Microbiota-independent antiviral protection conferred by aminoglycoside antibiotics

AbstractAntibiotics are widely used to treat infections in humans. However, the impact of antibiotic use on host cells is understudied. We have identified a novel antiviral effect of commonly used aminoglycoside antibiotics. We show that mucosal application of aminoglycosides increased host resistance to a broad range of viral infections including herpes simplex viruses, influenza A virus and Zika virus. Aminoglycoside treatment also reduced viral replication in primary human cells. This antiviral activity was independent of the microbiota as aminoglycoside treatment protected germ-free mice. Microarray analysis uncovered a marked upregulation of transcripts for interferon-stimulated genes (ISGs) following aminoglycoside application. ISG induction was mediated by TLR3, and required TIR-domain-containing adapter-inducing interferon-β (TRIF), signaling adaptor, and interferon regulatory factors 3 (IRF3) and IRF7, transcription factors that promote ISG expression. XCR1+ dendritic cells, which uniquely express TLR3, were recruited to the vaginal mucosa upon aminoglycoside treatment and were required for ISG induction. These results highlight an unexpected ability of aminoglycoside antibiotics to confer broad antiviral resistancein vivo.

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Complement Decay-Accelerating Factor is a modulator of influenza A virus lung immunopathology

PLoS Pathogens ◽

10.1371/journal.ppat.1009381 ◽

2021 ◽

Vol 17 (7) ◽

pp. e1009381

Author(s):

Nuno Brito Santos ◽

Zoé Enderlin Vaz da Silva ◽

Catarina Gomes ◽

Celso A. Reis ◽

Maria João Amorim

Keyword(s):

Influenza A Virus ◽

Complement Activation ◽

Influenza A ◽

Viral Infections ◽

Adaptive Immune System ◽

Surface Protein ◽

Decay Accelerating Factor ◽

Viral Loads ◽

The Impact

Clearance of viral infections, such as SARS-CoV-2 and influenza A virus (IAV), must be fine-tuned to eliminate the pathogen without causing immunopathology. As such, an aggressive initial innate immune response favors the host in contrast to a detrimental prolonged inflammation. The complement pathway bridges innate and adaptive immune system and contributes to the response by directly clearing pathogens or infected cells, as well as recruiting proinflammatory immune cells and regulating inflammation. However, the impact of modulating complement activation in viral infections is still unclear. In this work, we targeted the complement decay-accelerating factor (DAF/CD55), a surface protein that protects cells from non-specific complement attack, and analyzed its role in IAV infections. We found that DAF modulates IAV infection in vivo, via an interplay with the antigenic viral proteins hemagglutinin (HA) and neuraminidase (NA), in a strain specific manner. Our results reveal that, contrary to what could be expected, DAF potentiates complement activation, increasing the recruitment of neutrophils, monocytes and T cells. We also show that viral NA acts on the heavily sialylated DAF and propose that the NA-dependent DAF removal of sialic acids exacerbates complement activation, leading to lung immunopathology. Remarkably, this mechanism has no impact on viral loads, but rather on the host resilience to infection, and may have direct implications in zoonotic influenza transmissions.

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Impact of Influenza A Virus Shutoff Proteins on Host Immune Responses

Vaccines ◽

10.3390/vaccines9060629 ◽

2021 ◽

Vol 9 (6) ◽

pp. 629

Author(s):

Megan M. Dunagan ◽

Kala Hardy ◽

Toru Takimoto

Keyword(s):

