Day 2 New Frontiers Symposium on Microbiome
Summary of the 2nd day of the New Frontiers Symposium on Microbiome 2017 in Nijmegen, the Netherlands
The second day of the symposium began with an excellent session on microbiome & inflammation. First, Gregory Buck gave an introduction to the microbiome of the female reproductive system, and presented new data on alterations of this microbiome during pregnancy. Kjersti Aagaard went on to present on the controversial topic of early establishment of the human microbome. She hypothesized that low biomass bacterial communities in the placenta may have a crucial role in the immune development of the baby. Her group has shown that maternal high-fat diet has a persistent impact on offspring behavior in primate models. She also showed evidence that the mother’s diet affects human milk oligosaccharide composition in breast milk, thereby affecting the gut microbiota composition of the baby.
Melanie Schirmer presented a very interesting study in which metagenome data from fecal samples was compared with metatranscriptome data of the same samples. On average, the functional potential of an organism in the gut was proportional to its functional activity. However, the presence of an organism didn’t always mean it was contributing to the expressed pathways. Faecalibacterium prausnitzii was found to be a dominant transcriber of many pathways and Bacteroides vulgatus was differentially expresses in inflammatory bowel disease patients. This presentation sparked discussion about whether the results are affected by possible bacterial RNA degradation in stool, and whether the rate of RNA degradation would vary for different species depending on their localization in the intestinal tract. Thereafter Nanna Fyhrquist introduced yet another microbial niche, the skin. Her research links metagenomics data of the skin microbiome with host transcriptome data to understand the development of atopic dermatitis and psoriasis. Furthermore, she showed how exposure to soil in the living environment of mice reduced allergic responses compared to mice in a clean, laboratory environment. The last speaker of the session, Elizabeth Grice, continued on the skin microbiome and how antiseptics eliminate less abundant taxa from the skin. She showed that resident Staphylococcous species, which are removed by antiseptic treatments, can provide colonization resistance to Staphylococcus aureus.
The second session of the day was about the microbiome and neurodevelopment. Rochellys Diaz Heijtz suggested that the central activation of pattern recognition receptors by bacterial peptidoglycan receptors could be one of the signaling pathways mediating communication between microbiota and the developing brain. Christopher A. Lowry talked about microbiome-based strategies for prevention of stress-related psychiatric disorders. Ted Dinan gave an overview of the brain-gut-microbiome axis and pointed out that we especially need dose response studies as proper doses for probiotics are not known.
In he last session of the symposium, dealing with microbiome and therapy, David A. Relman presented about how we can use information about the microbiome in diagnostics, prognostics, therapy and prevention in the future. He discussed the mouth and intestinal microbiota and stated that after a brief, rapid disturbance of the microbiota, the community returns back to the initial state very quickly, showing resilience. These types of disturbances could also be used as clinical tools with the aim to establish an alternative stable state of the community. The symposium ended with presentations by Dominic Raj on targeted interventions of the microbiome, and by Ellen Blaak on the importance of the gut microbiota in metabolic health.