scholarly journals Mechanism and Function of Antiviral RNA Interference in Mice

mBio ◽  
2020 ◽  
Vol 11 (4) ◽  
Author(s):  
Qingxia Han ◽  
Gang Chen ◽  
Jinyan Wang ◽  
David Jee ◽  
Wan-Xiang Li ◽  
...  
Keyword(s):  
Rna Interference ◽  
Rna Replication ◽  
Interferon Response ◽  
Type I ◽  
Small Interfering Rnas ◽  
Guide Rna ◽  
Argonaute 2 ◽  
Adult Mice ◽  
And Function ◽  
Nodamura Virus

ABSTRACT Distinct mammalian RNA viruses trigger Dicer-mediated production of virus-derived small-interfering RNAs (vsiRNA) and encode unrelated proteins to suppress vsiRNA biogenesis. However, the mechanism and function of the mammalian RNA interference (RNAi) response are poorly understood. Here, we characterized antiviral RNAi in a mouse model of infection with Nodamura virus (NoV), a mosquito-transmissible positive-strand RNA virus encoding a known double-stranded RNA (dsRNA)-binding viral suppressor of RNAi (VSR), the B2 protein. We show that inhibition of NoV RNA replication by antiviral RNAi in mouse embryonic fibroblasts (MEFs) requires Dicer-dependent vsiRNA biogenesis and Argonaute-2 slicer activity. We found that VSR-B2 of NoV enhances viral RNA replication in wild-type but not RNAi-defective MEFs such as Argonaute-2 catalytic-dead MEFs and Dicer or Argonaute-2 knockout MEFs, indicating that VSR-B2 acts mainly by suppressing antiviral RNAi in the differentiated murine cells. Consistently, VSR-B2 expression in MEFs has no detectable effect on the induction of interferon-stimulated genes or the activation of global RNA cleavages by RNase L. Moreover, we demonstrate that NoV infection of adult mice induces production of abundant vsiRNA active to guide RNA slicing by Argonaute-2. Notably, VSR-B2 suppresses the biogenesis of both vsiRNA and the slicing-competent vsiRNA-Argonaute-2 complex without detectable inhibition of Argonaute-2 slicing guided by endogenous microRNA, which dramatically enhances viral load and promotes lethal NoV infection in adult mice either intact or defective in the signaling by type I, II, and III interferons. Together, our findings suggest that the mouse RNAi response confers essential protective antiviral immunity in both the presence and absence of the interferon response. IMPORTANCE Innate immune sensing of viral nucleic acids in mammals triggers potent antiviral responses regulated by interferons known to antagonize the induction of RNA interference (RNAi) by synthetic long double-stranded RNA (dsRNA). Here, we show that Nodamura virus (NoV) infection in adult mice activates processing of the viral dsRNA replicative intermediates into small interfering RNAs (siRNAs) active to guide RNA slicing by Argonaute-2. Genetic studies demonstrate that NoV RNA replication in mouse embryonic fibroblasts is inhibited by the RNAi pathway and enhanced by the B2 viral RNAi suppressor only in RNAi-competent cells. When B2 is rendered nonexpressing or nonfunctional, the resulting mutant viruses become nonpathogenic and are cleared in adult mice either intact or defective in the signaling by type I, II, and III interferons. Our findings suggest that mouse antiviral RNAi is active and necessary for the in vivo defense against viral infection in both the presence and absence of the interferon response.

scholarly journals The role of the Type I interferon response in the resistance of mice to filovirus infection

2001 ◽  
Vol 82 (6) ◽  
pp. 1365-1373 ◽  
Author(s):  
Mike Bray
Keyword(s):  
Type I Interferon ◽  
Antiviral Drug ◽  
Interferon Response ◽  
Type I ◽  
Antibody Treatment ◽  
Adult Mice ◽  
Lethal Infection ◽  
Series Of Experiments ◽  
Β Receptor ◽  
Immunocompetent Mice

