Broad-spectrum antiviral activity of 2-beta-D-ribofuranosylselenazole-4-carboxamide, a new antiviral agent.

ABSTRACT Favipiravir (T-705) is a broad-spectrum antiviral agent that has been approved in Japan for the treatment of influenza virus infections. T-705 also inhibits the replication of various RNA viruses, including chikungunya virus (CHIKV). We demonstrated earlier that the K291R mutation in the F1 motif of the RNA-dependent RNA polymerase (RdRp) of CHIKV is responsible for low-level resistance to T-705. Interestingly, this lysine is highly conserved in the RdRp of positive-sense single-stranded RNA (+ssRNA) viruses. To obtain insights into the unique broad-spectrum antiviral activity of T-705, we explored the role of this lysine using another +ssRNA virus, namely, coxsackievirus B3 (CVB3). Introduction of the corresponding K-to-R substitution in the CVB3 RdRp (K159R) resulted in a nonviable virus. Replication competence of the K159R variant was restored by spontaneous acquisition of an A239G substitution in the RdRp. A mutagenesis analysis at position K159 identified the K159M variant as the only other viable variant which had also acquired the A239G substitution. The K159 substitutions markedly decreased the processivity of the purified viral RdRp, which was restored by the introduction of the A239G mutation. The K159R A239G and K159M A239G variants proved, surprisingly, more susceptible than the wild-type virus to T-705 and exhibited lower fidelity in polymerase assays. Furthermore, the K159R A239G variant was found to be highly attenuated in mice. We thus demonstrate that the conserved lysine in the F1 motif of the RdRp of +ssRNA viruses is involved in the broad-spectrum antiviral activity of T-705 and that it is a key amino acid for the proper functioning of the enzyme. IMPORTANCE In this study, we report the key role of a highly conserved lysine residue of the viral polymerase in the broad-spectrum antiviral activity of favipiravir (T-705) against positive-sense single-stranded RNA viruses. Substitutions of this conserved lysine have a major negative impact on the functionality of the RdRp. Furthermore, we show that this lysine is involved in the fidelity of the RdRp and that the RdRp fidelity influences the sensitivity of the virus for the antiviral efficacy of T-705. Consequently, these results provide insights into the mechanism of the antiviral activity of T-705 and may lay the basis for the design of novel chemical scaffolds that may be endowed with a more potent broad-spectrum antiviral activity than that of T-705.

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Efficient incorporation and template-dependent polymerase inhibition are major determinants for the broad-spectrum antiviral activity of remdesivir

10.1101/2021.10.14.464416 ◽

2021 ◽

Author(s):

Matthias Götte ◽

Calvin J. Gordon ◽

Hery W. Lee ◽

Egor P. Tchesnokov ◽

Jason K. Perry ◽

...

Keyword(s):

Antiviral Activity ◽

Broad Spectrum ◽

Rna Viruses ◽

Cyano Group ◽

Nipah Virus ◽

Antiviral Agent ◽

Hemorrhagic Fever ◽

Inhibitory Effects ◽

Hemorrhagic Fever Virus ◽

Negative Sense

Remdesivir (RDV) is a direct antiviral agent that is approved in several countries for the treatment of coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). RDV exhibits broad-spectrum antiviral activity against positive-sense RNA viruses, e.g., SARS-CoV-2 and hepatitis C virus (HCV) and non-segmented negative-sense RNA viruses, e.g., Nipah virus (NiV), while several segmented negative-sense RNA viruses such as influenza (Flu) virus or Crimean-Congo hemorrhagic fever virus (CCHFV) are not sensitive to the drug. The reasons for this apparent pattern are unknown. Here, we expressed and purified representative RNA-dependent RNA polymerases (RdRp) and studied three biochemical parameters that have been associated with the inhibitory effects of RDV-triphosphate (TP): (i) selective incorporation of the nucleotide substrate RDV-TP, (ii) the effect of the incorporated RDV-monophosphate (MP) on primer extension, and (iii) the effect of RDV-MP in the template during incorporation of the complementary UTP. The results of this study revealed a strong correlation between antiviral effects and efficient incorporation of RDV-TP. Delayed chain-termination is heterogeneous and usually inefficient at higher NTP concentrations. In contrast, template-dependent inhibition of UTP incorporation opposite the embedded RDV-MP is seen with all polymerases. Molecular modeling suggests a steric conflict between the 1′-cyano group of RDV-MP and conserved residues of RdRp motif F. We conclude that future efforts in the development of nucleotide analogues with a broader spectrum of antiviral activities should focus on improving rates of incorporation while capitalizing on the inhibitory effects of a bulky 1′-modification.

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Faculty Opinions recommendation of Mechanism-based covalent neuraminidase inhibitors with broad-spectrum influenza antiviral activity.

