scholarly journals Bud13 Promotes a Type I Interferon Response by Countering Intron Retention in Irf7

2018 ◽  
Author(s):  
Luke S. Frankiw ◽  
Devdoot Majumdar ◽  
Christian Burns ◽  
Annie Moradian ◽  
Michael J. Sweredoski ◽  
...  

SUMMARYIntron retention (IR) has emerged as an important mechanism of gene expression control. Despite this, the factors that control IR events remain poorly understood. We observed consistent IR in one intron of the Irf7 gene and identified Bud13 as an RNA-binding protein that acts at this intron to increase the amount of successful splicing. Deficiency in Bud13 led to increased IR, decreased mature Irf7 transcript and protein levels, and consequently to a dampened type I interferon response. This impairment of Irf7 production in Bud13-deficient cells compromised their ability to withstand VSV infection. Global analysis of Bud13 knockdown and BUD13 cross-linking to RNA revealed a subset of introns that share many characteristics with the one found in Irf7 and are spliced in a Bud13-dependent manner. Deficiency of Bud13 led to decreased mature transcript from genes containing such introns. Thus, by acting as an antagonist to IR, Bud13 facilitates the expression of genes at which IR occurs.

2019 ◽  
Vol 73 (4) ◽  
pp. 803-814.e6 ◽  
Author(s):  
Luke Frankiw ◽  
Devdoot Majumdar ◽  
Christian Burns ◽  
Logan Vlach ◽  
Annie Moradian ◽  
...  

Cancers ◽  
2020 ◽  
Vol 12 (9) ◽  
pp. 2450
Author(s):  
Aneta Gandalovičová ◽  
Anna-Marie Šůchová ◽  
Vladimír Čermák ◽  
Ladislav Merta ◽  
Daniel Rösel ◽  
...  

The invasive behaviour of cancer cells underlies metastatic dissemination; however, due to the large plasticity of invasion modes, it is challenging to target. It is now widely accepted that various secreted cytokines modulate the tumour microenvironment and pro-inflammatory signalling can promote tumour progression. Here, we report that cells after mesenchymal–amoeboid transition show the increased expression of genes associated with the type I interferon response. Moreover, the sustained activation of type I interferon signalling in response to IFNβ mediated by the Stat1/Stat2/IRF9 complex enhances the round amoeboid phenotype in melanoma cells, whereas its downregulation by various approaches promotes the mesenchymal invasive phenotype. Overall, we demonstrate that interferon signalling is associated with the amoeboid phenotype of cancer cells and suggest a novel role of IFNβ in promoting cancer invasion plasticity, aside from its known role as a tumour suppressor.


2020 ◽  
Author(s):  
Hyeongjwa Choi ◽  
Juntae Kwon ◽  
Jiafang Sun ◽  
Min Soon Cho ◽  
Yifan Sun ◽  
...  

Abstract Accumulating evidence has shown that cellular double-stranded RNAs (dsRNAs) induce antiviral innate immune responses in human normal and malignant cancer cells. However, it is not fully understood how endogenous ‘self’ dsRNA homeostasis is regulated in the cell. Here, we show that an RNA-binding protein, DEAD-box RNA helicase 3X (DDX3X), prevents the aberrant accumulation of cellular dsRNAs. Loss of DDX3X induces dsRNA sensor-mediated type I interferon signaling and innate immune response in breast cancer cells due to abnormal cytoplasmic accumulation of dsRNAs. Dual depletion of DDX3X and a dsRNA-editing protein, ADAR1 synergistically activates the cytosolic dsRNA pathway in the breast cancer cells. Moreover, inhibiting DDX3X enhances the antitumor activity by increasing tumor intrinsic-type I interferon response, antigen presentation, and tumor-infiltration of cytotoxic T cells as well as dendritic cells in breast tumors, which may lead to the development of breast cancer therapy by targeting DDX3X in combination with immune checkpoint blockade.


