scholarly journals Non-segmented negative-sense RNA viruses utilize N6-methyladenosine (m6A) as a common strategy to evade host innate immunity

2021 ◽  
Author(s):  
Mijia Lu ◽  
Miaoge Xue ◽  
Hai-Tao Wang ◽  
Elizabeth L. Kairis ◽  
Sadeem Ahmad ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Signaling Pathway ◽  
Type I Interferon ◽  
Rna Viruses ◽  
Viral Rna ◽  
Type I ◽  
Viral Rnas ◽  
Common Strategy ◽  
Host Innate Immunity ◽  
Negative Sense

N6-methyladenosine (m6A) is the most abundant internal RNA modification catalyzed by host RNA methyltransferases. As obligate intracellular parasites, many viruses acquire m6A methylation in their RNAs. However, the biological functions of viral m6A methylation are poorly understood. Here, we found that viral m6A methylation serves as a molecular marker for host innate immunity to discriminate self from nonself RNA and that this novel biological function of viral m6A methylation is universally conserved in several families in non-segmented negative-sense (NNS) RNA viruses. Using m6A methyltransferase (METTL3)-knockout cells, we produced m6A-deficient virion RNA from the representative members of the families Pneumoviridae, Paramyxoviridae, and Rhabdoviridae and found that these m6A-deficient viral RNAs triggered significantly higher levels of type I interferon compared to the m6A-sufficient viral RNAs, in a RIG-I dependent manner. Reconstitution of the RIG-I pathway revealed that m6A-deficient virion RNA induced higher expression of RIG-I, bound to RIG-I more efficiently, enhanced RIG-I ubiquitination, and facilitated RIG-I conformational rearrangement and oligomerization. Furthermore, the m6A binding protein YTHDF2 is essential for suppression of type I interferon signaling pathway included by virion RNA. Collectively, our results suggest that several families in NNS RNA viruses acquire m6A in viral RNA as a common strategy to evade host innate immunity. IMPORTANCE The non-segmented negative-sense (NNS) RNA viruses share many common replication and gene expression strategies. There is no vaccine or antiviral drugs for many of these viruses. We found that representative members in the families of Pneumoviridae, Paramyxoviridae, and Rhabdoviridae in NNS RNA viruses acquire m6A methylation in their genome and antigenome as a means to escape the recognition by host innate immunity via a RIG-I dependent signaling pathway. Viral RNA lacking m6A methylation induces a significantly higher type I interferon compared to m6A sufficient viral RNA. In addition to uncovering m6A methylation as a common mechanism for many NNS RNA viruses to evade host innate immunity, this study discovered a novel strategy to enhance type I interferon responses, which may have important applications in vaccine development, as a robust innate immunity will likely promote the subsequent adaptive immunity.

scholarly journals N6-Methyladenosine modification of hepatitis B and C viral RNAs attenuates host innate immunity via RIG-I signaling

2020 ◽  
Vol 295 (37) ◽  
pp. 13123-13133 ◽  
Author(s):  
Geon-Woo Kim ◽  
Hasan Imam ◽  
Mohsin Khan ◽  
Aleem Siddiqui
Keyword(s):  
Innate Immunity ◽  
Hepatitis B ◽  
Viral Infections ◽  
Type I ◽  
Rna Recognition ◽  
Single Nucleotide ◽  
Viral Rnas ◽  
Dual Functional ◽  
Nucleotide Mutation ◽  
Host Innate Immunity

N6-Methyladenosine (m6A), the methylation of the adenosine base at the nitrogen 6 position, is the most common epitranscriptomic modification of mRNA that affects a wide variety of biological functions. We have previously reported that hepatitis B viral RNAs are m6A-modified, displaying a dual functional role in the viral life cycle. Here, we show that cellular m6A machinery regulates host innate immunity against hepatitis B and C viral infections by inducing m6A modification of viral transcripts. The depletion of the m6A writer enzymes (METTL3 and METTL14) leads to an increase in viral RNA recognition by retinoic acid–inducible gene I (RIG-I), thereby stimulating type I interferon production. This is reversed in cells in which m6A METTL3 and METTL14 are overexpressed. The m6A modification of viral RNAs renders RIG-I signaling less effective, whereas single nucleotide mutation of m6A consensus motif of viral RNAs enhances RIG-I sensing activity. Importantly, m6A reader proteins (YTHDF2 and YTHDF3) inhibit RIG-I–transduced signaling activated by viral RNAs by occupying m6A-modified RNAs and inhibiting RIG-I recognition. Collectively, our results provide new insights into the mechanism of immune evasion via m6A modification of viral RNAs.

