Special Issue on the “Regulation and Physiopathology of the Gut Barrier”

Impaired intestinal barrier function is a major feature of Crohn's disease (CD), leading to exacerbated inflammation in response to the microbiota. In this context, the translocation of intestinal bacteriophages (phages) and their effects on the host have been little investigated. We used phage fluorescence imaging coupled with ex-vivo and in-vitro models that mimic physiological and inflammatory conditions and found that phages can translocate across the intestinal barrier without disrupting its integrity. Although the translocation rate across the intestinal epithelium depended on phage morphology and the condition of the barrier, these factors did not influence the crossing of phage across the vascular endothelium. Virome analysis confirmed that viral sequences shared between blood and stool samples are more abundant in CD patients than healthy subjects, indicating that a barrier defect facilitates phage translocation from the gut to the bloodstream.

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Enteric glial NLRP3 inflammasome contributes to gut mucosal barrier alterations in a mouse model of diet‐induced obesity

D'Antongiovanni,

Fornai,

Colucci

et al. 2024

Acta Physiologica

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AimIn the present study, we investigated the involvement of NLRP3 inflammasome in the intestinal epithelial barrier (IEB) changes associated with obesity, and its role in the interplay between enteric glia and intestinal epithelial cells (IECs).MethodsWild‐type C57BL/6J and NLRP3‐KO (−/−) mice were fed with high‐fat diet (HFD) or standard diet for 8 weeks. Colonic IEB integrity and inflammasome activation were assessed. Immunolocalization of colonic mucosal GFAP‐ and NLRP3‐positive cells along with in vitro coculture experiments with enteric glial cells (EGCs) and IECs allowed to investigate the potential link between altered IEB, enteric gliosis, and NLRP3 activation.ResultsHFD mice showed increased body weight, altered IEB integrity, increased GFAP‐positive glial cells, and NLRP3 inflammasome hyperactivation. HFD‐NLRP3−/− mice showed a lower increase in body weight, an improvement in IEB integrity and an absence of enteric gliosis. Coculture experiments showed that palmitate and lipopolysaccharide contribute to IEB damage and promote enteric gliosis with consequent hyperactivation of enteric glial NLRP3/caspase‐1/IL‐1β signaling. Enteric glial‐derived IL‐1β release exacerbates the IEB alterations. Such an effect was abrogated upon incubation with anakinra (IL‐1β receptor antagonist) and with conditioned medium derived from silenced‐NLRP3 glial cells.ConclusionHFD intake elicits mucosal enteric gliotic processes characterized by a hyperactivation of NLRP3/caspase‐1/IL‐1β signaling pathway, that contributes to further exacerbate the disruption of intestinal mucosal barrier integrity. However, we cannot rule out the contribution of NLRP3 inflammasome activation from other cells, such as immune cells, in IEB alterations associated with obesity. Overall, our results suggest that enteric glial NLRP3 inflammasome might represent an interesting molecular target for the development of novel pharmacological approaches aimed at managing the enteric inflammation and intestinal mucosal dysfunctions associated with obesity.

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Special Issue on the “Regulation and Physiopathology of the Gut Barrier”

Abstract: The importance of gut barrier integrity in intestinal homeostasis and the consequences of its alteration in the etiology of human pathologies have been subjects of exponentially growing interest during the last decade [...]

Cited by 3 publications

References 85 publications

Effects of gut bacteria and their metabolites on gut health of animals

Effects of gut bacteria and their metabolites on gut health of animals

Differential translocation of bacteriophages across the intestinal barrier in health and Crohn’s disease

Enteric glial NLRP3 inflammasome contributes to gut mucosal barrier alterations in a mouse model of diet‐induced obesity

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