Gut Microbes Regulate Myelination in the Brain
APC scientists have shown for the first time that gut bacteria have a direct physical effect on the brain. The researchers have shown that myelination of nerves in the prefrontal cortex region of the brain is dependent on the presence of the host microbiome.
These surprising new findings have implications for treating demyelinating disorders such as multiple sclerosis. The research is published in the Nature Journal Translational Psychiatry. Over the past decade it is becoming increasingly clear that the microbes which reside within and around us play a clear role is our health and wellbeing. Perhaps most surprising of all is the realisation that gut bacteria can even influence brain function and behaviour.
John Cryan, Gerard Clarke and PhD student Alan Hoban have shown that germ-free mice which are completely devoid of gut bacteria display a greater increase in myelin-related gene expression in the prefrontal cortex. This region of the brain is key to higher cognitive functions and in the expression of anxiety and social behaviours. Importantly, the team were able to visualise the extent of this increase in myelination using transmission electron microscopy.
When a normal microbiome was introduced into these animals, some of the changes in myelination were reversed. More work is needed to advance our understanding of the mechanisms behind the relationship between the microbiota and myelination and why only the cortex seems to be susceptible to its potential influence.
“It is likely that key signals from the gut to the brain provide a brake on myelination processes” says Prof Cryan. Furthermore, he says that “understanding what these may open innovative gut microbiome-based strategies for tackling myelin-related disorders”.
This research continues to broaden the concept that the microbiome has a remarkable influence over fundamental brain processes and may be harnessed in the future for a wide range of brain disorders, including depression and anxiety. This research was supported by Science Foundation Ireland Centre grant to the APC Microbiome Institute.
‘Regulation of Prefrontal Cortex Myelination by the Microbiota’ Alan E. Hoban, Roman M Stilling, Feargal J. Ryan, Fergus Shanahan, Timothy G. Dinan, Marcus J. Claesson, Gerard Clarke & John F. Cryan Nature Translational Psychiatry
Photo : Dr Gerard Clarke, APC Microbiome Institute and Department of Psychiatry and Neurobehavioural Science, UCC; Alan Hoban, APC Microbiome Institute and Department of Anatomy & Neuroscience, UCC and Professor John Cryan, APC Microbiome Institute and Department of Anatomy & Neuroscience, UCC. Photo courtesy of Dr Alexander Zhdanov, UCC