Yvan Jamilloux1,2, Lucie Lefeuvre1,3, Flora Magnotti1,4,5, Amandine Martin1, Sarah Benezech1, Omran Allatif1,6, Mathilde Penel-Page7, Véronique Hentgen8, Pascal Sève2, Mathieu Gerfaud-Valentin2, Agnès Duquesne7, Marine Desjonquères7, Audrey Laurent7, Vanessa Rémy-Piccolo9, Rolando Cimaz4, Luca Cantarini5, Emilie Bourdonnay1, Thierry Walzer1, Bénédicte F Py1, Alexandre Belot1,7, Thomas Henry1. 1. Centre International de Recherche en Infectiologie (CIRI), Inserm U1111, Université Claude Bernard Lyon 1, CNRS, UMR5308, Ecole Normale Supérieure de Lyon, University of Lyon, F-69007. 2. Department of Internal Medicine, University Hospital Croix-Rousse, Hospices Civils de Lyon. 3. Department of General Medicine, Hospices Civils de Lyon, Lyon, France. 4. Pediatric Rheumatology Unit, AOU Meyer, University of Firenze, Firenze. 5. Research Center of Systemic Autoinflammatory Diseases and Behcet's Disease Clinic, Rheumatology Unit, University of Siena, Siena, Italy. 6. Bioinformatics and Biostatistics Service (BIBS), University of Lyon, Lyon. 7. Department of Paediatric Nephrology, Rheumatology, Dermatology, Hôpital Femme-Mère Enfant, Bron. 8. French Reference Centre for Autoinflammatory Diseases (CEREMAI), Versailles Hospital, Le Chesnay. 9. Department of Paediatric Rheumatology, Hôpital Nord Ouest, Villefranche sur Saône, France.
Abstract
Objectives: FMF is the most frequent autoinflammatory disease and is associated in most patients with bi-allelic MEFV mutations. MEFV encodes Pyrin, an inflammasome sensor activated following RhoGTPase inhibition. The functional consequences of MEFV mutations on the ability of Pyrin variants to act as inflammasome sensors are largely unknown. The aim of this study was to assess whether MEFV mutations affect the ability of Pyrin to detect RhoGTPase inhibition and other inflammasome stimuli. Methods: IL-1β and IL-18 released by monocytes from healthy donors (HDs) and FMF patients were measured upon specific engagement of the Pyrin, NLRP3 and NLRC4 inflammasomes. Cell death kinetics following Pyrin activation was monitored in real time. Results: Monocytes from FMF patients secreted significantly more IL-1β and IL-18 and died significantly faster than HD monocytes in response to low concentrations of Clostridium difficile toxin B (TcdB), a Pyrin-activating stimulus. Monocytes from patients bearing two MEFV exon 10 pathogenic variants displayed an increased Pyrin inflammasome response compared with monocytes from patients with a single exon 10 pathogenic variant indicating a gene-dosage effect. Using a short priming step, the response of monocytes from FMF patients to NLRP3- and NLRC4-activating stimuli was normal indicating that MEFV mutations trigger a specific hypersensitivity of monocytes to low doses of a Pyrin-engaging stimulus. Conclusion: Contrary to the NLRP3 mutations described in cryopyrin-associated periodic syndrome, FMF-associated MEFV mutations do not lead to a constitutive activation of Pyrin. Rather, FMF-associated mutations are hypermorphic mutations that specifically decrease the activation threshold of the Pyrin inflammasome without affecting other canonical inflammasomes.
Objectives:FMF is the most frequent autoinflammatory disease and is associated in most patients with bi-allelic MEFV mutations. MEFV encodes Pyrin, an inflammasome sensor activated following RhoGTPase inhibition. The functional consequences of MEFV mutations on the ability of Pyrin variants to act as inflammasome sensors are largely unknown. The aim of this study was to assess whether MEFV mutations affect the ability of Pyrin to detect RhoGTPase inhibition and other inflammasome stimuli. Methods: IL-1β and IL-18 released by monocytes from healthy donors (HDs) and FMFpatients were measured upon specific engagement of the Pyrin, NLRP3 and NLRC4 inflammasomes. Cell death kinetics following Pyrin activation was monitored in real time. Results: Monocytes from FMFpatients secreted significantly more IL-1β and IL-18 and died significantly faster than HD monocytes in response to low concentrations of Clostridium difficile toxin B (TcdB), a Pyrin-activating stimulus. Monocytes from patients bearing two MEFV exon 10 pathogenic variants displayed an increased Pyrin inflammasome response compared with monocytes from patients with a single exon 10 pathogenic variant indicating a gene-dosage effect. Using a short priming step, the response of monocytes from FMFpatients to NLRP3- and NLRC4-activating stimuli was normal indicating that MEFV mutations trigger a specific hypersensitivity of monocytes to low doses of a Pyrin-engaging stimulus. Conclusion: Contrary to the NLRP3 mutations described in cryopyrin-associated periodic syndrome, FMF-associated MEFV mutations do not lead to a constitutive activation of Pyrin. Rather, FMF-associated mutations are hypermorphic mutations that specifically decrease the activation threshold of the Pyrin inflammasome without affecting other canonical inflammasomes.
Authors: Iris Stoler; Judith Freytag; Banu Orak; Nadine Unterwalder; Stephan Henning; Katrin Heim; Horst von Bernuth; Renate Krüger; Stefan Winkler; Patience Eschenhagen; Eva Seipelt; Marcus A Mall; Dirk Foell; Christoph Kessel; Helmut Wittkowski; Tilmann Kallinich Journal: Front Immunol Date: 2020-06-11 Impact factor: 7.561