Faculty Opinions – Post-Publication Peer Review of the Biomedical Literature ◽

10.3410/f.717980442.793471723 ◽

2013 ◽

Author(s):

Xiayang Qiu ◽

Ye Che

Keyword(s):

Antiviral Activity ◽

Broad Spectrum ◽

Neuraminidase Inhibitors

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Filociclovir Is an Active Antiviral Agent against Ocular Adenovirus Isolates In Vitro and in the Ad5/NZW Rabbit Ocular Model

Pharmaceuticals ◽

10.3390/ph14040294 ◽

2021 ◽

Vol 14 (4) ◽

pp. 294

Author(s):

Eric G. Romanowski ◽

Islam T. M. Hussein ◽

Steven C. Cardinale ◽

Michelle M. Butler ◽

Lucas R. Morin ◽

...

Keyword(s):

Antiviral Activity ◽

Topical Treatment ◽

Antiviral Agent ◽

Human Adenovirus ◽

Treatment Groups ◽

Ocular Infections ◽

The Mean ◽

Eye Infection

Presently, there is no FDA- or EMA-approved antiviral for the treatment of human adenovirus (HAdV) ocular infections. This study determined the antiviral activity of filociclovir (FCV) against ocular HAdV isolates in vitro and in the Ad5/NZW rabbit ocular model. The 50% effective concentrations (EC50) of FCV and cidofovir (CDV) were determined for several ocular HAdV types using standard plaque reduction assays. Rabbits were topically inoculated in both eyes with HAdV5. On day 1, the rabbits were divided into four topical treatment groups: (1) 0.5% FCV 4x/day × 10 d; (2) 0.1% FCV 4x/day × 10 d; (3) 0.5% CDV 2x/day × 7 d; (4) vehicle 4x/day × 10 d. Eyes were cultured for virus on days 0, 1, 3, 4, 5, 7, 9, 11, and 14. The resulting viral eye titers were determined using standard plaque assays. The mean in vitro EC50 for FCV against tested HAdV types ranged from 0.50 to 4.68 µM, whereas those treated with CDV ranged from 0.49 to 30.3 µM. In vivo, compared to vehicle, 0.5% FCV, 0.1% FCV, and 0.5% CDV produced lower eye titers, fewer numbers of positive eye cultures, and shorter durations of eye infection. FCV demonstrated anti-adenovirus activity in vitro and in vivo.

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Ribavirin - current status of a broad spectrum antiviral agent

Expert Opinion on Pharmacotherapy ◽

10.1517/14656566.2.8.1317 ◽

2001 ◽

Vol 2 (8) ◽

pp. 1317-1324 ◽

Cited By ~ 119

Author(s):

Noel J C Snell

Keyword(s):

Broad Spectrum ◽

Antiviral Agent ◽

Current Status

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Broad-Spectrum Antiviral Activity of 3D8, a Nucleic Acid-Hydrolyzing Single-Chain Variable Fragment (scFv), Targeting SARS-CoV-2 and Multiple Coronaviruses In Vitro

Viruses ◽

10.3390/v13040650 ◽

2021 ◽

Vol 13 (4) ◽

pp. 650

Author(s):

Gunsup Lee ◽

Shailesh Budhathoki ◽

Geum-Young Lee ◽

Kwang-ji Oh ◽

Yeon Kyoung Ham ◽

...

Keyword(s):

Nucleic Acid ◽

Antiviral Activity ◽

Broad Spectrum ◽

Recombinant Antibody ◽

Therapeutic Effects ◽

Single Chain Variable Fragment ◽

Single Chain ◽

Diarrhea Virus ◽

3D8 Scfv

The virus behind the current pandemic, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is responsible for the etiology of novel coronavirus disease (COVID-19) and poses a critical public health threat worldwide. Effective therapeutics and vaccines against multiple coronaviruses remain unavailable. Single-chain variable fragment (scFv), a recombinant antibody, exhibits broad-spectrum antiviral activity against DNA and RNA viruses owing to its nucleic acid-hydrolyzing property. The antiviral activity of 3D8 scFv against SARS-CoV-2 and other coronaviruses was evaluated in Vero E6 cell cultures. Viral growth was quantified with quantitative RT-qPCR and plaque assay. The nucleic acid-hydrolyzing activity of 3D8 was assessed through abzyme assays of in vitro viral transcripts and cell viability was determined by MTT assay. We found that 3D8 inhibited the replication of SARS-CoV-2, human coronavirus OC43 (HCoV-OC43), and porcine epidemic diarrhea virus (PEDV). Our results revealed the prophylactic and therapeutic effects of 3D8 scFv against SARS-CoV-2 in Vero E6 cells. Immunoblot and plaque assays showed the reduction of coronavirus nucleoproteins and infectious particles, respectively, in 3D8 scFv-treated cells. These data demonstrate the broad-spectrum antiviral activity of 3D8 against SARS-CoV-2 and other coronaviruses. Thus, it could be considered a potential antiviral countermeasure against SARS-CoV-2 and zoonotic coronaviruses.

