scholarly journals Enisamium is a small molecule inhibitor of the influenza A virus and SARS-CoV-2 RNA polymerases

2020 ◽  
Author(s):  
Alexander P Walker ◽  
Haitian Fan ◽  
Jeremy R Keown ◽  
Victor Margitich ◽  
Jonathan M Grimes ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Influenza A Virus ◽  
Small Molecule ◽  
Broad Spectrum ◽  
Influenza A ◽  
Rna Synthesis ◽  
Rna Virus ◽  
Rna Polymerases ◽  
Influenza A Viruses ◽  
Molecule Inhibitor

AbstractInfluenza A virus and coronavirus strains cause a mild to severe respiratory disease that can result in death. Although vaccines exist against circulating influenza A viruses, such vaccines are ineffective against emerging pandemic influenza A viruses. Currently, no vaccine exists against coronavirus infections, including pandemic SARS-CoV-2, the causative agent of the Coronavirus Disease 2019 (COVID-19). To combat these RNA virus infections, alternative antiviral strategies are needed. A key drug target is the viral RNA polymerase, which is responsible for viral RNA synthesis. In January 2020, the World Health Organisation identified enisamium as a candidate therapeutic against SARS-CoV-2. Enisamium is an isonicotinic acid derivative that is an inhibitor of multiple influenza B and A virus strains in cell culture and clinically approved in 11 countries. Here we show using in vitro assays that enisamium and its putative metabolite, VR17-04, inhibit the activity of the influenza virus and the SARS-CoV-2 RNA polymerase. VR17-04 displays similar efficacy against the SARS-CoV-2 RNA polymerase as the nucleotide analogue remdesivir triphosphate. These results suggest that enisamium is a broad-spectrum small molecule inhibitor of RNA virus RNA synthesis, and implicate it as a possible therapeutic option for treating SARS-CoV-2 infection. Unlike remdesivir, enisamium does not require intravenous administration which may be advantageous for the development of COVID-19 treatments outside a hospital setting.ImportanceInfluenza A virus and SARS-CoV-2 are respiratory viruses capable of causing pandemics, and the latter is responsible for the Coronavirus Disease 2019 (COVID-19) pandemic. Both viruses encode RNA polymerases which transcribe their RNA genomes and are important targets for antiviral drugs including remdesivir. Here, we show that the antiviral drug enisamium inhibits the RNA polymerases of both influenza A virus and SARS-CoV-2. Furthermore, we show that a putative metabolite of enisamium is a more potent inhibitor, inhibiting the SARS-CoV-2 RNA polymerase with similar efficiency to remdesivir. Our data offer insight into the mechanism of action for enisamium, and implicate it as a broad-spectrum antiviral which could be used in the treatment of SARS-CoV-2 infection.

scholarly journals The host factor ANP32A is required for influenza A virus vRNA and cRNA synthesis

2021 ◽  
Author(s):  
Benjamin E. Nilsson-Payant ◽  
Benjamin R. tenOever ◽  
Aartjan J.W. te Velthuis
Keyword(s):  
Avian Influenza ◽  
Rna Polymerase ◽  
Viral Replication ◽  
Influenza A Virus ◽  
Virus Replication ◽  
Influenza A ◽  
Host Factor ◽  
Rna Polymerases ◽  
Viral Rna ◽  
Influenza A Viruses

