Japanese encephalitis virus non-coding RNA inhibits activation of interferon by blocking nuclear translocation of interferon regulatory factor 3

2013 ◽  
Vol 166 (1-2) ◽  
pp. 11-21 ◽  
Author(s):  
Ruey-Yi Chang ◽  
Ta-Wen Hsu ◽  
Yen-Lin Chen ◽  
Shu-Fan Liu ◽  
Yi-Jer Tsai ◽  
...  
2021 ◽  
Author(s):  
Aarti Tripathi ◽  
Bhupendra Singh Rawat ◽  
Sankar Addya ◽  
Milan Surjit ◽  
Prafullakumar B. Tailor ◽  
...  

Interferon Regulatory Factor 8 (IRF8), a myeloid lineage transcription factor, emerges as an essential regulator for microglia activation. However, the precise role of IRF8 during Japanese encephalitis virus (JEV) infection in the brain remains elusive. Here we report that JEV infection enhances IRF8 expression in the infected mice brain. Comparative transcriptional profiling of whole-brain RNA analysis and validation by qRT-PCR reveals an impaired IFNγ and related gene expression in Irf8 knockout ( Irf8 -/- ) infected mice. Further, Ifnγ knockout ( Ifnγ -/- ) mice exhibit a reduced level of Irf8. Both Ifnγ -/- and Irf8 -/- mice exhibit significantly reduced levels of activated (CD11b + CD45 hi , CD11b + CD45 lo , Cd68, and CD86 ) and infiltrating immune cells (Ly6C + , CD4, and CD8) in the infected brain as compared to WT mice. However, a higher level of granulocyte cells (Ly6G + ) infiltration is evident in Irf8 -/- mice and the increased concentration of TNFα, IL6, MCP1 levels in the brain. Interestingly, neither Irf8 -/- nor Ifnγ -/- has conferred protection against lethal JEV challenge to mice and exhibits augmentation in JEV replication in the brain. The gain of function of Irf8 by overexpressing functional IRF8 in an IRF8 deficient cell line attenuates viral replication and enhances IFNγ production. Overall, we summarise that in the murine model of JEV encephalitis, IRF8 modulation affects JEV replication. We also evidence that lack of Irf8 affects immune cells abundance in circulation and the infected brain leading to a reduction in IFNγ level and increased viral load in the brain. Importance Microglial cells, the resident macrophages in the brain, play a vital role in Japanese encephalitis virus (JEV) pathogenesis. The deregulated activity of microglia can be lethal for the brain. Therefore, it is crucial to understand the regulators that drive microglia's phenotype changes and induce inflammation in the brain. Interferon regulatory factor 8 (IRF8) is a myeloid lineage transcription factor involved in microglial activation. However, the impact of IRF8 modulation on JEV replication remains elusive. Moreover, the pathways regulated by IRF8 to initiate and amplify pathological neuroinflammation are not well understood. Here, we demonstrated the effect of IRF8 modulation on JEV replication, microglial activation, and immune cells infiltration in the brain.


Blood ◽  
2006 ◽  
Vol 109 (7) ◽  
pp. 2887-2893 ◽  
Author(s):  
Ezra Aksoy ◽  
Valentina Albarani ◽  
Muriel Nguyen ◽  
Jean-Francois Laes ◽  
Jean-Louis Ruelle ◽  
...  

