Evaluation of in vitro inhibitory potential of type-I interferons and different antiviral compounds on rabies virus replication

AbstractA subset of intracellular mono-ADP-ribosyltransferases diphtheria toxin-like (ARTDs, aka mono-PARPs) is induced by type I interferons. Some of these mono-ARTDs feature antiviral activity while certain RNA viruses, including Chikungunya virus (CHIKV), encode mono-ADP-ribosylhydrolases, suggesting a role for mono-ADP-ribosylation (MARylation) in host-virus conflicts. CHIKV expresses four non-structural proteins (nsP1-nsP4), with nsP3 containing a macrodomain that hydrolyzes and thereby reverses protein MARylation in vitro and in cells. This de-MARylation activity is essential as hydrolase inactivating mutations result in replication defective virus. However, the substrates of MARylation during CHIKV infection are unknown and thus it is unclear how the macrodomain contributes to virus replication and how mono-ARTD-dependent MARylation confers antiviral immunity. We identified ARTD10 and ARTD12 as restriction factors for CHIKV replication in a catalytic activity-dependent manner. CHIKV replication requires processing of the non-structural polyprotein nsP1-4 by the nsP2-encoded protease and the assembly of the four individual nsPs into a functional replication complex. Expression of ARTD10 and ARTD12 resulted in a reduction of processed nsPs. Similarly, MAR hydrolase inactive CHIKV replicon mutants revealed a decrease in processed nsPs, comparable to an nsP2 protease defective mutant. This suggested that the macrodomain contributes to nsP2 protease activity. In support, a hydrolase-deficient virus was complemented by a protease-deficient virus. We hypothesized that MARylation regulates the proteolytic function of nsP2. Indeed, we found that nsP2 is MARylated by ARTD10. This inhibited nsP2 protease activity, thereby preventing polyprotein processing and consequently virus replication. This inhibition was antagonized by the MAR hydrolase activity of nsP3. Together, our findings provide a mechanistic explanation for the need of the viral MAR hydrolase for efficient replication of CHIKV.Author SummaryInfectious diseases still pose major health threats. Especially fast evolving viruses find ever new strategies to manipulate the immune response. With climate warming and increased human mobility vector-borne pathogens like Chikungunya virus (CHIKV) spread and cause world-wide epidemics. Beyond the acute phase, CHIKV patients regularly suffer from chronic rheumatism. This entails a decline in life quality and an economic burden. To date no drugs are approved and the mode of pathogenesis remains elusive. Here we describe a mechanistic function of the CHIKV nsP3 macrodomain. We found that the viral nsP2 is mono-ADP-ribosylated interfering with its auto-proteolytic function. The nsP3 macrodomain removes this modification and restores the protease activity that is essential for replication. Because macrodomains are highly conserved they might represent broad antiviral targets.

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Expression of Interferon Gamma by a Recombinant Rabies Virus Strongly Attenuates the Pathogenicity of the Virus via Induction of Type I Interferon

Journal of Virology ◽

10.1128/jvi.01572-14 ◽

2014 ◽

Vol 89 (1) ◽

pp. 312-322 ◽

Cited By ~ 26

Author(s):

Darryll A. Barkhouse ◽

Samantha A. Garcia ◽

Emily K. Bongiorno ◽

Aurore Lebrun ◽

Milosz Faber ◽

...

Keyword(s):