Immune Response ◽

Immune Responses ◽

Influenza A Virus ◽

Influenza A ◽

Human Populations ◽

Lymphocyte Migration ◽

Host Immune Responses ◽

Mhc Molecules ◽

The Impact

Influenza A virus (IAV) is a significant human pathogen that causes seasonal epidemics. Although various types of vaccines are available, IAVs still circulate among human populations, possibly due to their ability to circumvent host immune responses. IAV expresses two host shutoff proteins, PA-X and NS1, which antagonize the host innate immune response. By transcriptomic analysis, we previously showed that PA-X is a major contributor for general shutoff, while shutoff active NS1 specifically inhibits the expression of host cytokines, MHC molecules, and genes involved in innate immunity in cultured human cells. So far, the impact of these shutoff proteins in the acquired immune response in vivo has not been determined in detail. In this study, we analyzed the effects of PA-X and NS1 shutoff activities on immune response using recombinant influenza A/California/04/2009 viruses containing mutations affecting the expression of shutoff active PA-X and NS1 in a mouse model. Our data indicate that the virus without shutoff activities induced the strongest T and B cell responses. Both PA-X and NS1 reduced host immune responses, but shutoff active NS1 most effectively suppressed lymphocyte migration to the lungs, antibody production, and the generation of IAV specific CD4+ and CD8+ T cells. NS1 also prevented the generation of protective immunity against a heterologous virus challenge. These data indicate that shutoff active NS1 plays a major role in suppressing host immune responses against IAV infection.

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Clinical use of Antiviral Drugs

Drug Intelligence & Clinical Pharmacy ◽

10.1177/106002808702100501 ◽

1987 ◽

Vol 21 (5) ◽

pp. 399-405 ◽

Cited By ~ 5

Author(s):

Milap C. Nahata

Keyword(s):

Influenza A ◽

Viral Infections ◽

Antiviral Agent ◽

Antiviral Drugs ◽

Investigational Drug ◽

Virus Infections ◽

Herpes Encephalitis ◽

Herpes Simplex Viruses ◽

Varicella Zoster ◽

Syncytial Virus

Remarkable progress has been made in antiviral chemotherapy. Six approved antiviral drugs are now available for the treatment of various viral infections. Trifluridine, idoxuridine and vidarabine are all effective in patients with herpes keratitis; trifluridine is preferred due to its low toxicity. Acyclovir is the drug of choice in patients with infections due to herpes simplex viruses, including genital herpes, herpes encephalitis, and neonatal herpes, and infections due to varicella-zoster virus. Amantadine is the only drug currently available for prophylaxis and treatment of influenza A, but an investigational drug, rimantadine, appears to be equally effective and less toxic than amantadine. Ribavirin is the most recently approved antiviral agent for the treatment of respiratory syncytial virus infections. Numerous antiviral drugs are being studied in patients with acquired immunodeficiency syndrome. Although currently available drugs have improved our ability to manage a variety of viral illnesses, much needs to be learned about specific dosage guidelines based on the studies of pharmacokinetics, pharmacodynamics, potential adverse effects and viral resistance, and the role of combination therapy to optimize therapy.

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Suppression of influenza A virus replication in human lung epithelial cells by noncytotoxic concentrations bafilomycin A1

AJP Lung Cellular and Molecular Physiology ◽

10.1152/ajplung.00011.2014 ◽

2015 ◽

Vol 308 (3) ◽

pp. L270-L286 ◽

Cited By ~ 46

Author(s):

Behzad Yeganeh ◽

Saeid Ghavami ◽

Andrea L. Kroeker ◽

Thomas H. Mahood ◽

Gerald L. Stelmack ◽

...

Keyword(s):

