scholarly journals Bclaf1 critically regulates the type I interferon response and is degraded by alphaherpesvirus US3

2018 ◽  
Author(s):  
Chao Qin ◽  
Rui Zhang ◽  
Yue Lang ◽  
Anwen Shao ◽  
Aotian Xu ◽  
...  
Keyword(s):  
Gene Transcription ◽  
Pseudorabies Virus ◽  
Viral Infections ◽  
Type I Interferon ◽  
Interferon Response ◽  
Interferon Α ◽  
Type I ◽  
Viral Inhibition ◽  
Simplex Virus ◽  
Hsv 1

AbstractType I interferon response plays a prominent role against viral infection, which is frequently disrupted by viruses. Here, we report Bcl-2 associated transcription factor 1 (Bclaf1) is degraded during the alphaherpesvirus Pseudorabies virus (PRV) and Herpes simplex virus type 1 (HSV-1) infections through the viral protein US3. We further reveal that Bclaf1 functions critically in type I interferon signaling. Knockdown or knockout of Bclaf1 in cells significantly impairs interferon-α (IFNα)-mediated gene transcription and viral inhibition against US3 deficient PRV and HSV-1. Mechanistically, Bclaf1 maintains a mechanism allowing STAT1 and STAT2 to be efficiently phosphorylated in response to IFNα, and more importantly, facilitates IFN-stimulated gene factor 3 (ISGF3) binding with IFN-stimulated response elements (ISRE) for efficient gene transcription by directly interacting with ISRE and STAT2. Our studies establish the importance of Bclaf1 in IFNα-induced antiviral immunity and in the control of viral infections.

scholarly journals The Type I Interferon Response Determines Differences in Choroid Plexus Susceptibility between Newborns and Adults in Herpes Simplex Virus Encephalitis

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Douglas R. Wilcox ◽  
Stephen S. Folmsbee ◽  
William J. Muller ◽  
Richard Longnecker
Keyword(s):  
Choroid Plexus ◽  
Type I Interferon ◽  
Adult Brain ◽  
Interferon Response ◽  
Type I ◽  
Β Receptor ◽  
Simplex Virus ◽  
The Brain ◽  
Hsv 1

ABSTRACTNewborns are significantly more susceptible to severe viral encephalitis than adults, with differences in the host response to infection implicated as a major factor. However, the specific host signaling pathways responsible for differences in susceptibility and neurologic morbidity have remained unknown. In a murine model of HSV encephalitis, we demonstrated that the choroid plexus (CP) is susceptible to herpes simplex virus 1 (HSV-1) early in infection of the newborn but not the adult brain. We confirmed susceptibility of the CP to HSV infection in a human case of newborn HSV encephalitis. We investigated components of the type I interferon (IFN) response in the murine brain that might account for differences in cell susceptibility and found that newborns have a dampened interferon response and significantly lower basal levels of the alpha/beta interferon (IFN-α/β) receptor (IFNAR) than do adults. To test the contribution of IFNAR to restricting infection from the CP, we infected IFNAR knockout (KO) adult mice, which showed restored CP susceptibility to HSV-1 infection in the adult. Furthermore, reduced IFNAR levels did not account for differences we found in the basal levels of several other innate signaling proteins in the wild-type newborn and the adult, including protein kinase R (PKR), that suggested specific regulation of innate immunity in the developing brain. Viral targeting of the CP, a region of the brain that plays a critical role in neurodevelopment, provides a link between newborn susceptibility to HSV and long-term neurologic morbidity among survivors of newborn HSV encephalitis.IMPORTANCECompared to adults, newborns are significantly more susceptible to severe disease following HSV infection. Over half of newborn HSV infections result in disseminated disease or encephalitis, with long-term neurologic morbidity in 2/3 of encephalitis survivors. We investigated differences in host cell susceptibility between newborns and adults that contribute to severe central nervous system disease in the newborn. We found that, unlike the adult brain, the newborn choroid plexus (CP) was susceptible early in HSV-1 infection. We demonstrated that IFN-α/β receptor levels are lower in the newborn brain than in the adult brain and that deletion of this receptor restores susceptibility of the CP in the adult brain. The CP serves as a barrier between the blood and the cerebrospinal fluid and plays a role in proper neurodevelopment. Susceptibility of the newborn choroid plexus to HSV-1 has important implications in viral spread to the brain and, also, in the neurologic morbidity following HSV encephalitis.

