Jamilloux Yvan, Lefeuvre Lucie, Magnotti Flora, Martin Amandine, Benezech Sarah, Allatif Omran, Penel-Page Mathilde, Hentgen Véronique, Sève Pascal, Gerfaud-Valentin Mathieu, Duquesne Agnès, Desjonquères Marine, Laurent Audrey, Rémy-Piccolo Vanessa, Cimaz Rolando, Cantarini Luca, Bourdonnay Emilie, Walzer Thierry, Py Bénédicte F, Belot Alexandre, Henry Thomas
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.
Department of Internal Medicine, University Hospital Croix-Rousse, Hospices Civils de Lyon.
Rheumatology (Oxford). 2018 Jan 1;57(1):100-111. doi: 10.1093/rheumatology/kex373.
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.
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.
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.
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.
家族性地中海热（FMF）是最常见的自身炎症性疾病，大多数患者与双等位基因MEFV突变相关。MEFV编码吡啉（Pyrin），一种在RhoGTPase抑制后被激活的炎性小体传感器。MEFV突变对Pyrin变体作为炎性小体传感器能力的功能影响在很大程度上尚不清楚。本研究的目的是评估MEFV突变是否影响Pyrin检测RhoGTPase抑制和其他炎性小体刺激的能力。
在Pyrin、NLRP3和NLRC4炎性小体特异性激活后，测量健康供体（HDs）和FMF患者单核细胞释放的白细胞介素-1β（IL-1β）和白细胞介素-18（IL-18）。实时监测Pyrin激活后的细胞死亡动力学。
在低浓度艰难梭菌毒素B（TcdB，一种Pyrin激活刺激物）作用下，FMF患者的单核细胞分泌的IL-1β和IL-18明显更多，且死亡速度明显快于HD单核细胞。携带两个MEFV第10外显子致病性变体的患者的单核细胞与携带单个第10外显子致病性变体的患者的单核细胞相比，显示出增强的Pyrin炎性小体反应，表明存在基因剂量效应。使用短的预激发步骤，FMF患者单核细胞对NLRP3和NLRC4激活刺激的反应正常，表明MEFV突变引发单核细胞对低剂量Pyrin激活刺激的特异性超敏反应。
与冷吡啉相关周期性综合征中描述的NLRP3突变相反，FMF相关的MEFV突变不会导致Pyrin的组成性激活。相反，FMF相关突变是超显性突变，可特异性降低Pyrin炎性小体的激活阈值，而不影响其他经典炎性小体。
