scholarly journals Understanding the Mechanism of the Broad-Spectrum Antiviral Activity of Favipiravir (T-705): Key Role of the F1 Motif of the Viral Polymerase

2017 ◽  
Vol 91 (12) ◽  
Author(s):  
Rana Abdelnabi ◽  
Ana Theresa Silveira de Morais ◽  
Pieter Leyssen ◽  
Isabelle Imbert ◽  
Stéphanie Beaucourt ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Broad Spectrum ◽  
Rna Viruses ◽  
Negative Impact ◽  
Antiviral Agent ◽  
Wild Type Virus ◽  
Viral Polymerase ◽  
Ssrna Virus ◽  
Positive Sense

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.

Role of GS-5734 (Remdesivir) in inhibiting SARS-CoV and MERS-CoV: The expected role of GS-5734 (Remdesivir) in COVID-19 (2019-nCoV) - VYTR hypothesis.

2020 ◽  
Vol 11 (SPL1) ◽  
Author(s):  
Vityala Yethindra
Keyword(s):  
Clinical Trials ◽  
Antiviral Activity ◽  
Protease Inhibitors ◽  
Human Body ◽  
Broad Spectrum ◽  
Rna Synthesis ◽  
Rna Viruses ◽  
Improved Outcomes ◽  
The Family

Coronaviruses (CoVs) are enveloped RNA viruses related to the family Coronaviridae, the order Nirdovales, and observed in humans and other mammals. In December 2019, many pneumonia cases reported by patients with unknown causes, mainly associated with seafood and wet animal market in Wuhan, China, and where clinically resembled viral pneumonia. At present, there is no existence of antiviral drugs for the treatment of CoV infections. The results of our study are GS-5734 strongly inhibits SARS-CoV and MERS-CoV in HAE cells, GS-5734 inhibits CoVs at early stages in replication by inhibiting viral RNA synthesis, the absence of ExoN-mediated proofreading in viruses sensitive to treatment with GS-5734. Protease inhibitors can show improved outcomes in some coronaviruses, but mostly 99% of protease inhibitors bind to proteins present in the human body, and only 1% attacks on existed viruses. The expected role of GS-5734 (Remdesivir) in the 2019-nCoV - VYTR hypothesis explained. As broad-spectrum drugs are capable of inhibiting CoV infections, GS-5734 is a broad-spectrum drug and may show inhibition on CoV infections and 2019-nCoV. GS-5734 will show desired results regarding antiviral activity against 2019-nCoV as it showed potent antiviral activity in other CoVs. More clinical trials and experiments needed to prove that GS-5734 (Remdesivir) is a potential and effective drug to treat 2019-nCoV.

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

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.

DDX3 inhibitors show antiviral activity against positive-sense single-stranded RNA viruses but not against negative-sense single-stranded RNA viruses: The coxsackie B model

2020 ◽  
Vol 178 ◽  
pp. 104750 ◽  
Author(s):  
Paola Quaranta ◽  
Giulia Lottini ◽  
Giulia Chesi ◽  
Flavia Contrafatto ◽  
Roberta Russotto ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Rna Viruses ◽  
Positive Sense ◽  
Negative Sense ◽  
Coxsackie B

scholarly journals Investigation of the role of GBF1 in the replication of positive-sense single-stranded RNA viruses

2018 ◽  
Vol 99 (8) ◽  
pp. 1086-1096 ◽  
Author(s):  
Juliette Ferlin ◽  
Rayan Farhat ◽  
Sandrine Belouzard ◽  
Laurence Cocquerel ◽  
Antoine Bertin ◽  
...  
Keyword(s):  
Rna Viruses ◽  
Positive Sense

scholarly journals 3D8, a nucleic acid-hydrolyzing scFv, confers antiviral activity against SARS-CoV-2 and multiple coronaviruses in vitro

2020 ◽  
Author(s):  
Gunsup Lee ◽  
Shailesh Budhathoki ◽  
Hyeok Soon Choi ◽  
Kwang-ji Oh ◽  
Geum-Young Lee ◽  
...  
Keyword(s):  
Nucleic Acid ◽  
Antiviral Activity ◽  
Broad Spectrum ◽  
Rna Viruses ◽  
Therapeutic Effects ◽  
List Type ◽  
Single Chain ◽  
Diarrhea Virus ◽  
Antiviral Effects ◽  
3D8 Scfv

