title: 5,6-Dimethylxanthenone-4-acetic acid (DMXAA) activates stimulator of interferon gene (STING)-dependent innate immune pathways and is regulated by mitochondrial membrane potential.
abstract: The chemotherapeutic agent 5,6-dimethylxanthenone-4-acetic acid (DMXAA) is a potent inducer of type I IFNs and other cytokines. This ability is essential for its chemotherapeutic benefit in a mouse cancer model and suggests that it might also be useful as an antiviral agent. However, the mechanism underlying DMXAA-induced type I IFNs, including the host proteins involved, remains unclear. Recently, it was reported that the antioxidant N-acetylcysteine (NAC) decreased DMXAA-induced TNF-α and IL-6, suggesting that oxidative stress may play a role. The goal of this study was to identify host proteins involved in DMXAA-dependent signaling and determine how antioxidants modulate this response. We found that expression of IFN-β in response to DMXAA in mouse macrophages requires the mitochondrial and endoplasmic reticulum resident protein STING. Addition of the antioxidant diphenylene iodonium (DPI) diminished DMXAA-induced IFN-β, but this decrease was independent of both the NADPH oxidase, Nox2, and de novo generation of reactive oxygen species. Additionally, IFN-β up-regulation by DMXAA was inhibited by agents that target the mitochondrial electron transport chain and, conversely, loss of mitochondrial membrane potential correlated with diminished innate immune signaling in response to DMXAA. Up-regulation of Ifnb1 gene expression mediated by cyclic dinucleotides was also impaired by DPI, whereas up-regulation of Ifnb1 mRNA due to cytosolic double-stranded DNA was not. Although both stimuli signal through STING, cyclic dinucleotides interact directly with STING, suggesting that recognition of DMXAA by STING may also be mediated by direct interaction.
authors.affiliation: Department of Microbiology and Immunology, University of Maryland, School of Medicine (UMB), Baltimore, Maryland 21201, USA.
authors.forename: Daniel
authors.initials: D
authors.lastname: Prantner
authors.forename: Darren J
authors.initials: DJ
authors.lastname: Perkins
authors.forename: Wendy
authors.initials: W
authors.lastname: Lai
authors.forename: Mark S
authors.initials: MS
authors.lastname: Williams
authors.forename: Shruti
authors.initials: S
authors.lastname: Sharma
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Fitzgerald
authors.forename: Stefanie N
authors.initials: SN
authors.lastname: Vogel
mesh_terms: D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D007113:Immunity, Innate / Q000187:drug effects* / Q000235:genetics; D016899:Interferon-beta / Q000096:biosynthesis / Q000235:genetics / Q000276:immunology; D015850:Interleukin-6 / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D017737:Macrophages, Peritoneal / Q000166:cytology / Q000276:immunology / Q000378:metabolism; D008562:Membrane Glycoproteins / Q000235:genetics / Q000378:metabolism; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects* / Q000235:genetics / Q000276:immunology; D008565:Membrane Proteins / Q000235:genetics / Q000276:immunology / Q000378:metabolism*; D051379:Mice; D018345:Mice, Knockout; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases / Q000235:genetics / Q000378:metabolism; D009861:Onium Compounds / Q000494:pharmacology; D016877:Oxidants / Q000494:pharmacology; D015398:Signal Transduction / Q000187:drug effects* / Q000235:genetics / Q000276:immunology; D014409:Tumor Necrosis Factor-alpha / Q000235:genetics / Q000276:immunology / Q000378:metabolism; D015854:Up-Regulation / Q000187:drug effects / Q000235:genetics / Q000276:immunology; D044004:Xanthones / Q000494:pharmacology*; D000099197:STING Protein
chemical_list: D000970:Antineoplastic Agents; D004791:Enzyme Inhibitors; D016899:Interferon-beta; D015850:Interleukin-6; D008562:Membrane Glycoproteins; D008565:Membrane Proteins; D000074662:NADPH Oxidase 2; D019255:NADPH Oxidases; D009861:Onium Compounds; D016877:Oxidants; D014409:Tumor Necrosis Factor-alpha; D044004:Xanthones; C530855:Sting1 protein, mouse; D000099197:STING Protein; C066668:vadimezan; C007517:diphenyleneiodonium; C488842:Cybb protein, mouse