scholarly journals LGP2 virus sensor enhances apoptosis by upregulating apoptosis regulatory genes through TRBP-bound miRNAs during viral infection

2019 ◽  
Vol 48 (3) ◽  
pp. 1494-1507 ◽  
Author(s):  
Tomoko Takahashi ◽  
Yuko Nakano ◽  
Koji Onomoto ◽  
Mitsutoshi Yoneyama ◽  
Kumiko Ui-Tei
Keyword(s):  
Viral Infection ◽  
Rna Silencing ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Sendai Virus ◽  
Cysteine Proteases ◽  
Regulatory Genes ◽  
Type I ◽  
Member Laboratory ◽  
Sensor Proteins

Abstract During viral infection, viral nucleic acids are detected by virus sensor proteins including toll-like receptor 3 or retinoic acid-inducible gene I-like receptors (RLRs) in mammalian cells. Activation of these virus sensor proteins induces type-I interferon production and represses viral replication. Recently, we reported that an RLR family member, laboratory of genetics and physiology 2 (LGP2), modulates RNA silencing by interacting with an RNA silencing enhancer, TAR-RNA binding protein (TRBP). However, the biological implications remained unclear. Here, we show that LGP2 enhances apoptosis by upregulating apoptosis regulatory genes during viral infection. Sendai virus (SeV) infection increased LGP2 expression approximately 900 times compared to that in non-virus-infected cells. Then, the induced LGP2 interacted with TRBP, resulting in the inhibition of maturation of the TRBP-bound microRNA (miRNA) and its subsequent RNA silencing activity. Gene expression profiling revealed that apoptosis regulatory genes were upregulated during SeV infection: caspases-2, -8, -3 and -7, four cysteine proteases with key roles in apoptosis, were upregulated directly or indirectly through the repression of a typical TRBP-bound miRNA, miR-106b. Our findings may shed light on the mechanism of apoptosis, induced by the TRBP-bound miRNAs through the interaction of TRBP with LGP2, as an antiviral defense system in mammalian cells.

scholarly journals Virus Sensor RIG-I Represses RNA Interference by Interacting with TRBP through LGP2 in Mammalian Cells

Genes ◽  
2018 ◽  
Vol 9 (10) ◽  
pp. 511 ◽  
Author(s):  
Tomoko Takahashi ◽  
Yuko Nakano ◽  
Koji Onomoto ◽  
Mitsutoshi Yoneyama ◽  
Kumiko Ui-Tei
Keyword(s):  
Rna Interference ◽  
Rna Silencing ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Type I ◽  
Hairpin Rna ◽  
Tar Rna ◽  
Sensor Proteins ◽  
The Relationship ◽  
Inducible Gene

Exogenous double-stranded RNAs (dsRNAs) similar to viral RNAs induce antiviral RNA silencing or RNA interference (RNAi) in plants or invertebrates, whereas interferon (IFN) response is induced through activation of virus sensor proteins including Toll like receptor 3 (TLR3) or retinoic acid-inducible gene I (RIG-I) like receptors (RLRs) in mammalian cells. Both RNA silencing and IFN response are triggered by dsRNAs. However, the relationship between these two pathways has remained unclear. Laboratory of genetics and physiology 2 (LGP2) is one of the RLRs, but its function has remained unclear. Recently, we reported that LGP2 regulates endogenous microRNA-mediated RNA silencing by interacting with an RNA silencing enhancer, TAR-RNA binding protein (TRBP). Here, we investigated the contribution of other RLRs, RIG-I and melanoma-differentiation-associated gene 5 (MDA5), in the regulation of RNA silencing. We found that RIG-I, but not MDA5, also represses short hairpin RNA (shRNA)-induced RNAi by type-I IFN. Our finding suggests that RIG-I, but not MDA5, interacts with TRBP indirectly through LGP2 to function as an RNAi modulator in mammalian cells.

scholarly journals Human Dicer helicase domain recruits PKR and dsRNA binding proteins during viral infection

2020 ◽  
Author(s):  
Thomas C. Montavon ◽  
Morgane Baldaccini ◽  
Mathieu Lefèvre ◽  
Erika Girardi ◽  
Béatrice Chane-Woon-Ming ◽  
...  
Keyword(s):  
Viral Infection ◽  
Rna Silencing ◽  
Mammalian Cells ◽  
Cellular Response ◽  
Binding Proteins ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Helicase Domain ◽  
Type I ◽  
Rna Helicases