scholarly journals PARP1 Enhances Influenza A Virus Propagation by Facilitating Degradation of Host Type I Interferon Receptor

2020 ◽  
Vol 94 (7) ◽  
Author(s):  
Chuan Xia ◽  
Jennifer J. Wolf ◽  
Chuankai Sun ◽  
Mengqiong Xu ◽  
Caleb J. Studstill ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Influenza Virus ◽  
Molecular Mechanism ◽  
Influenza A Virus ◽  
Influenza A ◽  
Type I Interferon ◽  
Type I ◽  
Type I Ifn ◽  
Host Type ◽  
Host Innate Immunity

ABSTRACT Influenza A virus (IAV) utilizes multiple strategies to confront or evade host type I interferon (IFN)-mediated antiviral responses in order to enhance its own propagation within the host. One such strategy is to induce the degradation of type I IFN receptor 1 (IFNAR1) by utilizing viral hemagglutinin (HA). However, the molecular mechanism behind this process is poorly understood. Here, we report that a cellular protein, poly(ADP-ribose) polymerase 1 (PARP1), plays a critical role in mediating IAV HA-induced degradation of IFNAR1. We identified PARP1 as an interacting partner for IAV HA through mass spectrometry analysis. This interaction was confirmed by coimmunoprecipitation analyses. Furthermore, confocal fluorescence microscopy showed altered localization of endogenous PARP1 upon transient IAV HA expression or during IAV infection. Knockdown or inhibition of PARP1 rescued IFNAR1 levels upon IAV infection or HA expression, exemplifying the importance of PARP1 for IAV-induced reduction of IFNAR1. Notably, PARP1 was crucial for the robust replication of IAV, which was associated with regulation of the type I IFN receptor signaling pathway. These results indicate that PARP1 promotes IAV replication by controlling viral HA-induced degradation of host type I IFN receptor. Altogether, these findings provide novel insight into interactions between influenza virus and the host innate immune response and reveal a new function for PARP1 during influenza virus infection. IMPORTANCE Influenza A virus (IAV) infections cause seasonal and pandemic influenza outbreaks, which pose a devastating global health concern. Despite the availability of antivirals against influenza, new IAV strains continue to persist by overcoming the therapeutics. Therefore, much emphasis in the field is placed on identifying new therapeutic targets that can more effectively control influenza. IAV utilizes several tactics to evade host innate immunity, which include the evasion of antiviral type I interferon (IFN) responses. Degradation of type I IFN receptor (IFNAR) is one known method of subversion, but the molecular mechanism for IFNAR downregulation during IAV infection remains unclear. Here, we have found that a host protein, poly(ADP-ribose) polymerase 1 (PARP1), facilitates IFNAR degradation and accelerates IAV replication. The findings reveal a novel cellular target for the potential development of antivirals against influenza, as well as expand our base of knowledge regarding interactions between influenza and the host innate immunity.

scholarly journals The Intestinal Microbiome Primes Host Innate Immunity against Enteric Virus Systemic Infection through Type I Interferon

mBio ◽  
2021 ◽  
Vol 12 (3) ◽  
Author(s):  
Xiao-Lian Yang ◽  
Gan Wang ◽  
Jin-Yan Xie ◽  
Han Li ◽  
Shu-Xian Chen ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Immune Responses ◽  
Type I Interferon ◽  
Systemic Infection ◽  
Enteric Virus ◽  
Innate Immune ◽  
Commensal Bacteria ◽  
Type I ◽  
Innate Immune Responses ◽  
Host Innate Immunity

