Regulation of intestinal epithelial cells transcriptome by enteric glial cells: impact on intestinal epithelial barrier functions

<p>Abstract</p> <p>Background</p> <p>Emerging evidences suggest that enteric glial cells (EGC), a major constituent of the enteric nervous system (ENS), are key regulators of intestinal epithelial barrier (IEB) functions. Indeed EGC inhibit intestinal epithelial cells (IEC) proliferation and increase IEB paracellular permeability. However, the role of EGC on other important barrier functions and the signalling pathways involved in their effects are currently unknown. To achieve this goal, we aimed at identifying the impact of EGC upon IEC transcriptome by performing microarray studies.</p> <p>Results</p> <p>EGC induced significant changes in gene expression profiling of proliferating IEC after 24 hours of co-culture. 116 genes were identified as differentially expressed (70 up-regulated and 46 down-regulated) in IEC cultured with EGC compared to IEC cultured alone. By performing functional analysis of the 116 identified genes using Ingenuity Pathway Analysis, we showed that EGC induced a significant regulation of genes favoring both cell-to-cell and cell-to-matrix adhesion as well as cell differentiation. Consistently, functional studies showed that EGC induced a significant increase in cell adhesion. EGC also regulated genes involved in cell motility towards an enhancement of cell motility. In addition, EGC profoundly modulated expression of genes involved in cell proliferation and cell survival, although no clear functional trend could be identified. Finally, important genes involved in lipid and protein metabolism of epithelial cells were shown to be differentially regulated by EGC.</p> <p>Conclusion</p> <p>This study reinforces the emerging concept that EGC have major protective effects upon the IEB. EGC have a profound impact upon IEC transcriptome and induce a shift in IEC phenotype towards increased cell adhesion and cell differentiation. This concept needs to be further validated under both physiological and pathophysiological conditions.</p

Multi-disciplinary insights from the First European Forum on Visceral Myopathy 2022 Meeting

Visceral myopathy is a rare, life-threatening disease linked to identified genetic mutations in 60% of cases. Mostly due to the dearth of knowledge regarding its pathogenesis, effective treatments are lacking. The disease is most commonly diagnosed in children with recurrent or persistent disabling episodes of functional intestinal obstruction, which can be life threatening, often requiring long-term parenteral or specialized enteral nutritional support. Although these interventions are undisputedly life-saving as they allow affected individuals to avoid malnutrition and related complications, they also seriously compromise their quality of life and can carry the risk of sepsis and thrombosis. Animal models for visceral myopathy, which could be crucial for advancing the scientific knowledge of this condition, are scarce. Clearly, a collaborative network is needed to develop research plans to clarify genotype–phenotype correlations and unravel molecular mechanisms to provide targeted therapeutic strategies. This paper represents a summary report of the first ‘European Forum on Visceral Myopathy’. This forum was attended by an international interdisciplinary working group that met to better understand visceral myopathy and foster interaction among scientists actively involved in the field and clinicians who specialize in care of people with visceral myopathy

Engineering a second brain in a dish

International audienceThe utilization of human pluripotent stem cells holds great promise in elucidating principles of developmental biology and applications in personalized and regenerative medicine. Breakthroughs from the last decade have allowed the scientific community to better understand and successfully manipulate human pluripotent stem cells using distinct differentiation strategies into a variety of target tissues. This manipulation relies solely on our understanding of developmental processes occurring in model organisms. The in vitro translation of our developmental knowledge upon stem cells provides a new means to generate specific tissue to understand developmental and disease mechanisms, as well as physiological processes. The generation of an integrated human intestinal tissue is one such example. In this review, we highlight the biological motivation behind the generation of human intestinal organoids. We further describe the integration of an enteric nervous system within the organoid to generate a functional intestine. Forthcoming strategies to add additional complexities to the intestinal tissue so as to better understand how our "second brain" functions within the gut are also discussed. The organoid system offers a promising avenue to understand how the enteric nervous system works and patterns the human intestine during both physiology and disease

Les cellules gliales entériques : source de 15d-PGJ2 impliquée dans le contrôle des fonctions de la barrière épithéliale intestinale et dans la survie neuronale

