1. Macrophage IL-1b-positive microvesicles exhibit thromboinflammatory properties and are detectable in patients with active juvenile idiopathic arthritis.
- Author
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Cambon, Audrey, Rebelle, Charlotte, Bachelier, Richard, Arnaud, Laurent, Robert, Stéphane, Lagarde, Marie, Muller, Romain, Tellier, Edwige, Kara, Yéter, Leroyer, Aurélie, Farnarier, Catherine, Vallier, Loris, Chareyre, Corinne, Retornaz, Karine, Jurquet, Anne-Laure, Tran, Tu-Anh, Lacroix, Romaric, Dignat-George, Françoise, and Kaplanski, Gilles
- Subjects
JUVENILE idiopathic arthritis ,EXTRACELLULAR vesicles ,INTERLEUKIN-1 ,MACROPHAGES ,NLRP3 protein - Abstract
Objective: IL-1b is a leaderless cytokine with poorly known secretory mechanisms that is barely detectable in serum of patients, including those with an IL-1b-mediated disease such as systemic juvenile idiopathic arthritis (sJIA). Leukocyte microvesicles (MVs) may be a mechanism of IL-1b secretion. The first objective of our study was to characterize IL-1b-positive MVs obtained from macrophage cell culture supernatants and to investigate their biological functions in vitro and in vivo. The second objective was to detect circulating IL-1b-positive MVs in JIA patients. Methods: MVs were purified by serial centrifugations from PBMCs, or THP-1 differentiated into macrophages, then stimulated with LPS ± ATP. MV content was analyzed for the presence of IL-1b, NLRP3 inflammasome, caspase-1, P2X7 receptor, and tissue factor (TF) using ELISA, Western blot, or flow cytometry. MV biological properties were studied in vitro by measuring VCAM-1, ICAM-1, and Eselectin expression after HUVEC co-culture and factor-Xa generation test was realized. In vivo, MVs’ ability to recruit leukocytes in a murine model of peritonitis was evaluated. Plasmatic IL-1b-positive MVs were studied ex vivo in 10 active JIA patients using flow cytometry. Results: THP-1-derived macrophages stimulated with LPS and ATP released MVs, which contained NLRP3, caspase-1, and the 33-kDa precursor and 17-kDa mature forms of IL-1b and bioactive TF. IL-1b-positive MVs expressed P2X7 receptor and released soluble IL-1b in response to ATP stimulation in vitro. In mice, MVs induced a leukocyte peritoneal infiltrate, which was reduced by treatment with the IL-1 receptor antagonist. Finally, IL-1b-positive MVs were detectable in plasma from 10 active JIA patients. Conclusion: MVs shed from activated macrophages contain IL-1b, NLRP3 inflammasome components, and TF, and constitute thrombo-inflammatory vectors that can be detected in the plasma from active JIA patients. [ABSTRACT FROM AUTHOR]
- Published
- 2023
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