scholarly journals TRIM25 and ZAP target the Ebola virus ribonucleoprotein complex to mediate interferon-induced restriction

2021 ◽  
Author(s):  
Rui Pedro Galao ◽  
Harry Wilson ◽  
Kristina L Schierhorn ◽  
Franka Debeljak ◽  
Bianca S Bodmer ◽  
...  

Ebola virus (EBOV) causes highly pathogenic disease in primates. Through screening a library of human interferon-stimulated genes (ISGs), we identified TRIM25 as a potent inhibitor of EBOV transcription-and-replication-competent virus-like particle (trVLP) propagation. TRIM25 overexpression inhibited the accumulation of viral genomic and messenger RNAs independently of the RNA sensor RIG-I or secondary proinflammatory gene expression. Deletion of TRIM25 strongly attenuated the sensitivity of trVLPs to inhibition by type-I interferon. The antiviral activity of TRIM25 required ZAP and the effect of type-I interferon was modulated by the CpG dinucleotide content of the viral genome. We find that TRIM25 interacts with the EBOV vRNP, resulting in its autoubiquitination and ubiquitination of the viral nucleoprotein (NP). TRIM25 is recruited to incoming vRNPs shortly after cell entry, and leads to dissociation of NP from the vRNA. We propose that TRIM25 targets the EBOV vRNP, exposing CpG-rich viral RNA species to restriction by ZAP.

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Elena N. Judd ◽  
Alison R. Gilchrist ◽  
Nicholas R. Meyerson ◽  
Sara L. Sawyer

Abstract Background The Type I interferon response is an important first-line defense against viruses. In turn, viruses antagonize (i.e., degrade, mis-localize, etc.) many proteins in interferon pathways. Thus, hosts and viruses are locked in an evolutionary arms race for dominance of the Type I interferon pathway. As a result, many genes in interferon pathways have experienced positive natural selection in favor of new allelic forms that can better recognize viruses or escape viral antagonists. Here, we performed a holistic analysis of selective pressures acting on genes in the Type I interferon family. We initially hypothesized that the genes responsible for inducing the production of interferon would be antagonized more heavily by viruses than genes that are turned on as a result of interferon. Our logic was that viruses would have greater effect if they worked upstream of the production of interferon molecules because, once interferon is produced, hundreds of interferon-stimulated proteins would activate and the virus would need to counteract them one-by-one. Results We curated multiple sequence alignments of primate orthologs for 131 genes active in interferon production and signaling (herein, “induction” genes), 100 interferon-stimulated genes, and 100 randomly chosen genes. We analyzed each multiple sequence alignment for the signatures of recurrent positive selection. Counter to our hypothesis, we found the interferon-stimulated genes, and not interferon induction genes, are evolving significantly more rapidly than a random set of genes. Interferon induction genes evolve in a way that is indistinguishable from a matched set of random genes (22% and 18% of genes bear signatures of positive selection, respectively). In contrast, interferon-stimulated genes evolve differently, with 33% of genes evolving under positive selection and containing a significantly higher fraction of codons that have experienced selection for recurrent replacement of the encoded amino acid. Conclusion Viruses may antagonize individual products of the interferon response more often than trying to neutralize the system altogether.


2021 ◽  
Vol 80 (Suppl 1) ◽  
pp. 1060.2-1060
Author(s):  
T. Suto ◽  
K. Von Dalwigk ◽  
A. Platzer ◽  
B. Niederreiter ◽  
T. M. Karonitsch

Background:TNF-mediated fibroblast-like synoviocyte (FLS) activation is important for inflammation and joint destruction in rheumatoid arthritis (RA). The role of TNF-receptor 1 (TNFR1) in FLS activation has thoroughly been characterized. The functions of TNFR2 are, however, largely unknown.Objectives:To investigate the contribution of TNFR2 to the TNF-mediated activation of FLS.Methods:RA-FLS were transfected with TNFR2-targeting siRNA pools and transcriptional changes were determined by RNA-seq. QPCR, ELISA and immunoblotting were used to confirm the RNA-seq results and to gain insights into the pathways that regulate TNFR2-mediated changes in FLS.Results:TNF stimulation of FLS resulted in a strong upregulation of proinflammatory cytokines, chemokines, tissue-degrading enzymes and other genes that are associated with synovial inflammation in RA. Silencing of TNFR2 markedly diminished the TNF-response of RA-FLS. Especially, “interferon”-stimulated-genes (ISGs) including putative master regulators of joint inflammation, such as the CXCR3 chemokines CXCL9, CXCL10 and CXCL11 were affected by the knockdown of TNFR2. Consistently, immunoblots showed that TNFR2 was required for the TNF-induced phosphorylation of the transcription factor STAT1, which is known to mediate the transcription of ISGs, such as CXCR3 chemokines.Conclusion:TNFR2 regulates proinflammatory gene expression in RA-FLS via STAT1 and thereby contributes to the detrimental effects of TNF in synovial joint inflammation.Disclosure of Interests:None declared


Diagnostics ◽  
2019 ◽  
Vol 9 (3) ◽  
pp. 113 ◽  
Author(s):  
Alessia Pin ◽  
Lorenzo Monasta ◽  
Andrea Taddio ◽  
Elisa Piscianz ◽  
Alberto Tommasini ◽  
...  