2017 ◽  
Vol 91 (8) ◽  
Author(s):  
Oladunni Olanubi ◽  
Jasmine Rae Frost ◽  
Sandi Radko ◽  
Peter Pelka

ABSTRACT Suppression of interferon signaling is of paramount importance to a virus. Interferon signaling significantly reduces or halts the ability of a virus to replicate; therefore, viruses have evolved sophisticated mechanisms that suppress activation of the interferon pathway or responsiveness of the infected cell to interferon. Adenovirus has multiple modes of inhibiting the cellular response to interferon. Here, we report that E1A, previously shown to regulate interferon signaling in multiple ways, inhibits interferon-stimulated gene expression by modulating RuvBL1 function. RuvBL1 was previously shown to affect type I interferon signaling. E1A binds to RuvBL1 and is recruited to RuvBL1-regulated promoters in an interferon-dependent manner, preventing their activation. Depletion of RuvBL1 impairs adenovirus growth but does not appear to significantly affect viral protein expression. Although RuvBL1 has been shown to play a role in cell growth, its depletion had no effect on the ability of the virus to replicate its genome or to drive cells into S phase. E1A was found to bind to RuvBL1 via the C terminus of E1A, and this interaction was important for suppression of interferon-stimulated gene transcriptional activation and recruitment of E1A to interferon-regulated promoters. Here, we report the identification of RuvBL1 as a new target for adenovirus in its quest to suppress the interferon response. IMPORTANCE For most viruses, suppression of the interferon signaling pathway is crucial to ensure a successful replicative cycle. Human adenovirus has evolved several different mechanisms that prevent activation of interferon or the ability of the cell to respond to interferon. The viral immediate-early gene E1A was previously shown to affect interferon signaling in several different ways. Here, we report a novel mechanism reliant on RuvBL1 that E1A uses to prevent activation of interferon-stimulated gene expression following infection or interferon treatment. This adds to the growing knowledge of how viruses are able to inhibit interferon and identifies a novel target used by adenovirus for modulation of the cellular interferon pathway.


2020 ◽  
Author(s):  
Hyeongjwa Choi ◽  
Juntae Kwon ◽  
Jiafang Sun ◽  
Min Soon Cho ◽  
Yifan Sun ◽  
...  

ABSTRACTAccumulating evidence has shown that cellular double-stranded RNAs (dsRNAs) induce antiviral innate immune responses in human normal and malignant cancer cells. However, it is not fully understood how endogenous ‘self’ dsRNA homeostasis is regulated in the cell. Here, we show that an RNA-binding protein, DEAD-box RNA helicase 3X (DDX3X), prevents the aberrant accumulation of cellular dsRNAs. Loss of DDX3X induces dsRNA sensor-mediated type I interferon signaling and innate immune response in breast cancer cells due to abnormal cytoplasmic accumulation of dsRNAs. Dual depletion of DDX3X and a dsRNA-editing protein, ADAR1 synergistically activates the cytosolic dsRNA pathway in breast cancer cell. Moreover, inhibiting DDX3X enhances the antitumor activity by increasing tumor intrinsic-type I interferon response, antigen presentation, and tumor-infiltration of cytotoxic T cells as well as dendritic cells in breast tumors, which may lead to the development of breast cancer therapy by targeting DDX3X in combination with immune checkpoint blockade.


2021 ◽  
Vol 12 ◽  
Author(s):  
Yueyan Liao ◽  
Xiangyu Ke ◽  
Tianyi Deng ◽  
Qingsong Qin

Human cytomegalovirus (HCMV) is a ubiquitous opportunistic pathogen and can be life-threatening for immunocompromised individuals. There is currently no available vaccine for the prevention of HCMV- associated diseases and most of the available antiviral drugs that target viral DNA synthesis become ineffective in treating HCMV mutants that arise after long-term use in immunocompromised patients. Here, we examined the effects of Eltanexor, a second-generation selective inhibitor of nuclear export (SINE), on HCMV replication. Eltanexor effectively inhibits HCMV replication in human foreskin fibroblasts in a dose-dependent manner. Eltanexor does not significantly inhibit viral entry and nuclear import of viral genomic DNA, but rather suppress the transcript and protein levels of viral immediate-early (IE), early (E) and late (L) genes, and abolishes the production of infectious virions. We further found Eltanexor treatment promotes proteasome-mediated degradation of XPO1, which contributes to the nuclear retention of interferon regulatory factor 3 (IRF-3), resulting in increased expression of type I interferon as well as interferon stimulating genes ISG15 and ISG54. This study reveals a novel antiviral mechanism of Eltanexor which suggests it has potential to inhibit a broad spectrum of viral pathogens.


2020 ◽  
Vol 22 (Supplement_2) ◽  
pp. ii109-ii109
Author(s):  
Brandon Wummer ◽  
Sadeem Qdaisat ◽  
Adam Grippin ◽  
Aida Karachi ◽  
Frances Weidert ◽  
...  

