Cross-Talk between Probiotic Nissle 1917 and Human Colonic Epithelium Affects the Metabolite Composition and Demonstrates Host Antibacterial Effect

Colonic epithelium–commensal interactions play a very important role in human health and disease development. Colonic mucus serves as an ecologic niche for a myriad of commensals and provides a physical barrier between the epithelium and luminal content, suggesting that communication between the host and microbes occurs mainly by soluble factors. However, the composition of epithelia-derived metabolites and how the commensal flora influences them is less characterized. Here, we used mucus-producing human adult stem cell-derived colonoid monolayers exposed apically to probiotic E. coli strain Nissle 1917 to characterize the host–microbial communication via small molecules. We measured the metabolites in the media from host and bacterial monocultures and from bacteria-colonoid co-cultures. We found that colonoids secrete amino acids, organic acids, nucleosides, and polyamines, apically and basolaterally. The metabolites from host-bacteria co-cultures markedly differ from those of host cells grown alone or bacteria grown alone. Nissle 1917 affects the composition of apical and basolateral metabolites. Importantly, spermine, secreted apically by colonoids, shows antibacterial properties, and inhibits the growth of several bacterial strains. Our data demonstrate the existence of a cross-talk between luminal bacteria and human intestinal epithelium via metabolites, which might affect the numbers of physiologic processes including the composition of commensal flora via bactericidal effects.

Cytotoxicity mechanisms and composition of the glyphosate formulated herbicide RangerPro

Understanding the nature of co-formulants and toxic effects of major glyphosate-based herbicide (GBH) formulations is considered a research priority. Indeed, the toxicity of the co-formulants present in GBHs have been widely discussed and the European Union recently banned the co-formulant polyoxyethylene tallow amine (POEA). We provide a foundation for the development of new environmental epidemiological studies by reporting the presence of the most commonly used POEA, known as POE-15 tallow amine, in the widely used US GBH RangerPro. In order to understand if POE-15 tallow amine is present in RangerPro at a concentration at which it can exert toxic effects, we also tested the cytotoxicity of this GBH compared to glyphosate and POE-15 tallow amine in the human epithelial cell line Caco-2, a representative of the human intestinal epithelium, and the first to be exposed from the human diet to glyphosate herbicides. The lethal concentration 50 for each of these substances was 125 ug/ml, 17200 ug/ml, and 5.7 ug/ml, for RangerPro, glyphosate and POE-15, respectively. The Caco-2 cell cytotoxicity assay indicated that RangerPro is more cytotoxic than glyphosate, suggesting that its toxicity can be due to the presence of the POE-15 surfactant. RangerPro and POE-15 tallow amine but not glyphosate exerted cell necrotic effects, but did not induce oxidative stress. We show that RangerPro contains POE-15 tallow amine at a concentration at which it could exert toxic effects, which offers a starting point for conducting surveys of co-formulant exposure in human populations.

A proximal-to-distal survey of healthy adult human small intestine and colon epithelium by single-cell transcriptomics

Background and Aims: Single-cell transcriptomics offer unprecedented resolution of tissue function at the cellular level, yet studies in healthy adult human small intestine and colon are sparse. Here, we present single-cell transcriptomics from 3 humans covering the duodenum, jejunum, ileum, and ascending, transverse, and descending colon. Methods: 12,590 single epithelial cells from three independently processed organ donors were evaluated for organ-specific lineage biomarkers, differentially regulated genes, receptors, and drug targets. Analyses focused on intrinsic cell properties and capacity for response to extrinsic signals along the gut axis across different humans. Results: Cells were assigned to 25 epithelial lineage clusters. Human intestinal stem cells (ISCs) are not specifically marked by many murine ISC markers. Lysozyme expression is not unique to Paneth cells (PCs), and PCs lack expression of expected niche-factors. BEST4 cells express NPY and show functional and maturational differences between SI and colon. Tuft cells possess a broad ability to interact with the innate and adaptive immune systems through previously unreported receptors. Some classes of mucins, hormones, cell-junction, and nutrient absorption genes show unappreciated regional expression differences across lineages. Differential expression of receptors and drug targets across lineages reveals biological variation and potential for variegated responses. Conclusions: Our study identifies novel lineage marker genes; covers regional differences; shows important differences between mouse and human gut epithelium; and reveals insight into how the epithelium responds to the environment and drugs. This comprehensive cell atlas of the healthy adult human intestinal epithelium resolves data gaps in anatomical regions along the gastrointestinal tract and advances our understanding of human intestinal physiology.

