Traditional and next-generation probiotics, inflammation, and intestinal dysbiosis

Principal investigators : Aurore Rincheval-Arnold and Eugénie Huillet 

Keywords: human commensal strains (Faecalibacterium), lactic acid probiotics (Lactobacillus), innate immunity, intestinal homeostasis, stem cells, IMD response, cell signaling, survival, ECC15 model, Upd3 model, Drosophila.

The interaction between intestinal cells, the microbiota, and the innate immune system is critical for intestinal homeostasis and is disrupted during the dysbiosis observed in many diseases.
The mechanisms of action for the majority of probiotic strains described in the literature remain largely unknown. Even for probiotic strains showing promise for human health, such as the Ex01 strain of Faecalibacterium prausnitzii, although their main molecular effectors have been identified, the mechanisms of action underlying the host’s response to these effectors remain poorly understood. There is therefore a need for faster and more cost-effective alternative experimental models to characterize these mechanisms.
In collaboration with the ProbiHôte team (Micalis, INRAE), we are developing a new experimental approach to simply characterize the protective effects of bacterial strains and their various fractions in models of post-infectious dysbiosis induced in Drosophila by oral ingestion of the phytopathogen ECC15. For two strains, as part of a doctoral thesis, we (i) evaluate their effect on Drosophila survival post-infection and (ii) characterize their effects on the magnitude of the phytopathogen-induced inflammatory and cellular responses of the intestinal epithelium.
 In particular, we are assessing the expression of genes encoding antimicrobial peptides (AMPs) or cytokines with the aim of identifying molecular mediators in these bacterial strains by leveraging the genetic and cellular tools of Drosophila.
This collaboration was initiated with support from the Université Paris-Saclay through the PNGdroso project, funded by the GS-LSH in 2024. Our latest funding, as part of a Université Paris-Saclay Poc In Labs (2026), allows us to further develop the Upd3 model and strengthen our research capabilities.