DISULFIRAM EXERTS DOSE-DEPENDENT ACTIVATING AND INHIBITORY EFFECTS ON THE HUMAN INFLAMMASOME

Abstract

TOPIC: Critical Care TYPE: Original Investigations PURPOSE: Gasdermin-D (GSDMD) is a pore-forming molecule that serves as the final effector of pyroptosis (a form of inflammatory cell death) following activation of the cellular inflammasome in monocytes. Disulfiram (DSM), a drug used in the treatment of alcohol abuse, has recently been shown to inhibit GSDMD via disruption of pore formation after its cleavage by the inflammatory caspases (1, 4, and 5). The aim of this study was to elucidate the inhibitory effects of DSM on GSDMD-mediated pyroptosis and explore its role as a potential therapeutic agent in sepsis. METHODS: A series of experiments was conducted using THP1 cells (a human monocytic cell line) or purified human monocytes from the blood of healthy donors. Samples were pretreated with DSM in various concentrations 30 minutes prior to inflammasome activation with bacterial lipopolysaccharide (LPS). Cells were then assessed under light microscopy for swelling and fluorescent microscopy for the formation of ASC specks (activated oligomers of the adaptor protein required for caspase activation). Cell death was assessed using a lactate dehydrogenase (LDH) cytotoxicity assay. Interleukin-1-beta (IL1s) release was measured by ELISA. GSDMD cleavage, pro-IL1s synthesis, and caspase-1 cleavage were assessed using immunoblots. RESULTS: Unexpectedly, low dose DSM accentuated inflammasome activation. Dramatic inflammasome induction was observed at a concentration of 10uM, a dose associated with near peak inhibition in the prior study. However, higher doses of 50 to 100 uM suppressed pyroptosis as evidenced by loss of cell swelling and ASC speck formation, as well as LDH and IL-1s release. The DSM effect occurred downstream of caspase-1 activation as evidenced by preserved intracellular pro-IL1s synthesis and caspase-1 cleavage in the presence of DSM. Contrary to the prior report, GSDMD cleavage appeared to be inhibited at these higher doses. CONCLUSIONS: DSM unexpectedly exhibits upstream activation of the inflammasome at low doses but downstream inhibition at high doses. CLINICAL IMPLICATIONS: Although DSM's inhibitory effects on inflammasome function make it a promising agent for the future treatment of acute inflammatory conditions such as sepsis and covid-19, our results indicate that further study is needed to better characterize its possible activating effects at lower concentrations. DISCLOSURES: Collaboration via BARDA grant funding relationship with Beckman Coulter, Inc. Please note: 9/19/2019-8/31/2014 Added 04/27/2021 by Elliott Crouser, source=Web Response, value=Grant/Research Support No relevant relationships by Gregory Eisinger, source=Web Response No relevant relationships by Mikhail Gavrilin, source=Web Response No relevant relationships by Wissam Osman, source=Web Response No relevant relationships by Evan Prather, source=Web Response No relevant relationships by Mark Wewers, source=Web Response