scholarly journals Viral polymerase binding and broad-spectrum antiviral activity of molnupiravir against human seasonal coronaviruses

Virology ◽  
2021 ◽  
Vol 564 ◽  
pp. 33-38
Author(s):  
Yining Wang ◽  
Pengfei Li ◽  
Kundan Solanki ◽  
Yang Li ◽  
Zhongren Ma ◽  
...  
2017 ◽  
Vol 91 (12) ◽  
Author(s):  
Rana Abdelnabi ◽  
Ana Theresa Silveira de Morais ◽  
Pieter Leyssen ◽  
Isabelle Imbert ◽  
Stéphanie Beaucourt ◽  
...  

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.


Viruses ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 650
Author(s):  
Gunsup Lee ◽  
Shailesh Budhathoki ◽  
Geum-Young Lee ◽  
Kwang-ji Oh ◽  
Yeon Kyoung Ham ◽  
...  

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.


2018 ◽  
Vol 26 ◽  
pp. 204020661880758 ◽  
Author(s):  
Evelyn J Franco ◽  
Jaime L Rodriquez ◽  
Justin J Pomeroy ◽  
Kaley C Hanrahan ◽  
Ashley N Brown

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.


ChemMedChem ◽  
2014 ◽  
Vol 9 (12) ◽  
pp. 2633-2637 ◽  
Author(s):  
Matthew C. O'Reilly ◽  
Thomas H. Oguin ◽  
Sarah A. Scott ◽  
Paul G. Thomas ◽  
Charles W. Locuson ◽  
...  

2021 ◽  
Author(s):  
Jessie Pannu ◽  
Susan Ciotti ◽  
Shyamala Ganesan ◽  
George Arida ◽  
Chad Costley ◽  
...  

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.


2012 ◽  
Vol 86 (13) ◽  
pp. 7292-7297 ◽  
Author(s):  
J. K. Marklund ◽  
Q. Ye ◽  
J. Dong ◽  
Y. J. Tao ◽  
R. M. Krug

2018 ◽  
Vol 150 ◽  
pp. 123-129 ◽  
Author(s):  
Christin Müller ◽  
Falk W. Schulte ◽  
Kerstin Lange-Grünweller ◽  
Wiebke Obermann ◽  
Ramakanth Madhugiri ◽  
...  

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