scholarly journals Comprehensive Mutagenesis of Herpes Simplex Virus 1 Genome Identifies UL42 as an Inhibitor of Type I Interferon Induction

2019 ◽  
Vol 93 (23) ◽  
Author(s):  
Maxime Chapon ◽  
Kislay Parvatiyar ◽  
Saba Roghiyh Aliyari ◽  
Jeffrey S. Zhao ◽  
Genhong Cheng
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
High Throughput ◽  
Type I Interferon ◽  
Viral Proteins ◽  
Interferon Response ◽  
Type I ◽  
Herpes Simplex Virus 1 ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACT In spite of several decades of research focused on understanding the biology of human herpes simplex virus 1 (HSV-1), no tool has been developed to study its genome in a high-throughput fashion. Here, we describe the creation of a transposon insertion mutant library of the HSV-1 genome. Using this tool, we aimed to identify novel viral regulators of type I interferon (IFN-I). HSV-1 evades the host immune system by encoding viral proteins that inhibit the type I interferon response. Applying differential selective pressure, we identified the three strongest viral IFN-I regulators in HSV-1. We report that the viral polymerase processivity factor UL42 interacts with the host transcription factor IFN regulatory factor 3 (IRF-3), inhibiting its phosphorylation and downstream beta interferon (IFN-β) gene transcription. This study represents a proof of concept for the use of high-throughput screening of the HSV-1 genome in investigating viral biology and offers new targets both for antiviral therapy and for oncolytic vector design. IMPORTANCE This work is the first to report the use of a high-throughput mutagenesis method to study the genome of HSV-1. We report three novel viral proteins potentially involved in regulating the host type I interferon response. We describe a novel mechanism by which the viral protein UL42 is able to suppress the production of beta interferon. The tool we introduce in this study can be used to study the HSV-1 genome in great detail to better understand viral gene functions.

scholarly journals Sex-Dependent Intestinal Replication of an Enteric Virus

2017 ◽  
Vol 91 (7) ◽  
Author(s):  
Christopher M. Robinson ◽  
Yao Wang ◽  
Julie K. Pfeiffer
Keyword(s):  
Gastrointestinal Tract ◽  
Viral Replication ◽  
Sex Hormones ◽  
Viral Infections ◽  
Type I Interferon ◽  
Enteric Virus ◽  
Interferon Response ◽  
Sex Bias ◽  
Type I ◽  
Peripheral Tissues

ABSTRACT Coxsackievirus is an enteric virus that initiates infection in the gastrointestinal tract before disseminating to peripheral tissues to cause disease, but intestinal factors that influence viral replication are understudied. Furthermore, a sex bias for severe sequelae from coxsackievirus infections has been observed in humans. While mouse models mimicking human pathogenesis have been well characterized, many of these experiments use intraperitoneal injection of coxsackievirus to infect mice, bypassing the intestine. In light of recent studies identifying intestinal factors, such as the microbiota, that alter enteric viral replication, we sought to investigate coxsackievirus replication within the intestine. Here, we orally infected mice with coxsackievirus B3 (CVB3) and found that CVB3 replication in the intestine is sex dependent. CVB3 replicated efficiently in the intestine of male mice but not female mice. Additionally, we found that the type I interferon response and sex hormones can alter both viral replication and lethality. Overall, these data suggest that sex and the immune response play a vital role in CVB3 replication in the intestine and should be considered in light of the sex bias observed in human disease. IMPORTANCE Sex bias in severe sequelae from enteric viral infections has been observed. Since viruses have evolved to achieve optimal levels of fitness in their environmental niches, it is imperative to study viruses at the site of initial replication. Here, we used an oral inoculation system for CVB3, which follows the natural route of infection in the gastrointestinal tract. We found that sex can influence the replication of CVB3 in the intestine. Additionally, the type I interferon response and sex hormones alter both CVB3 intestinal replication and lethality. Overall this work highlights the fact that sex should be considered in investigations of enteric viral replication and pathogenesis.

