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

Aim: In the present study, we investigated the involvement of NLRP3 inflamma-some in the intestinal epithelial barrier (IEB) changes associated with obesity, and its role in the interplay between enteric glia and intestinal epithelial cells (IECs).Methods: Wild- 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.Results: HFD mice showed increased body weight, altered IEB integrity, in-creased 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 en-teric gliosis with consequent hyperactivation of enteric glial NLRP3/caspase- 1/IL- 1 beta signaling. Enteric glial- derived IL- 1 beta release exacerbates the IEB alterations. Such an effect was abrogated upon incubation with anakinra (IL- 1 beta receptor an-tagonist) and with conditioned medium derived from silenced- NLRP3 glial cells.Conclusion: HFD intake elicits mucosal enteric gliotic processes characterized by a hyperactivation of NLRP3/caspase- 1/IL- 1 beta signaling pathway, that contrib-utes to further exacerbate the disruption of intestinal mucosal barrier integrity. However, we cannot rule out the contribution of NLRP3 inflammasome activa-tion 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.