Increasing evidences suggest that enteric glial cells (EGC) are critical for intestinal epithelial barrier (IEB) functions and enteric neurons survival. EGC effects are currently associated to the release of glial-derived factors. In this context, this work leads to the identification of 15-deoxy-delta12,14 prostaglandin J2 (15d-PGJ2), an omega-6 fatty acid derivative, as a new mediator synthesised and secreted by EGC. Results show that both EGC and 15d-PGJ2 inhibit intestinal epithelial cells (IEC) proliferation and promote IEC differenciation through a PPARγ dependant pathway. In addition, our results show a neuroprotective effect of EGC and 15d-PGJ2 on enteric neurons, against an oxidative stress, with the activation of glutathione synthesis, associated to the Nrf2 pathway. Finally, in vivo murine colorectal carcinogenesis was associated with an alteration of glial markers and prostaglandin enzyme expression. An in situ analysis of enteric nervous system, using a method developed in this work, might complete these pathophysiological studies. The pleiotropic effects revealing of this new glial-derived lipidic mediator, the 15d- PGJ2, arise the crucial role of EGC in the neuro-glio-epithelial unit and in digestive function control.Des études récentes suggèrent que les cellules gliales entériques (CGE) ont un rôle essentiel dans les fonctions de la barrière épithéliale intestinale (BEI) et dans la survie neuronale, les effets des CGE étant souvent associés à la libération de facteurs gliaux. Dans ce contexte, ce travail de thèse a d'abord permis d'identifier la 15-déoxy-delta12,14 prostaglandine J2 (15d-PGJ2), un dérivé de l'acide arachidonique, comme nouveau facteur synthétisé et sécrété par les CGE. Les résultats obtenus montrent que les CGE et la 15d-PGJ2 inhibent la prolifération des cellules épithéliales intestinales (CEI) et augmentent leur différenciation en utilisant une voie de signalisation dépendante de PPARγ. Nos résultats montrent également un effet neuroprotecteur des CGE et de la 15d-PGJ2 sur les neurones entériques dans des situations de stress oxydant avec une activation de la synthèse du glutathion dans les neurones, associée à une voie de signalisation dépendante de Nrf2. Enfin, dans une étude in vivo de carcinogénèse colique chez la souris, des altérations de marqueurs gliaux et des enzymes impliquées dans la synthèse des prostaglandines ont été mis en évidence. Une approche globale in situ du système nerveux entérique mise au point dans ce travail devrait permettre de compléter ces études physiopathologiques. La mise en évidence des effets pléïotropiques de ce nouveau médiateur lipidique d'origine gliale, la 15d-PGJ2, souligne l'importance des CGE au sein de l'unité neuro-glioépithéliale et dans le contrôle des fonctions digestives

Façonner l’intestin à partir des cellules souches pluripotentes humaines

L’étude des maladies digestives est parfois limitée par l’accès aux tissus de patients et les modèles précliniques ne sont pas toujours fidèles aux pathologies observées chez l’homme. Dans ce contexte, le développement d’organoïdes intestinaux à partir de cellules souches pluripotentes humaines représente une avancée importante dans l’étude des processus physiologiques et des pathologies digestives. Dans cette revue, nous rappelons les étapes majeures du développement du tractus digestif chez l’homme et décrivons le rationnel de la différenciation dirigée des cellules souches pluripotentes humaines. Nous faisons également un état des lieux sur les différents types d’organoïdes intestinaux existants et leurs applications en recherche fondamentale et préclinique. Enfin, nous discutons des opportunités offertes par les organoïdes intestinaux humains dans un contexte de médecine de précision et de médecine réparatrice

Community metabolic modeling of host-microbiota interactions through multi-objective optimization

The human gut microbiota comprises various microorganisms engaged in intricate interactions among themselves and with the host, affecting its health. While advancements in omics technologies have led to the inference of clear associations between microbiome composition and health conditions, we usually lack a causal and mechanistic understanding of these associations. For modeling mechanisms driving the interactions, we simulated the organism’s metabolism using in silico Genome-Scale Metabolic Models (GEMs). We used multi-objective optimization to predict and explain metabolic interactions among gut microbes and an intestinal epithelial cell. We developed a score integrating model simulation results to predict the type (competition, neutralism, mutualism) and quantify the interaction between several organisms. This framework uncovered a potential cross-feeding for choline, explaining the predicted mutualism between Lactobacillus rhamnosus GG and the epithelial cell. Finally, we analyzed a five-organism ecosystem, revealing that a minimal microbiota can favor the epithelial cell’s maintenance

Intestinal multicellular organoids to study colorectal cancer

International audienceModeling colorectal cancer (CRC) using organoids has burgeoned in the last decade, providing enhanced in vitro models to study the development and possible treatment options for this type of cancer. In this review, we describe both normal and CRC intestinal organoid models and their utility in the cancer research field. Besides highlighting studies that develop epithelial CRC organoid models, i.e. organoids without tumor microenvironment (TME) cellular components, we emphasize on the need for TME in CRC modeling, to help reduce translational disparities in this area. Also, we discuss the utilization of CRC organoids derived from pluripotent stem cells, as well as their potential to be used in cancer research. Finally, limitations and challenges in the current CRC organoids field, are discussed

Transplantation of human intestinal organoids into the mouse mesentery: A more physiologic and anatomic engraftment site

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Intestinal Stem Cell-on-Chip to Study Human Host-Microbiota Interaction

International audienceThe gut is a tubular organ responsible for nutrient absorption and harbors our intestinal microbiome. This organ is composed of a multitude of specialized cell types arranged in complex barrier-forming crypts and villi covered by a mucosal layer controlling nutrient passage and protecting from invading pathogens. The development and self-renewal of the intestinal epithelium are guided by niche signals controlling the differentiation of specific cell types along the crypt-villus axis in the epithelium. The emergence of microphysiological systems, or organ-on-chips, has paved the way to study the intestinal epithelium within a dynamic and controlled environment. In this review, we describe the use of organ-on-chip technology to control and guide these differentiation processes in vitro. We further discuss current applications and forthcoming strategies to investigate the mechanical processes of intestinal stem cell differentiation, tissue formation, and the interaction of the intestine with the microbiota in the context of gastrointestinal diseases

In Vivo Human PSC-Derived Intestinal Organoids to Study Stem Cell Maintenance

International audienceHuman intestinal organoids (HIOs), derived from pluripotent stem cells, are a new tool to gain insights in gastrointestinal development, physiology, and associated diseases. Herein, we present a method for renal transplantation of HIOs in immunocompromised mice and subsequent analysis to study intestinal epithelial cell proliferation. In addition, we describe how to generate enteroids from transplanted HIOs. The method highlights the specific steps to successful engraftment and provides insight into the study of human intestinal stem cells