Rabies Virus ◽

Interferon Gamma ◽

Virus Replication ◽

Neutralizing Antibodies ◽

Type I Interferon ◽

Lethal Dose ◽

Type I Interferons ◽

Type I ◽

Antiviral Effects ◽

Ifn Γ

ABSTRACTPrevious animal model experiments have shown a correlation between interferon gamma (IFN-γ) expression and both survival from infection with attenuated rabies virus (RABV) and reduction of neurological sequelae. Therefore, we hypothesized that rapid production of murine IFN-γ by the rabies virus itself would induce a more robust antiviral response than would occur naturally in mice. To test this hypothesis, we used reverse engineering to clone the mouse IFN-γ gene into a pathogenic rabies virus backbone, SPBN, to produce the recombinant rabies virus designated SPBNγ. Morbidity and mortality were monitored in mice infected intranasally with SPBNγ or SPBN(−) control virus to determine the degree of attenuation caused by the expression of IFN-γ. Incorporation of IFN-γ into the rabies virus genome highly attenuated the virus. SPBNγ has a 50% lethal dose (LD50)more than 100-fold greater than SPBN(−).In vitroandin vivomouse experiments show that SPBNγ infection enhances the production of type I interferons. Furthermore, knockout mice lacking the ability to signal through the type I interferon receptor (IFNAR−/−) cannot control the SPBNγ infection and rapidly die. These data suggest that IFN-γ production has antiviral effects in rabies, largely due to the induction of type I interferons.IMPORTANCESurvival from rabies is dependent upon the early control of virus replication and spread. Once the virus reaches the central nervous system (CNS), this becomes highly problematic. Studies of CNS immunity to RABV have shown that control of replication begins at the onset of T cell entry and IFN-γ production in the CNS prior to the appearance of virus-neutralizing antibodies. Moreover, antibody-deficient mice are able to control but not clear attenuated RABV from the CNS. We find here that IFN-γ triggers the early production of type I interferons with the expected antiviral effects. We also show that engineering a lethal rabies virus to express IFN-γ directly in the infected tissue reduces rabies virus replication and spread, limiting its pathogenicity in normal and immunocompromised mice. Therefore, vector delivery of IFN-γ to the brain may have the potential to treat individuals who would otherwise succumb to infection with rabies virus.

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Type I interferon-dependent CCL4 is induced by a cGAS/STING pathway that bypasses viral inhibition and protects infected tissue, independent of viral burden

10.1101/616888 ◽

2019 ◽

Author(s):

Nikhil J. Parekh ◽

Tracy E. Krouse ◽

Irene E. Reider ◽

Ryan P. Hobbs ◽

Brian M. Ward ◽

...

Keyword(s):

Virus Replication ◽

Infected Tissue ◽

Type I Interferons ◽

Type I ◽

Wild Type ◽

Inflammatory Monocytes ◽

Viral Burden ◽

Infected Cells

AbstractType I interferons (T1-IFN) are critical in the innate immune response, acting upon infected and uninfected cells to initiate an antiviral state by expressing genes that inhibit multiple stages of the lifecycle of many viruses. T1-IFN triggers the production of Interferon-Stimulated Genes (ISGs), activating an antiviral program that reduces virus replication. The importance of the T1-IFN response is highlighted by the evolution of viral evasion strategies to inhibit the production or action of T1-IFN in virus-infected cells. T1-IFN is produced via activation of pathogen sensors within infected cells, a process that is targeted by virus-encoded immunomodulatory molecules. This is probably best exemplified by the prototypic poxvirus, Vaccinia virus (VACV), which uses at least 6 different mechanisms to completely block the production of T1-IFN within infected cells in vitro. Yet, mice lacking aspects of T1-IFN signaling are often more susceptible to infection with many viruses, including VACV, than wild-type mice. How can these opposing findings be rationalized? The cytosolic DNA sensor cGAS has been implicated in immunity to VACV, but has yet to be linked to the production of T1-IFN in response to VACV infection. Indeed, there are two VACV-encoded proteins that effectively prevent cGAS-mediated activation of T1-IFN. We find that the majority of VACV-infected cells in vivo do not produce T1-IFN, but that a small subset of VACV-infected cells in vivo utilize cGAS to sense VACV and produce T1-IFN to protect infected mice. The protective effect of T1-IFN is not mediated via ISG-mediated control of virus replication. Rather, T1-IFN drives expression of CCL4, which recruits inflammatory monocytes that constrain the VACV lesion in a virus replication-independent manner by limiting spread within the tissue. Our findings have broad implications in our understanding of pathogen detection and viral evasion in vivo, and highlight a novel immune strategy to protect infected tissue.SummaryThe recognition of virus infection leads to a quick and robust antiviral response mediated by type I interferons (T1-IFN). Nearly all viruses have acquired genes that block the induction or action of T1-IFN in order to attain a replicative advantage. Some viruses thwart the T1-IFN response so thoroughly, that cells infected in vitro do not produce any T1-IFN. And yet, animal models with defects in T1-IFN signaling are more sensitive to infection with these viruses than their wild-type counterparts. In this study, we find evidence to explain these otherwise contradicting findings. We show that a small population of infected cells in vivo are able to utilize a pathogen-sensing pathway that is completely blocked in vitro. T1-IFN produced by these specialized cells protects mice by recruiting inflammatory monocytes that restrict the spread of virus within infected tissue, independent of viral burden. Our findings have a direct impact on our understanding of how viruses are detected in infected tissue, and present a novel strategy of the immune system to limit pathology at peripheral sites of infection.

