scholarly journals Novel Antiviral Agent DTriP-22 Targets RNA-Dependent RNA Polymerase of Enterovirus 71

2009 ◽  
Vol 53 (7) ◽  
pp. 2740-2747 ◽  
Author(s):  
Tzu-Chun Chen ◽  
Hwan-You Chang ◽  
Pei-Fen Lin ◽  
Jyh-Haur Chern ◽  
John Tsu-An Hsu ◽  
...  
Keyword(s):  
Potent Inhibitor ◽  
Antiviral Agents ◽  
Enterovirus 71 ◽  
Antiviral Agent ◽  
Viral Rna ◽  
Drug Resistant ◽  
Rna Dependent Rna Polymerase ◽  
Rna Accumulation ◽  
Elongation Activity

ABSTRACT Enterovirus 71 (EV71) has emerged as an important virulent neurotropic enterovirus in young children. DTriP-22 (4{4-[(2-bromo-phenyl)-(3-methyl-thiophen-2-yl)-methyl]-piperazin-1-yl}-1-pheny-1H-pyrazolo[3,4-d]pyrimidine) was found to be a novel and potent inhibitor of EV71. The molecular target of this compound was identified by analyzing DTriP-22-resistant viruses. A substitution of lysine for Arg163 in EV71 3D polymerase rendered the virus drug resistant. DTriP-22 exhibited the ability to inhibit viral replication by reducing viral RNA accumulation. The compound suppressed the accumulated levels of both positive- and negative-stranded viral RNA during virus infection. An in vitro polymerase assay indicated that DTriP-22 inhibited the poly(U) elongation activity, but not the VPg uridylylation activity, of EV71 polymerase. These findings demonstrate that the nonnucleoside analogue DTriP-22 acts as a novel inhibitor of EV71 polymerase. DTriP-22 also exhibited a broad spectrum of antiviral activity against other picornaviruses, which highlights its potential in the development of antiviral agents.

scholarly journals Staufen1 Protein Participates Positively in the Viral RNA Replication of Enterovirus 71

Viruses ◽  
2019 ◽  
Vol 11 (2) ◽  
pp. 142 ◽  
Author(s):  
Young-Mao Chen ◽  
Bo-Ting Ou ◽  
Chao-Ying Chen ◽  
Han-Hsiang Chan ◽  
Chih-Jung Chen ◽  
...  
Keyword(s):  
Rna Binding ◽  
Rna Virus ◽  
Rna Stability ◽  
Enterovirus 71 ◽  
Viral Rna ◽  
Viral Translation ◽  
Rna Translation ◽  
Rna Accumulation

The double-stranded RNA-binding protein Staufen1 (Stau1) has multiple functions during RNA virus infection. In this study, we investigated the role of Stau1 in viral translation by using a combination of enterovirus 71 (EV-A71) infection, RNA reporter transfection, and in vitro functional and biochemical assays. We demonstrated that Stau1 specifically binds to the 5′-untranslated region of EV-A71 viral RNA. The RNA-binding domain 2-3 of Stau1 is responsible for this binding ability. Subsequently, we created a Stau1 knockout cell line using the CRISPR/Cas9 approach to further characterize the functional role of Stau1’s interaction with viral RNA in the EV-A71-infected cells. Both the viral RNA accumulation and viral protein expression were downregulated in the Stau1 knockout cells compared with the wild-type naïve cells. Moreover, dysregulation of viral RNA translation was observed in the Stau1 knockout cells using ribosome fractionation assay, and a reduced RNA stability of 5′-UTR of the EV-A71 was also identified using an RNA stability assay, which indicated that Stau1 has a role in facilitating viral translation during EV-A71 infection. In conclusion, we determined the functional relevance of Stau1 in the EV-A71 infection cycle and herein describe the mechanism of Stau1 participation in viral RNA translation through its interaction with viral RNA. Our results suggest that Stau1 is an important host factor involved in viral translation and influential early in the EV-A71 replication cycle.

scholarly journals Spatial Perturbations within an RNA Promoter Specifically Recognized by a Viral RNA-Dependent RNA Polymerase (RdRp) Reveal That RdRp Can Adjust Its Promoter Binding Sites

1999 ◽  
Vol 73 (1) ◽  
pp. 198-204 ◽  
Author(s):  
Scott Stevenson Stawicki ◽  
C. Cheng Kao
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Core Promoter ◽  
Brome Mosaic Virus ◽  
Viral Rna ◽  
Rna Dependent Rna Polymerase ◽  
Dna And Rna ◽  
In The Wild ◽  
Nucleotide Insertions

