• Thomas Gicquel, Sacha Robert, Pascal Loyer, Tatiana Victoni, Aude Bodin, Catherine Ribault, Florence Gleonnec, Isabelle Couillin, Elisabeth Boichot, and Vincent Lagente.
• *Unité Mixte de Recherche 991, Institut National de la Santé et de la Recherche Médicale, Université de Rennes 1, Rennes, France; Laboratoire de Toxicologie Biologique et Médico-Légale, Centre Hospitalier Universitaire de Rennes, Rennes, France; and Experimental and Molecular Immunology and Neurogenetics, Centre National de la Recherche Scientifique, Unité Mixte de Recherche 7355, Université d'Orleans, Orleans, France thomas.gicquel@univ-rennes1.fr.
• FASEB J. 2015 Oct 1; 29 (10): 4162-73.

AbstractThe Nod-like receptor family protein 3 (NLRP3)-inflammasome pathway is known to be activated by danger signals such as monosodium urate (MSU). We investigated the role of P2 purinergic receptors in the activation of NLRP3-inflammasome pathway after MSU treatment of primary human monocyte-derived macrophages (MDMs). After initial stimulation with a low concentration of LPS (0.1 µg/ml), a 6 h treatment with MSU crystals (250, 500, and 1000 µg/ml) induced the MDMs to release IL-1β, IL-1α, and IL-6 in a dose-dependent manner. Moreover, the caspase 1 inhibitor Z-YVAD-FMK and the cathepsin B inhibitor CA-074Me reduced production of IL-1β in a dose-dependent manner after LPS + MSU treatment. We used real-time reverse transcription-quantitative PCR to show that treatment with LPS and MSU (500 µg/ml) induced significantly greater expression of NLRP3 and IL-1β than after treatment with LPS. We also found that MSU treatment induced P2X purinergic receptor 7 (P2X7R) mRNA and protein expression. Furthermore, addition of the P2X7 purinergic receptor antagonist A-740003 significantly impeded IL-1β production and pro-IL-1β cleavage after treatment with LPS + MSU. Remarkably, RNA silencing of P2X7R (but not P2X4R) inhibited the release of IL-1β and other M1 macrophage cytokines (such as IL-1α, IL-6, and TNF-α) from MDMs stimulated with LPS + MSU. Taken as a whole, our results show that P2 purinergic receptors and the NLRP3 inflammasome pathway are involved in the secretion of IL-1β from MSU-stimulated human macrophages. This pathway may constitute a novel therapeutic target for controlling the inflammatory process in several associated pathologies.© FASEB.

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