Convallatoxin inhibits IL-1β production by suppressing zinc finger protein 91 (ZFP91)-mediated pro-IL-1β ubiquitination and caspase-8 inflammasome activity.

Abstract

BACKGROUND AND PURPOSE:

ZFP91 positively regulates IL-1β production in macrophages and may be a potential therapeutic target to treat inflammatory-related diseases. We investigated whether this process is modulated by convallatoxin, which is a cardiac glycoside isolated from the traditional Chinese medicinal plant Adonis amurensis Regel et Radde.

EXPERIMENTAL APPROACH:

In vitro, the mechanisms by which convallatoxin inhibits ZFP91-regulated IL-1β expression were investigated using molecular docking, western blotting, RT-PCR, ELISA, immunofluorescence and immunoprecipitation assays.In vivo, mice liver injury was induced by an intraperitoneal injection of D-GalN and LPS, colitis was induced by oral administration of dextran sulfate sodium (DSS) in drinking water and peritonitis was induced by an intraperitoneal injection of alum.

KEY RESULTS:

We confirmed that convallatoxin inhibited the release of IL-1β by down-regulating ZFP91. Importantly, we found that convallatoxin significantly reduced K63-linked polyubiquitination of pro-IL-1β regulated by ZFP91 and decreased the efficacy of pro-IL-1β cleavage. Moreover, convallatoxin suppressed ZFP91-mediated activation of the non-canonical cysteine-requiring aspartate protease-8 (caspase-8) inflammasome and MAPK signalling pathways in macrophages. Furthermore, we showed that ZFP91 promoted the assembly of the caspase-8 inflammasome complex, whereas convallatoxin treatment reversed this result. Mice in vivo studies further demonstrated that convallatoxin ameliorated D-GalN/LPS-induced liver injury, DSS-induced colitis and alum-induced peritonitis by down-regulating ZFP91.

CONCLUSION AND IMPLICATIONS:

We show for the first time that convallatoxin-mediated inhibition of ZFP91 is an important regulatory event that prevents inappropriate inflammatory responses to maintain immune homeostasis. This mechanism provides new insight for the development of convallatoxin as a novel anti-inflammatory drug targeting ZFP91.

LINKED ARTICLES:

This article is part of a themed issue on Inflammation, Repair and Ageing. To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v179.9/issuetoc.

• Authors: Yue Xing, Jing Ying Wang, Ming Yue Li, Zhi Hong Zhang, Hong Lan Jin, Hong Xiang Zuo, Juan Ma, Xuejun Jin
• Journal: British journal of pharmacology (Br J Pharmacol) Vol. 179 Issue 9 Pg. 1887-1907 (05 2022) ISSN: 1476-5381 [Electronic] England
• PMID: 34825365 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
• Copyright: © 2021 The British Pharmacological Society.

Chemical References

• DNA-Binding Proteins
• IL1B protein, mouse
• Inflammasomes
• Interleukin-1beta
• NLR Family, Pyrin Domain-Containing 3 Protein
• Strophanthins
• Transcription Factors
• Casp8 protein, mouse
• Caspase 8
• Caspase 1
• convallatoxin

Topics

• Animals
• Caspase 1 (metabolism)
• Caspase 8 (metabolism)
• DNA-Binding Proteins (antagonists & inhibitors)
• Inflammasomes (drug effects, metabolism)
• Interleukin-1beta (antagonists & inhibitors, biosynthesis)
• Mice
• Mice, Inbred C57BL
• Molecular Docking Simulation
• NLR Family, Pyrin Domain-Containing 3 Protein (metabolism)
• Strophanthins (pharmacology)
• Transcription Factors (antagonists & inhibitors)
• Ubiquitination
• Zinc Fingers