Dataset Information

NLRP3 inflammasome is expressed and regulated in human islets.

ABSTRACT: NRLP3 inflammasome is a protein complex involved in the maturation of IL1?. In the onset of type 1 diabetes as well as in islet transplantation, IL-1? is one of the cytokines involved in the recruitment of immune cells in islets and eventually in islet destruction. Whether IL-1? is produced by islet cells is still under debate and NLRP3 inflammasome-dependent IL-1? production has not been yet determined in human islets. The aim of this study was to determine the expression and the regulation of the NRLP3 inflammasome in human islets. Human islets were stimulated with LPS and successively with ATP (LPS?+?ATP) in the presence or absence of the inflammasome inhibitor glyburide. Islets were also incubated in hypoxic or normoxic conditions for 24?h in the presence or absence of glyburide. Then, IL1B and NLRP3 expression was studied by real time PCR, protein expression by western blot, protein localization by immunofluorescence and protein secretion by ELISA. LPS?+?ATP increased gene expression of NRLP3 and IL1B. Glyburide partially prevented this effect. IL-1? protein was localized in ? and non-? cells. Moreover, LPS?+?ATP increased IL-1? protein expression and production, which were prevented by glyburide. Hypoxia increased gene expression of NRLP3 and IL1B and induced IL-1? and caspase-1 production. Finally, hypoxia-induced cell death which was not prevented by inhibition of NLRP3 inflammasome. NRLP3 inflammasome is expressed and plays a role in IL-1? production by human islets. By contrast, NRLP3 inflammasome activation is not involved in islet cell death induced by hypoxia.

SUBMITTER: Lebreton F

PROVIDER: S-EPMC6018156 | biostudies-literature | 2018 Jun

REPOSITORIES: biostudies-literature

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NLRP3 inflammasome is expressed and regulated in human islets.

Lebreton Fanny F Berishvili Ekaterine E Parnaud Géraldine G Rouget Caroline C Bosco Domenico D Berney Thierry T Lavallard Vanessa V

Cell death & disease 20180625 7

NRLP3 inflammasome is a protein complex involved in the maturation of IL1β. In the onset of type 1 diabetes as well as in islet transplantation, IL-1β is one of the cytokines involved in the recruitment of immune cells in islets and eventually in islet destruction. Whether IL-1β is produced by islet cells is still under debate and NLRP3 inflammasome-dependent IL-1β production has not been yet determined in human islets. The aim of this study was to determine the expression and the regulation of ...[more]

PMID: 29941940

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Project description:Imbalance in lipid homeostasis is associated with discrepancies in immune signaling and is tightly linked to metabolic disorders. The diverse ways in which lipids impact immune signaling, however, remain ambiguous. The phospholipid phosphatidylinositol (PI), which is implicated in numerous immune disorders, is chiefly defined by its phosphorylation status. By contrast, the significance of the two fatty acid chains attached to the PI remains unknown. In this study, by using a mass spectrometry-based assay, we demonstrate a role for PI acyl group chains in regulating both the priming and activation steps of the NOD-like receptor family pyrin domain-containing 3 (NLRP3) inflammasome in mouse macrophages. In response to NLRP3 stimuli, cells deficient in ABC transporter ATP Binding Cassette Subfamily B Member 1 (ABCB1), which effluxes lipid derivatives, revealed defective inflammasome activation. Mechanistically, Abcb1 deficiency shifted the total PI configuration exhibiting a reduced ratio of short-chain to long-chain PI acyl lipids. Consequently, Abcb1 deficiency initiated the rapid degradation of Toll/IL-1R domain-containing adaptor protein, the TLR adaptor protein that binds PI (4,5)-bisphosphate, resulting in defective TLR-dependent signaling, and thus NLRP3 expression. Moreover, this accompanied increased NLRP3 phosphorylation at the Ser291 position and contributed to blunted inflammasome activation. Exogenously supplementing wild-type cells with linoleic acid (LA), but not arachidonic acid, reconfigured PI acyl chains. Accordingly, LA supplementation increased Toll/IL-1R domain-containing adaptor protein degradation, elevated NLRP3 phosphorylation, and abrogated inflammasome activation. Furthermore, NLRP3 Ser291 phosphorylation was dependent on PGE2-induced protein kinase A signaling because pharmacological inhibition of this pathway in LA-enriched cells dephosphorylated NLRP3. Altogether, our study reveals, to our knowledge, a novel metabolic-inflammatory circuit that contributes to calibrating immune responses.

Project description:BackgroundCompared with the precise targeting of drug-resistant mutant cancer cells, strategies for eliminating non-genetic adaptation-mediated resistance are limited. The pros and cons of the existence of inflammasomes in cancer have been reported. Nevertheless, the dynamic response of inflammasomes to therapies should be addressed.MethodsTumor-derived exosomes were purified by differential ultracentrifugation and validated by nanoparticle tracking analysis and transmission electron microscopy. A proximity ligation assay and interleukin-1β (IL-1β) level were used for detecting activation of NLRP3 inflammasomes. RNA sequencing was used to analyze the exosomal RNAs. MIR21 knocked out human monocytic THP cells and mir21 knocked out murine oral cancer MTCQ1 cells were generated for confirming the exosomal delivery of microRNA (miR)-21. Syngeneic murine models for head and neck cancer (C57BLJ/6J), breast cancer (BALB/C) and lung cancer (C57BL/6J) were applied for examining the impact of Snail-miR21 axis on inflammasome activation in vivo. Single-cell RNA sequencing was used for analyzing the tumor-infiltrated immune cells. Head and neck patient samples were used for validating the findings in clinical samples.ResultsWe demonstrated that in cancer cells undergoing Snail-induced epithelial-mesenchymal transition (EMT), tumor cells suppress NLRP3 inflammasome activities of tumor-associated macrophages (TAMs) in response to chemotherapy through the delivery of exosomal miR-21. Mechanistically, miR-21 represses PTEN and BRCC3 to facilitate NLRP3 phosphorylation and lysine-63 ubiquitination, inhibiting NLRP3 inflammasome assembly. Furthermore, the Snail-miR-21 axis shapes the post-chemotherapy tumor microenvironment (TME) by repopulating TAMs and by activating CD8+ T cells. In patients with head and neck cancer, the Snail-high cases lacked post-chemotherapy IL-1β surge and were correlated with a worse response.ConclusionsThis finding reveals the mechanism of EMT-mediated resistance beyond cancer stemness through modulation of post-treatment inflammasome activity. It also highlights the dynamic remodeling of the TME throughout metastatic evolution.

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NLRP3 inflammasome is expressed and regulated in human islets.

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NLRP3 inflammasome is expressed and regulated in human islets.

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