Abstract BACKGROUND Molecular drivers of cancer immunogenicity in brain tumors are still being unraveled. While BATF3 expression, STING, and interferon response factors (IRFs) are necessary for cancer immunogenicity, the presence of type I interferon (IFN-I) is contextual having been reported to elicit both anti-tumoral and pro-tumoral effects. A better understanding of IFN-I signaling mechanisms is necessary to elucidate drivers of brain cancer immunogenicity and resistance. OBJECTIVE We sought to assess the role of IFN-I signaling in brain tumor immunogenicity and response to immune checkpoint inhibitors (ICIs) in ICI sensitive brain tumor models (i.e. GL261). We then sought to develop strategies to reset IFN-I signaling in ICI resistant brain tumor models (i.e. KR158b). METHODS To reset IFN-I signaling in immunologically ‘cold’ tumors unresponsive to ICIs, we developed lipid-nanoparticles (NPs) to deliver mRNA payloads to the brain tumor microenvironment (TME). RESULTS In immune-sensitive GL261 tumors, we showed that early release of IFN-I unlocks cancer immunogenicity and ICI response. Blockade of IFN-I during tumorigenesis (within 24h, but not days later) increases tumorigenicity and abrogates ICI activity in sensitive tumors. In ICI resistant KR158b tumors, we show that systemic administration of tumor-derived RNA-NPs localize to myeloid cells within the TME for simultaneous activation of multiple innate pathways including BATF3 (necessary for effector DCs), IRF5 (necessary for M2 to M1 macrophage reprograming), and IRF7 (necessary for IFN-I production). These RNA-NPs induce near-immediate release of IFN-I (within hours), reprogram the brain TME in an IFNAR1 (IFN-I receptor) dependent manner, and elicit significant anti-KR158b efficacy as a monotherapy. Following IFNAR1 blockade, RNA-NP mediated anti-tumor efficacy was abrogated. We demonstrated safety of tumor-specific RNA-NPs (derived from KR158b) in acute/chronic GLP toxicity studies without normal-brain cross-reactivity, and confirmed feasibility/safety and immunologic activity in large-animal studies. FUTURE DIRECTIONS We have since received FDA-IND approval for first-in-human trials (IND#BB-19304) in glioblastoma patients.


2016 ◽  
Vol 90 (18) ◽  
pp. 8281-8292 ◽  
Author(s):  
Longjun Guo ◽  
Xiaolei Luo ◽  
Ren Li ◽  
Yunfei Xu ◽  
Jian Zhang ◽  
...  

ABSTRACTPorcine epidemic diarrhea virus (PEDV) is a worldwide-distributed alphacoronavirus, but the pathogenesis of PEDV infection is not fully characterized. During virus infection, type I interferon (IFN) is a key mediator of innate antiviral responses. Most coronaviruses develop some strategy for at least partially circumventing the IFN response by limiting the production of IFN and by delaying the activation of the IFN response. However, the molecular mechanisms by which PEDV antagonizes the antiviral effects of interferon have not been fully characterized. Especially, how PEDV impacts IFN signaling components has yet to be elucidated. In this study, we observed that PEDV was relatively resistant to treatment with type I IFN. Western blot analysis showed that STAT1 expression was markedly reduced in PEDV-infected cells and that this reduction was not due to inhibition of STAT1 transcription. STAT1 downregulation was blocked by a proteasome inhibitor but not by an autophagy inhibitor, strongly implicating the ubiquitin-proteasome targeting degradation system. Since PEDV infection-induced STAT1 degradation was evident in cells pretreated with the general tyrosine kinase inhibitor, we conclude that STAT1 degradation is independent of the IFN signaling pathway. Furthermore, we report that PEDV-induced STAT1 degradation inhibits IFN-α signal transduction pathways. Pharmacological inhibition of STAT1 degradation rescued the ability of the host to suppress virus replication. Collectively, these data show that PEDV is capable of subverting the type I interferon response by inducing STAT1 degradation.IMPORTANCEIn this study, we show that PEDV is resistant to the antiviral effect of IFN. The molecular mechanism is the degradation of STAT1 by PEDV infection in a proteasome-dependent manner. This PEDV infection-induced STAT1 degradation contributes to PEDV replication. Our findings reveal a new mechanism evolved by PEDV to circumvent the host antiviral response.


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