scholarly journals Activation of RIG-I-mediated antiviral signaling triggers autophagy through the MAVS-TRAF6-Beclin-1 signaling axis

2018 ◽  
Author(s):  
Na-Rae Lee ◽  
Junsu Ban ◽  
Noh-Jin Lee ◽  
Chae-Min Yi ◽  
Jiyoon Choi ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Sendai Virus ◽  
Feedback Mechanism ◽  
Innate Immune ◽  
Beclin 1 ◽  
Interferon Response ◽  
Type I ◽  
Interferon Signaling ◽  
Negative Feedback Mechanism ◽  
Signaling Axis

AbstractAutophagy has been implicated in innate immune responses against various intracellular pathogens. Recent studies have reported that autophagy can be triggered by pathogen recognizing sensors, including Toll-like receptors and cyclic guanosine monophosphate-adenosine monophosphate synthase, to participate in innate immunity. In the present study, we examined whether the RIG-I signaling pathway, which detects viral infections by recognizing viral RNA, triggers the autophagic process. The introduction of polyI:C into the cytoplasm, or Sendai virus infection, significantly induced autophagy in normal cells but not in RIG-I-deficient cells. PolyI:C transfection or Sendai virus infection induced autophagy in the cells lacking type-I interferon signaling. This demonstrated that the effect was not due to interferon signaling. RIG-I-mediated autophagy diminished by the deficiency of mitochondrial antiviral signaling protein (MAVS) or tumor necrosis factor receptor-associated factor (TRAF)6, showing that the RIG-I-MAVS-TRAF6 signaling axis was critical for RIG-I-mediated autophagy. We also found that Beclin-1 was translocated to the mitochondria, and it interacted with TRAF6 upon RIG-I activation. Furthermore, Beclin-1 underwent K63-polyubiquitination upon RIG-I activation, and the ubiquitination decreased in TRAF6-deficient cells. This suggests that the RIG-I-MAVS-TRAF6 axis induced K63-linked polyubiquitination of Beclin-1, which has been implicated in triggering autophagy. Collectively, the results of this study show that the recognition of viral infection by RIG-I is capable of inducing autophagy to control viral replication. As deficient autophagy increases the type-I interferon response, the induction of autophagy by the RIG-I pathway might also contribute to preventing an excessive interferon response as a negative-feedback mechanism.ImportanceMammalian cells utilize various innate immune sensors to detect pathogens. Among those sensors, RIG-I recognizes viral RNA to detect intracellular viral replication. Although cells experience diverse physiological changes upon viral infection, studies to understand the role of RIG-I signaling have focused on the induction of type-I interferon. Autophagy is a process that sequesters cytosolic regions and degrades the contents to maintain cellular homeostasis. Autophagy participates in the immune system, and has been known to be triggered by some innate immune sensors, such as TLR4 and cGAS. We demonstrated that autophagy can be triggered by the activation of RIG-I. In addition, we also proved that MAVS-TRAF6 downstream signaling is crucial for the process. Beclin-1, a key molecule in autophagy, is translocated to mitochondria, where it undergoes K63-ubiquitination in a TRAF6-dependent manner upon RIG-I activation. As autophagy negatively regulates RIG-I-mediated signaling, the RIG-I-mediated activation of autophagy may function as a negative-feedback mechanism.

scholarly journals Vitamin D Potentiates the Inhibitory Effect of MicroRNA-130a in Hepatitis C Virus Replication Independent of Type I Interferon Signaling Pathway

2015 ◽  
Vol 2015 ◽  
pp. 1-5 ◽  
Author(s):  
Xiaoqiong Duan ◽  
Yujuan Guan ◽  
Yujia Li ◽  
Shan Chen ◽  
Shilin Li ◽  
...  
Keyword(s):  
Vitamin D ◽  
Type I Interferon ◽  
Inhibitory Effect ◽  
Therapeutic Strategies ◽  
Innate Immune ◽  
Type I ◽  
Interferon Signaling ◽  
Host Innate Immune Response ◽  
Antiviral Mechanism