ABSTRACT RNA synthesis during viral replication requires specific recognition of RNA promoters by the viral RNA-dependent RNA polymerase (RdRp). Four nucleotides (−17, −14, −13, and −11) within the brome mosaic virus (BMV) subgenomic core promoter are required for RNA synthesis by the BMV RdRp (R. W. Siegel et al., Proc. Natl. Acad. Sci. USA 94:11238–11243, 1997). The spatial requirements for these four nucleotides and the initiation (+1) cytidylate were examined in RNAs containing nucleotide insertions and deletions within the BMV subgenomic core promoter. Spatial perturbations between nucleotides −17 and −11 resulted in decreased RNA synthesis in vitro. However, synthesis was still dependent on the key nucleotides identified in the wild-type core promoter and the initiation cytidylate. In contrast, changes between nucleotides −11 and +1 had a less severe effect on RNA synthesis but resulted in RNA products initiated at alternative locations in addition to the +1 cytidylate. The results suggest a degree of flexibility in the recognition of the subgenomic promoter by the BMV RdRp and are compared with functional regions in other DNA and RNA promoters.

scholarly journals Comparative in vitro imunotoxicology of acyclovir and other antiviral agents

1980 ◽  
Vol 28 (3) ◽  
pp. 957-962 ◽  
Author(s):  
R W Steele ◽  
D J Marmer ◽  
R E Keeney
Keyword(s):  
Cytosine Arabinoside ◽  
Antiviral Agents ◽  
Specific Antigen ◽  
Antiviral Agent ◽  
Inhibitory Factor ◽  
Adenine Arabinoside ◽  
Leukocyte Inhibitory Factor ◽  
Herpes Group ◽  
Cellular Immune

In vitro lymphocyte blastogenic responses to the commonly employed mitogens phytohemagglutinin, pokeweed, and concanavalin A were evaluated when acyclovir, adenine arabinoside, cytosine arabinoside, and idoxuridine were added to the culture materials. Similarly, specific antigen-induced blastogenic responses, including herpes group antigens, and cytotoxicity and leukocyte inhibitory factor assays with herpes group viruses were determined in the presence and absence of antiviral agents. No depression of these cellular immmune responses by acyclovir or adenine arabinoside ws demonstrated. This was in contrast to the effects of cytosine arabinoside and idoxuridine, which severely inhibited blastogenic and cytotoxic responses but not leukocyte inhibitory factor production. Even at concentrations up to 20 microgram/ml, the antiviral agent acyclovir did not depress selected cellular immune responses that are important for successful elimination of invading herpes group viruses.

scholarly journals Has Ivermectin Virus-Directed Effects against SARS-CoV-2? Rationalizing the Action of a Potential Multitarget Antiviral Agent

2020 ◽  
Author(s):  
Antonio Francés-Monerris ◽  
Cristina Garcia-Iriepa ◽  
Isabel Iriepa ◽  
Cecilia Hognon ◽  
Tom Miclot ◽  
...  
Keyword(s):  
Wide Spectrum ◽  
Antiviral Agents ◽  
Antiviral Agent ◽  
Host Immune System ◽  
Structural Protein ◽  
Cell Infection ◽  
Viral Proteases ◽  
Potent Inhibition ◽  
Dynamics Simulations

The novel SARS-CoV-2 coronavirus is causing a devastating pandemic in 2020, threatening public health in many countries. An unprecedented rapid and global response has been set in motion to identify efficient antiviral agents against SARS-CoV-2, mostly relying on the repurposing of drugs presenting or not previously known antiviral activity. Ivermectin is an approved drug used as antiparasitic in humans and animals with well documented broad-spectrum antiviral properties that emerge from host-directed effects. Recent results reported by Wagstaff and coworkers (Antiviral Research <b>2020</b>, <i>178</i>, 104787) show a potent inhibition of SARS-CoV-2 replication <i>in vitro </i>by ivermectin, and clinical trials with human volunteers have already started. However, the mode of action of ivermectin is still largely unknown, especially at the molecular level. Here, we employ advanced molecular dynamics simulations to assess the influence of ivermectin on several key viral protein targets, with the aim to reveal the molecular bases of antiviral mechanisms against SARS-CoV-2. Interestingly, we show that ivermectin could be regarded as a multitarget agent, inhibiting different viral functions. These include blocking the recognition by the SARS-CoV-2 Receptor Binding Domain (RBD) of the Angiotensin-Converting Enzyme 2 (ACE2), the interactions with the two viral proteases 3CL<sup>pro</sup> and PL<sup>pro</sup>, and the SARS Unique Domain (SUD) non-structural protein. Hence, the wide spectrum of actions involving i) the interference with cell infection, ii) the inhibition of viral replication, and iii) elusion of the host immune system, could point to an unprecedented synergy between host- and virus-directed effects explaining the high anti-SARS-CoV-2 activity observed for this compound.

scholarly journals Structural and Functional Analysis of the cis-Acting Elements Required for Plus-Strand RNA Synthesis of Bamboo Mosaic Virus

