Scientific Publications
Human resident gut microbe Bacteroides thetaiotamicron normalises colonic innervation and function
Gut Microbes
Background and Aims:
As the importance of gut-brain interactions increases, understanding how specific gut microbes interact with the enteric nervous system (ENS), which is the first point of neuronal exposure becomes critical. Our aim was to understand how the dominant human gut bacterium Bacteroides thetaiotamicron (Bt) regulates anatomical and functional characteristics of the ENS.
Methods:
Neuronal cell populations, as well as enteroendocrine cells were assessed in proximal colonic sections using fluorescent immunohistochemistry in specific pathogen free (SPF), germ free (GF) and Bt conventionalised-germ free mice (Bt-CONV). RNA expression of tight junction proteins and toll like receptors (TLR) were measured using qPCR. Colonic motility was analysed using in vitro colonic manometry.
Results:
Bt-CONV of GF mice resulted in increased neuronal and vagal afferent innervation in both the mucosa and myenteric plexus. Bt-CONV also restored expression of nitric oxide synthase expressing inhibitory neurones and of choline acetyltransferase and substance P expressing excitatory motor neurons comparable to those of SPF mice. Neurite outgrowth and glial cells were also upregulated by Bt-CONV. RNA expression of the tight junction protein claudin 3 was downregulated while TLR 2 was upregulated by Bt-CONV. The numbers of enteroendocrine cell subtypes L-cells and enterochromaffin cells were reduced in GF mice, with Bt-CONV restoring L-cell numbers. Motility as measured by colonic migrating motor complexes (CMMCs) increased in GF and Bt-CONV.
Conclusion:
Our study reveals a key role for a common gut bacteria, Bt, in regulating enteric neuronal cell populations and neurogenic colonic activity. This highlights the potential use of this resident gut bacteria for maintaining healthy gut function.
Gut Microbes
View Publication
