scholarly journals HCFC2 is needed for IRF1- and IRF2-dependent Tlr3 transcription and for survival during viral infections

2017 ◽  
Vol 214 (11) ◽  
pp. 3263-3277 ◽  
Author(s):  
Lei Sun ◽  
Zhengfan Jiang ◽  
Victoria A. Acosta-Rodriguez ◽  
Michael Berger ◽  
Xin Du ◽  
...  

Transcriptional regulation of numerous interferon-regulated genes, including Toll-like receptor 3 (Tlr3), which encodes an innate immune sensor of viral double-stranded RNA, depends on the interferon regulatory factor 1 (IRF1) and IRF2 transcription factors. We detected specific abrogation of macrophage responses to polyinosinic-polycytidylic acid (poly(I:C)) resulting from three independent N-ethyl-N-nitrosourea–induced mutations in host cell factor C2 (Hcfc2). Hcfc2 mutations compromised survival during influenza virus and herpes simplex virus 1 infections. HCFC2 promoted the binding of IRF1 and IRF2 to the Tlr3 promoter, without which inflammatory cytokine and type I IFN responses to the double-stranded RNA analogue poly(I:C) are reduced in mouse macrophages. HCFC2 was also necessary for the transcription of a large subset of other IRF2-dependent interferon-regulated genes. Deleterious mutations of Hcfc2 may therefore increase susceptibility to diverse infectious diseases.

Endocrinology ◽  
2011 ◽  
Vol 152 (12) ◽  
pp. 4984-4992 ◽  
Author(s):  
Bo Wang ◽  
Kaori Koga ◽  
Yutaka Osuga ◽  
Ingrid Cardenas ◽  
Gentaro Izumi ◽  
...  

Indoleamine 2,3-dioxygenase (IDO) is an enzyme that degrades an essential amino acid, tryptophan, and plays a role in inhibiting the proliferation of T cells and intracellular pathogens. Inhibiting IDO in mice leads to fetal rejection, suggesting its significance in establishing pregnancy. Toll-like receptor 3 (TLR-3) is a key component of the innate immune system that recognizes viral double-stranded RNA and triggers immune reactions by producing type I interferon. Using a human trophoblast cell culture system, we studied the effect of TLR-3 ligation on IDO expression and function by treating trophoblasts with polyinosinic-polycytidylic acid [poly(I:C)] (a synthetic double stranded RNA, which mimics viral RNA). Real-time PCR and Western blot analysis revealed that IDO mRNA and protein expression was significantly induced by poly(I:C). The activity of IDO was also increased by poly(I:C) given that the l-kynurenine concentrations were elevated in conditioned media. Conditioned media from poly(I:C)-treated trophoblasts were found to inhibit the proliferation of human T cells significantly. Poly(I:C) was also shown to induce interferon (IFN)-β mRNA expression in trophoblasts. Recombinant human IFN-β increased IDO mRNA expression in trophoblasts more rapidly than poly(I:C). Pretreating with neutralizing antibody against IFN-β significantly suppressed IDO induction by poly(I:C). Collectively we have demonstrated that ligation of TLR-3 by poly(I:C) induces IDO expression in human first-trimester trophoblasts via an IFN-β-dependent pathway. These findings suggest that upon viral infection, trophoblasts induce IDO and in turn contribute to antimicrobial activity and maintenance of fetomaternal tolerance.


2021 ◽  
Vol 22 (9) ◽  
pp. 4668
Author(s):  
Jin Zhao ◽  
Ruiting Li ◽  
Yanjun Li ◽  
Jiaoshan Chen ◽  
Fengling Feng ◽  
...  

Deeply understanding the virus-host interaction is a prerequisite for developing effective anti-viral strategies. Traditionally, the transporter associated with antigen processing type 1 (TAP1) is critical for antigen presentation to regulate adaptive immunity. However, its role in controlling viral infections through modulating innate immune signaling is not yet fully understood. In the present study, we reported that TAP1, as a product of interferon-stimulated genes (ISGs), had broadly antiviral activity against various viruses such as herpes simplex virus 1 (HSV-1), adenoviruses (AdV), vesicular stomatitis virus (VSV), dengue virus (DENV), Zika virus (ZIKV), and influenza virus (PR8) etc. This antiviral activity by TAP1 was further confirmed by series of loss-of-function and gain-of-function experiments. Our further investigation revealed that TAP1 significantly promoted the interferon (IFN)-β production through activating the TANK binding kinase-1 (TBK1) and the interferon regulatory factor 3 (IRF3) signaling transduction. Our work highlighted the broadly anti-viral function of TAP1 by modulating innate immunity, which is independent of its well-known function of antigen presentation. This study will provide insights into developing novel vaccination and immunotherapy strategies against emerging infectious diseases.


