Op0106 a Novel Knock-in Mouse Model of Caps That Develops Amyloidosis: Therapeutic Efficacy of Proton Pump Inhibitors

Abstract

BackgroundCryopyrin associated periodic syndromes (CAPS) are a group of autoinflammatory diseases linked to gain-of-function mutations in the NLRP3 gene that cause uncontrolled IL-1β secretion. CINCA syndrome is the most severe CAPS disease characterized by central nervous system disabilities with a long-term risk of secondary amyloidosis.Proton pump inhibitors (PPIs), commonly used as inhibitors of gastric acid production, also display anti-inflammatory properties, making them promising drugs in sepsis and in inflammatory disorders.ObjectivesTo develop a novel NLRP3 knock-in (KI) mouse model of CAPS to evaluate amyloid deposition and to test alternative therapeutic approaches.MethodsWe generated KI mice by engineering N475K mutation associated with CAPS phenotype into mouse Nlrp3 gene. KI and Wild Type (WT) mice received PPIs or PBS intraperitoneally and were analyzed for survival, inflammation, cytokine secretion, and amyloidosis development. Cytokines secretion from bone marrow derived dendritic cells (BMDCs) and peritoneal macrophages (PMs) was evaluated by ELISA. Hystological analysis of all organs was evaluated by hematoxylin and eosin staining. Amyloid deposition was quantified through Congo Red staining.ResultsMutant NLRP3 KI mice displayed features that recapitulates the immunological and clinical phenotype of CAPS. These mice had systemic inflammation, with high levels of serum pro-inflammatory cytokines compared to WT controls. Hystological analysis revealed the presence of acute and chronic inflammatory cell infiltrates and amyloid deposits in spleen, liver and kidneys. As in CAPS monocytes, BMDCs and PM from KI mice showed a strong increase in IL-1β, IL-18, and IL-1α secretion and decreased levels in interleukin-1 receptor antagonist (IL-1Ra), the naturally occurring IL-1b inhibitor.PPIs treatment of KI mice showed a clear clinical impact with improvement of inflammatory conditions and regression of amyloid deposits. Remarkably, BMDCs and PMs from PPI-treated mice presented reduced secretion of pro-inflammatory cytokines and re-established the levels of IL-1RA.ConclusionNLRP3 KI mice display a CAPS phenotype with many characteristics of autoinflammation, including amyloidosis. The therapeutic effectiveness associated with lack of toxicity indicates that PPIs could represent relevant adjuvants to the anti-IL-1 drugs in IL-1 driven diseases.References[1] Gattorno M, Martini A. Beyond the NLRP3 inflammasome: autoinflammatory diseases reach adolescence. Arthritis Rheum. 2013;[2] Brydges SD, Mueller JL, McGeough MD, Pena CA, Misaghi A, Gandhi C Putnam CD, et al. Inflammasome-mediated disease animal models reveal roles for innate but not adaptive immunity. Immunity. 2009;[3] Balza E, Piccioli P, Carta S, Lavieri R, Gattorno M, Semino Cet al. Proton pump inhibitors protect mice from acute sistemic inflammation and induce long-term cross-tolerance. Cell Death Dis. 2016.Disclosure of InterestsArinna Bertoni: None declared, Sonia Carta: None declared, Chiara Baldovini: None declared, Federica Penco: None declar...

Lycopene ameliorates atrazine-induced pyroptosis in spleen by suppressing the Ox-mtDNA/Nlrp3 inflammasome pathway

“…A previous study has reported that Nlrp3 mutation caused amyloid deposits and inflammatory infiltrates in spleen. 29 Also, the Nlrp3's reads per kilobase per million mapped reads (RPKM) of spleen is highest among the organs in adult mice (NCBI, Mouse ENCODE transcriptome data). Thus, we explored whether ATZ could induce the activation of Nlrp3 in spleen.…”