DNA Methylation Profiles of and in Gut and Brain of -Treated .

The bidirectional microbiota-gut-brain axis has raised increasing interest over the past years in the context of health and disease, but there is a lack of information on molecular mechanisms underlying this connection. We hypothesized that change in microbiota composition may affect brain epigenetics leading to long-lasting effects on specific brain gene regulation. To test this hypothesis, we used (Danio Rerio) as a model system. As previously shown, treatment with high doses of probiotics can modulate behavior in , causing significant changes in the expression of some brain-relevant genes, such as and . Using an ultra-deep targeted analysis, we investigated the methylation state of the and promoter region in the brain and gut of probiotic-treated and untreated Thanks to the high resolution power of our analysis, we evaluated cell-to-cell methylation differences. At this resolution level, we found slight DNA methylation changes in probiotic-treated samples, likely related to a subgroup of brain and gut cells, and that specific DNA methylation signatures significantly correlated with specific behavioral scores.