A team of researchers led by Prof. Jacob Raber recently published an article in Scientific Reports, identifying links between the gut microbiome, altered DNA methylation in the hippocampus, and cognitive performance in mouse models of Alzheimer's disease (AD).
Several lines of preclinical research point to the existence of a gut-brain axis, connections that link the enteric (or intestinal) nervous system with the central nervous system and brain. How our gut microbiome - the collection of bacteria and other microorganisms that live in our intestines - influences the gut-brain axis is a hot topic for investigation, with recent research indicating that there may be a connection between reduced microbial diversity and AD.
In their article, Prof. Raber and colleagues sought to identify whether the gut microbiome influences behavioural and cognitive performance in animal models of AD. Using two different mouse models of AD, they observed that the biodiversity and composition of the gut microbiome appeared to be linked to different behavioural and cognitive traits (e.g nest building), which in turn were influenced by the AD genotype of the mice. Looking more closely at epigenetic marks in DNA from brain cells of these mice, the researchers observed altered methylation - a chemical modification that can determine whether a gene is expressed or repressed - in regions within the Tomm40 and ApoE genes. Altered methylation of these genes, both of which are linked with AD, appeared to correlate with changes in the gut microbiome. Moving forwards, future work will focus on identifying whether modifying the diet of these mice can influence the genetic changes and cognitive traits linked to AD.