Adult immunocompetent mice inoculated with Ebola (EBO) or Marburg (MBG) virus do not become ill. A suckling-mouse-passaged variant of EBO Zaire ’76 (‘mouse-adapted EBO-Z’) causes rapidly lethal infection in adult mice after intraperitoneal (i.p.) inoculation, but does not cause apparent disease when inoculated subcutaneously (s.c.). A series of experiments showed that both forms of resistance to infection are mediated by the Type I interferon response. Mice lacking the cell-surface IFN-α/β receptor died within a week after inoculation of EBO-Z ’76, EBO Sudan, MBG Musoke or MBG Ravn, or after s.c. challenge with mouse-adapted EBO-Z. EBO Reston and EBO Ivory Coast did not cause illness, but immunized the mice against subsequent challenge with mouse-adapted EBO-Z. Normal adult mice treated with antibodies against murine IFN-α/β could also be lethally infected with i.p.-inoculated EBO-Z ’76 or EBO Sudan and with s.c.-inoculated mouse-adapted EBO-Z. Severe combined immunodeficient (SCID) mice became ill 3–4 weeks after inoculation with EBO-Z ’76, EBO Sudan or MBG Ravn, but not the other viruses. Treatment with anti-IFN-α/β antibodies markedly accelerated the course of EBO-Z ’76 infection. Antibody treatment blocked the effect of a potent antiviral drug, 3-deazaneplanocin A, indicating that successful filovirus therapy may require the active participation of the Type I IFN response. Mice lacking an IFN-α/β response resemble primates in their susceptibility to rapidly progressive, overwhelming filovirus infection. The outcome of filovirus transfer between animal species appears to be determined by interactions between the virus and the innate immune response.

scholarly journals AGO CLIP-based imputation of potent siRNA sequences targeting SARS-CoV-2 with antifibrotic miRNA-like activity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Seung Hyun Ahn ◽  
Dowoon Gu ◽  
Yongjun Koh ◽  
Hye-Sook Lee ◽  
Sung Wook Chi
Keyword(s):  
Rna Interference ◽  
Rna Folding ◽  
Rna Viruses ◽  
Sequence Variants ◽  
Structural Protein ◽  
Small Interfering Rnas ◽  
Rna Dependent Rna Polymerase ◽  
Target Sites ◽  
And Function ◽  
Sirna Target

AbstractCoronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), is associated with fatal pulmonary fibrosis. Small interfering RNAs (siRNAs) can be developed to induce RNA interference against SARS-CoV-2, and their susceptible target sites can be inferred by Argonaute crosslinking immunoprecipitation sequencing (AGO CLIP). Here, by reanalysing AGO CLIP data in RNA viruses, we delineated putative AGO binding in the conserved non-structural protein 12 (nsp12) region encoding RNA-dependent RNA polymerase (RdRP) in SARS-CoV-2. We utilised the inferred AGO binding to optimise the local RNA folding parameter to calculate target accessibility and predict all potent siRNA target sites in the SARS-CoV-2 genome, avoiding sequence variants. siRNAs loaded onto AGO also repressed seed (positions 2–8)-matched transcripts by acting as microRNAs (miRNAs). To utilise this, we further screened 13 potential siRNAs whose seed sequences were matched to known antifibrotic miRNAs and confirmed their miRNA-like activity. A miR-27-mimicking siRNA designed to target the nsp12 region (27/RdRP) was validated to silence a synthesised nsp12 RNA mimic in lung cell lines and function as an antifibrotic miR-27 in regulating target transcriptomes related to TGF-β signalling. siRNA sequences with an antifibrotic miRNA-like activity that could synergistically treat COVID-19 are available online (http://clip.korea.ac.kr/covid19).

Zebrafish as an animal model for the antiviral RNA interference pathway

2021 ◽  
Author(s):  
Yanxin Ren ◽  
Xueyu Li ◽  
Zhonghui Tian ◽  
Yan Xu ◽  
Ruilin Zhang ◽  
...  
Keyword(s):  
Rna Interference ◽  
Sindbis Virus ◽  
Rna Virus ◽  
Model Organism ◽  
Model Organisms ◽  
Rnai Pathway ◽  
Small Interfering Rnas ◽  
Argonaute 2 ◽  
Larval Zebrafish ◽  
Vertebrate Model