ABSTRACT Intestinal microbiomes are of vital importance in antagonizing systemic viral infection. However, very little literature has shown whether commensal bacteria play a crucial role in protecting against enteric virus systemic infection from the aspect of modulating host innate immunity. In the present study, we utilized an enteric virus, encephalomyocarditis virus (EMCV), to inoculate mice treated with phosphate-buffered saline (PBS) or given an antibiotic cocktail (Abx) orally or intraperitoneally to examine the impact of microbiota depletion on virulence and viral replication in vivo. Microbiota depletion exacerbated the mortality, neuropathogenesis, viremia, and viral burden in brains following EMCV infection. Furthermore, Abx-treated mice exhibited severely diminished mononuclear phagocyte activation and impaired type I interferon (IFN) production and expression of IFN-stimulated genes (ISG) in peripheral blood mononuclear cells (PBMC), spleens, and brains. With the help of fecal bacterial 16S rRNA sequencing of PBS- and Abx-treated mice, we identified a single commensal bacterium, Blautia coccoides, that can restore mononuclear phagocyte- and IFNAR (IFN-α/β receptor)-dependent type I IFN responses to restrict systemic enteric virus infection. These findings may provide insight into the development of novel therapeutics for preventing enteric virus infection or possibly alleviating clinical diseases by activating host systemic innate immune responses via respective probiotic treatment using B. coccoides. IMPORTANCE While cumulative data indicate that indigenous commensal bacteria can facilitate enteric virus infection, little is known regarding whether intestinal microbes have a protective role in antagonizing enteric systemic infection by modulating host innate immunity. Although accumulating literature has pointed out that the microbiota has a fundamental impact on host systemic antiviral innate immune responses mediated by type I interferon (IFN), only a few specific commensal bacteria species have been revealed to be capable of regulating IFN-I and ISG expression, not to mention the underlying mechanisms. Thus, it is important to understand the cross talk between microbiota and host anti-enteric virus innate immune responses and characterize the specific bacterial species that possess protective functions. Our study demonstrates how fundamental innate immune mediators such as mononuclear phagocytes and type I IFN are regulated by commensal bacteria to antagonize enteric virus systemic infection. In particular, we have identified a novel commensal bacterium, Blautia coccoides, that can restrict enteric virus replication and neuropathogenesis by activating IFN-I and ISG responses in mononuclear phagocytes via an IFNAR- and STAT1-mediated signaling pathway.

scholarly journals The Intestinal Microbiome Primes Host Innate Immunity Against Enteric Virus Systemic Infection Through Type I Interferon

2021 ◽  
Author(s):  
Xiao-Lian Yang ◽  
Gan Wang ◽  
Jin-Yan Xie ◽  
Han Li ◽  
Wei Liu ◽  
...  
Keyword(s):  
Innate Immunity ◽  
Type I Interferon ◽  
Systemic Infection ◽  
Enteric Virus ◽  
Encephalomyocarditis Virus ◽  
Commensal Bacteria ◽  
Intestinal Microbiome ◽  
Type I ◽  
Type I Ifn ◽  
Host Innate Immunity

Abstract BackgroundIntestinal microbiomes are of vital importance in antagonizing systemic viral infection. However, very little literature has shown whether commensal bacteria play a crucial role in protecting enteric virus systemic infection from the aspect of modulating host innate immunity. Also, only a few specific commensal bacteria species have been revealed to be capable in regulating antiviral innate immune responses mediated by type I interferon (IFN). The underlying mechanisms have not yet been elucidated.ResultsWe utilized an enteric virus, encephalomyocarditis virus (EMCV) to inoculate PBS-treated or antibiotic cocktail-administrated mice (Abx) orally or intraperitoneally to examine the impact of microbiota depletion on virulence and viral replication in vivo. Microbiota depletion exacerbated the mortality, neuropathogenesis, viremia and viral burden in brain following EMCV infection. Furthermore, Abx-treated mice exhibited severely diminished macrophage activation and impaired type I IFN production and ISG expression in PBMC, spleen or brain. With the help of fecal bacterial 16S rRNA sequencing of PBS and Abx mice, we identified a single commensal bacterium Blautia coccoides (B. coccoides) that can restore macrophage- and IFNAR-dependent type I IFN responses to restrict systemic enteric virus infection.ConclusionOur present study demonstrates that intestinal microbiome is fundamental for protecting from enteric virus systemic infection through activating macrophages and type I IFN responses. Reconstitution with B. coccoides can inhibit enteric virus infection and mitigate its neuropathogenesis by activating IFN-I and ISG responses in macrophages via IFNAR- and STAT1-mediated signaling pathway.