Epithelial Cells ◽

Host Cell ◽

Influenza A Virus ◽

Influenza A ◽

Life Cycles ◽

Host Cells ◽

Nuclear Accumulation ◽

Low Concentration ◽

High Concentrations ◽

The Impact

Subcellular trafficking within host cells plays a critical role in viral life cycles, including influenza A virus (IAV). Thus targeting relevant subcellular compartments holds promise for effective intervention to control the impact of influenza infection. Bafilomycin A1(Baf-A1), when used at relative high concentrations (≥10 nM), inhibits vacuolar ATPase (V-ATPase) and reduces endosome acidification and lysosome number, thus inhibiting IAV replication but promoting host cell cytotoxicity. We tested the hypothesis that much lower doses of Baf-A1also have anti-IAV activity, but without toxic effects. Thus we assessed the antiviral activity of Baf-A1at different concentrations (0.1–100 nM) in human alveolar epithelial cells (A549) infected with IAV strain A/PR/8/34 virus (H1N1). Infected and mock-infected cells pre- and cotreated with Baf-A1were harvested 0–24 h postinfection and analyzed by immunoblotting, immunofluorescence, and confocal and electron microscopy. We found that Baf-A1had disparate concentration-dependent effects on subcellular organelles and suppressed affected IAV replication. At concentrations ≥10 nM Baf-A1inhibited acid lysosome formation, which resulted in greatly reduced IAV replication and release. Notably, at a very low concentration of 0.1 nM that is insufficient to reduce lysosome number, Baf-A1retained the capacity to significantly impair IAV nuclear accumulation as well as IAV replication and release. In contrast to the effects of high concentrations of Baf-A1, very low concentrations did not exhibit cytotoxic effects or induce apoptotic cell death, based on morphological and FACS analyses. In conclusion, our results reveal that low-concentration Baf-A1is an effective inhibitor of IAV replication, without impacting host cell viability.

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The Interferon-Stimulated Gene IFITM3 Restricts Infection and Pathogenesis of Arthritogenic and Encephalitic Alphaviruses

Journal of Virology ◽

10.1128/jvi.00655-16 ◽

2016 ◽

Vol 90 (19) ◽

pp. 8780-8794 ◽

Cited By ~ 46

Author(s):

Subhajit Poddar ◽

Jennifer L. Hyde ◽

Matthew J. Gorman ◽

Michael Farzan ◽

Michael S. Diamond

Keyword(s):

Viral Infections ◽

Transmembrane Protein ◽

Flow Cytometric Analysis ◽

Antiviral Effect ◽

Host Cells ◽

Type I ◽

Targeted Gene Deletion ◽

Multiple Organs ◽

Viral Burden ◽

Alphavirus Infection

ABSTRACTHost cells respond to viral infections by producing type I interferon (IFN), which induces the expression of hundreds of interferon-stimulated genes (ISGs). Although ISGs mediate a protective state against many pathogens, the antiviral functions of the majority of these genes have not been identified. IFITM3 is a small transmembrane ISG that restricts a broad range of viruses, including orthomyxoviruses, flaviviruses, filoviruses, and coronaviruses. Here, we show that alphavirus infection is increased inIfitm3−/−andIfitmlocus deletion (Ifitm-del) fibroblasts and, reciprocally, reduced in fibroblasts transcomplemented with Ifitm3. Mechanistic studies showed that Ifitm3 did not affect viral binding or entry but inhibited pH-dependent fusion. In a murine model of chikungunya virus arthritis,Ifitm3−/−mice sustained greater joint swelling in the ipsilateral ankle at days 3 and 7 postinfection, and this correlated with higher levels of proinflammatory cytokines and viral burden. Flow cytometric analysis suggested thatIfitm3−/−macrophages from the spleen were infected at greater levels than observed in wild-type (WT) mice, results that were supported by experiments withIfitm3−/−bone marrow-derived macrophages.Ifitm3−/−mice also were more susceptible than WT mice to lethal alphavirus infection with Venezuelan equine encephalitis virus, and this was associated with greater viral burden in multiple organs. Collectively, our data define an antiviral role for Ifitm3 in restricting infection of multiple alphaviruses.IMPORTANCEThe interferon-induced transmembrane protein 3 (IFITM3) inhibits infection of multiple families of viruses in cell culture. Compared to other viruses, much less is known about the antiviral effect of IFITM3 on alphaviruses. In this study, we characterized the antiviral activity of mouse Ifitm3 against arthritogenic and encephalitic alphaviruses using cells and animals with a targeted gene deletion ofIfitm3as well as deficient cells transcomplemented with Ifitm3. Based on extensive virological analysis, we demonstrate greater levels of alphavirus infection and disease pathogenesis when Ifitm3 expression is absent. Our data establish an inhibitory role for Ifitm3 in controlling infection of alphaviruses.

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Silver Nanoparticles as Potential Antiviral Agents

Pharmaceutics ◽

10.3390/pharmaceutics13122034 ◽

2021 ◽

Vol 13 (12) ◽

pp. 2034

Author(s):

Zubair Ahmed Ratan ◽

Fazla Rabbi Mashrur ◽

Anisha Parsub Chhoan ◽

Sadi Md. Shahriar ◽

Mohammad Faisal Haidere ◽

...