The zebrafish (Danio rerio) possesses evolutionarily conserved innate and adaptive immunity as a mammal and has recently become a popular vertebrate model to exploit infection and immunity. Antiviral RNA interference (RNAi) has been illuminated in various model organisms, including Arabidopsis thaliana, Drosophila melanogaster, Caenorhabditis elegans and mice. However, to date, there is no report on the antiviral RNAi pathway of zebrafish. Here, we have evaluated the possible use of zebrafish to study antiviral RNAi with Sindbis virus (SINV), vesicular stomatitis virus (VSV) and Nodamura virus (NoV). We find that SINVs and NoVs induce the production of virus-derived small interfering RNAs (vsiRNAs), the hallmark of antiviral RNAi, with a preference for a length of 22 nucleotides, after infection of larval zebrafish. Meanwhile, the suppressor of RNAi (VSR) protein, NoV B2, may affect the accumulation of the NoV in zebrafish. Furthermore, taking advantage of the fact that zebrafish argonaute-2 (Ago2) protein is naturally deficient in cleavage compared with that of mammals, we provide evidence that the slicing activity of human Ago2 can virtually inhibit the accumulation of RNA virus after being ectopically expressed in larval zebrafish. Thus, zebrafish may be a unique model organism to study the antiviral RNAi pathway.

scholarly journals RNA interference and the use of small interfering RNA to study gene function in mammalian systems

2004 ◽  
Vol 33 (3) ◽  
pp. 545-557 ◽  
Author(s):  
I Bantounas ◽  
L A Phylactou ◽  
J B Uney
Keyword(s):  
Rna Interference ◽  
Gene Function ◽  
Viral Vector ◽  
Sirna Delivery ◽  
Interferon Response ◽  
Rnai Pathway ◽  
Small Interfering Rnas ◽  
Rnai Technology

In the past 2 years, extraordinary developments in RNA interference (RNAi)-based methodologies have seen small interfering RNAs (siRNA) become the method of choice for researchers wishing to target specific genes for silencing. In this review, an historic overview of the biochemistry of the RNAi pathway is described together with the latest advances in the RNAi field. Particular emphasis is given to strategies by which siRNAs are used to study mammalian gene function. In this regard, the use of plasmid-based and viral vector-based systems to mediate long-term RNAi in vitro and in vivo are described. However, recent work has shown that non-specific silencing effects and activation of the interferon response may occur following the use of some siRNA and delivery vector combinations. Future goals must therefore be to understand the mechanisms by which siRNA delivery leads to unwanted gene silencing effects in cells and, in this way, RNAi technology can reach its tremendous potential as a scientific tool and ultimately be used for therapeutic purposes.

scholarly journals Alphavirus-Induced Membrane Rearrangements during Replication, Assembly, and Budding

Pathogens ◽  
2021 ◽  
Vol 10 (8) ◽  
pp. 984
Author(s):  
Zeinab Elmasri ◽  
Benjamin L. Nasal ◽  
Joyce Jose
Keyword(s):  
Current Knowledge ◽  
Rna Replication ◽  
Type I ◽  
Type Ii ◽  
Fatal Disease ◽  
Structural Modifications ◽  
Host Interactions ◽  
Infected Cells ◽  
Membrane Type ◽  
And Function

Alphaviruses are arthropod-borne viruses mainly transmitted by hematophagous insects that cause moderate to fatal disease in humans and other animals. Currently, there are no approved vaccines or antivirals to mitigate alphavirus infections. In this review, we summarize the current knowledge of alphavirus-induced structures and their functions in infected cells. Throughout their lifecycle, alphaviruses induce several structural modifications, including replication spherules, type I and type II cytopathic vacuoles, and filopodial extensions. Type I cytopathic vacuoles are replication-induced structures containing replication spherules that are sites of RNA replication on the endosomal and lysosomal limiting membrane. Type II cytopathic vacuoles are assembly induced structures that originate from the Golgi apparatus. Filopodial extensions are induced at the plasma membrane and are involved in budding and cell-to-cell transport of virions. This review provides an overview of the viral and host factors involved in the biogenesis and function of these virus-induced structures. Understanding virus–host interactions in infected cells will lead to the identification of new targets for antiviral discovery.

scholarly journals Chronic hypercapnia alters lung matrix composition in mouse pups

2010 ◽  
Vol 109 (1) ◽  
pp. 203-210 ◽  
Author(s):  
Julie Ryu ◽  
Gregory P. Heldt ◽  
Mary Nguyen ◽  
Orit Gavrialov ◽  
Gabriel G. Haddad
Keyword(s):  
Collagen Type I ◽  
Matrix Composition ◽  
Independent Effect ◽  
Type I ◽  
Mrna Levels ◽  
Permissive Hypercapnia ◽  
Lung Volumes ◽  
Total Lung Volume ◽  
Adult Mice ◽  
And Function