Influenza A viruses are negative-sense RNA viruses that rely on their own viral replication machinery to replicate and transcribe their segmented single-stranded RNA genome. The viral ribonucleoprotein complexes in which viral RNA is replicated consist of a nucleoprotein scaffold around which the RNA genome is bound, and a heterotrimeric RNA-dependent RNA polymerase that catalyzes viral replication. The RNA polymerase copies the viral RNA (vRNA) via a replicative intermediate, called the complementary RNA (cRNA), and subsequently uses this cRNA to make more vRNA copies. To ensure that new cRNA and vRNA molecules are associated with ribonucleoproteins in which they can be amplified, the active RNA polymerase recruits a second polymerase to encapsidate the cRNA or vRNA. Host factor ANP32A has been shown to be essential for viral replication and to facilitate the formation of a dimer between viral RNA polymerases. Differences between mammalian and avian ANP32A proteins are sufficient to restrict viral replication. It has been proposed that ANP32A is only required for the synthesis of vRNA molecules from a cRNA, but not vice versa. However, this view does not match recent molecular evidence. Here we use minigenome assays, virus infections, and viral promoter mutations to demonstrate that ANP32A is essential for both vRNA and cRNA synthesis. Moreover, we show that ANP32 is not only needed for the actively replicating polymerase, but also for the polymerase that is encapsidating nascent viral RNA products. Overall, these results provide new insights into influenza A virus replication and host adaptation. IMPORTANCE Zoonotic avian influenza A viruses pose a constant threat to global health, and they have the potential to cause pandemics. Species variations in host factor ANP32A play a key role in supporting the activity of avian influenza A virus RNA polymerases in mammalian hosts. Here we show that ANP32A acts at two stages in the influenza A virus replication cycle, supporting recent structural experiments, in line with its essential role. Understanding how ANP32A supports viral RNA polymerase activity and how it supports avian polymerase function in mammalian hosts is important for understanding influenza A virus replication and the development of antiviral strategies against influenza A viruses.

scholarly journals The host factor ANP32A is required for influenza A virus vRNA and cRNA synthesis

2021 ◽  
Author(s):  
Benjamin E Nilsson-Payant ◽  
Benjamin R. tenOever ◽  
Aartjan J.W. te Velthuis
Keyword(s):  
Rna Polymerase ◽  
Viral Replication ◽  
Influenza A Virus ◽  
Influenza A ◽  
Host Factor ◽  
Viral Rna ◽  
Molecular Evidence ◽  
Influenza A Viruses ◽  
Ribonucleoprotein Complexes ◽  
Rna Genome

Influenza A viruses are negative-sense RNA viruses that rely on their own viral replication machinery to replicate and transcribe their segmented single-stranded RNA genome. The viral ribonucleoprotein complexes in which viral RNA is replicated consist of a nucleoprotein scaffold around which the RNA genome is bound, and a heterotrimeric RNA-dependent RNA polymerase that catalyzes viral replication. The RNA polymerase copies the viral RNA (vRNA) via a replicative intermediate, called the complementary RNA (cRNA), and subsequently uses this cRNA to make more vRNA copies. To ensure that new cRNA and vRNA molecules are associated with ribonucleoproteins in which they can be amplified, the active RNA polymerase recruits a second polymerase to encapsidate the cRNA or vRNA. Host factor ANP32A has been shown to be essential for viral replication and to facilitate the formation of a dimer between viral RNA polymerases and differences between mammalian and avian ANP32A proteins are sufficient to restrict viral replication. It has been proposed that ANP32A is only required for the synthesis of vRNA molecules from a cRNA, but not vice versa. However, this view does not match recent molecular evidence. Here we use minigenome assays, virus infections, and viral promoter mutations to demonstrate that ANP32A is essential for both vRNA and cRNA synthesis. Moreover, we show that ANP32 is not only needed for the actively replicating polymerase, but also for the polymerase that is encapsidating nascent viral RNA products. Overall, these results provide new insights into influenza A virus replication and host adaptation.

scholarly journals Role of the PB2 627 Domain in Influenza A Virus Polymerase Function

2017 ◽  
Vol 91 (7) ◽  
Author(s):  
Benjamin E. Nilsson ◽  
Aartjan J. W. te Velthuis ◽  
Ervin Fodor
Keyword(s):  
Influenza Virus ◽  
Rna Polymerase ◽  
Influenza A Virus ◽  
Influenza A ◽  
Influenza A Viruses ◽  
Viral Polymerase ◽  
Virus Rna ◽  
Rna Genome ◽  
Transcription And Replication

