A shotgun metagenomic study identified short-chain fatty acid-producing species and their functions in the gut microbiome of adults with depressive symptoms: Large-scale shotgun sequencing data of the gut microbiota using a cross-sectional design

Background: The gut-brain axis is emerging as a novel mechanism to explain depressive disorders. Methods: We performed shotgun metagenomic sequencing of stool samples obtained from 133 individuals with depression and 532 without depression. This study examined the taxonomy, functional pathways, and predicted metabolites profiles associated with depressive symptoms, using generalized linear models. To explore links between the taxonomic and functional pathway results, we compared the relative abundance of specific species contributing to pathways significantly associated with depressive symptoms. Results: Taxonomic composition suggested a disruption in short-chain fatty acid (SCFA)-producing capacity of the gut microbiome in the depressed group. Pathways related to SCFA biosynthesis were also depleted in this group. Faecalibacterium prausnitzii, a well-known SCFA-producing bacterium, was significantly decreased in the depressed group and was identified as a major contributor to the depleted pathways. When inferring the metabolites related to depression from metagenomic data, higher levels of docosapentaenoic acid, stearoyl ethanolamide, putrescine, and bilirubin were more likely to be found in the depressed group. Conclusion: The present findings highlight the altered gut microbiota and associated SCFA-related pathways in individuals with depression. The depletion of F. prausnitzii and its contribution to SCFA production suggest that it is a potential therapeutic target for depression.