AbstractThe current pandemic severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pose a critical public health threat worldwide. Coronaviruses (subfamily Orthocoronavirinae, family Coronaviridae, order Nidovirales) are a group of enveloped positive-sense single-stranded RNA viruses. Six pathogenic human coronaviruses, likely zoonotic viruses, cause the common cold in humans. A new emerging coronavirus, SARS-CoV-2, become a crucial etiology for the Coronavirus-induced disease 19 (COVID-19). However, effective therapeutics and vaccines against multiple coronaviruses remain unavailable. This study aimed to investigate an antiviral molecule, single chain variable fragment (scFv), against SARS-CoV-2 and other coronaviruses. 3D8, a recombinant scFv, exhibits broad-spectrum antiviral activity against DNA and RNA viruses owing to its nucleic acid-hydrolyzing property. Here, we report that 3D8 scFv 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 absence of coronavirus nucleoproteins and infectious particles in 3D8 scFv-treated cells, respectively. In addition, we observed the antiviral effects of 3D8 against HCoV-OC43 and PEDV. In conclusion, this study provides insights into the broad-spectrum antiviral agent of 3D8 scFv; thus, it could be considered a potential antiviral countermeasure against SARS-CoV-2 and zoonotic coronaviruses.Key points (Main message)3D8, a nucleic acid-hydrolyzing scFv, exhibits potent prophylactic and therapeutic antiviral effects on SARS-CoV-2.3D8 exhibits broad-spectrum antiviral activity against multiple coronaviruses: hCoV OC43 and PEDV.3D8 potentially degrades viral RNA.

scholarly journals Deletion of Cytoplasmic Double-Stranded RNA Sensors Does Not Uncover Viral Small Interfering RNA Production in Human Cells

mSphere ◽  
2017 ◽  
Vol 2 (4) ◽  
Author(s):  
Susan Schuster ◽  
Lotte E. Tholen ◽  
Gijs J. Overheul ◽  
Frank J. M. van Kuppeveld ◽  
Ronald P. van Rij
Keyword(s):  
Rna Interference ◽  
Antiviral Activity ◽  
Mammalian Cells ◽  
Rna Viruses ◽  
Antiviral Immunity ◽  
Antiviral Effect ◽  
Interferon Response ◽  
Rnai Pathway ◽  
Differentiated Cells ◽  
Positive Sense

ABSTRACT The contribution of the RNA interference (RNAi) pathway in antiviral immunity in vertebrates has been widely debated. It has been proposed that RNAi possesses antiviral activity in mammalian systems but that its antiviral effect is masked by the potent antiviral interferon response in differentiated mammalian cells. In this study, we show that inactivation of the interferon response is not sufficient to uncover antiviral activity of RNAi in human epithelial cells infected with three wild-type positive-sense RNA viruses. Antiviral immunity in insects and plants is mediated by the RNA interference (RNAi) pathway in which viral long double-stranded RNA (dsRNA) is processed into small interfering RNAs (siRNAs) by Dicer enzymes. Although this pathway is evolutionarily conserved, its involvement in antiviral defense in mammals is the subject of debate. In vertebrates, recognition of viral RNA induces a sophisticated type I interferon (IFN)-based immune response, and it has been proposed that this response masks or inhibits antiviral RNAi. To test this hypothesis, we analyzed viral small RNA production in differentiated cells deficient in the cytoplasmic RNA sensors RIG-I and MDA5. We did not detect 22-nucleotide (nt) viral siRNAs upon infection with three different positive-sense RNA viruses. Our data suggest that the depletion of cytoplasmic RIG-I-like sensors is not sufficient to uncover viral siRNAs in differentiated cells. IMPORTANCE The contribution of the RNA interference (RNAi) pathway in antiviral immunity in vertebrates has been widely debated. It has been proposed that RNAi possesses antiviral activity in mammalian systems but that its antiviral effect is masked by the potent antiviral interferon response in differentiated mammalian cells. In this study, we show that inactivation of the interferon response is not sufficient to uncover antiviral activity of RNAi in human epithelial cells infected with three wild-type positive-sense RNA viruses.