Calcitriol, the bioactive metabolite of vitamin D, was reported to inhibit HCV production in a synergistic fashion with interferon, a treatmentin vitro. Our previous study established that miR-130a inhibits HCV replication by restoring the host innate immune response. We aimed to determine whether there is additive inhibitory effect of calcitriol and miR-130a on HCV replication. Here we showed that calcitriol potentiates the anti-HCV effect of miR-130a in both Con1b replicon and J6/JFH1 culture systems. Intriguingly, this potentiating effect of calcitriol on miR-130a was not through upregulating the expression of cellular miR-130a or through increasing the miR-130a-mediated IFNα/βproduction. All these findings may contribute to the development of novel anti-HCV therapeutic strategies although the antiviral mechanism needs to be further investigated.

scholarly journals The Severe Acute Respiratory Syndrome Coronavirus Nucleocapsid Inhibits Type I Interferon Production by Interfering with TRIM25-Mediated RIG-I Ubiquitination

2017 ◽  
Vol 91 (8) ◽  
Author(s):  
Yong Hu ◽  
Wei Li ◽  
Ting Gao ◽  
Yan Cui ◽  
Yanwen Jin ◽  
...  
Keyword(s):  
Severe Acute Respiratory Syndrome ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Innate Immune ◽  
Atypical Pneumonia ◽  
Type I ◽  
Spry Domain ◽  
N Protein ◽  
Host Interaction ◽  
C Terminus

ABSTRACT Severe acute respiratory syndrome (SARS) is a respiratory disease, caused by a coronavirus (SARS-CoV), that is characterized by atypical pneumonia. The nucleocapsid protein (N protein) of SARS-CoV plays an important role in inhibition of type I interferon (IFN) production via an unknown mechanism. In this study, the SARS-CoV N protein was found to bind to the SPRY domain of the tripartite motif protein 25 (TRIM25) E3 ubiquitin ligase, thereby interfering with the association between TRIM25 and retinoic acid-inducible gene I (RIG-I) and inhibiting TRIM25-mediated RIG-I ubiquitination and activation. Type I IFN production induced by poly I·C or Sendai virus (SeV) was suppressed by the SARS-CoV N protein. SARS-CoV replication was increased by overexpression of the full-length N protein but not N amino acids 1 to 361, which could not interact with TRIM25. These findings provide an insightful interpretation of the SARS-CoV-mediated host innate immune suppression caused by the N protein. IMPORTANCE The SARS-CoV N protein is essential for the viral life cycle and plays a key role in the virus-host interaction. We demonstrated that the interaction between the C terminus of the N protein and the SPRY domain of TRIM25 inhibited TRIM25-mediated RIG-I ubiquitination, which resulted in the inhibition of IFN production. We also found that the Middle East respiratory syndrome CoV (MERS-CoV) N protein interacted with TRIM25 and inhibited RIG-I signaling. The outcomes of these findings indicate the function of the coronavirus N protein in modulating the host's initial innate immune response.

scholarly journals Viperin binds STING and enhances the type-I interferon response following dsDNA detection

2018 ◽  
Author(s):  
Keaton M. Crosse ◽  
Ebony A. Monson ◽  
Arti B. Dumbrepatil ◽  
Monique Smith ◽  
Yeu-Yang Tseng ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Innate Immune ◽  
Signalling Pathway ◽  
Interferon Response ◽  
Type I ◽  
Viral Pathogens ◽  
Radical Sam ◽  
Signalling Molecules ◽  
Inducible Protein ◽  
Interferon Inducible Protein

AbstractViperin is an interferon-inducible protein that is pivotal for eliciting an effective immune response against an array of diverse viral pathogens. Here we describe a mechanism of viperin’s broad antiviral activity by demonstrating the protein’s ability to synergistically enhance the innate immune dsDNA signalling pathway to limit viral infection. Viperin co-localised with the key signalling molecules of the innate immune dsDNA sensing pathway, STING and TBK1; binding directly to STING and inducing enhanced K63-linked polyubiquitination of TBK1. Subsequent analysis identified viperin’s necessity to bind the cytosolic iron-sulphur assembly component 2A, to prolong its enhancement of the type-I interferon response to aberrant dsDNA. Here we show that viperin facilitates the formation of a signalling enhanceosome, to coordinate efficient signal transduction following activation of the dsDNA signalling pathway; which results in an enhanced antiviral state. We also provide evidence for viperin’s radical SAM enzymatic activity to self-limit its immunomodulatory functions. This data further defines viperin’s role as a positive regulator of innate immune signalling, offering a mechanism of viperin’s broad antiviral capacity.