Interferon-stimulated genes (ISGs) are a set of genes whose transcription is induced by interferon (IFN). The measure of the expression of ISGs enables calculating an IFN score, which gives an indirect estimate of the exposition of cells to IFN-mediated inflammation. The measure of the IFN score is proposed for the screening of monogenic interferonopathies, like the Aicardi-Goutières syndrome, or to stratify subjects with systemic lupus erythematosus to receive IFN-targeted treatments. Apart from these scenarios, there is no agreement on the diagnostic value of the score in distinguishing IFN-related disorders from diseases dominated by other types of cytokines. Since the IFN score is currently measured in several research hospitals, merging experiences could help define the potential of scoring IFN inflammation in clinical practice. However, the IFN score calculated at different laboratories may be hardly comparable due to the distinct sets of IFN-stimulated genes assessed and to different controls used for data normalization. We developed a reliable approach to minimize the inter-laboratory variability, thereby providing shared strategies for the IFN signature analysis and allowing different centers to compare data and merge their experiences.


Intervirology ◽  
2006 ◽  
Vol 50 (1) ◽  
pp. 32-39 ◽  
Author(s):  
Hideaki Taniguchi ◽  
Yoshiaki Iwasaki ◽  
Akira Takahashi ◽  
Hiroyuki Shimomura ◽  
Akio Moriya ◽  
...  

Cytokine ◽  
2009 ◽  
Vol 48 (1-2) ◽  
pp. 15
Author(s):  
Keiko Ozato ◽  
Tsung-Hsien Chang ◽  
Toru Kubota ◽  
Mayumi Matsuoka ◽  
Mike Bray ◽  
...  
Keyword(s):  

2014 ◽  
Vol 275 (1-2) ◽  
pp. 94
Author(s):  
Fei Xing ◽  
Tomoh Matsumiya ◽  
Ryo Hayakari ◽  
Hidemi Yoshida ◽  
Tadaatsu Imaizumi

2021 ◽  
Vol 55 (3) ◽  
pp. 256-264

BACKGROUND/AIMS: During an immune response, type I interferon (IFN-I) signaling induces a wide range of changes, including those which are required to overcome viral infection and those which suppress cytotoxic T cells to avoid immunopathology. During certain bacterial infections, IFN-I signaling exerts largely detrimental effects. Although the IFN-I family of proteins all share one common receptor, biologic responses to signaling vary depending on IFN-I subtype. Here, we asked if one IFN-I subtype dominates the pro-bacterial effect of IFN-I signaling and found that control of Listeria monocytogenes (L.m.) infection is more strongly suppressed by IFN-β than IFN-α. METHODS: To study this, we measured bacterial titers in IFNAR-/-, IFN-β‑/‑, Stat2-/-, Usp18fl/fl and Usp18fl/fl x CD11c-Cre mice models in addition to IFN-I blocking antibodies. Moreover, we measured interferon stimulated genes in bone marrow derived dendritic cells after treatment with IFN-α4 and IFN-β. RESULTS: Specifically, we show that genetic deletion of IFN-β or antibody-mediated IFN-β neutralization was sufficient to reduce bacterial titers to levels similar to those observed in mice that completely lack IFN-I signaling (IFNAR-/- mice). However, IFN-α blockade failed to significantly reduce L.m. titers, suggesting that IFN-β is the dominant IFN-I subtype responsible for the pro-bacterial effect of IFN-I. Mechanistically, when focusing on IFN-I signals to dendritic cells, we found that IFN-β induces ISGs more robustly than IFN-α, including USP18, the protein we previously identified as driving the pro-bacterial effects of IFN-I. Further, we found that this induction was STAT1/STAT2 heterodimer- or STAT2/STAT2 homodimer-dependent, as STAT2-deficient mice were more resistant to L.m. infection. CONCLUSION: In conclusion, IFN-Β is the principal member of the IFN-I family responsible for driving the pro-bacterial effect of IFN-I.


2017 ◽  
Vol 64 (2) ◽  
Author(s):  
Weronika Ratajczak ◽  
Paulina Niedźwiedzka-Rystwej ◽  
Beata Tokarz-Deptuła ◽  
Wiesław Deptuła

Interferons (IFN) are pivotal regulators of immunological processes. The paper describes mainly type I interferons -α and –β and its recently recounted signaling pathways, especially ISG – interferon stimulated genes, having a crucial role in regulating IFN recruitment. Moreover, the paper shows the data on the role of interferons -α and –β in infections – not only commonly known viral infections, but also bacterial, fungal and parasitic. 


2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Hale Tunbak ◽  
Rocio Enriquez-Gasca ◽  
Christopher H. C. Tie ◽  
Poppy A. Gould ◽  
Petra Mlcochova ◽  
...  

Abstract The Human Silencing Hub (HUSH) complex is necessary for epigenetic repression of LINE-1 elements. We show that HUSH-depletion in human cell lines and primary fibroblasts leads to induction of interferon-stimulated genes (ISGs) through JAK/STAT signaling. This effect is mainly attributed to MDA5 and RIG-I sensing of double-stranded RNAs (dsRNAs). This coincides with upregulation of primate-conserved LINE-1s, as well as increased expression of full-length hominid-specific LINE-1s that produce bidirectional RNAs, which may form dsRNA. Notably, LTRs nearby ISGs are derepressed likely rendering these genes more responsive to interferon. LINE-1 shRNAs can abrogate the HUSH-dependent response, while overexpression of an engineered LINE-1 construct activates interferon signaling. Finally, we show that the HUSH component, MPP8 is frequently downregulated in diverse cancers and that its depletion leads to DNA damage. These results suggest that LINE-1s may drive physiological or autoinflammatory responses through dsRNA sensing and gene-regulatory roles and are controlled by the HUSH complex.


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