2020 ◽  
Vol 2020 ◽  
pp. 1-8 ◽  
Author(s):  
Yuanyuan Li ◽  
Yueqi Song ◽  
Leqing Zhu ◽  
Xiao Wang ◽  
Brittany Richers ◽  
...  

Type I interferon kappa (IFNκ) is selectively expressed in human keratinocytes. Herpes simplex virus-1 (HSV-1) is a human pathogen that infects keratinocytes and causes lytic skin lesions. Whether IFNκ plays a role in keratinocyte host defense against HSV-1 has not been investigated. In this study, we found that IFNκ mRNA expression was induced by addition of recombinant IFNκ and poly (I:C); and its expression level was significantly greater than IFNa2, IFNb1, and IFNL1 in both undifferentiated and differentiated normal human epidermal keratinocytes (NHEKs) under resting and stimulation conditions. Although IFNe was expressed at a relatively higher level than other IFNs in resting undifferentiated NHEK, its expression level did not change after stimulation with recombinant IFNκ and poly (I:C). HSV-1 infection inhibited gene expression of IFNκ and IFNe in NHEK. Silencing IFNκ in NHEK led to significantly enhanced HSV-1 replication in both undifferentiated and differentiated NHEK compared to scrambled siRNA-transfected cells, while the addition of recombinant IFNκ significantly reduced HSV-1 replication in NHEK. In addition, we found that IFNκ did not regulate protein expression of NHEK differentiation markers. Our results demonstrate that IFNκ is the dominant type of IFNs in keratinocytes and it has an important function for keratinocytes to combat HSV-1 infection.


2020 ◽  
Vol 10 (1) ◽  
Author(s):  
David Shahnazaryan ◽  
Rana Khalil ◽  
Claire Wynne ◽  
Caroline A. Jefferies ◽  
Joan Ní Gabhann-Dromgoole ◽  
...  

AbstractHerpes simplex keratitis (HSK), caused by herpes simplex virus type 1 (HSV-1) infection, is the commonest cause of infectious blindness in the developed world. Following infection the virus is initially suspended in the tear film, where it encounters a multi-pronged immune response comprising enzymes, complement, immunoglobulins and crucially, a range of anti-viral and pro-inflammatory cytokines. However, given that HSV-1 can overcome innate immune responses to establish lifelong latency throughout a susceptible individual’s lifetime, there is significant interest in understanding the mechanisms employed by HSV-1 to downregulate the anti-viral type I interferon (IFN) mediated immune responses. This study aimed to investigate the interactions between infected cell protein (ICP)0 and key elements of the IFN pathway to identify possible novel targets that contribute to viral immune evasion. Reporter gene assays demonstrated the ability of ICP0 to inhibit type I IFN activity downstream of pathogen recognition receptors (PRRs) which are known to be involved in host antiviral defences. Further experiments identified interferon regulatory factor (IRF)7, a driver of type I IFN, as a potential target for ICP0. These findings increase our understanding of the pathogenesis of HSK and suggest IRF7 as a potential therapeutic target.


Cells ◽  
2021 ◽  
Vol 10 (3) ◽  
pp. 530
Author(s):  
Soo Jin Oh ◽  
Ok Sarah Shin

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the coronavirus disease 2019 (COVID-19) that has resulted in the current pandemic. The lack of highly efficacious antiviral drugs that can manage this ongoing global emergency gives urgency to establishing a comprehensive understanding of the molecular pathogenesis of SARS-CoV-2. We characterized the role of the nucleocapsid protein (N) of SARS-CoV-2 in modulating antiviral immunity. Overexpression of SARS-CoV-2 N resulted in the attenuation of retinoic acid inducible gene-I (RIG-I)-like receptor-mediated interferon (IFN) production and IFN-induced gene expression. Similar to the SARS-CoV-1 N protein, SARS-CoV-2 N suppressed the interaction between tripartate motif protein 25 (TRIM25) and RIG-I. Furthermore, SARS-CoV-2 N inhibited polyinosinic: polycytidylic acid [poly(I:C)]-mediated IFN signaling at the level of Tank-binding kinase 1 (TBK1) and interfered with the association between TBK1 and interferon regulatory factor 3 (IRF3), subsequently preventing the nuclear translocation of IRF3. We further found that both type I and III IFN production induced by either the influenza virus lacking the nonstructural protein 1 or the Zika virus were suppressed by the SARS-CoV-2 N protein. Our findings provide insights into the molecular function of the SARS-CoV-2 N protein with respect to counteracting the host antiviral immune response.


2018 ◽  
Vol 2018 ◽  
pp. 1-10 ◽  
Author(s):  
Yongxiang Liu ◽  
Xiaoxiao Liu ◽  
Hongtao Kang ◽  
Xiaoliang Hu ◽  
Jiasen Liu ◽  
...  