Maturation of human intestinal epithelium from pluripotency in vitro

Methods to generate human intestinal tissue from pluripotent stem cells (PSCs) open new inroads into modeling intestine development and disease. However, current protocols require organoid transplantation into an immunocompromised mouse to achieve matured and differentiated epithelial cell states. Inspired by developmental reconstructions from primary tissues, we establish a regimen of inductive cues that enable stem cell maturation and epithelial differentiation entirely in vitro. We show that the niche factor Neuregulin1 (NRG1) promotes morphological change from proliferative epithelial cysts to matured epithelial tissue in three-dimensional cultures. Single-cell transcriptome analyses reveal differentiated epithelial cell populations, including diverse secretory and absorptive lineages. Comparison to multi-organ developmental and adult intestinal cell atlases confirm the specificity and maturation state of cell populations. Altogether, this work opens a new direction to use in vitro matured epithelium from human PSCs to study human intestinal epithelium development, disease, and evolution in controlled culture environments.

A Review on In vitro Cell Culture Model for Bacterial Adhesion and Invasion: From Simple Monoculture to Co-Culture Human Intestinal Epithelium Model

Aim: This paper reviews the different in vitro models of human intestinal epithelium that have been utilized for studying the adhesion and invasion properties. Problem Statement: The cell adhesion and invasion are the key mechanisms of bacterial pathogenicity that determines their possible routes of transmission. Numerous investigations related to the adhesion and invasion ability of bacterial isolates have been reported on monoculture human intestinal cells. However, the use of monoculture cells has several major disadvantages, such as the inability to reproduce the complex structure that defines the intestine and the inability to accurately predict the mechanism of bacterial adhesion and invasion. Approach: Co-culture models of human intestine have been developed as an alternative to improve the monoculture epithelial cell for adhesion and invasion studies, which provide more flexibility and overcome some of the limitations Conclusion: With the use of diverse in vitro approach, it could provide thorough information on different ability of bacterial adhesion and invasion and it could help to clarify the intricacy of host-pathogen interactions that underpin bacterial pathogenesis.

Food Contaminants Effects on an In Vitro Model of Human Intestinal Epithelium

Pesticide residues represent an important category of food contaminants. Furthermore, during food processing, some advanced glycation end-products resulting from the Maillard reaction can be formed. They may have adverse health effects, in particular on the digestive tract function, alone and combined. We sought to validate an in vitro model of the human intestinal barrier to mimic the effects of these food contaminants on the epithelium. A co-culture of Caco-2/TC7 cells and HT29-MTX was stimulated for 6 h with chlorpyrifos (300 μM), acrylamide (5 mM), Nε-Carboxymethyllysine (300 μM) alone or in cocktail with a mix of pro-inflammatory cytokines. The effects of those contaminants on the integrity of the gut barrier and the inflammatory response were analyzed. Since the co-culture responded to inflammatory stimulation, we investigated whether this model could be used to evaluate the effects of food contaminants on the human intestinal epithelium. CPF alone affected tight junctions’ gene expression, without inducing any inflammation or alteration of intestinal permeability. CML and acrylamide decreased mucins gene expression in the intestinal mucosa, but did not affect paracellular intestinal permeability. CML exposure activated the gene expression of MAPK pathways. The co-culture response was stable over time. This cocktail of food contaminants may thus alter the gut barrier function.