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Type I Interferons promote maintenance and function of follicular T helper cells in vitro

10.1055/s-0038-1677255 ◽

2019 ◽

Author(s):

S Ehrlich ◽

K Wild ◽

M Smits ◽

K Zoldan ◽

M Hofmann ◽

...

Keyword(s):

T Helper Cells ◽

Type I Interferons ◽

Type I ◽

T Helper ◽

Helper Cells ◽

Follicular T Helper Cells ◽

And Function

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HIV-Infected Macrophages Are Infected and Killed by the Interferon-Sensitive Rhabdovirus MG1

Journal of Virology ◽

10.1128/jvi.01953-20 ◽

2021 ◽

Vol 95 (9) ◽

Author(s):

Teslin S. Sandstrom ◽

Nischal Ranganath ◽

Stephanie C. Burke Schinkel ◽

Syim Salahuddin ◽

Oussama Meziane ◽

...

Keyword(s):

Cancer Cells ◽

Oncolytic Viruses ◽

Type I Interferons ◽

Viral Reservoir ◽

Type I ◽

Antiviral Signaling ◽

Infected Cells ◽

Hiv 1

ABSTRACT The use of unique cell surface markers to target and eradicate HIV-infected cells has been a longstanding objective of HIV-1 cure research. This approach, however, overlooks the possibility that intracellular changes present within HIV-infected cells may serve as valuable therapeutic targets. For example, the identification of dysregulated antiviral signaling in cancer has led to the characterization of oncolytic viruses capable of preferentially killing cancer cells. Since impairment of cellular antiviral machinery has been proposed as a mechanism by which HIV-1 evades immune clearance, we hypothesized that HIV-infected macrophages (an important viral reservoir in vivo) would be preferentially killed by the interferon-sensitive oncolytic Maraba virus MG1. We first showed that HIV-infected monocyte-derived macrophages (MDM) were more susceptible to MG1 infection and killing than HIV-uninfected cells. As MG1 is highly sensitive to type I interferons (IFN-I), we then investigated whether we could identify IFN-I signaling differences between HIV-infected and uninfected MDM and found evidence of impaired IFN-α responsiveness within HIV-infected cells. Finally, to assess whether MG1 could target a relevant, primary cell reservoir of HIV-1, we investigated its effects in alveolar macrophages (AM) obtained from effectively treated individuals living with HIV-1. As observed with in vitro-infected MDM, we found that HIV-infected AM were preferentially eliminated by MG1. In summary, the oncolytic rhabdovirus MG1 appears to preferentially target and kill HIV-infected cells via impairment of antiviral signaling pathways and may therefore provide a novel approach to an HIV-1 cure. IMPORTANCE Human immunodeficiency virus type 1 (HIV-1) remains a treatable, but incurable, viral infection. The establishment of viral reservoirs containing latently infected cells remains the main obstacle in the search for a cure. Cure research has also focused on only one cellular target of HIV-1 (the CD4+ T cell) while largely overlooking others (such as macrophages) that contribute to HIV-1 persistence. In this study, we address these challenges by describing a potential strategy for the eradication of HIV-infected macrophages. Specifically, we show that an engineered rhabdovirus—initially developed as a cancer therapy—is capable of preferential infection and killing of HIV-infected macrophages, possibly via the same altered antiviral signaling seen in cancer cells. As this rhabdovirus is currently being explored in phase I/II clinical trials, there is potential for this approach to be readily adapted for use within the HIV-1 cure field.

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A host type I interferon response is induced by cytosolic sensing of the bacterial second messenger cyclic-di-GMP

Journal of Experimental Medicine ◽

10.1084/jem.20082874 ◽

2009 ◽

Vol 206 (9) ◽

pp. 1899-1911 ◽

Cited By ~ 202

Author(s):

Sarah M. McWhirter ◽

Roman Barbalat ◽

Kathryn M. Monroe ◽

Mary F. Fontana ◽

Mamoru Hyodo ◽

...