scholarly journals NSUN2-mediated m5C methylation of IRF3 mRNA negatively regulates type I interferon responses

2021 ◽  
Author(s):  
Hongyun Wang ◽  
Lu Zhang ◽  
Cong Zeng ◽  
Jiangpeng Feng ◽  
Yu Zhou ◽  
...  
Keyword(s):  
Viral Infection ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Negative Regulator ◽  
Interferon Response ◽  
Rna Modification ◽  
Type I ◽  
Mrna Levels ◽  
Interferon Responses

5-Methylcytosine (m5C) is a widespread post-transcriptional RNA modification and is reported to be involved in manifold cellular responses and biological processes through regulating RNA metabolism. However, its regulatory role in antiviral innate immunity has not yet been elucidated. Here, we report that NSUN2, a typical m5C methyltransferase, can negatively regulate type I interferon responses during viral infection. NSUN2 specifically mediates m5C methylation of IRF3 mRNA and accelerates its degradation, resulting in low levels of IRF3 and downstream IFN-β production. Knockout or knockdown of NSUN2 could enhance type I interferon responses and downstream ISG expression after viral infection in vitro. And in vivo, the antiviral innate responses is more dramatically enhanced in Nsun2+/− mice than in Nsun2+/+ mice. Four highly m5C methylated cytosines in IRF3 mRNA were identified, and their mutation could enhance the cellular IRF3 mRNA levels. Moreover, infection with Sendai virus (SeV), vesicular stomatitis virus (VSV), herpes simplex virus 1 (HSV-1), Zika virus (ZIKV), or especially SARS-CoV-2 resulted in a reduction in endogenous levels of NSUN2. Together, our findings reveal that NSUN2 serves as a negative regulator of interferon response by accelerating the fast turnover of IRF3 mRNA, while endogenous NSUN2 levels decrease after viral infection to boost antiviral responses for the effective elimination of viruses. Our results suggest a paradigm of innate antiviral immune responses ingeniously involving NSUN2-mediated m5C modification.

scholarly journals Type I interferon–mediated monogenic autoinflammation: The type I interferonopathies, a conceptual overview

2016 ◽  
Vol 213 (12) ◽  
pp. 2527-2538 ◽  
Author(s):  
Mathieu P. Rodero ◽  
Yanick J. Crow
Keyword(s):  
Lupus Erythematosus ◽  
Clinical Medicine ◽  
Type I Interferon ◽  
Treatment Options ◽  
Clinical Importance ◽  
Innate Immune ◽  
Interferon Response ◽  
Type I ◽  
Monogenic Diseases ◽  
Type I Interferonopathies

Type I interferon is a potent substance. As such, the induction, transmission, and resolution of the type I interferon–mediated immune response are tightly regulated. As defined, the type I interferonopathies represent discrete examples of a disturbance of the homeostatic control of this system caused by Mendelian mutations. Considering the complexity of the interferon response, the identification of further monogenic diseases belonging to this disease grouping seems likely, with the recognition of type I interferonopathies becoming of increasing clinical importance as treatment options are developed based on an understanding of disease pathology and innate immune signaling. Definition of the type I interferonopathies indicates that autoinflammation can be both interferon and noninterferon related, and that a primary disturbance of the innate immune system can “spill over” into autoimmunity in some cases. Indeed, that several non-Mendelian disorders, most particularly systemic lupus erythematosus and dermatomyositis, are also characterized by an up-regulation of type I interferon signaling suggests the possibility that insights derived from this work will have relevance to a broader field of clinical medicine.

scholarly journals The brain parenchyma has a type I interferon response that can limit virus spread

