Toll-like receptor 9 trafficking and signaling for type I interferons requires PIKfyve activity

DDX3 is a DEAD-box RNA helicase that we and others have previously implicated in antiviral immune signalling pathways leading to type I interferon (IFN) induction. We previously demonstrated that it directly interacts with the kinase IKKε (IκB kinase ε), enhances it activation, and then facilitates phosphorylation of the transcription factor IRF3 by IKKε. However, the TLR7/9 (Toll-like receptor 7/9)-mediated pathway, one of the most physiologically relevant IFN induction pathways, proceeds independently of IKKε or the related kinase TBK1 (TANK-binding kinase 1). This pathway induces type I IFN production via the kinases NIK (NF-κB-inducing kinase) and IKKα and is activated when plasmacytoid dendritic cells sense viral nucleic acids. In the present study, we demonstrate that DDX3 also directly interacts with IKKα and enhances its autophosphorylation and -activation. Modulation of DDX3 expression consequently affected NIK/IKKα-mediated IRF7 phosphorylation and induction of type I interferons. In addition, alternative NF-κB (nuclear factor-κB) activation, another pathway regulated by NIK and IKKα, was also down-regulated in DDX3 knockdown cells. This substantially broadens the effects of DDX3 in innate immune signalling to pathways beyond TBK1/IKKε and IFN induction. Dysregulation of these pathways is involved in disease states, and thus, our research might implicate DDX3 as a potential target for their therapeutic manipulation.

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The protective role of Toll-like receptor 3 and type-I interferons in the pathophysiology of vein graft disease

Journal of Molecular and Cellular Cardiology ◽

10.1016/j.yjmcc.2018.06.001 ◽

2018 ◽

Vol 121 ◽

pp. 16-24 ◽

Cited By ~ 5

Author(s):

K.H. Simons ◽

M.R. de Vries ◽

H.A.B. Peters ◽

J.F. Hamming ◽

J.W. Jukema ◽

...

Keyword(s):

Vein Graft ◽

Protective Role ◽

Type I Interferons ◽

Type I ◽

Toll Like Receptor ◽

Vein Graft Disease ◽

Graft Disease

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A Computational Probe into the Structure and Dynamics of the Full-Length Toll-Like Receptor 3 in a Phospholipid Bilayer

International Journal of Molecular Sciences ◽

10.3390/ijms21082857 ◽

2020 ◽

Vol 21 (8) ◽

pp. 2857

Author(s):

Mahesh Chandra Patra ◽

Maria Batool ◽

Muhammad Haseeb ◽

Sangdun Choi

Keyword(s):

Interleukin 1 ◽

Full Length ◽

Phospholipid Bilayer ◽

Type I Interferons ◽

Type I ◽

Toll Like Receptor ◽

Phosphate Backbone ◽

Dimerization Interface ◽

Dynamics Simulations ◽

Tir Domains

Toll-like receptor 3 (TLR3) provides the host with antiviral defense by initiating an immune signaling cascade for the production of type I interferons. The X-ray structures of isolated TLR3 ectodomain (ECD) and transmembrane (TM) domains have been reported; however, the structure of a membrane-solvated, full-length receptor remains elusive. We investigated an all-residue TLR3 model embedded inside a phospholipid bilayer using molecular dynamics simulations. The TLR3-ECD exhibited a ~30°–35° tilt on the membrane due to the electrostatic interaction between the N-terminal subdomain and phospholipid headgroups. Although the movement of dsRNA did not affect the dimer integrity of TLR3, its sugar-phosphate backbone was slightly distorted with the orientation of the ECD. TM helices exhibited a noticeable tilt and curvature but maintained a consistent crossing angle, avoiding the hydrophobic mismatch with the bilayer. Residues from the αD helix and the CD and DE loops of the Toll/interleukin-1 receptor (TIR) domains were partially absorbed into the lower leaflet of the bilayer. We found that the previously unknown TLR3-TIR dimerization interface could be stabilized by the reciprocal contact between αC and αD helices of one subunit and the αC helix and the BB loop of the other. Overall, the present study can be helpful to understand the signaling-competent form of TLR3 in physiological environments.

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Toll-Like Receptor 3 Mediates Establishment of an Antiviral State against Hepatitis C Virus in Hepatoma Cells

Journal of Virology ◽

10.1128/jvi.01125-09 ◽

2009 ◽

Vol 83 (19) ◽

pp. 9824-9834 ◽

Cited By ~ 148

Author(s):

Nan Wang ◽

Yuqiong Liang ◽

Santhana Devaraj ◽

Jie Wang ◽

Stanley M. Lemon ◽

...