scholarly journals Ribonuclease fromBacillusActs as an Antiviral Agent against Negative- and Positive-Sense Single Stranded Human Respiratory RNA Viruses

2017 ◽  
Vol 2017 ◽  
pp. 1-11 ◽  
Author(s):  
Raihan Shah Mahmud ◽  
Christin Müller ◽  
Yulia Romanova ◽  
Ahmed Mostafa ◽  
Vera Ulyanova ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Influenza A ◽  
Rna Viruses ◽  
A549 Cells ◽  
Antiviral Agent ◽  
Housekeeping Genes ◽  
Antiviral Effect ◽  
Viral Mrna ◽  
Mrna Accumulation ◽  
Positive Sense

Bacillus pumilusribonuclease (binase) was shown to be a promising antiviral agent in animal models and cell cultures. However, the mode of its antiviral action remains unknown. To assess the binase effect on intracellular viral RNA we have selected single stranded negative- and positive-sense RNA viruses, influenza virus, and rhinovirus, respectively, which annually cause respiratory illnesses and are characterized by high contagious nature, mutation rate, and antigen variability. We have shown that binase exerts an antiviral effect on both viruses at the same concentration, which does not alter the spectrum of A549 cellular proteins and expression of housekeeping genes. The titers of influenza A (H1N1pdm) virus and human rhinovirus serotype 1A were reduced by 40% and 65%, respectively. A preincubation of influenza virus with binase before infection significantly reduced viral titer after single-cycle replication of the virus. Using influenza A virus mini genome system we showed that binase reduced GFP reporter signaling indicating a binase action on the expression of viral mRNA. Binase reduced the level of H1N1pdm viral NP mRNA accumulation in A549 cells by 20%. Since the viral mRNA is a possible target for binase this agent could be potentially applied in the antiviral therapy against both negative- and positive-sense RNA viruses.

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

1983 ◽  
Vol 24 (3) ◽  
pp. 353-361 ◽  
Author(s):  
J J Kirsi ◽  
J A North ◽  
P A McKernan ◽  
B K Murray ◽  
P G Canonico ◽  
...  
Keyword(s):  
Antiviral Activity ◽  
Broad Spectrum ◽  
Antiviral Agent

scholarly journals Predicting Broad-Spectrum Antiviral Drugs against RNA Viruses Using Transcriptional Responses to Exogenous RNA

2021 ◽  
Author(s):  
Akpeli V. Nordor ◽  
Geoffrey H. Siwo
Keyword(s):  
Antiviral Activity ◽  
Small Molecules ◽  
Broad Spectrum ◽  
Rna Viruses ◽  
Antiviral Drugs ◽  
Viral Rna ◽  
Host Cells ◽  
Target Cells ◽  
Transcriptional Responses ◽  
Exogenous Rna

All RNA viruses deliver their genomes into target host cells through processes distinct from normal trafficking of cellular RNA transcripts. The delivery of viral RNA into most cells hence triggers innate antiviral defenses that recognize viral RNA as foreign. In turn, viruses have evolved mechanisms to subvert these defenses, allowing them to thrive in target cells. Therefore, drugs activating defense to exogenous RNA could serve as broad-spectrum antiviral drugs. Here we show that transcriptional signatures associated with cellular responses to the delivery of a non-viral exogenous RNA sequence into human cells predict small molecules with broad-spectrum antiviral activity. In particular, transcriptional responses to the delivery of Cas9 mRNA into human hematopoietic stem and progenitor cells (HSPCs) highly matches those triggered by small molecules with broad-spectrum antiviral activity such as emetine, homoharringtonine, pyrvinium pamoate and anisomycin, indicating that these drugs are potentially active against other RNA viruses. Furthermore, these drugs have been approved for other indications and could thereby be repurposed to novel viruses. We propose that the antiviral activity of these drugs to SARS-CoV-2 should therefore be determined as they have been shown as active against other coronaviruses including SARS-CoV-1 and MERS-CoV. Indeed, two of these drugs- emetine and homoharringtonine- were independently shown to inhibit SARS-CoV-2 as this article was in preparation. These drugs could also be explored as potential adjuvants to COVID-19 vaccines in development due to their potential effect on the innate antiviral defenses that could bolster adaptive immunity when delivered alongside vaccine antigens.

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