AbstractThe antiviral innate immune response mainly involves type I interferon (IFN) in mammalian cells. The contribution of the RNA silencing machinery remains to be established, but several recent studies indicate that the ribonuclease DICER can generate viral siRNAs in specific conditions. It has also been proposed that type I IFN and RNA silencing could be mutually exclusive antiviral responses. In order to decipher the implication of DICER during infection of human cells with the Sindbis virus, we determined its interactome by proteomics analysis. We show that DICER specifically interacts with several double-stranded RNA binding proteins and RNA helicases during viral infection. In particular, proteins such as DHX9, ADAR-1 and the protein kinase RNA-activated (PKR) are enriched with DICER in virus-infected cells. We demonstrate the importance of DICER helicase domain in its interaction with PKR and showed that it has functional consequences for the cellular response to viral infection.

scholarly journals Human DICER helicase domain recruits PKR and modulates its antiviral activity

2021 ◽  
Vol 17 (5) ◽  
pp. e1009549
Author(s):  
Thomas C. Montavon ◽  
Morgane Baldaccini ◽  
Mathieu Lefèvre ◽  
Erika Girardi ◽  
Béatrice Chane-Woon-Ming ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Mammalian Cells ◽  
Sindbis Virus ◽  
Rna Binding ◽  
Semliki Forest Virus ◽  
Rna Binding Proteins ◽  
Helicase Domain ◽  
Type I ◽  
Dependent Manner ◽  
Rna Helicases

The antiviral innate immune response mainly involves type I interferon (IFN) in mammalian cells. The contribution of the RNA silencing machinery remains to be established, but several recent studies indicate that the ribonuclease DICER can generate viral siRNAs in specific conditions. It has also been proposed that type I IFN and RNA silencing could be mutually exclusive antiviral responses. In order to decipher the implication of DICER during infection of human cells with alphaviruses such as the Sindbis virus and Semliki forest virus, we determined its interactome by proteomics analysis. We show that DICER specifically interacts with several double-stranded RNA binding proteins and RNA helicases during viral infection. In particular, proteins such as DHX9, ADAR-1 and the protein kinase RNA-activated (PKR) are enriched with DICER in virus-infected cells. We demonstrate that the helicase domain of DICER is essential for this interaction and that its deletion confers antiviral properties to this protein in an RNAi-independent, PKR-dependent, manner.

scholarly journals Mutual Regulation of RNA Silencing and the IFN Response as an Antiviral Defense System in Mammalian Cells

2020 ◽  
Vol 21 (4) ◽  
pp. 1348 ◽  
Author(s):  
Tomoko Takahashi ◽  
Kumiko Ui-Tei
Keyword(s):  
Protein Interactions ◽  
Rna Silencing ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Rna Binding Proteins ◽  
Structural Features ◽  
Type I ◽  
Antiviral Defense ◽  
Defense System ◽  
Mutual Regulation

RNA silencing is a posttranscriptional gene silencing mechanism directed by endogenous small non-coding RNAs called microRNAs (miRNAs). By contrast, the type-I interferon (IFN) response is an innate immune response induced by exogenous RNAs, such as viral RNAs. Endogenous and exogenous RNAs have typical structural features and are recognized accurately by specific RNA-binding proteins in each pathway. In mammalian cells, both RNA silencing and the IFN response are induced by double-stranded RNAs (dsRNAs) in the cytoplasm, but have long been considered two independent pathways. However, recent reports have shed light on crosstalk between the two pathways, which are mutually regulated by protein–protein interactions triggered by viral infection. This review provides brief overviews of RNA silencing and the IFN response and an outline of the molecular mechanism of their crosstalk and its biological implications. Crosstalk between RNA silencing and the IFN response may reveal a novel antiviral defense system that is regulated by miRNAs in mammalian cells.

scholarly journals Differential Requirement for TANK-binding Kinase-1 in Type I Interferon Responses to Toll-like Receptor Activation and Viral Infection