187 Glucocorticoid regulation of the type I interferon-JAK/STAT signaling pathway

Cytokine ◽  
2008 ◽  
Vol 43 (3) ◽  
pp. 283-284
Author(s):  
Jamie R. Flammer ◽  
Megan A. Kennedy ◽  
Yurii Chinenov ◽  
Lionel B. Ivashkiv ◽  
Inez Rogatsky
Keyword(s):  
Signaling Pathway ◽  
Type I Interferon ◽  
Type I ◽  
Stat Signaling

TO005OPERATIONAL TOLERANCE IN KIDNEY TRANSPLANT RECIPIENTS: TOMOGRAM TRANSCRIPTOMIC STUDY

2020 ◽  
Vol 35 (Supplement_3) ◽  
Author(s):  
Ondrej Viklicky ◽  
Jiri Klema ◽  
Petra Mrazova ◽  
Daniel Abramowicz ◽  
Marc Abramowicz ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Kidney Transplant ◽  
Type I Interferon ◽  
Gene Annotation ◽  
Interferon Γ ◽  
Type I ◽  
Transplant Recipients ◽  
Interferon Signaling ◽  
Kidney Transplant Recipients ◽  
Operational Tolerance

Abstract Background and Aims TOMOGRAM, multicenter study founded by DESCARTES ERA/EDTA WG, aims to identify transcriptomic and genomic signatures of operational tolerance (OT) in recently identified cohort of OT kidney transplant recipients. Method RNA sequencing of peripheral blood was evaluated in 15 OT patients recently identified by TOMOGRAM consortium in 8 European countries, 23 stable patients (≥ 15 years on immunosuppression, STA), 14 CABMR patients (≥ 1 year, CR), 14 non-transplant CNI-treated patients and 14 healthy controls (HC). Differential expression was performed using DESEq2 and gene annotation analysis using Enrichr. Besides immunosuppression unadjusted model, robust negative-binomial regression model was created to adjust for immunosuppression intake. The models was trained on homogeneous group of STA patients. Results Using model unadjusted for immunosuppression, no differences in transcriptomic profiles between OT, STA and HC groups were identified. Nine transcripts were upregulated and 2 downregulated in OT compared CR group. The number of deregulated transcripts substantially increased when the model was adjusted for immunosuppression. Gene annotation analysis of top ranked deregulated 1109 transcripts (FC>2, adjusted p value <0.0001) showed deregulation of biological processes related to interferon-γ-mediated signaling pathway (p=1.4*10-5), response to cytokine (p=1.5*10-5), type I interferon signaling pathway (p=0.00036), regulation of I-kappaB kinase/NF-kappaB signaling (p=0.0021), cytokine-mediated signaling pathway (p=0.019) and neutrophil mediated immunity (p=0.033). While interferon-γ-mediated and type I interferon signaling were related to transcripts increased in CR, neutrophils associated transcripts were increased in OT. Analysis of cell types transcripts showed enrichment of CD19 B cells (p=1.6*10-9) in CR, while CD56NK cells (p=2.5*10-11) and CD8 T cells (p=1.6*10-11) transcripts predominated in OT. To reveal probability of operational tolerance inside STA group, 13 transcripts able to discriminate OT and CR cohorts with high AUC (>0.89) were used in PCA analysis (ADGRG3, ATG2A, GDPD5, IL16, MX2, SLA2, PRKD2, SLIRP, GNLY, SRCAP, ARGHAP9, IGHM, CD5). The high probability of OT signature was found in a single STA patient. Conclusion Contrary to previous reports which pointed out towards naïve B cell signatures, unique OT patients exhibit other specific immunosuppression-independent transcriptomic profiles.

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