2016 ◽  
Vol 114 (1) ◽  
pp. E95-E104 ◽  
Author(s):  
Eugene Drokhlyansky ◽  
Didem Göz Aytürk ◽  
Timothy K. Soh ◽  
Ryan Chrenek ◽  
Elaine O’Loughlin ◽  
...  
Keyword(s):  
Immune Response ◽  
Innate Immune Response ◽  
Type I Interferon ◽  
Brain Parenchyma ◽  
Innate Immune ◽  
Interferon Response ◽  
Type I ◽  
Virus Spread ◽  
Viral Spread ◽  
The Brain

The brain has a tightly regulated environment that protects neurons and limits inflammation, designated “immune privilege.” However, there is not an absolute lack of an immune response. We tested the ability of the brain to initiate an innate immune response to a virus, which was directly injected into the brain parenchyma, and to determine whether this response could limit viral spread. We injected vesicular stomatitis virus (VSV), a transsynaptic tracer, or naturally occurring VSV-derived defective interfering particles (DIPs), into the caudate–putamen (CP) and scored for an innate immune response and inhibition of virus spread. We found that the brain parenchyma has a functional type I interferon (IFN) response that can limit VSV spread at both the inoculation site and among synaptically connected neurons. Furthermore, we characterized the response of microglia to VSV infection and found that infected microglia produced type I IFN and uninfected microglia induced an innate immune response following virus injection.

scholarly journals Role of NLRs in the Regulation of Type I Interferon Signaling, Host Defense and Tolerance to Inflammation

2021 ◽  
Vol 22 (3) ◽  
pp. 1301
Author(s):  
Ioannis Kienes ◽  
Tanja Weidl ◽  
Nora Mirza ◽  
Mathias Chamaillard ◽  
Thomas A. Kufer
Keyword(s):  
Viral Infections ◽  
Type I Interferon ◽  
Tissue Injury ◽  
Interferon Response ◽  
Type I ◽  
Interferon Signaling ◽  
Microbial Products ◽  
Interferon Responses

Type I interferon signaling contributes to the development of innate and adaptive immune responses to either viruses, fungi, or bacteria. However, amplitude and timing of the interferon response is of utmost importance for preventing an underwhelming outcome, or tissue damage. While several pathogens evolved strategies for disturbing the quality of interferon signaling, there is growing evidence that this pathway can be regulated by several members of the Nod-like receptor (NLR) family, although the precise mechanism for most of these remains elusive. NLRs consist of a family of about 20 proteins in mammals, which are capable of sensing microbial products as well as endogenous signals related to tissue injury. Here we provide an overview of our current understanding of the function of those NLRs in type I interferon responses with a focus on viral infections. We discuss how NLR-mediated type I interferon regulation can influence the development of auto-immunity and the immune response to infection.

scholarly journals A type I interferon response defines a conserved microglial state required for effective phagocytosis

2021 ◽  
Author(s):  
Leah C Dorman ◽  
Phi T Nguyen ◽  
Caroline C Escoubas ◽  
Ilia D Vainchtein ◽  
Yinghong Xiao ◽  
...  
Keyword(s):  
Type I Interferon ◽  
Meta Analysis ◽  
Transcriptional Profiling ◽  
Innate Immune ◽  
Interferon Response ◽  
Type I ◽  
Whole Cells ◽  
Microglial Phagocytosis ◽  
The Brain

Microglia, the innate immune cells of the brain, are exquisitely sensitive to dynamic changes in the brain environment. We used single cell RNA sequencing to define glial responses in the early postnatal somatosensory cortex after partial whisker lesion, revealing transcriptomic shifts in both astrocytes and microglia during the resulting topographic remapping. The most distinct change was the emergence of a type I interferon (IFN-I) responsive microglia population that was rare in the resting cortex but expanded 20-fold after whisker deprivation. The top gene candidate in this cluster, Ifitm3, marked a conserved but transient subset of microglia that were in the process of phagocytosing whole cells. IFITM3 protein identified this subset in vivo, where it was enriched in early microglial phagosomes. Loss of canonical IFN-I signaling in Ifnar1-/- animals resulted in abnormal 'bubble' microglia with deficient phagolysosomal processing. In a meta-analysis of transcriptomes, we identified the IFN-I signature in microglia across a range of pathologies. We identified phagocytic IFITM3+ microglia in two murine disease models: SARS-CoV-2 infection and Alzheimer's Disease. These data reveal the potential of transcriptional profiling after defined perturbation to elicit transient microglial states, and identify a novel role for IFN-I signaling in regulating microglial phagocytosis.