Keyword(s):

Silver Nanoparticles ◽

Potential Role ◽

Viral Infections ◽

Antiviral Agents ◽

Host Cells ◽

Characterization Methods ◽

New Horizons ◽

Bacteria And Fungi ◽

The Impact

Since the early 1990s, nanotechnology has led to new horizons in nanomedicine, which encompasses all spheres of science including chemistry, material science, biology, and biotechnology. Emerging viral infections are creating severe hazards to public health worldwide, recently, COVID-19 has caused mass human casualties with significant economic impacts. Interestingly, silver nanoparticles (AgNPs) exhibited the potential to destroy viruses, bacteria, and fungi using various methods. However, developing safe and effective antiviral drugs is challenging, as viruses use host cells for replication. Designing drugs that do not harm host cells while targeting viruses is complicated. In recent years, the impact of AgNPs on viruses has been evaluated. Here, we discuss the potential role of silver nanoparticles as antiviral agents. In this review, we focus on the properties of AgNPs such as their characterization methods, antiviral activity, mechanisms, applications, and toxicity.

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Epitope specificity plays a critical role in regulating antibody-dependent cell-mediated cytotoxicity against influenza A virus

Proceedings of the National Academy of Sciences ◽

10.1073/pnas.1609316113 ◽

2016 ◽

Vol 113 (42) ◽

pp. 11931-11936 ◽

Cited By ~ 88

Author(s):

Wenqian He ◽

Gene S. Tan ◽

Caitlin E. Mullarkey ◽

Amanda J. Lee ◽

Mannie Man Wai Lam ◽

...

Keyword(s):

Influenza Virus ◽

Influenza A Virus ◽

Neutralizing Antibodies ◽

Influenza A ◽

Critical Role ◽

Host Cells ◽

Viral Glycoprotein ◽

Effector Functions ◽

Dependent Cell

The generation of strain-specific neutralizing antibodies against influenza A virus is known to confer potent protection against homologous infections. The majority of these antibodies bind to the hemagglutinin (HA) head domain and function by blocking the receptor binding site, preventing infection of host cells. Recently, elicitation of broadly neutralizing antibodies which target the conserved HA stalk domain has become a promising “universal” influenza virus vaccine strategy. The ability of these antibodies to elicit Fc-dependent effector functions has emerged as an important mechanism through which protection is achieved in vivo. However, the way in which Fc-dependent effector functions are regulated by polyclonal influenza virus-binding antibody mixtures in vivo has never been defined. Here, we demonstrate that interactions among viral glycoprotein-binding antibodies of varying specificities regulate the magnitude of antibody-dependent cell-mediated cytotoxicity induction. We show that the mechanism responsible for this phenotype relies upon competition for binding to HA on the surface of infected cells and virus particles. Nonneutralizing antibodies were poor inducers and did not inhibit antibody-dependent cell-mediated cytotoxicity. Interestingly, anti-neuraminidase antibodies weakly induced antibody-dependent cell-mediated cytotoxicity and enhanced induction in the presence of HA stalk-binding antibodies in an additive manner. Our data demonstrate that antibody specificity plays an important role in the regulation of ADCC, and that cross-talk among antibodies of varying specificities determines the magnitude of Fc receptor-mediated effector functions.

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In VitroSusceptibility of Canine Influenza A (H3N8) Virus to Nitazoxanide and Tizoxanide

Veterinary Medicine International ◽

10.4061/2010/891010 ◽

2010 ◽

Vol 2010 ◽

pp. 1-5 ◽

Cited By ~ 8

Author(s):

Laura V. Ashton ◽

Robert L. Callan ◽

Sangeeta Rao ◽

Gabriele A. Landolt

Keyword(s):

