infections and are now being tested in a clinical trial for ulcerative colitis. However, we still do not know which components produce these beneficial effects or whether some may instead promote inflammation.

TI-2 will investigate how NCMCs differ between individuals and change over time, and whether specific signatures are associated with disease trajectories or responses to microbiome-based therapies. We will also explore how these components influence the immune system and dysbiotic microbiomes, potentially revealing new biomarkers and therapeutic targets.