scholarly journals Endogenous mitochondrial double‐stranded RNA is not an activator of the type I interferon response in human pancreatic beta cells

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Alexandra Coomans de Brachène ◽  
Angela Castela ◽  
Anyïshai E. Musuaya ◽  
Lorella Marselli ◽  
Piero Marchetti ◽  
...  
Keyword(s):  
Beta Cells ◽  
Pancreatic Beta Cells ◽  
Viral Infections ◽  
Human Islets ◽  
Interferon Response ◽  
Interferon Α ◽  
Type I ◽  
Type I Ifn ◽  
Danger Signal ◽  
Double Stranded Rna

Abstract Background Type 1 diabetes (T1D) is an autoimmune disease characterized by the progressive destruction of pancreatic beta cells. Interferon-α (IFNα), an antiviral cytokine, is expressed in the pancreatic islets in early T1D, which may be secondary to viral infections. However, not all patients harboring a type I IFN signature present signals of viral infection, suggesting that this response might be initiated by other “danger signals”. Accumulation of mitochondrial double-stranded RNA (mtdsRNA; a danger signal), secondary to silencing of members of the mitochondrial degradosome, PNPT1 and SUV3, has been described to activate the innate immune response. Methods To evaluate whether mtdsRNA represents a “danger signal” for pancreatic beta cells in the context of T1D, we silenced PNPT1 and/or SUV3 in slowly proliferating human insulin-secreting EndoC-βH1 cells and in non-proliferating primary human beta cells and evaluated dsRNA accumulation by immunofluorescence and the type I IFN response by western blotting and RT-qPCR. Results Only the simultaneous silencing of PNPT1/SUV3 induced dsRNA accumulation in EndoC-βH1 cells but not in dispersed human islets, and there was no induction of a type I IFN response. By contrast, silencing of these two genes individually was enough to induce dsRNA accumulation in fibroblasts present in the human islet preparations. Conclusions These data suggest that accumulation of endogenous mtdsRNA following degradosome knockdown depends on the proliferative capacity of the cells and is not a mediator of the type I IFN response in human pancreatic beta cells.

scholarly journals Pseudorabies Virus dUTPase UL50 Induces Lysosomal Degradation of Type I Interferon Receptor 1 and Antagonizes the Alpha Interferon Response

2017 ◽  
Vol 91 (21) ◽  
Author(s):  
Rui Zhang ◽  
Aotian Xu ◽  
Chao Qin ◽  
Qiong Zhang ◽  
Shifan Chen ◽  
...  
Keyword(s):  
Pseudorabies Virus ◽  
Type I Interferon ◽  
Antiviral Drug ◽  
Ectopic Expression ◽  
Interferon Response ◽  
Type I ◽  
Type I Ifn ◽  
Lysosomal Degradation ◽  
Independent Manner ◽  
Strong Inhibitor