2004 ◽  
Vol 199 (12) ◽  
pp. 1651-1658 ◽  
Author(s):  
Andrea K. Perry ◽  
Edward K. Chow ◽  
Julia B. Goodnough ◽  
Wen-Chen Yeh ◽  
Genhong Cheng
Keyword(s):  
Viral Infection ◽  
Nuclear Translocation ◽  
Sendai Virus ◽  
Cell Types ◽  
Receptor Activation ◽  
Northern Blotting ◽  
Type I ◽  
Toll Like Receptor ◽  
Embryonic Fibroblasts ◽  
Iκb Kinase

TANK-binding kinase-1 (TBK1) and the inducible IκB kinase (IKK-i) have been shown recently to activate interferon (IFN) regulatory factor-3 (IRF3), the primary transcription factor regulating induction of type I IFNs. Here, we have compared the role and specificity of TBK1 in the type I IFN response to lipopolysaccharide (LPS), polyI:C, and viral challenge by examining IRF3 nuclear translocation, signal transducer and activator of transcription 1 phosphorylation, and induction of IFN-regulated genes. The LPS and polyI:C-induced IFN responses were abolished and delayed, respectively, in macrophages from mice with a targeted disruption of the TBK1 gene. When challenged with Sendai virus, the IFN response was normal in TBK1−/− macrophages, but defective in TBK1−/− embryonic fibroblasts. Although both TBK1 and IKK-i are expressed in macrophages, only TBK1 but not IKK-i was detected in embryonic fibroblasts by Northern blotting analysis. Furthermore, the IFN response in TBK1−/− embryonic fibroblasts can be restored by reconstitution with wild-type IKK-i but not a mutant IKK-i lacking kinase activity. Thus, our studies suggest that TBK1 plays an important role in the Toll-like receptor–mediated IFN response and is redundant with IKK-i in the response of certain cell types to viral infection.

scholarly journals Comparison of Type I Interferon Expression in Adult and Neonatal Mice during Respiratory Viral Infection

10.29007/ltkw ◽  
2019 ◽  
Author(s):  
Zifeng Liang
Keyword(s):  
Immune Response ◽  
Viral Infection ◽  
Mouse Models ◽  
Post Infection ◽  
Type I Interferon ◽  
Sendai Virus ◽  
Killer Cell ◽  
Type I ◽  
Respiratory Viral Infection ◽  
Neonatal Mice

The aim of this paper is to identify the difference of type I interferon expression in 2- day neonatal and six-to-eight-weeks adult mice infected by Sendai virus (SeV), a single- stranded RNA virus of the family Paramyxoviridae. Sendai virus mimics the influence of respiratory syncytial virus (RSV) on humans, but does not infect humans. Although RSV has a fatal impact on people across age groups, little is understood about this common virus and the disparity between neonatal and adult immune response to it. It has been suggested by past findings that Type I interferon mRNA is present in higher levels in adults than in neonates, however there is a greater amount of interferon proteins in neonates rather than adults. To test the hypothesis that neonates are more capable of interferon production and preventing the translation of viral protein, I observed mouse models of respiratory viral infection and determined the expression of IFN-α1, IFN-α2, IFN-α5, IFN-α6, IFN-α7, IFN-β in archived mouse lung tissue samples harvested on different days post-infection with quantitative real time PCR. Expression of Glyceraldehyde 3-phosphate dehydrogenase(GAPDH), a housekeeping gene expressed constitutively in all mouse models, was used as a positive control of the experiment. To determine the ideal concentration of primer used in qPCR, primer reconstitution, primer optimization, and gel electrophoresis were conducted in advance. In addition, technical replicates and biological replicates were used to reduce error and confirm results in qPCR. In accordance with previous discovery, I found an upward trend in adults’ interferon expression from post-infection day 1 to day 5, and levels off in day 7. In contrast, neonatal levels were much higher on day 1 and remained high over the course of infection. This explains how type I interferon expression is altered in neonates to help them clear the virus at the same efficiency as adults without causing inflammation. Future research on immune response differences in human infection should focus on the evaluation of interferon protein amounts, as well as the analysis of activation of molecules downstream of the type I interferon receptors, such as signal transducer and activator of transcription (STAT) protein family. It is also crucial to compare immune cells like macrophages and natural killer cell activity in adult and neonatal mice during viral infection.

scholarly journals Roles of Emerging RNA-Binding Activity of cGAS in Innate Antiviral Response