Keyword(s):

Mammalian Cells ◽

Map Kinases ◽

Second Messenger ◽

Innate Immune ◽

Guanosine Monophosphate ◽

Host Cells ◽

Type I Interferons ◽

Interferon Response ◽

Type I

The innate immune system responds to unique molecular signatures that are widely conserved among microbes but that are not normally present in host cells. Compounds that stimulate innate immune pathways may be valuable in the design of novel adjuvants, vaccines, and other immunotherapeutics. The cyclic dinucleotide cyclic-di–guanosine monophosphate (c-di-GMP) is a recently appreciated second messenger that plays critical regulatory roles in many species of bacteria but is not produced by eukaryotic cells. In vivo and in vitro studies have previously suggested that c-di-GMP is a potent immunostimulatory compound recognized by mouse and human cells. We provide evidence that c-di-GMP is sensed in the cytosol of mammalian cells via a novel immunosurveillance pathway. The potency of cytosolic signaling induced by c-di-GMP is comparable to that induced by cytosolic delivery of DNA, and both nucleic acids induce a similar transcriptional profile, including triggering of type I interferons and coregulated genes via induction of TBK1, IRF3, nuclear factor κB, and MAP kinases. However, the cytosolic pathway that senses c-di-GMP appears to be distinct from all known nucleic acid–sensing pathways. Our results suggest a novel mechanism by which host cells can induce an inflammatory response to a widely produced bacterial ligand.

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Cannabinoid Reduces Inflammatory Cytokines, Tumor Necrosis Factor-α, and Type I Interferons in Dermatomyositis In Vitro

Journal of Investigative Dermatology ◽

10.1016/j.jid.2017.05.035 ◽

2017 ◽

Vol 137 (11) ◽

pp. 2445-2447 ◽

Cited By ~ 12

Author(s):

Elizabeth S. Robinson ◽

Paul Alves ◽

Muhammad M. Bashir ◽

Majid Zeidi ◽

Rui Feng ◽

...

Keyword(s):

Tumor Necrosis Factor ◽

Inflammatory Cytokines ◽

Tumor Necrosis ◽

Tumor Necrosis Factor Α ◽

Type I Interferons ◽

Type I ◽

Factor Α ◽

Necrosis Factor

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Thioredoxin 2 Negatively Regulates Innate Immunity to RNA Viruses by Disrupting the Assembly of the Virus-Induced Signaling Adaptor Complex

Journal of Virology ◽

10.1128/jvi.01756-19 ◽

2020 ◽

Vol 94 (7) ◽

Cited By ~ 1

Author(s):

Dan Li ◽

Wenping Yang ◽

Yi Ru ◽

Jingjing Ren ◽

Xiangtao Liu ◽

...

Keyword(s):

Complex Formation ◽

Rna Viruses ◽

Critical Role ◽

Type I Interferons ◽

Type I ◽

Host Proteins ◽

Innate Antiviral Response ◽

Thioredoxin 2

ABSTRACT The virus-induced signaling adaptor (VISA) complex plays a critical role in the innate immune response to RNA viruses. However, the mechanism of VISA complex formation remains unclear. Here, we demonstrate that thioredoxin 2 (TRX2) interacts with VISA at mitochondria both in vivo and in vitro. Knockdown and knockout of TRX2 enhanced the formation of the VISA-associated complex, as well as virus-triggered activation of interferon regulatory factor 3 (IRF3) and transcription of the interferon beta 1 (IFNB1) gene. TRX2 inhibits the formation of VISA aggregates by repressing reactive oxygen species (ROS) production, thereby disrupting the assembly of the VISA complex. Furthermore, our data suggest that the C93 residue of TRX2 is essential for inhibition of VISA aggregation, whereas the C283 residue of VISA is required for VISA aggregation. Collectively, these findings uncover a novel mechanism of TRX2 that negatively regulates VISA complex formation. IMPORTANCE The VISA-associated complex plays pivotal roles in inducing type I interferons (IFNs) and eliciting the innate antiviral response. Many host proteins are identified as VISA-associated-complex proteins, but how VISA complex formation is regulated by host proteins remains enigmatic. We identified the TRX2 protein as an important regulator of VISA complex formation. Knockout of TRX2 increases virus- or poly(I·C)-triggered induction of type I IFNs at the VISA level. Mechanistically, TRX2 inhibits the production of ROS at its C93 site, which impairs VISA aggregates at its C283 site, and subsequently impedes the assembly of the VISA complex. Our findings suggest that TRX2 plays an important role in the regulation of VISA complex assembly.

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