ABSTRACT Alphaherpesviruses that establish persistent infections rely partly on their ability to evade host antiviral responses, notably the type I interferon (IFN) response. However, the mechanisms employed by alphaherpesviruses to avoid this response are not well understood. Pseudorabies virus (PRV) is an economically important pathogen and a useful model system for studying alphaherpesvirus biology. To identify PRV proteins that antagonize type I IFN signaling, we performed a screen by using an IFN-stimulated response element reporter in the swine cell line CRL. Unexpectedly, we identified the dUTPase UL50 as a strong inhibitor. We confirmed that UL50 has the ability to inhibit type I IFN signaling by performing ectopic expression of UL50 in cells and deletion of UL50 in PRV. Mechanistically, UL50 impeded type I IFN-induced STAT1 phosphorylation, likely by accelerating lysosomal degradation of IFN receptor 1 (IFNAR1). In addition, this UL50 activity was independent of its dUTPase activity and required amino acids 225 to 253 in the C-terminal region. The UL50 encoded by herpes simplex virus 1 (HSV-1) also possessed similar activity. Moreover, UL50-deleted PRV was more susceptible to IFN than UL50-proficient PRV. Our results suggest that in addition to its dUTPase activity, the UL50 protein of alphaherpesviruses possesses the ability to suppress type I IFN signaling by promoting lysosomal degradation of IFNAR1, thereby contributing to immune evasion. This finding reveals UL50 as a potential antiviral target. IMPORTANCE Alphaherpesviruses can establish lifelong infections and cause many diseases in humans and animals. Pseudorabies virus (PRV) is a swine alphaherpesvirus that threatens pig production. Using PRV as a model, we found that this alphaherpesvirus could utilize its encoded dUTPase UL50 to induce IFNAR1 degradation and inhibit type I IFN signaling in an enzymatic activity-independent manner. Our finding reveals a mechanism employed by an alphaherpesvirus to evade the immune response and indicates that UL50 is an important viral protein in pathogenesis and is a potential target for antiviral drug development.

scholarly journals HSV-1 Targets Lymphatic Vessels in the Eye and Draining Lymph Node of Mice Leading to Edema in the Absence of a Functional Type I Interferon Response

2013 ◽  
Vol 183 (4) ◽  
pp. 1233-1242 ◽  
Author(s):  
Katie M. Bryant-Hudson ◽  
Ana J. Chucair-Elliott ◽  
Christopher D. Conrady ◽  
Alex Cohen ◽  
Min Zheng ◽  
...  
Keyword(s):  
Lymph Node ◽  
Type I Interferon ◽  
Lymphatic Vessels ◽  
Interferon Response ◽  
Type I ◽  
Functional Type ◽  
Draining Lymph Node ◽  
Hsv 1

scholarly journals The Latency-Associated Transcript Inhibits Apoptosis via Downregulation of Components of the Type I Interferon Pathway during Latent Herpes Simplex Virus 1 Ocular Infection

2019 ◽  
Vol 93 (10) ◽  
Author(s):  
Kati Tormanen ◽  
Sariah Allen ◽  
Kevin R. Mott ◽  
Homayon Ghiasi
Keyword(s):  
Herpes Simplex Virus ◽  
Herpes Simplex ◽  
Type I Interferon ◽  
Gene Expression Pattern ◽  
Ocular Infection ◽  
Transcriptional Level ◽  
Type I ◽  
Human Pathology ◽  
Simplex Virus ◽  
Hsv 1

ABSTRACTThe herpes simplex virus (HSV-1) latency-associated transcript (LAT) has been shown to inhibit apoptosis via inhibiting activation of proapoptotic caspases. However, the mechanism of LAT control of apoptosis is unclear, because LAT is not known to encode a functional protein, and the LAT transcript is found largely in the nucleus. We hypothesized that LAT inhibits apoptosis by regulating expression of genes that control apoptosis. Consequently, we sought to establish the molecular mechanism of antiapoptosis functions of LAT at a transcriptional level during latent HSV-1 ocular infection in mice. Our results suggest the following. (i) LAT likely inhibits apoptosis via upregulation of several components of the type I interferon (IFN) pathway. (ii) LAT does not inhibit apoptosis via the caspase cascade at a transcriptional level or via downregulating Toll-like receptors (TLRs). (iii) The mechanism of LAT antiapoptotic effect is distinct from that of the baculovirus inhibitor of apoptosis (cpIAP) because replacement of LAT with the cpIAP gene resulted in a different gene expression pattern than in either LAT+or LAT−viruses. (iv) Replacement of LAT with the cpIAP gene does not cause upregulation of CD8 or markers of T cell exhaustion despite their having similar levels of latency, further supporting that LAT and cpIAP function via distinct mechanisms.IMPORTANCEThe HSV-1 latency reactivation cycle is the cause of significant human pathology. The HSV-1 latency-associated transcript (LAT) functions by regulating latency and reactivation, in part by inhibiting apoptosis. However, the mechanism of this process is unknown. Here we show that LAT likely controls apoptosis via downregulation of several components in the JAK-STAT pathway. Furthermore, we provide evidence that immune exhaustion is not caused by the antiapoptotic activity of the LAT.