AbstractThe synthesis of interferon-β (IFNβ) and IFN-inducible factors elicited by lipopolysaccharide (LPS) depends on the transcriptional activity of interferon regulatory factor 3 (IRF-3) downstream of Toll-like receptor-4 (TLR4). To examine the ability of human newborns to mount TLR4-mediated IRF-3–dependent responses, we analyzed the pattern of genes expressed on the addition of LPS to cord blood or cord blood monocyte-derived dendritic cells (moDCs). Expression of IFNβ and IFN-inducible genes was selectively impaired in neonatal blood and moDCs as compared with their adult counterparts. This selective defect was confirmed by microarray experiments on moDCs. Altered expression of IFN-inducible genes was related to impaired IFNβ synthesis because IFNβ signaling was functional in neonatal moDCs. However, addition of exogenous IFNβ failed to restore LPS-induced IL-12p70 synthesis which was previously shown to be defective in neonatal moDCs. Although LPS-induced IRF-3 nuclear translocation was observed both in adult and neonatal moDCs, IRF-3 DNA-binding activity and association with the coactivator CREB-binding protein (CBP) were decreased in neonatal as compared with adult moDCs. We conclude that impaired IRF-3/CBP interaction in neonatal blood cells exposed to LPS is associated with impaired expression of IFNβ and IFN-inducible genes. Because IRF-3 activity is also required for IL-12p70 synthesis, our findings provide a molecular basis for the decreased ability of LPS-stimulated neonatal moDCs to elicit Th1-type responses.


2012 ◽  
Vol 87 (3) ◽  
pp. 1821-1833 ◽  
Author(s):  
Daniel C. Peltier ◽  
Helen M. Lazear ◽  
Jocelyn R. Farmer ◽  
Michael S. Diamond ◽  
David J. Miller

ABSTRACTCell-intrinsic innate immune responses mediated by the transcription factor interferon regulatory factor 3 (IRF-3) are often vital for early pathogen control, and effective responses in neurons may be crucial to prevent the irreversible loss of these critical central nervous system cells after infection with neurotropic pathogens. To investigate this hypothesis, we used targeted molecular and genetic approaches with cultured neurons to study cell-intrinsic host defense pathways primarily using the neurotropic alphavirus western equine encephalitis virus (WEEV). We found that WEEV activated IRF-3-mediated neuronal innate immune pathways in a replication-dependent manner, and abrogation of IRF-3 function enhanced virus-mediated injury by WEEV and the unrelated flavivirus St. Louis encephalitis virus. Furthermore, IRF-3-dependent neuronal protection from virus-mediated cytopathology occurred independently of autocrine or paracrine type I interferon activity. Despite being partially controlled by IRF-3-dependent signals, WEEV also disrupted antiviral responses by inhibiting pattern recognition receptor pathways. This antagonist activity was mapped to the WEEV capsid gene, which disrupted signal transduction downstream of IRF-3 activation and was independent of capsid-mediated inhibition of host macromolecular synthesis. Overall, these results indicate that innate immune pathways have important cytoprotective activity in neurons and contribute to limiting injury associated with infection by neurotropic arboviruses.


2011 ◽  
Vol 286 (27) ◽  
pp. 24113-24124 ◽  
Author(s):  
Christian Ehlting ◽  
Natalia Ronkina ◽  
Oliver Böhmer ◽  
Ute Albrecht ◽  
Konrad A. Bode ◽  
...  

In LPS-treated macrophages, activation of STAT3 is considered to be crucial for terminating the production of inflammatory cytokines. By analyzing the role of MAPK-activated protein kinase (MK) 2 and MK3 for LPS-induced STAT3 activation in macrophages, the present study provides evidence that MK2 is crucial for STAT3 activation in response to LPS because it prevents MK3 from impeding IFNβ gene expression. Accordingly, LPS-induced IFNβ gene expression is down-regulated in MK2-deficient macrophages and can be reconstituted by additional ablation of the MK3 gene in MK2/3−/− macrophages. This is in contrast to LPS-induced IL-10 expression, which essentially requires the presence of MK2. Further analysis of downstream signaling events involved in the transcriptional regulation of IFNβ gene expression suggests that, in the absence of MK2, MK3 impairs interferon regulatory factor 3 protein expression and activation and inhibits nuclear translocation of p65. This inhibition of p65 nuclear translocation coincides with enhanced expression and delayed degradation of IκBβ, whereas expression of IκBα mRNA and protein is impaired in the absence of MK2. The observation that siRNA directed against IκBβ is able to reconstitute IκBα expression in MK2−/− macrophages suggests that enhanced expression and delayed degradation of IκBβ and impaired NFκB-dependent IκBα expression are functionally linked. In summary, evidence is provided that MK2 regulates LPS-induced IFNβ expression and downstream STAT3 activation as it restrains MK3 from mediating negative regulatory effects on NFκB- and interferon regulatory factor 3-dependent LPS signaling.