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The effectiveness of antiviral agents with broad-spectrum activity against chikungunya virus varies between host cell lines

Antiviral Chemistry and Chemotherapy ◽

10.1177/2040206618807580 ◽

2018 ◽

Vol 26 ◽

pp. 204020661880758 ◽

Cited By ~ 14

Author(s):

Evelyn J Franco ◽

Jaime L Rodriquez ◽

Justin J Pomeroy ◽

Kaley C Hanrahan ◽

Ashley N Brown

Keyword(s):

Antiviral Activity ◽

Host Cell ◽

Cell Line ◽

Cell Lines ◽

Broad Spectrum ◽

Chikungunya Virus ◽

Plaque Assay ◽

A549 Cells ◽

Western Hemisphere ◽

Viral Burden

Chikungunya virus (CHIKV) is a mosquito-borne virus that has recently emerged in the Western Hemisphere. Approved antiviral therapies or vaccines for the treatment or prevention of CHIKV infections are not available. This study aims to evaluate the antiviral activity of commercially available broad-spectrum antivirals against CHIKV. Due to host cell-specific variability in uptake and intracellular processing of drug, we evaluated the antiviral effects of each agent in three cell lines. Antiviral activities of ribavirin (RBV), interferon-alfa (IFN-α) and favipiravir (FAV) were assessed in CHIKV-infected Vero, HUH-7, and A549 cells. CHIKV-infected cells were treated with increasing concentrations of each agent for three days and viral burden was quantified by plaque assay on Vero cells. Cytotoxic effects of RBV, FAV and IFN-α were also evaluated. Antiviral activity differed depending on the cell line used for evaluation. RBV had the greatest antiviral effect in HUH-7 cells (EC50 = 2.575 µg/mL); IFN-α was most effective in A549 cells (EC50 = 4.235 IU/mL); and FAV in HUH-7 cells (EC50 = 20.00 μg/mL). The results of our study show FAV and IFN-α are the most promising candidates, as their use led to substantial reductions in viral burden at clinically achievable concentrations in two human-derived cell lines. FAV is an especially attractive candidate for further investigation due to its oral bioavailability. These findings also highlight the importance of cell line selection for preclinical drug trials.

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Discovery of a Highly Selective PLD2 Inhibitor (ML395): A New Probe with Improved Physiochemical Properties and Broad-Spectrum Antiviral Activity against Influenza Strains

ChemMedChem ◽

10.1002/cmdc.201402333 ◽

2014 ◽

Vol 9 (12) ◽

pp. 2633-2637 ◽

Cited By ~ 13

Author(s):

Matthew C. O'Reilly ◽

Thomas H. Oguin ◽

Sarah A. Scott ◽

Paul G. Thomas ◽

Charles W. Locuson ◽

...

Keyword(s):

Antiviral Activity ◽

Broad Spectrum ◽

Physiochemical Properties

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Nanodroplet-Benzalkonium Chloride Formulation Demonstrates In Vitro and Ex- Vivo Broad-Spectrum Antiviral Activity Against SARS-CoV-2 and other Enveloped Viruses

10.21203/rs.3.rs-362864/v1 ◽

2021 ◽

Author(s):

Jessie Pannu ◽

Susan Ciotti ◽

Shyamala Ganesan ◽

George Arida ◽

Chad Costley ◽

...

Keyword(s):

Antiviral Activity ◽

Broad Spectrum ◽

Benzalkonium Chloride ◽

Ex Vivo ◽

Viral Disease ◽

Influenza B ◽

Human Coronavirus ◽

Enveloped Viruses ◽

Nasal Irritation

Abstract Objective: The Covid-19 pandemic has highlighted the importance of aerosolized droplets inhaled into the nose in the transmission of respiratory viral disease. Inactivating pathogenic viruses at the nasal port of entry may reduce viral loads, thereby reducing infection, transmission and spread. In this communication, we demonstrate safe and broad anti-viral activity of oil-in-water nanoemulsion (nanodroplet) formulation containing the potent antiseptic 0.13% Benzalkonium Chloride (NE-BZK). Results: We have demonstrated that NE-BZK exhibits broad-spectrum, long-lasting antiviral activity with >99.9% in vitro killing of enveloped viruses including SARS-CoV-2, human coronavirus, RSV, and influenza B. In vitro and ex-vivo studies demonstrated continued killing of >99.99% of human coronavirus with diluted NE-BZK and persistent for 8 hours post application, respectively. The repeated application of NE-BZK, twice daily for 2 weeks into rabbit nostrils demonstrated its safety with no nasal irritation. These findings demonstrate that formulating BZK into the proprietary nanodroplets offers a safe and effective antiviral and a significant addition to strategies to combat the spread of respiratory viral infectious diseases.

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