Organoids to Dissect Gastrointestinal Virus–Host Interactions: What Have We Learned?

Historically, knowledge of human host–enteric pathogen interactions has been elucidated from studies using cancer cells, animal models, clinical data, and occasionally, controlled human infection models. Although much has been learned from these studies, an understanding of the complex interactions between human viruses and the human intestinal epithelium was initially limited by the lack of nontransformed culture systems, which recapitulate the relevant heterogenous cell types that comprise the intestinal villus epithelium. New investigations using multicellular, physiologically active, organotypic cultures produced from intestinal stem cells isolated from biopsies or surgical specimens provide an exciting new avenue for understanding human specific pathogens and revealing previously unknown host–microbe interactions that affect replication and outcomes of human infections. Here, we summarize recent biologic discoveries using human intestinal organoids and human enteric viral pathogens.

P034 Human primary 2D culture as a tool to explore JAK1 pathway inhibition in the intestinal epithelium using siRNA technology

Background Oral inhibitors of JAK1 have become promising therapeutic agents for the treatment of inflammatory bowel diseases (IBD); however, concerns have been raised regarding their specificity and safety profiles. Currently, a local therapy based on specific JAK1 siRNA combined with lipid nanoparticle (LNP) technology is under investigation as a safer alternative to JAK inhibitors.The purpose of this study is to explore the inhibition of the JAK1 pathway in the intestinal epithelium mediated by siRNA/LNP technology, using human primary 2D culture. Methods Human primary 2D cultures were generated from colonic 3D organoids of non-IBD donors. The efficiency of JAK1 pathway inhibition was tested in IFN-y stimulated cultures using either filgotinib (a JAK1 inhibitor, used as a control) or the novel human JAK1 siRNA. JAK1 siRNA transfection was performed using Lipofectamine or LNPs. qPCR was performed on a panel of JAK1 target genes to evaluate the efficiency of JAK1 pathway inhibition. Results Incubation of the 2D culture with IFN-y induced the activation of the JAK1 pathway, as suggested by the significant up-regulation of JAK1-dependent genes (i.e., CXCL10, SOCS1, SOCS3 and PLA2G2A). The addition of filgotinib to the culture efficiently inhibited the JAK1 pathway by suppressing the expression of JAK1-target genes. JAK1 siRNA transfection using Lipofectamine reduced JAK1 mRNA expression by 50%, which was mirrored by the concomitant down-regulation (between 60 and 80%) of JAK1-dependent genes. Importantly, the silencing efficiency of the JAK1-dependent pathway by LNPs was comparable to that observed using Lipofectamine. Conclusion Organoid-derived 2D culture is a useful model for investigating the activation of the JAK1 pathway and its pharmacological inhibition in human intestinal epithelium. In particular, siRNA/LNP nanoplexes may be a promising technology for locally delivering highly specific siRNAs to the intestinal mucosa, which could pave the way for the development of more effective treatments for IBD patients.

Comparative analysis of public RNA-sequencing data from human intestinal enteroid (HIEs) infected with enteric RNA viruses identifies universal and virus-specific epithelial responses

Acute gastroenteritis (AGE) has a significant disease burden on society. Noroviruses, rotaviruses and astroviruses are important viral causes of AGE but are relatively understudied enteric pathogens. Recent developments in novel biomimetic human models of enteric disease are opening new possibilities for studying human-specific host-microbe interactions. Human intestinal enteroids (HIE), which are epithelium-only intestinal organoids derived from stem cells isolated from human intestinal biopsy tissues, have been successfully used to culture representative norovirus, rotavirus and astrovirus strains. Previous studies investigated host-virus interactions at the intestinal epithelial interface by individually profiling the epithelial transcriptional response to a member of each virus family by RNA sequencing (RNA-seq). We used these publicly available datasets to uniformly analyze these data and identify shared and unique transcriptional changes in the human intestinal epithelium upon human enteric virus infections.