LiveFaecalibacterium prausnitziiin an apical anaerobic model of the intestinal epithelial barrier

Abstract

Summary Faecalibacterium prausnitzii, an abundant member of the human commensal microbiota, has been proposed to have a protective role in the intestine. However, it is an obligate anaerobe, difficult to co‐culture in viable form with oxygen‐requiring intestinal cells. To overcome this limitation, a unique apical anaerobic model of the intestinal barrier, which enabled co‐culture of live obligate anaerobes with the human intestinal cell line Caco‐2, was developed. Caco‐2 cells remained viable and maintained an intact barrier for at least 12 h, consistent with gene expression data, which suggested Caco‐2 cells had adapted to survive in an oxygen‐reduced atmosphere. Live F. prausnitzii cells, but not ultraviolet (UV)‐killed F. prausnitzii, increased the permeability of mannitol across the epithelial barrier. Gene expression analysis showed inflammatory mediators to be expressed at lower amounts in Caco‐2 cells exposed to live F. prausnitzii than UV‐killed F. prausnitzii, This, consistent with previous reports, implies that live F. prausnitzii produces an anti‐inflammatory compound in the culture supernatant, demonstrating the value of a physiologically relevant co‐culture system that allows obligate anaerobic bacteria to remain viable.

Non-digestible carbohydrates in infant formula as substitution for human milk oligosaccharide functions: Effects on microbiota and gut maturation

“…To overcome this problem, many studies use ultraviolet (UV)-killed bacteria or bacterial components. This, however, might not reflect the physiological situation as there are studies reporting that live bacteria exert greater beneficial effects than non-viable bacteria (Ulluwishewa et al 2015). Furthermore, the absence of living bacteria in an in vitro system leads to the absence of components secreted by bacteria.…”

“…A major challenge for creating a physiological relevant in vitro model is the creation of a microenvironment in which both aerobic epithelial cells and aerobic as well as anaerobic microbiota species can survive and exchange information (Ulluwishewa et al 2015). About 90% of the commensal microbiota are obligate anaerobes and therefore should be cultured in an anaerobic environment.…”

“…This was done in order to study interactions between F. Prausnitzii and epithelial cells. In another study, Ulluwishewa et al (Ulluwishewa et al 2015) used a unique apical anaerobic model of the intestinal epithelial barrier, which enabled co-culturing of living obligate anaerobes with Caco-2 cells. In this model a trans well insert with a human intestinal epithelial Caco-2 cell monolayer was fitted on a chamber lid.…”

“…This sealed of a chamber filled with aerobic cell culture medium from the anaerobic environment. The insert was filled with anaerobic cell culture medium (Ulluwishewa et al 2015). In this way, the Caco-2 cells were exposed to an aerobic environment on the basal side, while the apical side was exposed to an anaerobic environment, making it able to co-culture human intestinal epithelial Caco-2 cells with anaerobic bacteria in the apical compartment (Ulluwishewa et al 2015).…”

“…Although this is a simple and logical way to create an anaerobic compartment, it will not be possible to study NDC fermentation, since agar will be fermented as well and interfere with studies on fermentation and utilization of the NDCs. The model of Ulluwishewa et al (Ulluwishewa et al 2015) only used a single bacteria strain in the anaerobic compartment. To test NDC effects, whole microbiota samples should be applied.…”