TBK1 and IKKε Act Redundantly to Mediate STING-Induced NF-κB Responses in Myeloid Cells

• Published in: Cell reports (Cambridge) Vol. 31; no. 1; p. 107492
• Main Authors: Balka, Katherine R., Louis, Cynthia, Saunders, Tahnee L., Smith, Amber M., Calleja, Dale J., D’Silva, Damian B., Moghaddas, Fiona, Tailler, Maximilien, Lawlor, Kate E., Zhan, Yifan, Burns, Christopher J., Wicks, Ian P., Miner, Jonathan J., Kile, Benjamin T., Masters, Seth L., De Nardo, Dominic
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 07.04.2020; Elsevier
• Subjects: Animals; cGAS; cytokines; Female; HEK293 Cells; Humans; I-kappa B Kinase - metabolism; I-kappa B Kinase - physiology; IKKε; Immunity, Innate; innate immunity; Interferon Regulatory Factor-3 - metabolism; Interferon-beta - metabolism; Male; Membrane Proteins - metabolism; Membrane Proteins - physiology; Mice; Mice, Inbred C57BL; Myeloid Cells - metabolism; NF-kappa B - metabolism; NF-κB; Nucleotides, Cyclic - metabolism; Phosphorylation; protein kinases; Protein Serine-Threonine Kinases - metabolism; Protein Serine-Threonine Kinases - physiology; signal transduction; Signal Transduction - immunology; STING; TBK1; type I interferons; NF-κB; TBK1; innate immunity; signal transduction; cGAS; protein kinases; STING; cytokines; IKKε; type I interferons
• ISSN: 2211-1247; 2211-1247
• DOI: 10.1016/j.celrep.2020.03.056

Stimulator of Interferon Genes (STING) is a critical component of host innate immune defense but can contribute to chronic autoimmune or autoinflammatory disease. Once activated, the cyclic guanosine monophosphate (GMP)-adenosine monophosphate (AMP) (cGAMP) synthase (cGAS)-STING pathway induces both type I interferon (IFN) expression and nuclear factor-κB (NF-κB)-mediated cytokine production. Currently, these two signaling arms are thought to be mediated by a single upstream kinase, TANK-binding kinase 1 (TBK1). Here, using genetic and pharmacological approaches, we show that TBK1 alone is dispensable for STING-induced NF-κB responses in human and mouse immune cells, as well as in vivo. We further demonstrate that TBK1 acts redundantly with IκB kinase ε (IKKε) to drive NF-κB upon STING activation. Interestingly, we show that activation of IFN regulatory factor 3 (IRF3) is highly dependent on TBK1 kinase activity, whereas NF-κB is significantly less sensitive to TBK1/IKKε kinase inhibition. Our work redefines signaling events downstream of cGAS-STING. Our findings further suggest that cGAS-STING will need to be targeted directly to effectively ameliorate the inflammation underpinning disorders associated with STING hyperactivity. [Display omitted] •TBK1 is dispensable for NF-κB activation downstream of STING in vitro and in vivo•TBK1 and IKKε act redundantly to elicit STING-induced NF-κB activation•STING-NF-κB is less sensitive to TBK1/IKKε kinase inhibition than type I IFN•TAK1 and IKK complexes are required for STING-mediated NF-κB responses Activation of NF-κB via STING is considered to be exclusively dependent on TBK1. Balka et al. now show that, although TBK1 and its kinase activity are critical for IRF3 activation and type I IFNs, it is dispensable for NF-κB. Instead, TBK1 and IKKε act redundantly to mediate STING-induced NF-κB responses.