Very interesting new paper from the APC Microbiome Institute at University College in Cork Ireland = https://microbiomejournal.biomedcentral.com/articles/10.1186/s40168-017-0321-3
This paper made some important strides in identifying the undying mechanisms for the microbiome in our gut (our 2nd brain) to “talk” to the areas of the 1st brain in our heads involved in anxiety, stress, and fear (amygdala and pre-frontal cortex) – via microRNAs (miRNAa) that act through translational repression to control gene translation and have also been implicated in anxiety-like behaviors.
Highlights from the paper:
- growing evidence for a role of the gut microbiome in shaping behavior relevant to many psychiatric and neurological disorders
- it’s been repeatedly demonstrated that manipulation of the gut microbiome modulates anxiety-like behaviors
- certain probiotics and prebiotics have anxiolytic-like activity (anti-anxiety)
- potential of microbiota-mediated therapeutic approaches for treating anxiety-related disorders
Here is the Abstract from the publication:
Microbial regulation of microRNA expression in the amygdala and prefrontal cortex
Microbiome 2017 5:102
Published: 25 August 2017
There is growing evidence for a role of the gut microbiome in shaping behaviour relevant to many psychiatric and neurological disorders. Preclinical studies using germ-free (GF) animals have been essential in contributing to our current understanding of the potential importance of the host microbiome for neurodevelopment and behaviour. In particular, it has been repeatedly demonstrated that manipulation of the gut microbiome modulates anxiety-like behaviours. The neural circuits that underlie anxiety- and fear-related behaviours are complex and heavily depend on functional communication between the amygdala and prefrontal cortex (PFC). Previously, we have shown that the transcriptional networks within the amygdala and PFC of GF mice are altered. MicroRNAs (miRNAs) act through translational repression to control gene translation and have also been implicated in anxiety-like behaviours. However, it is unknown whether these features of host post-transcriptional machinery are also recruited by the gut microbiome to exert control over CNS transcriptional networks.
We conducted Illumina® next-generation sequencing (NGS) in the amygdala and PFC of conventional, GF and germ-free colonized mice (exGF). We found a large proportion of miRNAs to be dysregulated in GF animals in both brain regions (103 in the amygdala and 31 in the PFC). Additionally, colonization of GF mice normalized some of the noted alterations. Next, we used a complementary approach to GF by manipulating the adult rat microbiome with an antibiotic cocktail to deplete the gut microbiota and found that this strategy also impacted the expression of relevant miRNAs.
These results suggest that the microbiome is necessary for appropriate regulation of miRNA expression in brain regions implicated in anxiety-like behaviours.
Amygdala Prefrontal cortex Microbiome-gut-brain axis MicroRNAs Germ-free Antibiotics miR-206-3p