Rationale: permissive hypercapnia, a stretch-limiting ventilation strategy, often results in high PaCO2. This strategy is associated with reduced morbidity and mortality in premature infants and its benefits have been attributed to diminished barotrauma. However, little is known about the independent effect of high CO2 levels during the lung development. Methods: mice were exposed to 8% CO2 or room air for 2 wk either from postnatal day 2 through 17 or as adults (∼2 mo of age). Lungs were excised and processed for protein, RNA, histology, and total lung volumes. Results: histologic analysis demonstrated that alveolar walls of CO2-exposed mouse pups were thinner than those of controls and had twice the total lung volume. Molecular analysis revealed that several matrix proteins in the lung were downregulated in mouse pups exposed to hypercapnia. Interstitial collagen type I α1, type III α1, elastin and fibronectin protein, and mRNA levels were less than half of controls while collagen IV α5 was unaffected. This decrease in interstitial collagen could thus account for the thinning of the interstitial matrix and the altered lung biomechanics. Matrix metalloproteinase (MMP)-8, a collagenase that has specificity for collagen types I and III, increased in hypercapnic mouse pups, suggesting increased collagen degradation. Moreover, tissue inhibitor of MMP (TIMP)-1, a potent inhibitor of MMP-8, was significantly decreased. However, unlike pups, adult mice exposed to hypercapnia demonstrated only a mild increase in total lung volumes and did not exhibit similar molecular or histologic changes. Conclusions: although permissive hypercapnia may prevent lung injury from barotrauma, our study revealed that exposure to hypercapnia may be an important factor in lung remodeling and function, especially in early life.

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

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

PLASMACYTOID DENDRITIC CELLS FUNCTION IN HIV INFECTION

2008 ◽  
Vol 31 (4) ◽  
pp. 13
Author(s):  
Martin Hyrcza ◽  
Mario Ostrowski ◽  
Sandy Der
Keyword(s):  
Dendritic Cells ◽  
Influenza Virus ◽  
Hiv Infection ◽  
Gene Transcription ◽  
Sendai Virus ◽  
Plasmacytoid Dendritic Cells ◽  
Type I Interferons ◽  
Interferon Response ◽  
Type I ◽  
Type I Ifn

Plasmacytoid dendritic cells (pDCs) are innate immune cells able to produce large quantities of type I interferons (IFN) when activated. Human immunodeficiency virus (HIV)-infected patients show generalized immune dysfunction characterized in part by chronic interferon response. In this study we investigated the role of dendritic cells inactivating and maintaining this response. Specifically we compared the IFN geneactivity in pDCs in response to several viruses and TLR agonists. We hypothesized that 1) the pattern of IFN gene transcription would differ in pDCs treated with HIV than with other agents, and 2) that pDCs from patients from different stages of disease would respond differently to the stimulations. To test these hypotheses, we obtained pDCs from 15 HIV-infected and uninfected individuals and treated freshly isolated pDCs with either HIV (BAL strain), influenza virus (A/PR/8/34), Sendai virus (Cantell strain), TLR7 agonist(imiquimod), or TLR9 agonist (CpG-ODN) for 6h. Type I IFN gene transcription was monitored by real time qPCRfor IFNA1, A2, A5, A6, A8,A17, B1, and E1, and cytokine levels were assayed by Cytometric Bead Arrays forTNF?, IL6, IL8, IL10, IL1?, and IL12p70. pDC function as determined by these two assays showed no difference between HIV-infected and uninfected patients or between patients with early or chronic infection. Specifically, HIV did notinduce type I IFN gene expression, whereas influenza virus, Sendai virus and imiquimod did. Similarly, HIV failed to induce any cytokine release from pDCs in contrast to influenza virus, Sendai virus and imiquimod, which stimulatedrelease of TNF?, IL6, or IL8. Together these results suggest that the reaction of pDCs to HIV virus is quantitatively different from the response to agents such as virus, Sendai virus, and imiquimod. In addition, pDCs from HIV-infected persons have responses similar to pDCs from uninfected donors, suggesting, that the DC function may not be affected by HIV infection.

Sign in / Sign up

Export Citation Format

Share Document