Interferons (IFNs) can inhibit most, if not all, viral infections by eliciting the transcription of hundreds of interferon-stimulated genes (ISGs). Feline calicivirus (FCV) is a highly contagious pathogen of cats and a surrogate for Norwalk virus. Interferon efficiently inhibits the replication of FCV, but the mechanism of the antiviral activity is poorly understood. Here, we evaluated the anti-FCV activity of ten ISGs, whose antiviral activities were previously reported. The results showed that interferon regulatory factor 1 (IRF1) can significantly inhibit the replication of FCV, whereas the other ISGs tested in this study failed. Further, we found that IRF1 was localized in the nucleus and efficiently activated IFN-β and the ISRE promoter. IRF1 can trigger the production of endogenous interferon and the expression of ISGs, suggesting that IRF1 can positively regulate IFN signalling. Importantly, the mRNA and protein levels of IRF1 were reduced upon FCV infection, which may be a new strategy for FCV to evade the innate immune system. Finally, the antiviral activity of IRF1 against feline panleukopenia virus, feline herpesvirus, and feline infectious peritonitis virus was demonstrated. These data indicate that feline IRF1 plays an important role in regulating the host type I IFN response and inhibiting feline viral infections.


2019 ◽  
Author(s):  
Paulino Barragan-Iglesias ◽  
Úrzula Franco-Enzástiga ◽  
Vivekanand Jeevakumar ◽  
Andi Wangzhou ◽  
Vinicio Granados-Soto ◽  
...  

ABSTRACTOne of the first signs of viral infection is body-wide aches and pain. While this type of pain usually subsides, at the extreme, viral infections can induce painful neuropathies that can last for decades. Neither of these types of pain sensitization are well understood. A key part of the response to viral infection is production of interferons (IFNs), which then activate their specific receptors (IFNRs) resulting in downstream activation of cellular signaling and a variety of physiological responses. We sought to understand how type I IFNs (IFN-α and IFN-β) might act directly on nociceptors in the dorsal root ganglion (DRG) to cause pain sensitization. We demonstrate that type I IFNRs are expressed in small/medium DRG neurons and that their activation produces neuronal hyper-excitability and mechanical pain in mice. Type I IFNs stimulate JAK/STAT signaling in DRG neurons but this does not apparently result in PKR-eIF2α activation that normally induces an anti-viral response by limiting mRNA translation. Rather, type I interferons stimulate MNK-mediated eIF4E phosphorylation in DRG neurons to promote pain hypersensitivity. Endogenous release of type I IFNs with the double stranded RNA mimetic poly(I:C) likewise produces pain hypersensitivity that is blunted in mice lacking MNK-eIF4E signaling. Our findings reveal mechanisms through which type I IFNs cause nociceptor sensitization with implications for understanding how viral infections promote pain and can lead to neuropathies.SIGNIFICANCE STATEMENTIt is increasingly understood that pathogens interact with nociceptors to alert organisms to infection as well as to mount early host defenses. While specific mechanisms have been discovered for diverse bacteria and fungal pathogens, mechanisms engaged by viruses have remained elusive. Here we show that type 1 interferons, one of the first mediators produced by viral infection, act directly on nociceptors to produce pain sensitization. Type I interferons act via a specific signaling pathway (MNK-eIF4E signaling) that is known to produce nociceptor sensitization in inflammatory and neuropathic pain conditions. Our work reveals a mechanism through which viral infections cause heightened pain sensitivity


2021 ◽  
Vol 17 (9) ◽  
pp. e1009950
Author(s):  
Nikhil Sharma ◽  
Chenyao Wang ◽  
Patricia Kessler ◽  
Ganes C. Sen

STING is a nodal point for cellular innate immune response to microbial infections, autoimmunity and cancer; it triggers the synthesis of the antiviral proteins, type I interferons. Many DNA viruses, including Herpes Simplex Virus 1 (HSV1), trigger STING signaling causing inhibition of virus replication. Here, we report that HSV1 evades this antiviral immune response by inducing a cellular microRNA, miR-24, which binds to the 3’ untranslated region of STING mRNA and inhibits its translation. Expression of the gene encoding miR-24 is induced by the transcription factor AP1 and activated by MAP kinases in HSV1-infected cells. Introduction of exogenous miR-24 or prior activation of MAPKs, causes further enhancement of HSV1 replication in STING-expressing cells. Conversely, transfection of antimiR-24 inhibits virus replication in those cells. HSV1 infection of mice causes neuropathy and death; using two routes of infection, we demonstrated that intracranial injection of antimiR-24 alleviates both morbidity and mortality of the infected mice. Our studies reveal a new immune evasion strategy adopted by HSV1 through the regulation of STING and demonstrates that it can be exploited to enhance STING’s antiviral action.


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