scholarly journals Inhibiting DDX3X Triggers Tumor-Intrinsic Type I Interferon Response and Enhances Anti-Tumor Immunity

2020 ◽  
Author(s):  
Hyeongjwa Choi ◽  
Juntae Kwon ◽  
Jiafang Sun ◽  
Min Soon Cho ◽  
Yifan Sun ◽  
...  
Keyword(s):  
Breast Cancer ◽  
Cancer Cells ◽  
Breast Cancer Cells ◽  
Rna Binding ◽  
Type I Interferon ◽  
Cytotoxic T Cells ◽  
Immune Checkpoint Blockade ◽  
Innate Immune ◽  
Interferon Response ◽  
Type I

Abstract Accumulating evidence has shown that cellular double-stranded RNAs (dsRNAs) induce antiviral innate immune responses in human normal and malignant cancer cells. However, it is not fully understood how endogenous ‘self’ dsRNA homeostasis is regulated in the cell. Here, we show that an RNA-binding protein, DEAD-box RNA helicase 3X (DDX3X), prevents the aberrant accumulation of cellular dsRNAs. Loss of DDX3X induces dsRNA sensor-mediated type I interferon signaling and innate immune response in breast cancer cells due to abnormal cytoplasmic accumulation of dsRNAs. Dual depletion of DDX3X and a dsRNA-editing protein, ADAR1 synergistically activates the cytosolic dsRNA pathway in the breast cancer cells. Moreover, inhibiting DDX3X enhances the antitumor activity by increasing tumor intrinsic-type I interferon response, antigen presentation, and tumor-infiltration of cytotoxic T cells as well as dendritic cells in breast tumors, which may lead to the development of breast cancer therapy by targeting DDX3X in combination with immune checkpoint blockade.

scholarly journals A Sendai Virus-Derived RNA Agonist of RIG-I as a Virus Vaccine Adjuvant

2012 ◽  
Vol 87 (3) ◽  
pp. 1290-1300 ◽  
Author(s):  
L. Martínez-Gil ◽  
P. H. Goff ◽  
R. Hai ◽  
A. García-Sastre ◽  
M. L. Shaw ◽  
...  
Keyword(s):  
Immune System ◽  
Innate Immune System ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Innate Immune ◽  
Specific Response ◽  
Type I ◽  
Potent Inducer ◽  
Starting Point

ABSTRACTThe innate immune system is responsible for recognizing invading pathogens and initiating a protective response. In particular, the retinoic acid-inducible gene 1 protein (RIG-I) participates in the recognition of single- and double-stranded RNA viruses. RIG-I activation leads to the production of an appropriate cytokine and chemokine cocktail that stimulates an antiviral state and drives the adaptive immune system toward an efficient and specific response against the ongoing infection. One of the best-characterized natural RIG-I agonists is the defective interfering (DI) RNA produced by Sendai virus strain Cantell. This 546-nucleotide RNA is a well-known activator of the innate immune system and an extremely potent inducer of type I interferon. We designed anin vitro-transcribed RNA that retains the type I interferon stimulatory properties, and the RIG-I affinity of the Sendai virus produced DI RNA bothin vitroandin vivo. Thisin vitro-synthesized RNA is capable of enhancing the production of anti-influenza virus hemagglutinin (HA)-specific IgG after intramuscular or intranasal coadministration with inactivated H1N1 2009 pandemic vaccine. Furthermore, our adjuvant is equally effective at increasing the efficiency of an influenza A/Puerto Rico/8/34 virus inactivated vaccine as a poly(I·C)- or a squalene-based adjuvant. Ourin vitro-transcribed DI RNA represents an excellent tool for the study of RIG-I agonists as vaccine adjuvants and a starting point in the development of such a vaccine.

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