TNF regulates transcription of NLRP3 inflammasome components and inflammatory molecules in cryopyrinopathies
Matthew D. McGeough, … , Ariel E. Feldstein, Hal M. Hoffman
Matthew D. McGeough, … , Ariel E. Feldstein, Hal M. Hoffman
Published November 13, 2017
Citation Information: J Clin Invest. 2017;127(12):4488-4497. https://doi.org/10.1172/JCI90699.
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Research Article Immunology Inflammation

TNF regulates transcription of NLRP3 inflammasome components and inflammatory molecules in cryopyrinopathies

Abstract

The NLRP3 inflammasome is a protein complex responsible for caspase-1–dependent maturation of the proinflammatory cytokines IL-1β and IL-18. Gain-of-function missense mutations in NLRP3 cause the disease spectrum known as the cryopyrin-associated periodic syndromes (CAPS). In this study, we generated Nlrp3-knockin mice on various KO backgrounds including Il1b/Il18-, caspase-1–, caspase-11– (Casp1/11-), and Tnf-deficient strains. The Nlrp3L351P Il1b–/– Il18–/– mutant mice survived and grew normally until adulthood and, at 6 months of age, exhibited marked splenomegaly and leukophilia. Injection of these mice with low-dose LPS resulted in elevated serum TNF levels compared with Nlrp3L351P Casp1/11–/– mice and Il1b–/– Il18–/– littermates. Treatment of Nlrp3A350V mice with the TNF inhibitor etanercept resulted in all pups surviving to adulthood, with normal body and spleen/body weight ratios. Nlrp3A350V Tnf–/– mice showed a similar phenotypic rescue, with marked reductions in serum IL-1β and IL-18, reduced myeloid inflammatory infiltrate in the skin and spleen, and substantial decreases in splenic mRNA expression of both inflammasome components (Nlrp3, Pycard, pro-Casp1) and pro-cytokines (Il1b, Il18). Likewise, we observed a reduction in the expression of both pro-Casp1 and pro-Il1b in cultured Nlrp3A350V Tnf–/– BM-derived DCs. Our data show that TNF is an important transcriptional regulator of NLRP3 inflammasome components in murine inflammasomopathies. Moreover, these results may have therapeutic implications for CAPS patients with partial responses to IL-1–targeted therapies.

Authors

Matthew D. McGeough, Alexander Wree, Maria E. Inzaugarat, Ariela Haimovich, Casey D. Johnson, Carla A. Peña, Raphaela Goldbach-Mansky, Lori Broderick, Ariel E. Feldstein, Hal M. Hoffman

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Figure 6

TNF ablation significantly reduces splenic myeloid infiltrate and expression of NLRP3 inflammasome components and pro-cytokines.

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TNF ablation significantly reduces splenic myeloid infiltrate and expres...
(A) IHC shows strong MPO-positive staining in splenic tissue from Nlrp3A350V mice, with resolution and intermediate staining in Nlrp3A350V Tnf–/– and Nlrp3A350V Tnf+/– mice, respectively. Sections are representative of 6 mice per group (original magnification, ×40 for H&E staining and ×20 for F4/80 and MPO staining). Scale bar: 100 μm. (B and C) Splenic mRNA levels of Ly6c, iNos, Mpo, Cxcl1, and Cxcl2 were all significantly decreased in Nlrp3A350V Tnf–/– animals compared with levels in intact-Nlrp3A350V mice. Nlrp3A350V Tnf+/– mice had a nonsignificant trend toward reduced Ly6c, Mpo, and Cxcl2 mRNA levels and similar values for iNos and Cxcl1 when compared with Nlrp3A350V mice. (D and E) Examination of inflammasome components revealed significant reductions in splenic mRNA expression of Nlrp3, Asc, pro-Casp1, pro-Il1, and pro-Il18 in Nlrp3A350V Tnf–/– mice, with a trend toward reductions in all correlates in Nlrp3A350V Tnf+/– animals compared with Nlrp3A350V animals (n = 10 for Nlrp3A350V, n = 12 for Tnf–/–, n = 13 for Nlrp3A350V Tnf–/–, and n = 19 for Nlrp3A350V Tnf+/– mice in B–E). *P < 0.05, by Kruskal-Wallis with Dunn’s multiple comparisons test. Data represent the mean ± SEM.