IL-1 receptor antagonist ameliorates inflammasome-dependent alcoholic steatohepatitis in mice
Jan Petrasek, … , Evelyn A. Kurt-Jones, Gyongyi Szabo
Jan Petrasek, … , Evelyn A. Kurt-Jones, Gyongyi Szabo
Published September 4, 2012
Citation Information: J Clin Invest. 2012;122(10):3476-3489. https://doi.org/10.1172/JCI60777.
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Research Article Hepatology

IL-1 receptor antagonist ameliorates inflammasome-dependent alcoholic steatohepatitis in mice

Abstract

Alcoholic liver disease (ALD) is characterized by steatosis and upregulation of proinflammatory cytokines, including IL-1β. IL-1β, type I IL-1 receptor (IL-1R1), and IL-1 receptor antagonist (IL-1Ra) are all important regulators of the IL-1 signaling complex, which plays a role in inflammation. Furthermore, IL-1β maturation is dependent on caspase-1 (Casp-1). Using IL-1Ra–treated mice as well as 3 mouse models deficient in regulators of IL-1β activation (Casp-1 and ASC) or signaling (IL-1R1), we found that IL-1β signaling is required for the development of alcohol-induced liver steatosis, inflammation, and injury. Increased IL-1β was due to upregulation of Casp-1 activity and inflammasome activation. The pathogenic role of IL-1 signaling in ALD was attributable to the activation of the inflammasome in BM-derived Kupffer cells. Importantly, in vivo intervention with a recombinant IL-1Ra blocked IL-1 signaling and markedly attenuated alcohol-induced liver inflammation, steatosis, and damage. Furthermore, physiological doses of IL-1β induced steatosis, increased the inflammatory and prosteatotic chemokine MCP-1 in hepatocytes, and augmented TLR4-dependent upregulation of inflammatory signaling in macrophages. In conclusion, we demonstrated that Casp-1–dependent upregulation of IL-1β and signaling mediated by IL-1R1 are crucial in ALD pathogenesis. Our findings suggest a potential role of IL-1R1 inhibition in the treatment of ALD.

Authors

Jan Petrasek, Shashi Bala, Timea Csak, Dora Lippai, Karen Kodys, Victoria Menashy, Matthew Barrieau, So-Yun Min, Evelyn A. Kurt-Jones, Gyongyi Szabo

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Figure 9

BM-derived cells mediate pathogenic effects of Casp-1 in ALD.

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BM-derived cells mediate pathogenic effects of Casp-1 in ALD. (A–E) LMNC...
(A–E) LMNCs or primary hepatocytes were isolated from the livers of chow-fed WT mice as described in Methods. Pro–Casp-1 levels in cell lysate were evaluated using immunoblotting and normalized to β-actin (A). Expression of pro-Casp-1, Asc, Nlrp3, and pro-Il-1b was measured using qPCR (B). WT mice received 1 dose of intragastric EtOH (5 g/kg body weight) or isocaloric dextran-maltose per day on 3 consecutive days. 12 hours after the third intragastric gavage, LMNCs or primary hepatocytes were isolated. Cleaved forms of Casp-1 and IL-1β in cell lysates (C) were analyzed using antibodies that identify both full-length (short exposure, presented in linear contrast mode) and cleaved forms (long exposure, presented in sigmoidal contrast mode) and normalized to β-actin (D and E). LMNCs or hepatocytes were pooled from 5 (A and C–E) or 11 (B) mice per group. (F–L) WT/WT-BM, Casp-1–KO/WT-BM, and WT/Casp-1–KO–BM mice were fed control (n = 4–5 per genotype) or alcohol (n = 8 per genotype) diet and sacrificed 4 weeks later, as described in Methods. Liver injury was assessed by liver H&E staining and serum ALT (F and H). Steatosis was evaluated by Oil-red-O staining (G and I). Serum levels of IL-1β (J), TNF-α (K), and MCP-1 (L) were measured by specific ELISA. Numbers in graphs denote P values. Original magnification, ×200.