Influenza Virus ◽

Influenza A ◽

The United States ◽

Canine Influenza Virus ◽

Valuable Adjunct ◽

Canine Influenza ◽

The Impact ◽

H3n8 Virus

Infection of dogs with canine influenza virus (CIV) is considered widespread throughout the United States following the first isolation of CIV in 2004. While vaccination against influenza A infection is a common and important practice for disease control, antiviral therapy can serve as a valuable adjunct in controlling the impact of the disease. In this study, we examined the antiviral activity of nitazoxanide (NTZ) and tizoxanide (TIZ) against three CIV isolatesin vitro. NTZ and TIZ inhibited virus replication of all CIVs with 50% and 90% inhibitory concentrations ranging from 0.17 to 0.21 μMand from 0.60 to 0.76 μM, respectively. These results suggest that NTZ and TIZ are effective against CIV and may be useful for treatment of canine influenza in dogs but further investigation of thein vivoefficacy against CIV as well as the drug's potential for toxicity in dogs is needed.

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Vγ9Vδ2 T Cells: Can We Re-Purpose a Potent Anti-Infection Mechanism for Cancer Therapy?

Cells ◽

10.3390/cells9040829 ◽

2020 ◽

Vol 9 (4) ◽

pp. 829 ◽

Cited By ~ 5

Author(s):

Klaus-Peter Künkele ◽

Daniela Wesch ◽

Hans-Heinrich Oberg ◽

Martin Aichinger ◽

Verena Supper ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

Tumor Therapy ◽

Γδ T Cells ◽

Host Cells ◽

Advantages And Disadvantages ◽

Therapeutic Concepts ◽

Vγ9vδ2 T Cells ◽

The Impact

Cancer therapies based on in vivo stimulation, or on adoptive T cell transfer of Vγ9Vδ2 T cells, have been tested in the past decades but have failed to provide consistent clinical efficacy. New, promising concepts such as γδ Chimeric Antigen Receptor (CAR) -T cells and γδ T-cell engagers are currently under preclinical evaluation. Since the impact of factors, such as the relatively low abundance of γδ T cells within tumor tissue is still under investigation, it remains to be shown whether these effector T cells can provide significant efficacy against solid tumors. Here, we highlight key learnings from the natural role of Vγ9Vδ2 T cells in the elimination of host cells bearing intracellular bacterial agents and we translate these into the setting of tumor therapy. We discuss the availability and relevance of preclinical models as well as currently available tools and knowledge from a drug development perspective. Finally, we compare advantages and disadvantages of existing therapeutic concepts and propose a role for Vγ9Vδ2 T cells in immune-oncology next to Cluster of Differentiation (CD) 3 activating therapies.

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In vivo analysis of influenza A mRNA secondary structures identifies critical regulatory motifs

Nucleic Acids Research ◽

10.1093/nar/gkz318 ◽

2019 ◽

Vol 47 (13) ◽

pp. 7003-7017 ◽

Cited By ~ 15

Author(s):

Lisa Marie Simon ◽

Edoardo Morandi ◽

Anna Luganini ◽

Giorgio Gribaudo ◽

Luis Martinez-Sobrido ◽

...

Keyword(s):

Secondary Structure ◽

Influenza A ◽

Host Cells ◽

Messenger Rnas ◽

Infected Cells ◽

In Vivo Analysis ◽

First Time ◽

Negative Sense

AbstractThe influenza A virus (IAV) is a continuous health threat to humans as well as animals due to its recurring epidemics and pandemics. The IAV genome is segmented and the eight negative-sense viral RNAs (vRNAs) are transcribed into positive sense complementary RNAs (cRNAs) and viral messenger RNAs (mRNAs) inside infected host cells. A role for the secondary structure of IAV mRNAs has been hypothesized and debated for many years, but knowledge on the structure mRNAs adopt in vivo is currently missing. Here we solve, for the first time, the in vivo secondary structure of IAV mRNAs in living infected cells. We demonstrate that, compared to the in vitro refolded structure, in vivo IAV mRNAs are less structured but exhibit specific locally stable elements. Moreover, we show that the targeted disruption of these high-confidence structured domains results in an extraordinary attenuation of IAV replicative capacity. Collectively, our data provide the first comprehensive map of the in vivo structural landscape of IAV mRNAs, hence providing the means for the development of new RNA-targeted antivirals.

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