Nocturnal Light Pollution Induces Weight Gain in Mice and Reshapes the Structure, Functions, and Interactions of Their Colonic Microbiota

Abstract

In mammals, the daily variation in the ecology of the intestinal microbiota is tightly coupled to the circadian rhythm of the host. On the other hand, a close correlation between increased body weight and light pollution at night has been reported in humans and animal models. However, the mechanisms underlying such weight gain in response to light contamination at night remain elusive. In the present study, we tested the hypothesis that dim light pollution at night alters the colonic microbiota of mice, which could correlate with weight gain in the animals. By developing an experimental protocol using a mouse model that mimics light contamination at night in urban residences (dLAN, dim light at night), we found that mice exposed to dLAN showed a significant weight gain compared with mice exposed to control standard light/dark (LD) photoperiod. To identify possible changes in the microbiota, we sampled two stages from the resting period of the circadian cycle of mice (ZT0 and ZT10) and evaluated them by high-throughput sequencing technology. Our results indicated that microbial diversity significantly differed between ZT0 and ZT10 in both LD and dLAN samples and that dLAN treatment impacted the taxonomic composition, functions, and interactions of mouse colonic microbiota. Together, these results show that bacterial taxa and microbial metabolic pathways might be involved with the mechanisms underlying weight gain in mice subjected to light contamination at night.

The role of gut microbiota in the occurrence and progression of non-alcoholic fatty liver disease

“…When restricting the control groups to patients with obesity, there were still significant reductions in alpha diversity among patients with NAFLD compared with controls. This phenomenon indicates that although obesity may affect the diversity of the gut microbiome (Sarmiento et al, 2022), NALFD could play a more crucial role in decreasing the gut microbial diversity. The integration of LEFSE-based and Random Forest methods identifies crucial genera that significantly decreased in the occurrence or development of NAFLD.…”

The Impact of Environmental Gaseous Pollutants on the Cultivable Bacterial and Fungal Communities of the Aerobiome

“…Since we aimed to isolate the impact of pollutant gases on the cultivable communities, we standardized the effect of gases with non-gas-exposed communities, similar to what has been applied in other microbial community studies [ 24 , 25 ]. This approach ensured an unbiased and more specific analysis of our data, considering the observed variation in meteorological factors among sites, like temperature ( Figure 1 D), a known driver of the environmental microbial structure [ 34 , 35 ].…”

“…Additionally, to isolate the impact of the pollutant gases between sites on the cultivable communities and exclude the influence of other environmental differential factors between sites, the abundances of ASVs in each gas-exposed community (g+) were standardized based on their counterparts’ non-gas-exposed community (g−) for all microbial analyses. For this, samples with zero (0) relative abundance in the g− condition were replaced with a one (1) since any number divided by one is equal to the number itself; therefore, the abundance difference between g+ and g− was maintained [ 24 , 25 ]. Hence, the input data were the nine abundance g+/g− ratios obtained for each ASV (three g+ replicates and three g− replicates) of each condition.…”

Targeting the blood–brain barrier to delay aging-accompanied neurological diseases by modulating gut microbiota, circadian rhythms, and their interplays

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