Mitochondrial ROS induced by chronic ethanol exposure promote hyper-activation of the NLRP3 inflammasome
Laura R. Hoyt,
Matthew J. Randall,
Jennifer L. Ather,
Daniel P. DePuccio,
Christopher C. Landry,
Xi Qian,
Yvonne M. Janssen-Heininger,
Albert van der Vliet,
Anne E. Dixon,
Eyal Amiel,
Matthew E. Poynter
Affiliations
Laura R. Hoyt
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Division of Pulmonary Disease and Critical Care, Department of Medicine, University of Vermont, Burlington, VT 05405, USA
Matthew J. Randall
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Division of Pulmonary Disease and Critical Care, Department of Medicine, University of Vermont, Burlington, VT 05405, USA
Jennifer L. Ather
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Division of Pulmonary Disease and Critical Care, Department of Medicine, University of Vermont, Burlington, VT 05405, USA
Daniel P. DePuccio
Department of Chemistry, University of Vermont, Burlington, VT 05405, USA
Christopher C. Landry
Department of Chemistry, University of Vermont, Burlington, VT 05405, USA; Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, USA
Xi Qian
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, VT 05405, USA
Yvonne M. Janssen-Heininger
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, VT 05405, USA; Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, USA
Albert van der Vliet
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Department of Pathology and Laboratory Medicine, University of Vermont, Burlington, VT 05405, USA; Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, USA
Anne E. Dixon
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Division of Pulmonary Disease and Critical Care, Department of Medicine, University of Vermont, Burlington, VT 05405, USA
Eyal Amiel
Department of Medical Laboratory and Radiation Sciences, University of Vermont, Burlington, VT 05405, USA; Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, USA
Matthew E. Poynter
Vermont Lung Center, University of Vermont, Burlington, VT 05405, USA; Division of Pulmonary Disease and Critical Care, Department of Medicine, University of Vermont, Burlington, VT 05405, USA; Cellular, Molecular, and Biomedical Sciences Graduate Program, University of Vermont, Burlington, VT 05405, USA; Correspondence to: Division of Pulmonary Disease and Critical Care Department of Medicine, University of Vermont, Given E410A 89 Beaumont Avenue, Burlington, VT 05405, USA.
Alcohol use disorders are common both in the United States and globally, and are associated with a variety of co-morbid, inflammation-linked diseases. The pathogenesis of many of these ailments are driven by the activation of the NLRP3 inflammasome, a multi-protein intracellular pattern recognition receptor complex that facilitates the cleavage and secretion of the pro-inflammatory cytokines IL-1β and IL-18. We hypothesized that protracted exposure of leukocytes to ethanol would amplify inflammasome activation, which would help to implicate mechanisms involved in diseases associated with both alcoholism and aberrant NLRP3 inflammasome activation. Here we show that long-term ethanol exposure of human peripheral blood mononuclear cells and a mouse macrophage cell line (J774) amplifies IL-1β secretion following stimulation with NLRP3 agonists, but not with AIM2 or NLRP1b agonists. The augmented NRLP3 activation was mediated by increases in iNOS expression and NO production, in conjunction with increases in mitochondrial membrane depolarization, oxygen consumption rate, and ROS generation in J774 cells chronically exposed to ethanol (CE cells), effects that could be inhibited by the iNOS inhibitor SEITU, the NO scavenger carboxy-PTIO, and the mitochondrial ROS scavenger MitoQ. Chronic ethanol exposure did not alter K+ efflux or Zn2+ homeostasis in CE cells, although it did result in a lower intracellular concentration of NAD+. Prolonged administration of acetaldehyde, the product of alcohol dehydrogenase (ADH) mediated metabolism of ethanol, mimicked chronic ethanol exposure, whereas ADH inhibition prevented ethanol-induced IL-1β hypersecretion. Together, these results indicate that increases in iNOS and mitochondrial ROS production are critical for chronic ethanol-induced IL-1β hypersecretion, and that protracted exposure to the products of ethanol metabolism are probable mediators of NLRP3 inflammasome hyperactivation. Keywords: Inflammasome, IL-1β, Ethanol, Inflammation
