Methods to extract and study the biological effects of murine gut microbiota using Caenorhabditis elegans as a screening host

Abstract

Gut microbiota has been established as a main regulator of health. However, how changes in gut microbiota are directly associated with physiological and cellular alterations has been difficult to tackle on a large-scale basis, notably because of the cost and labor-extensive resources required for rigorous experiments in mammals. In the present study, we used the nematode Caenorhabditis elegans as a model organism to elucidate microbiota-host interactions. We developed a method to extract gut microbiota (MCB) from murine feces, and tested its potential as food source for and its impact on C. elegans biology compared to the standard bacterial diet Escherichia coli OP50. Although less preferred than OP50, MCB was not avoided but had a lower energy density (triglycerides and glucose). Consistently, MCB-fed worms exhibited smaller body length and size, lower fertility, and lower fat content than OP50-fed worms, but had a longer mean lifespan, which resembles the effects of calorie restriction in mammals. However, these outcomes were altered when bacteria were inactivated, suggesting an important role of symbiosis of MCB beyond nutrient source. Taken together, our findings support the effectiveness of gut MCB processing to test its effects in C. elegans. More work comparing MCB of differently treated mice or humans is required to further validate relevance to mammals before large-scale screening assays.

Caenorhabditis elegans as a Screening Model for Probiotics with Properties against Metabolic Syndrome

“…In this context, a recent study demonstrated that supplementation with gut microbiota (MCB) from murine feces represented lower energy density (glucose and triglycerides) in comparison with E. coli OP50. Consequently, MCB-fed worms exhibited smaller body length and size, lower fertility, lower fat content, and an extended lifespan in comparison to those fed with the standard diet [65]. Moreover, Gu et al demonstrated the differential fatty acid composition of C. elegans exposed to E. cloacae in comparison with E. coli OP50 [36].…”

Caenorhabditis elegans as a Convenient Animal Model for Microbiome Studies

“…Testing C. elegans with different gut microbiota or E. coli OP50 shows differences in growth and lifespan. C. elegans fed on murine gut microbes show reduction in diet preference, body size, fecundity, as well as carbohydrate and lipid content, yet these worms exhibit longer lifespans, similar to the influence of diet restriction in mammals [ 25 ]. C. elegans is also used for studying human infection with pathogens [ 26 , 27 ] and for screening drug–microbe interactions [ 28 ].…”