Billions of healthy, commensal bacteria help to digest foods, acquire nutrients and prevent the colonisation of bacterial pathogens that cause disease. These probiotic bacteria are often used in nutritional supplements and foods to promote well-being and healthy functioning, especially of the intestine. To widen the study of probiotic bacteria, the EU has funded a Marie Curie Initial Training Network to train young scientists in the emerging field of microbiome metagenomics, the interactions between gut microbiota and the human host. Each of the 18 fellows worked on individual research projects, contributing to the identification of biological components and strains conferring health advantages. The project CROSS-TALK (Health-promoting cross-talk between intestinal microbiota and humans) geared its training activity towards human microbiome metagenomics. A new discipline, it is particularly appropriate for this study as it combines molecular biology, microbiology, cell biology, immunology, and animal and human physiology. The scientists identified a large number of probiotic strains with documented effects on eukaryotic cell physiology and characterised them to decipher the mechanisms involved during host interaction. They focused on a large panel of bacteria, including lactic acid bacteria (Bifidobacteria and Lactobacilli), gram-positive commensals (Roseburia, Akkermancia, Clostridi) as well as metagenomic clones. Pathophysiological effects were analysed using animal models and human ex-vivo technologies. The therapeutic potential of these bacteria is still under investigation in 11 out of the 18 ongoing research projects. CROSS-TALK also characterised overall tissue responses using transcriptomics and integrated cell-signalling studies to select probiotic bacteria of high health potential. Findings could significantly improve our understanding of bacterial symbiosis in the gut and its impact on gut physiology, and are expected to have important commercial applications. A total of 30 scientific articles from CROSS-TALK research have been published in high-profile journals. In September 2012 the Cross-Talk Scientific Network (CTSN) was founded. Supported by the Lactic Acid Bacteria Industrial Platform incorporating major food manufacturers, it is open to a large scientific and industrial audience.
Gut, probiotic, human microbiome metagenomics, lactic acid bacteria, symbiosis