Glycerol Supplementation Enhances L. reuteri’s Protective Effect against S. Typhimurium Colonization in a 3-D Model of Colonic Epithelium

Abstract

The probiotic effects of Lactobacillus reuteri have been speculated to partly depend on its capacity to produce the antimicrobial substance reuterin during the reduction of glycerol in the gut. In this study, the potential of this process to protect human intestinal epithelial cells against infection with Salmonella enterica serovar Typhimurium was investigated. We used a three-dimensional (3-D) organotypic model of human colonic epithelium that was previously validated and applied to study interactions between S. Typhimurium and the intestinal epithelium that lead to enteric salmonellosis. Using this model system, we show that L. reuteri protects the intestinal cells against the early stages of Salmonella infection and that this effect is significantly increased when L. reuteri is stimulated to produce reuterin from glycerol. More specifically, the reuterin-containing ferment of L. reuteri caused a reduction in Salmonella adherence and invasion (1 log unit), and intracellular survival (2 log units). In contrast, the L. reuteri ferment without reuterin stimulated growth of the intracellular Salmonella population with 1 log unit. The short-term exposure to reuterin or the reuterin-containing ferment had no observed negative impact on intestinal epithelial cell health. However, long-term exposure (24 h) induced a complete loss of cell-cell contact within the epithelial aggregates and compromised cell viability. Collectively, these results shed light on a potential role for reuterin in inhibiting Salmonella-induced intestinal infections and may support the combined application of glycerol and L. reuteri. While future in vitro and in vivo studies of reuterin on intestinal health should fine-tune our understanding of the mechanistic effects, in particular in the presence of a complex gut microbiota, this the first report of a reuterin effect on the enteric infection process in any mammalian cell type.

Three-dimensional organotypic co-culture model of intestinal epithelial cells and macrophages to study Salmonella enterica colonization patterns

“…In this study, we advanced our previously characterized 3-D model of human colonic epithelium 7, 16, 17 towards a more immunocompetent 3-D model through the co-culture of HT-29 cells and phagocytic U937 macrophages using the RWV bioreactor. To our knowledge, this model represents the first RWV-derived 3-D co-culture model comprised of intestinal epithelial cells and macrophages.…”

Enhanced Probiotic Potential of Lactobacillus reuteri When Delivered as a Biofilm on Dextranomer Microspheres That Contain Beneficial Cargo

“…L. reuteri is a popular choice for commercialization due to its production of lactic acid and the antimicrobial compound reuterin, a metabolite of glycerol metabolism known chemically as 3-hydroxypropionaldehyde (3-HPA), which typically exists in equilibrium with other downstream products such as 3-HPA hydrate and acrolein (Talarico et al, 1988; Engels et al, 2016). Reuterin induces oxidative stress in a broad range of microorganisms (Schaefer et al, 2010), and is highly effective at inhibiting growth of many gastrointestinal pathogens (el-Ziney and Debevere, 1998; Arques et al, 2004; Spinler et al, 2008; De Weirdt et al, 2012). In addition to the antimicrobial reuterin, L. reuteri also produces anti-inflammatory factors including histamine that modulate cytokine production in vitro (Jones and Versalovic, 2009) and ameliorate the symptoms of inflammatory bowel disease (Ghouri et al, 2014).…”

Modeling Host-Pathogen Interactions in the Context of the Microenvironment: Three-Dimensional Cell Culture Comes of Age

“…It was the first technology used to develop 3-D models for infection studies with bacterial (Salmonella) and viral (rhinovirus) pathogens (11,51). A range of RWV-derived 3-D models have been developed using cell lines, stem cells, and/or primary cells, including small and large intestine (11,80,141,143,145,146,152,(168)(169)(170)(171)(172)(173)(174)(175)(176)(177), lung (144,147,(178)(179)(180)(181)(182), liver (148,153,174,183,184), bladder (8,(185)(186)(187), reproductive tissue (149)(150)(151)(188)(189)(190), heart (191)(192)(193), prostate (142,186,194), pancreas (195,<...>…”