Circadian Disruption Changes Gut Microbiome Taxa and Functional Gene Composition

Abstract

Disrupted circadian rhythms and alterations of the gut microbiome composition were proposed to affect host health. Therefore, the aim of this research was to identify whether these events are connected and if circadian rhythm disruption by abnormal light–dark (LD) cycles affects microbial community gene expression and host vulnerability to intestinal dysfunction. Mice were subjected to either a 4-week period of constant 24-h light or of normal 12-h LD cycles. Stool samples were collected at the beginning and after the circadian rhythm disruption. A metatranscriptomic analysis revealed an increase in Ruminococcus torques, a bacterial species known to decrease gut barrier integrity, and a decrease in Lactobacillus johnsonii, a bacterium that helps maintain the intestinal epithelial cell layer, after circadian rhythm disruption. In addition, genes involved in pathways promoting host beneficial immune responses were downregulated, while genes involved in the synthesis and transportation of the endotoxin lipopolysaccharide were upregulated in mice with disrupted circadian cycles. Importantly, these mice were also more prone to dysfunction of the intestinal barrier. These results further elucidate the impact of light-cycle disruption on the gut microbiome and its connection with increased incidence of disease in response to circadian rhythm disturbances.

Neuroinflammation in mouse models of Alzheimer's disease

“…This “gut–brain axis” has consequently received attention in several research fields. While it was reported that factors, such as obesity, exercise, diet/nutrition, circadian rhythm, sleep, stress and aging, modulate gut microbiotic conditions, such factors might also affect brain function and brain disorders. The body's macroenvironment, particularly the role played by inflammatory factors and immune cells including microglia and astrocytes, almost certainly contributes to the correct physiological functioning of the brain, as well as to the pathogenesis of brain disorders when this environment is disturbed.…”

“Photobiomics”: Can Light, Including Photobiomodulation, Alter the Microbiome?

“…The metabolome is intimately associated with chronobiology and hence with ambient light, 13 with the circadian clock regulating levels of metabolites, including those from the microbiome, which in turn can affect metabolome. 15 The effect of the circadian rhythm on the microbiome has been demonstrated [16][17][18] and the bacteria responsible for decreased gut integrity and increased lipopolysaccharide transport are upregulated in mice after disruption of the sleep/wake cycle. 18 In addition to circadian rhythm, light also has an indirect effect on the microbiome through vitamin D, produced by the action of sunlight on keratinocytes.…”

“…15 The effect of the circadian rhythm on the microbiome has been demonstrated [16][17][18] and the bacteria responsible for decreased gut integrity and increased lipopolysaccharide transport are upregulated in mice after disruption of the sleep/wake cycle. 18 In addition to circadian rhythm, light also has an indirect effect on the microbiome through vitamin D, produced by the action of sunlight on keratinocytes. Vitamin D is known to boost immune function by the induction of antimicrobial peptide genes and the regulation of tight junction proteins in the epithelial layer of the intestine 19,20 and to maintain microbiome homeostasis and protect against colitis in mice, 21 possibly by controlling inflammation.…”

Diel patterning in the bacterial community associated with the sea anemone Nematostella vectensis

“…Photoperiods and circadian clocks are an integral part of diverse biological processes for animals, ranging from immune performance to metabolism to host-microbe associations (Heath-Heckman, 2016; Hubbard et al, 2018;Liang et al, 2015;Zarrinpar, Chaix, Yooseph, & Panda, 2014). In traditional mammalian systems, such as mice and humans, the composition of the gut microbiota of individuals entrained to light:dark or constant darkness differs for particular taxonomic groups of bacteria (Deaver, Eum, & Toborek, 2018;Wu et al, 2018). Thus, the photoperiod may influence compositional dynamics of host-associated bacterial communities in other animals, and the responses may also involve an endogenous circadian clock.…”