Colonocyte metabolism shapes the gut microbiota.
Litvak Y, Byndloss MX, Bäumler AJ
Science. Nov 2018
COMMENT: The gut microbiota affects human health, but we are only just beginning to develop a mechanistic understanding of some of the host-microbe interactions involved. Litvak et al. review how host colon epithelial cells mediate the symbiosis.
During gut homeostasis, the metabolism of surface colonocytes is directed toward oxidative phosphorylation and oxidation of fatty acids, resulting in high epithelial oxygen consumption. The consequent epithelial hypoxia helps to maintain a microbial community dominated by obligate anaerobic bacteria, which provide benefit by converting fiber into fermentation products that are absorbed by the host. Conditions that shift the metabolism of colonocytes away from lipid oxidation cause an increase in the amount of oxygen emanating from the mucosal surface, thereby driving a shift in the microbial community from obligate to facultative anaerobes, a hallmark of dysbiosis in the colon. Thus, the metabolism of colonocytes functions as a control switch of the gut microbiota, mediating a shift between homeostatic and dysbiotic communities. Subversion of colonocyte cell metabolism by enteric pathogens is a recently uncovered virulence strategy that enables these intruders to escape niche protection conferred by the gut microbiota
Some intracellular bacterial pathogens can alter macrophage polarization to obtain nutrients from host cells to support microbial growth and long-term persistence in host tissue
Similar to an exploitation of macrophage polarization, recent findings suggest that bacterial pathogens can also manipulate colonocyte metabolism to favor their luminal growth during competition with the gut microbiota
The reverse strategy, a metabolic reprogramming to restore colonocyte hypoxia, represents a promising new therapeutic approach for rebalancing the colonic microbiota in a broad spectrum of human diseases