Depressive Disorders, major depressive disorder, MDD
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- One previously uncultured bacterium, provisionally named Evtepia gabavorous KLE1738, which required the presence of Bacteroides fragilis KLE1758 for growth. Using bio-assay driven purification of B. fragilis supernatant, Gama-aminobutyric acid (GABA), the major inhibitory neurotransmitter of the mammalian central nervous system, was identified as the growth factor of E. gabavorous. In vitro feeding experiments and genomic analysis of E. gabavorous suggests an unusual metabolism focused on consuming GABA.
- Using growth of E. gabavorous as an indicator. Reduced levels of GABA are associated with depression, and we found fewer GABA producers in a human cohort of depressed, bipolar, and/or schizophrenic individuals. By modulating the level of GABA, microbial producers and consumers of this neurotransmitter may be influencing host.
- GABA is the growth factor produced by Bacteroides fragilis.
- An inverse relationship between the relative abundance of fecal Bacteroidesand functional connectivity in a part of the brain associated with elevated activity during depression. This means that low abundance of Bacteroides was associated with high activity in that part of the brain, and vice versa.
- Lactobacillus rhamnosus reduce stress-induced corticosterone and anxiety- and depression-related behavior.
- There is a decrease in the endocannabinoid (eCB) signaling due to lower peripheral levels of fatty acid precursors of eCB ligands.
- The adverse effects of UCMS-transferred microbiota is alleviated by selectively enhancing the central eCB or by complementation with a strain of the Lactobacilli genus.
- Chemogenetic activation of striatal microglia induces an aversive affective state
- Chemogenetic inhibition of microglia blocks inflammation-induced aversion
- Microglial interleukin 6 signaling and prostaglandin synthesis regulate affective state
- Prostaglandin E2 from activated microglia reduces the excitability of striatal neurons
- Researchers identified two bacterial genera " Coprococcus and Dialister " were depleted in patients with depression whether or not they were taking antidepressants.
- [1.1] Growing Uncultured Bacteria from the Human Gut Microbiome – Potential Influence of the Hidden Majority on Host Physiology, Including Mental Health  [Research]  [Others]
- [1.2] Effect of gut microbiota on depressive-like behaviors in mice is mediated by the endocannabinoid system  [Research]  [Nature communications]
- [1.3] GABA-modulating bacteria of the human gut microbiota  [Research]  [Nature Microbiology]
- [1.4] Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve  [Research]  [PNAS]
- [1.5] Microglial activation elicits a negative affective state through prostaglandin-mediated modulation of striatal neurons  [Report]  [ScienceDirect]
- [1.6] The neuroactive potential of the human gut microbiota in quality of life and depression  [Abstract]  [Nature Microbiology]