1999 ◽  
Vol 19 (4) ◽  
pp. 2465-2474 ◽  
Author(s):  
Rongtuan Lin ◽  
Yael Mamane ◽  
John Hiscott

ABSTRACT The interferon regulatory factor 3 (IRF-3) gene encodes a 55-kDa protein which is expressed constitutively in all tissues. In unstimulated cells, IRF-3 is present in an inactive cytoplasmic form; following Sendai virus infection, IRF-3 is posttranslationally modified by protein phosphorylation at multiple serine and threonine residues located in the carboxy terminus. Virus-induced phosphorylation of IRF-3 leads to cytoplasmic to nuclear translocation of phosphorylated IRF-3, association with the transcriptional coactivator CBP/p300, and stimulation of DNA binding and transcriptional activities of virus-inducible genes. Using yeast and mammalian one-hybrid analysis, we now demonstrate that an extended, atypical transactivation domain is located in the C terminus of IRF-3 between amino acids (aa) 134 and 394. We also show that the C-terminal domain of IRF-3 located between aa 380 and 427 participates in the autoinhibition of IRF-3 activity via an intramolecular association with the N-terminal region between aa 98 and 240. After Sendai virus infection, an intermolecular association between IRF-3 proteins is detected, demonstrating a virus-dependent formation of IRF-3 homodimers; this interaction is also observed in the absence of virus infection with a constitutively activated form of IRF-3. Substitution of the C-terminal Ser-Thr phosphorylation sites with the phosphomimetic Asp in the region ISNSHPLSLTSDQ between amino acids 395 and 407 [IRF-3(5D)], but not the adjacent S385 and S386 residues, generates a constitutively activated DNA binding form of IRF-3. In contrast, substitution of S385 and S386 with either Ala or Asp inhibits both DNA binding and transactivation activities of the IRF-3(5D) protein. These studies thus define the transactivation domain of IRF-3, two domains that participate in the autoinhibition of IRF-3 activity, and the regulatory phosphorylation sites controlling IRF-3 dimer formation, DNA binding activity, and association with the CBP/p300 coactivator.


1998 ◽  
Vol 18 (7) ◽  
pp. 3796-3802 ◽  
Author(s):  
Lorena Navarro ◽  
Kerri Mowen ◽  
Steven Rodems ◽  
Brian Weaver ◽  
Nancy Reich ◽  
...  

ABSTRACTInterferon establishes an antiviral state in numerous cell types through the induction of a set of immediate-early response genes. Activation of these genes is mediated by phosphorylation of latent transcription factors of the STAT family. We found that infection of primary foreskin fibroblasts with human cytomegalovirus (HCMV) causes selective transcriptional activation of the alpha/beta-interferon-responsive ISG54 gene. However, no activation or nuclear translocation of STAT proteins was detected. Activation of ISG54 occurs independent of protein synthesis but is prevented by protein tyrosine kinase inhibitors. Further analysis revealed that HCMV infection induced the DNA binding of a novel complex, tentatively called cytomegalovirus-induced interferon-stimulated response element binding factor (CIF). CIF is composed, at least in part, of the recently identified interferon regulatory factor 3 (IRF3), but it does not contain the STAT1 and STAT2 proteins that participate in the formation of interferon-stimulated gene factor 3. IRF3, which has previously been shown to possess no intrinsic transcriptional activation potential, interacts with the transcriptional coactivator CREB binding protein, but not with p300, to form CIF. Activating interferon-stimulated genes without the need for prior synthesis of interferons might provide the host cell with a potential shortcut in the activation of its antiviral defense.


2020 ◽  
Author(s):  
Xiaolong Zhou ◽  
Qiongyu Yuan ◽  
Chen Zhang ◽  
Zhenglie Dai ◽  
Chengtao Du ◽  
...  