2021 ◽  
Vol 12 ◽  
Author(s):  
Yuying Ma ◽  
Xiaohui Wang ◽  
Weisheng Luo ◽  
Ji Xiao ◽  
Xiaowei Song ◽  
...  
Keyword(s):  
Dna Binding ◽  
Mammalian Cells ◽  
Rna Binding ◽  
Binding Protein ◽  
Structural Similarity ◽  
Antiviral Response ◽  
Binding Activity ◽  
Type I Interferons ◽  
Type I ◽  
Innate Antiviral Response

cGAS, a DNA sensor in mammalian cells, catalyzes the generation of 2’-3’-cyclic AMP-GMP (cGAMP) once activated by the binding of free DNA. cGAMP can bind to STING, activating downstream TBK1-IRF-3 signaling to initiate the expression of type I interferons. Although cGAS has been considered a traditional DNA-binding protein, several lines of evidence suggest that cGAS is a potential RNA-binding protein (RBP), which is mainly supported by its interactions with RNAs, RBP partners, RNA/cGAS-phase-separations as well as its structural similarity with the dsRNA recognition receptor 2’-5’ oligoadenylate synthase. Moreover, two influential studies reported that the cGAS-like receptors (cGLRs) of fly Drosophila melanogaster sense RNA and control 3′-2′-cGAMP signaling. In this review, we summarize and discuss in depth recent studies that identified or implied cGAS as an RBP. We also comprehensively summarized current experimental methods and computational tools that can identify or predict RNAs that bind to cGAS. Based on these discussions, we appeal that the RNA-binding activity of cGAS cannot be ignored in the cGAS-mediated innate antiviral response. It will be important to identify RNAs that can bind and regulate the activity of cGAS in cells with or without virus infection. Our review provides novel insight into the regulation of cGAS by its RNA-binding activity and extends beyond its DNA-binding activity. Our review would be significant for understanding the precise modulation of cGAS activity, providing the foundation for the future development of drugs against cGAS-triggering autoimmune diseases such as Aicardi-Gourtières syndrome.

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 The RNA binding protein La/SS-B promotes RIG-I-mediated type I and type III IFN responses following Sendai viral infection

2017 ◽  
Vol 7 (1) ◽  
Author(s):  
Rebecca Mahony ◽  
Lindsay Broadbent ◽  
Jacen S. Maier-Moore ◽  
Ultan F. Power ◽  
Caroline A. Jefferies
Keyword(s):  
Viral Infection ◽  
Rna Binding ◽  
Binding Protein ◽  
Rna Binding Protein ◽  
Type I ◽  
Type Iii ◽  
Type Iii Ifn

scholarly journals LGP2 binds to PACT to regulate RIG-I– and MDA5-mediated antiviral responses

2019 ◽  
Vol 12 (601) ◽  
pp. eaar3993 ◽  
Author(s):  
Raul Y. Sanchez David ◽  
Chantal Combredet ◽  
Valérie Najburg ◽  
Gael A. Millot ◽  
Guillaume Beauclair ◽  
...  
Keyword(s):  
Rna Silencing ◽  
Rna Binding ◽  
Inflammatory Responses ◽  
Innate Immune ◽  
Type I ◽  
Double Stranded Rna ◽  
Rna Molecules ◽  
Protein Protein Interaction ◽  
Antiviral Responses ◽  
Inducible Gene

The retinoic acid–inducible gene I (RIG-I)–like receptors (RLRs) RIG-I, MDA5, and LGP2 stimulate inflammatory and antiviral responses by sensing nonself RNA molecules produced during viral replication. Here, we investigated how LGP2 regulates the RIG-I– and MDA5-dependent induction of type I interferon (IFN) signaling and showed that LGP2 interacted with different components of the RNA-silencing machinery. We identified a direct protein-protein interaction between LGP2 and the IFN-inducible, double-stranded RNA binding protein PACT. The LGP2-PACT interaction was mediated by the regulatory C-terminal domain of LGP2 and was necessary for inhibiting RIG-I–dependent responses and for amplifying MDA5-dependent responses. We described a point mutation within LGP2 that disrupted the LGP2-PACT interaction and led to the loss of LGP2-mediated regulation of RIG-I and MDA5 signaling. These results suggest a model in which the LGP2-PACT interaction regulates the inflammatory responses mediated by RIG-I and MDA5 and enables the cellular RNA-silencing machinery to coordinate with the innate immune response.

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