Series: MCDB seminar series
Speaker: Jhimmy Talbot, Talbot Lab, Fred Hutchinson Cancer Center
Title: Neuronal integration of intestinal immunity and nutrition
Key takeaway: Fatty acids cause the gut into tradeoff nutrient absorption, risking infections and dysbiosis. This control of tradeoff happens through the nervous system, though currently it is not clear how else the nervous system controls the immune response other than control release of anti-microbial peptides. And it looks like other nutrients do not seem to influence this tradeoff, making fatty acids somewhat special (though, this needs more investigation).
What is clear is that prolonged reduction in antimicrobial peptides will reduce the depth of the demilitarized zone and destabilize the gut microbiome (as described in 2016_Yong-I contain multitudes). As a corollary, fiber rich diet will not do this and is a good way of keeping the gut microbiome stable.
My notes
- The rate of release of anti-microbial peptides by the epithelial cells into the mucus wall is controlled by IL-22 released my macrophages.
My interpretation: depth of the demilitarized zone (described in 2016_Yong-I contain multitudes) depends directly on IL-22 released by macrophages. Lower rate of IL-22 → lower rate of anti-microbial peptide release → shorter demilitarized zone and smaller mucus wall. - VIP neurons somehow control IL-22 release of macrophages, likely through specific neuropeptide release. Activation of VIP neurons reduces IL-22 release, which in turn causes lower rates of anti-microbial peptide release (thereby shortening the demilitarized zone).
- Monosaturated and Polysaturated fatty acids in the gut activate VIP neurons, through the Vagus nerve.
My interpretation: Fatty acids are such an important resource that animals are willing to reduce their demilitarized zone, likely to reduce (diffusion) distance epithelial cells and the gut. - Continual activation of VIP neurons, which reduces the demilitarized zone, increases gut infections in mice.
My interpretation: This is a tradeoff that animals make - risking infections and dysbiosis to acquire calorie rich nutrients.
My drawings