Abstract Background: Japanese encephalitis virus is a mosquito-borne neurotropic flavivirus that causes acute viral encephalitis in humans. Pigs are crucial amplifier host of JEV. Recently, increasing evidences have shown that long non-coding RNAs (lncRNAs) play important roles in virus infection. Methods: The JEV proliferation was evaluated after overexpression or knockdown of lncRNA-NONSUST006715.1 using western blotting and reverse-transcription polymerase chain reaction (RT-PCR). C-C chemokine receptor type 1 (CCR1) was found to regulate the expression of lncRNA-NONSUST006715.1 by inhibitors screen. The expression of lncRNA-NONSUST006715.1 was detected using RT-PCR after overexpression or knockdown of transcription factor SP1. In addition, the enrichments of transcription factor SP1 on the promoter of lncRNA-NONSUST006715.1 were analyzed by chromatin immunoprecipitation. Results: In this study, we demonstrated that swine lncRNA-NONSUST006715.1 could suppress JEV proliferation in PK-15 cells. We also found that CCR1 inhibited the expression of lncRNA-NONSUST006715.1 via the transcription factor SP1. In addition, knockdown of CCR1 could upregulated the expression of SP1 and lncRNA-NONSUST006715.1, resulting in resistance to JEV proliferation. Conclusions: These findings illustrate the importance of lncRNAs in virus proliferation, and reveal how this virus regulates lncRNAs in host cells to promote its proliferation.


2021 ◽  
Vol 12 ◽  
Author(s):  
Farooq Rashid ◽  
Muhammad Suleman ◽  
Abdullah Shah ◽  
Emmanuel Enoch Dzakah ◽  
Haiying Wang ◽  
...  

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been continuously mutating since its first emergence in early 2020. These alterations have led this virus to gain significant difference in infectivity, pathogenicity, and host immune evasion. We previously found that the open-reading frame 8 (ORF8) of SARS-CoV-2 can inhibit interferon production by decreasing the nuclear translocation of interferon regulatory factor 3 (IRF3). Since several mutations in ORF8 have been observed, therefore, in the present study, we adapted structural and biophysical analysis approaches to explore the impact of various mutations of ORF8, such as S24L, L84S, V62L, and W45L, the recently circulating mutant in Pakistan, on its ability to bind IRF3 and to evade the host immune system. We found that mutations in ORF8 could affect the binding efficiency with IRF3 based on molecular docking analysis, which was further supported by molecular dynamics simulations. Among all the reported mutations, W45L was found to bind most stringently to IRF3. Our analysis revealed that mutations in ORF8 may help the virus evade the immune system by changing its binding affinity with IRF3.


2020 ◽  
Author(s):  
Xiaolong Zhou ◽  
Qiongyu Yuan ◽  
Chen Zhang ◽  
Zhenglie Dai ◽  
Chengtao Du ◽  
...  

Abstract Background: Japanese encephalitis virus is a mosquito-borne neurotropic flavivirus that causes acute viral encephalitis in humans. Pigs are crucial amplifier host of JEV. Recently, long non-coding RNAs have received increasing attention for their antiviral function. Methods: LncRNA-NONSUST006715.1 was overexpression or knockdown using western blotting and reverse-transcription polymerase chain reaction (RT-PCR) to detect the effect of lncRNA on JEV proliferation. CCR1 was found to regulate the expression of lncRNA-NONSUST006715.1 by inhibitors screen. Transcription factor SP1 was overexpression or knockdown using RT-PCR to detect the influence of SP1 on the expression of lncRNA. In addition, the enrichments of transcription factor SP1 on the promoter of lncRNA-NONSUST006715.1 were analyzed by Chromatin immunoprecipitation.Results: In this study, we demonstrated a new function of lncRNA-NONSUST006715.1, the inhibition of JEV proliferation in PK-15 cells. We found that C-C chemokine receptor type 1 inhibited the expression of lncRNA-NONSUST006715.1 via the transcription factor SP1. Knockdown of CCR1 could upregulated the expression of SP1 and lncRNA-NONSUST006715.1, resulting in resistance to JEV proliferation. Conclusions: These findings illustrate the importance of lncRNAs in virus proliferation, and reveal how this virus regulates lncRNAs in host cells to promote its proliferation.


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