ABSTRACT The RNA genome of influenza A viruses is transcribed and replicated by the viral RNA-dependent RNA polymerase, composed of the subunits PA, PB1, and PB2. High-resolution structural data revealed that the polymerase assembles into a central polymerase core and several auxiliary highly flexible, protruding domains. The auxiliary PB2 cap-binding and the PA endonuclease domains are both involved in cap snatching, but the role of the auxiliary PB2 627 domain, implicated in host range restriction of influenza A viruses, is still poorly understood. In this study, we used structure-guided truncations of the PB2 subunit to show that a PB2 subunit lacking the 627 domain accumulates in the cell nucleus and assembles into a heterotrimeric polymerase with PB1 and PA. Furthermore, we showed that a recombinant viral polymerase lacking the PB2 627 domain is able to carry out cap snatching, cap-dependent transcription initiation, and cap-independent ApG dinucleotide extension in vitro, indicating that the PB2 627 domain of the influenza virus RNA polymerase is not involved in core catalytic functions of the polymerase. However, in a cellular context, the 627 domain is essential for both transcription and replication. In particular, we showed that the PB2 627 domain is essential for the accumulation of the cRNA replicative intermediate in infected cells. Together, these results further our understanding of the role of the PB2 627 domain in transcription and replication of the influenza virus RNA genome. IMPORTANCE Influenza A viruses are a major global health threat, not only causing disease in both humans and birds but also placing significant strains on economies worldwide. Avian influenza A virus polymerases typically do not function efficiently in mammalian hosts and require adaptive mutations to restore polymerase activity. These adaptations include mutations in the 627 domain of the PB2 subunit of the viral polymerase, but it still remains to be established how these mutations enable host adaptation on a molecular level. In this report, we characterize the role of the 627 domain in polymerase function and offer insights into the replication mechanism of influenza A viruses.

scholarly journals A Non-phylogeny-dependent Reassortment Detection Method for Influenza A Viruses

2021 ◽  
Vol 1 ◽  
Author(s):  
Xingfei Gong ◽  
Mingda Hu ◽  
Boqian Wang ◽  
Haoyi Yang ◽  
Yuan Jin ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Detection Method ◽  
Rna Virus ◽  
Self Organizing Map ◽  
Influenza A Viruses ◽  
Multiple Sequence ◽  
Distance Methods ◽  
Virus Reassortment ◽  
Pandemic Strains

Influenza A virus is a segmented RNA virus whose genome consists of 8 single-stranded negative-sense RNA segments. This unique genetic structure allows viruses to exchange their segments through reassortment when they infect the same host cell. Studying the determination and nature of influenza A virus reassortment is critical to understanding the generation of pandemic strains and the spread of viruses across species. Reassortment detection is the first step in influenza A virus reassortment research. Several methods for automatic detection of reassortment have been proposed, which can be roughly divided into two categories: phylogenetic methods and distance methods. In this article, we proposed a reassortment detection method that does not require multiple sequence alignment and phylogenetic analysis. We extracted the codon features from the segment sequence and expressed the sequence as a feature vector, and then used the clustering method of self-organizing map to cluster the sequence for each segment. Based on the clustering results and the epidemiological information of the virus, the reassortment detection was implemented. We used this method to perform reassortment detection on the collected 7,075 strains from Asia and identified 516 reassortment events. We also conducted a statistical analysis of the identified reassortment events and found conclusions consistent with previous studies. Our method will provide new insights for automating reassortment detection tasks and understanding the reassortment patterns of influenza A viruses.

scholarly journals Model Suggesting that Replication of Influenza Virus Is Regulated by Stabilization of Replicative Intermediates

