Biology subjects

de Wouters, T.

Publications and source records attributed to de Wouters, T..

5 recordsLinked to original sources

bioRxiv2023

Stratification of human gut microbiomes by succinotype is associated with inflammatory bowel disease status

The human gut microbiome produces and consumes a variety of compounds that interact with the host and impact health. Succinate is of particular interest as it intersects with both host and microbiome metabolism. However, which gut bacteria are most responsible for the consumption of intestinal succinate is poorly understood. Here, we build upon an enrichment-based whole fecal sample culturing approach and identify two main bacterial taxa that are responsible for succinate consumption in the human intestinal microbiome, Phascolarctobacterium and Dialister. These two taxa have the hallmark of a functional guild and are strongly mutual exclusive across over 20,000 fecal samples in nearly 100 cohorts and can thus be used to assign a robust succinotype to an individual. We show that they differ with respect to their rate of succinate consumption in vitro and that this is associated with higher concentrations of fecal succinate. Finally, individuals suffering from inflammatory bowel disease (IBD) are more likely to have the Dialister succinotype compared to healthy subjects. The functionally meaningful classification of human intestinal microbiota based on succinotype thus builds a bridge between microbiome function and IBD pathophysiology related to succinate.

microbiology↗

bioRxiv2023

A flexible high-throughput cultivation protocol to assess the response of individuals' gut microbiota to diet-, drug-, and host-related factors

Anaerobic cultivation of fecal microbiota is a promising approach to investigate how gut microbial communities respond to specific intestinal conditions and perturbations. Here, we describe a practical protocol using 96-deepwell plates to cultivate stool-derived gut microbiota. Our protocol addresses key challenges in high-throughput culturing, including a thorough assessment of the impact of gas phase on medium chemistry, a modular medium preparation process to enable testing of several conditions in parallel, a medium formulation designed to maximize the compositional similarity of fecal cultures with the donor microbiota, and the creation of a step-by-step protocol detailing all practical procedures from material preparation to sample handling for analyses. Finally, we validated the protocol by demonstrating that cultivated fecal microbiota responded similarly to dietary fibers (resistant dextrin, soluble starch) and drugs (ciprofloxacin, 5-fluorouracil) as reported in vivo. This high-throughput cultivation protocol can facilitate culture-dependent studies, accelerate the discovery of gut microbiota-diet-drug-host interactions, and pave the way to personalized and microbiota-centered interventions. MOTIVATIONThe human gut microbiota is a complex ecosystem unique to each individual. The extent of this diversity has limited our capacity to fully comprehend microbial dynamics that apply to the entire human population. To probe the response of donor-specific microbial communities to intestinal conditions or perturbations, in vitro cultivation of stool-derived gut microbiota can be employed. However, cultivating gut microbiota under strictly anaerobic conditions is commonly performed using individual gas-tight tubes, which is a highly time-consuming strategy that limits the number of conditions and donor microbiota that can be tested in parallel. A flexible high-throughput protocol to cultivate and test donor-specific gut microbiota is therefore required. Hence, we developed a robust procedure for cultivating stool-derived microbiota (and pure gut microbial cultures) in 96-deepwell plates within an anaerobic chamber.

microbiology↗

bioRxiv2023

Mapping gut bacteria into functional niches reveals the ecological structure of human gut microbiomes

Microbiomes are an essential contributor to the metabolic activity in the human gastrointestinal tract. The fermentation of otherwise indigestible nutritional components like dietary fibers relies on a complex interplay of metabolic pathways that are distributed across the individual bacteria. Yet, which of the bacteria are responsible for which parts of the distributed metabolism and how they should be grouped together is insufficiently understood. Here, we present the NicheMap, an approach to map the different bacterial taxa that make up the gut microbiome onto the different functional niches of microbial carbohydrate fermentation. Our approach uses in vitro measurements of bacterial growth and metabolic activity to identify which bacterial taxa are responsible for which metabolic function in the relevant complex context of whole human fecal microbiomes. We identified characteristic taxa selected for by a panel growth substrates representative of dietary components that are resistant to digestion by host enzymes. These characteristic taxa offer predictions of which bacteria are stimulated by the various components of human diet. We validated these predictions using microbiome data from a human nutritional supplementation study. We suggest a template of how bacterial taxonomic diversity is organized along the trophic cascade of intestinal carbohydrate fermentation. We anticipate that our results and our approach will provide a key contribution towards building a structure-function map for gut microbiomes. Having such a map on hand is an important step in moving the microbiome from a descriptive science to an interventional one.

microbiology↗

bioRxiv2021

Co-cultivation is a powerful approach to produce a robust functionally designed synthetic consortium as a live biotherapeutic product (LBP)

The successes of fecal microbiota transplants (FMT) have provided the necessary proof-of-concept for microbiome therapeutics. Because of the many risks and uncertainties associated with feces-based therapies, defined microbial consortia that modify the microbiome in a targeted manner have emerged as a promising safer alternative to FMT. The development of such live biotherapeutic products has important challenges, including the selection of appropriate strains and the production of the consortia at scale. Here, we report on an ecology and biotechnology-based approach to microbial consortium design that overcomes these issues. We designed a nine-strain consortium that emulates the central metabolic pathways of carbohydrate fermentation in the healthy human gut microbiota. We show that continuous co-culturing the bacteria produce a stable consortium whose activity is distinct from an equivalent mix of individually cultured strains. Further, we showed that our function-based consortium is as effective as FMT in counteracting dysbiosis in a dextran sodium sulfate mouse model of acute colitis. We propose that combining a bottom-up functional design with continuous co-cultivation is a powerful strategy to produce robust, functionally designed synthetic consortia for therapeutic use.

microbiology↗

bioRxiv2019

Species-specific enhancement of enterohemorrhagic E. Coli pathogenesis mediated by microbiome metabolites

BackgroundSpecies-specific differences in tolerance to infection are exemplified by the high susceptibility of humans to enterohemorrhagic E. coli (EHEC) infection whereas mice are relatively resistant to this pathogen. This intrinsic species-specific difference in EHEC infection limits the translation of murine research to human. Furthermore, studying the mechanisms underlying this differential susceptibility is a difficult problem due to complex in vivo interactions between the host, pathogen, and disparate commensal microbial communities.\n\nResultsWe utilize organ-on-a-chip (Organ Chip) microfluidic culture technology to model damage of the human colonic epithelium induced by EHEC infection, and show that epithelial injury is greater when exposed to metabolites derived from the human gut microbiome compared to mouse. Using a multi-omics approach, we discovered four human microbiome metabolites -- 4-methyl benzoic acid, 3,4-dimethylbenzoic acid, hexanoic acid, and heptanoic acid -- that are sufficient to mediate this effect. The active human microbiome metabolites preferentially induce expression of flagellin, a bacterial protein associated with motility of EHEC and increased epithelial injury. Thus, the decreased tolerance to infection observed in humans versus other species may be due in part to the presence of compounds produced by the human intestinal microbiome that actively promote bacterial pathogenicity.\n\nConclusionOrgan on chip technology allowed the identification of specific human microbiome metabolites modulating EHEC pathogenesis. These identified metabolites are sufficient to increase susceptibility to EHEC in our human Colon Chip model and they contribute to species-specific tolerance. This work suggests that higher concentrations of these metabolites could be the reason for higher susceptibility to EHEC infection in certain human populations, such as children. Furthermore, this research lays the foundation for therapeutic-modulation of microbe products in order to prevent and treat human bacterial infection.

bioengineering↗