scholarly journals Role of NLRs in the Regulation of Type I Interferon Signaling, Host Defense and Tolerance to Inflammation

2021 ◽  
Vol 22 (3) ◽  
pp. 1301
Author(s):  
Ioannis Kienes ◽  
Tanja Weidl ◽  
Nora Mirza ◽  
Mathias Chamaillard ◽  
Thomas A. Kufer
Keyword(s):  
Viral Infections ◽  
Type I Interferon ◽  
Tissue Injury ◽  
Interferon Response ◽  
Type I ◽  
Interferon Signaling ◽  
Microbial Products ◽  
Interferon Responses

Type I interferon signaling contributes to the development of innate and adaptive immune responses to either viruses, fungi, or bacteria. However, amplitude and timing of the interferon response is of utmost importance for preventing an underwhelming outcome, or tissue damage. While several pathogens evolved strategies for disturbing the quality of interferon signaling, there is growing evidence that this pathway can be regulated by several members of the Nod-like receptor (NLR) family, although the precise mechanism for most of these remains elusive. NLRs consist of a family of about 20 proteins in mammals, which are capable of sensing microbial products as well as endogenous signals related to tissue injury. Here we provide an overview of our current understanding of the function of those NLRs in type I interferon responses with a focus on viral infections. We discuss how NLR-mediated type I interferon regulation can influence the development of auto-immunity and the immune response to infection.

scholarly journals Alphaherpesvirus-induced activation of plasmacytoid dendritic cells depends on the viral glycoprotein gD and is inhibited by non-infectious light particles

2021 ◽  
Vol 17 (11) ◽  
pp. e1010117
Author(s):  
Jonas L. Delva ◽  
Cliff Van Waesberghe ◽  
Barbara G. Klupp ◽  
Thomas C. Mettenleiter ◽  
Herman W. Favoreel
Keyword(s):  
Dendritic Cells ◽  
Pseudorabies Virus ◽  
Viral Infections ◽  
Critical Role ◽  
Plasmacytoid Dendritic Cells ◽  
Type I ◽  
Viral Glycoprotein ◽  
Dna Viruses ◽  
Endosomal Acidification ◽  
Simplex Virus

Plasmacytoid dendritic cells (pDC) are important innate immune cells during the onset of viral infections as they are specialized in the production of massive amounts of antiviral type I interferon (IFN). Alphaherpesviruses such as herpes simplex virus (HSV) or pseudorabies virus (PRV) are double stranded DNA viruses and potent stimulators of pDC. Detailed information on how PRV activates porcine pDC is lacking. Using PRV and porcine primary pDC, we report here that PRV virions, so-called heavy (H-)particles, trigger IFNα production by pDC, whereas light (L-) particles that lack viral DNA and capsid do not. Activation of pDC requires endosomal acidification and, importantly, depends on the PRV gD envelope glycoprotein and O-glycosylations. Intriguingly, both for PRV and HSV-1, we found that L-particles suppress H-particle-mediated activation of pDC, a process which again depends on viral gD. This is the first report describing that gD plays a critical role in alphaherpesvirus-induced pDC activation and that L-particles directly interfere with alphaherpesvirus-induced IFNα production by pDC.

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