2004 ◽  
Vol 78 (17) ◽  
pp. 9568-9572 ◽  
Author(s):  
Frank T. Vreede ◽  
Tanis E. Jung ◽  
George G. Brownlee
Keyword(s):  
Rna Polymerase ◽  
Influenza A Virus ◽  
Influenza A ◽  
Rna Synthesis ◽  
Viral Rna ◽  
Mrna Transcription ◽  
Rna Dependent Rna Polymerase ◽  
Replicative Intermediates ◽  
Negative Sense ◽  
Transcription And Replication

ABSTRACT The RNA-dependent RNA polymerase of influenza A virus is responsible for both transcription and replication of negative-sense viral RNA. It is thought that a “switching” mechanism regulates the transition between these activities. We demonstrate that, in the presence of preexisting viral RNA polymerase and nucleoprotein (NP), influenza A virus synthesizes both mRNA (transcription) and cRNA (replication) early in infection. We suggest that there may be no switch regulating the initiation of RNA synthesis and present a model suggesting that nascent cRNA is degraded by host cell nucleases unless it is stabilized by newly synthesized viral RNA polymerase and NP.

A small molecule multi-kinase inhibitor reduces influenza A virus replication by restricting viral RNA synthesis

2013 ◽  
Vol 100 (1) ◽  
pp. 29-37 ◽  
Author(s):  
Luis Martinez-Gil ◽  
Judith G. Alamares-Sapuay ◽  
M.V. Ramana Reddy ◽  
Peter H. Goff ◽  
E. Premkumar Reddy ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Virus Replication ◽  
Small Molecule ◽  
Influenza A ◽  
Rna Synthesis ◽  
Kinase Inhibitor ◽  
Viral Rna

scholarly journals A Novel Small Molecule Inhibitor of Influenza A Viruses that Targets Polymerase Function and Indirectly Induces Interferon

2012 ◽  
Vol 8 (4) ◽  
pp. e1002668 ◽  
Author(s):  
Mila Brum Ortigoza ◽  
Oliver Dibben ◽  
Jad Maamary ◽  
Luis Martinez-Gil ◽  
Victor H. Leyva-Grado ◽  
...  
Keyword(s):  
Small Molecule ◽  
Influenza A ◽  
Small Molecule Inhibitor ◽  
Influenza A Viruses ◽  
Molecule Inhibitor

scholarly journals Zinc-embedded fabrics inactivate SARS-CoV-2 and influenza A virus

2020 ◽  
Author(s):  
Vikram Gopal ◽  
Benjamin E. Nilsson-Payant ◽  
Hollie French ◽  
Jurre Y. Siegers ◽  
Wai-shing Yung ◽  
...  
Keyword(s):  
Influenza A Virus ◽  
Influenza A ◽  
Rna Virus ◽  
Zinc Content ◽  
Respiratory Viruses ◽  
Zinc Ions ◽  
Liquid Droplets ◽  
Influenza A Viruses ◽  
Wide Range ◽  
Polyamide 6.6

AbstractInfections with respiratory viruses can spread via liquid droplets and aerosols, and cause diseases such as influenza and COVID-19. Face masks and other personal protective equipment (PPE) can act as barriers that prevent the spread of respiratory droplets containing these viruses. However, influenza A viruses and coronaviruses are stable for hours on various materials, which makes frequent and correct disposal of these PPE important. Metal ions embedded into PPE may inactivate respiratory viruses, but confounding factors such as absorption of viruses make measuring and optimizing the inactivation characteristics difficult. Here we used polyamide 6.6 (PA66) fibers that had zinc ions embedded during the polymerisation process and systematically investigated if these fibers can absorb and inactivate pandemic SARS-CoV-2 and influenza A virus H1N1. We find that these viruses are readily absorbed by PA66 fabrics and inactivated by zinc ions embedded into this fabric. The inactivation rate (pfu·gram−1·min−1) exceeds the number of active virus particles expelled by a cough and supports a wide range of viral loads. Moreover, we found that the zinc content and the virus inactivating property of the fabric remain stable over 50 standardized washes. Overall, these results provide new insight into the development of “pathogen-free” PPE and better protection against RNA virus spread.

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