Keyword(s):

Hepatitis C Virus ◽

Hepatitis C ◽

Hepatitis Virus ◽

Hepatoma Cells ◽

Human Hepatocytes ◽

Hcv Infection ◽

Type I Interferons ◽

Type I ◽

Toll Like Receptor ◽

Virus Infections

ABSTRACT Toll-like receptor-3 (TLR3) senses double-stranded RNA, initiating signaling that activates NF-κB and interferon regulatory factor 3 (IRF-3), thereby inducing the synthesis of proinflammatory cytokines, type I interferons, and numerous interferon-stimulated genes (ISGs). This pathway has not been extensively investigated in human hepatocytes, and its role in sensing and protecting against hepatitis virus infections is uncertain. We show here that primary human hepatocytes express TLR3 and robustly upregulate ISGs upon poly(I·C) stimulation. We also show that TLR3 senses hepatitis C virus (HCV) infection when expressed in permissive hepatoma cells, acting independently of retinoic acid-inducible gene I and inducing IRF-3 activation and the synthesis of ISGs that restrict virus replication. In turn, HCV infection reduces the abundance of TRIF, an essential TLR3 adaptor, and impairs poly(I·C)-induced signaling. The induction and disruption of TLR3 signaling by HCV may be important factors in determining the outcome of infection and the ability of HCV to establish persistent infections.

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Type I Interferons Protect From Toll-Like Receptor 9–Associated Liver Injury and Regulate IL-1 Receptor Antagonist in Mice

Gastroenterology ◽

10.1053/j.gastro.2010.08.020 ◽

2011 ◽

Vol 140 (2) ◽

pp. 697-708.e4 ◽

Cited By ~ 71

Author(s):

Jan Petrasek ◽

Angela Dolganiuc ◽

Timea Csak ◽

Evelyn A. Kurt–Jones ◽

Gyongyi Szabo

Keyword(s):

Liver Injury ◽

Receptor Antagonist ◽

Type I Interferons ◽

Type I ◽

Toll Like Receptor

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Toll-like Receptor 3–Mediated Suppression of TRAMP Prostate Cancer Shows the Critical Role of Type I Interferons in Tumor Immune Surveillance

Cancer Research ◽

10.1158/0008-5472.can-09-1162 ◽

2010 ◽

Vol 70 (7) ◽

pp. 2595-2603 ◽

Cited By ~ 70

Author(s):

Arnold I. Chin ◽

Andrea K. Miyahira ◽

Anthony Covarrubias ◽

Juli Teague ◽

Beichu Guo ◽

...

Keyword(s):

Prostate Cancer ◽

Critical Role ◽

Immune Surveillance ◽

Type I Interferons ◽

Type I ◽

Toll Like Receptor

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Toll-like receptor 3 agonist complexed with cationic liposome augments vaccine-elicited antitumor immunity by enhancing TLR3–IRF3 signaling and type I interferons in dendritic cells

Vaccine ◽

10.1016/j.vaccine.2012.05.027 ◽

2012 ◽

Vol 30 (32) ◽

pp. 4790-4799 ◽

Cited By ~ 46

Author(s):

Ce Wang ◽

Yan Zhuang ◽

Yijuan Zhang ◽

Zichao Luo ◽

Ningning Gao ◽

...

Keyword(s):

Dendritic Cells ◽

Antitumor Immunity ◽

Cationic Liposome ◽

Type I Interferons ◽

Type I ◽

Toll Like Receptor

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Priming of the cGAS-STING-TBK1 Pathway Enhances LPS-Induced Release of Type I Interferons

Cells ◽

10.3390/cells10040785 ◽

2021 ◽

Vol 10 (4) ◽

pp. 785

Author(s):

Alessandra Tesser ◽

Giulia Maria Piperno ◽

Alessia Pin ◽

Elisa Piscianz ◽

Valentina Boz ◽

...

Keyword(s):

Nucleic Acids ◽

Lupus Erythematosus ◽

Bacterial Infections ◽

Type I Interferons ◽

Type I ◽

Toll Like Receptor ◽

Systemic Lupus ◽

Toll Like Receptor 4 ◽

Murine Bone Marrow ◽

Cellular Models

Cytoplasmic nucleic acids sensing through cGAS-STING-TBK1 pathway is crucial for the production of antiviral interferons (IFNs). IFN production can also be induced by lipopolysaccharide (LPS) stimulation through Toll-like receptor 4 (TLR4) in appropriate conditions. Of note, both IFN production and dysregulated LPS-response could play a role in the pathogenesis of Systemic Lupus Erythematosus (SLE). Indeed, LPS can trigger SLE in lupus-prone mice and bacterial infections can induce disease flares in human SLE. However, the interactions between cGAS and TLR4 pathways to IFNs have been poorly investigated. To address this issue, we studied LPS-stimulation in cellular models with a primed cGAS-STING-TBK1 pathway. cGAS-stimulation was naturally sustained by undigested self-nucleic acids in fibroblasts from DNase2-deficiency interferonopathy, whilst it was pharmacologically obtained by cGAMP-stimulation in THP1 cells and murine bone marrow-derived dendritic cells. We showed that cells with a primed cGAS-STING-TBK1 pathway displayed enhanced IFNs production after TLR4-challenge. STING-inhibition did not affect IFN production after LPS alone, but prevented the amplified IFN production in cGAMP-primed cells, suggesting that functional STING is required for priming-dependent enhancement. Furthermore, we speculated that an increased PIK3AP1 expression in DNase2-deficient fibroblasts may link cGAMP-priming with increased LPS-induced IFN production. We showed that both the hyper-expression of PIK3API and the enhanced LPS-induced IFN production can be contrasted by STING inhibitors. Our results may explain how bacterial LPS can synergize with cGAS-pathway in promoting the development of SLE-like autoimmunity.

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