2005 ◽  
Vol 79 (14) ◽  
pp. 9046-9053 ◽  
Author(s):  
Jen-Wen Lin ◽  
Hsiao-Ning Chiu ◽  
I-Hsuan Chen ◽  
Tzu-Chi Chen ◽  
Yau-Heiu Hsu ◽  
...  
Keyword(s):  
Mosaic Virus ◽  
Rna Synthesis ◽  
Viral Rna ◽  
Minus Strand ◽  
Internal Deletion ◽  
Stem Loop ◽  
Cis Acting ◽  
Rna Accumulation

ABSTRACT Bamboo mosaic virus (BaMV) has a single-stranded positive-sense RNA genome. The secondary structure of the 3′-terminal sequence of the minus-strand RNA has been predicted by MFOLD and confirmed by enzymatic structural probing to consist of a large, stable stem-loop and a small, unstable stem-loop. To identify the promoter for plus-strand RNA synthesis in this region, transcripts of 39, 77, and 173 nucleotides (Ba-39, Ba-77, and Ba-173, respectively) derived from the 3′ terminus of the minus-strand RNA were examined by an in vitro RNA-dependent RNA polymerase assay for the ability to direct RNA synthesis. Ba-77 and Ba-39 appeared to direct the RNA synthesis efficiently, while Ba-173 failed. Ba-77/Δ5, with a deletion of the 3′-terminal UUUUC sequence in Ba-77, directed the RNA synthesis only to 7% that of Ba-77. However, Ba-77/Δ16 and Ba-77/Δ31, with longer deletions but preserving the terminal UUUUC sequence of Ba-77, restored the template activity to about 60% that of the wild type. Moreover, mutations that changed the sequence in the stem of the large stem-loop interfered with the efficiency of RNA synthesis and RNA accumulation in vivo. The mutant with an internal deletion in the region between the terminal UUUUC sequence and the large stem-loop reduced the viral RNA accumulation in protoplasts, but mutants with insertions did not. Taken together, these results suggest that three cis-acting elements in the 3′ end of the minus-strand RNA, namely, the terminal UUUUC sequence, the sequence in the large stem-loop, and the distance between these two regions, are involved in modulating the efficiency of BaMV plus-strand viral RNA synthesis.

scholarly journals The Imidazopyrrolopyridine Analogue AG110 Is a Novel, Highly Selective Inhibitor of Pestiviruses That Targets the Viral RNA-Dependent RNA Polymerase at a Hot Spot for Inhibition of Viral Replication

2007 ◽  
Vol 81 (20) ◽  
pp. 11046-11053 ◽  
Author(s):  
Jan Paeshuyse ◽  
Jean-Michel Chezal ◽  
Matheus Froeyen ◽  
Pieter Leyssen ◽  
Hélène Dutartre ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Rna Synthesis ◽  
Hot Spot ◽  
Resistance Mutation ◽  
Drug Resistance Mutation ◽  
Drug Binding ◽  
Viral Rna ◽  
Rna Dependent Rna Polymerase ◽  
Diarrhea Virus

ABSTRACT Ethyl 2-methylimidazo[1,2-a]pyrrolo[2,3-c]pyridin-8-carboxylate (AG110) was identified as a potent inhibitor of pestivirus replication. The 50% effective concentration values for inhibition of bovine viral diarrhea virus (BVDV)-induced cytopathic effect, viral RNA synthesis, and production of infectious virus were 1.2 ± 0.5 μM, 5 ± 1 μM, and 2.3 ± 0.3 μM, respectively. AG110 proved inactive against the hepatitis C virus and a flavivirus. AG110 inhibits BVDV replication at a time point that coincides with the onset of intracellular viral RNA synthesis. Drug-resistant mutants carry the E291G mutation in the viral RNA-dependent RNA polymerase (RdRp). AG110-resistant virus is cross-resistant to the cyclic urea compound 1453 which also selects for the E291G drug resistance mutation. Moreover, BVDV that carries the F224S mutation (because of resistance to the imidazopyridine 5-[(4-bromophenyl)methyl]-2-phenyl-5H-imidazo[4,5-c]pyridine [BPIP]and VP32947) is also resistant to AG110. AG110 did not inhibit the in vitro activity of recombinant BVDV RdRp but inhibited the activity of BVDV replication complexes (RCs). Molecular modeling revealed that E291 is located in a small cavity near the tip of the finger domain of the RdRp about 7 Å away from F224. Docking of AG110 in the crystal structure of the BVDV RdRp revealed several potential contacts including with Y257. The E291G mutation might enable the free rotation of Y257, which might in turn destabilize the backbone of the loop formed by residues 223 to 226, rendering more mobility to F224 and, hence, reducing the affinity for BPIP and VP32947. It is concluded that a single drug-binding pocket exists within the finger domain region of the BVDV RdRp that consists of two separate but potentially overlapping binding sites rather than two distinct drug-binding pockets.

scholarly journals Establishment of an antiviral assay system and identification of severe fever with thrombocytopenia syndrome virus inhibitors

2017 ◽  
Vol 25 (3) ◽  
pp. 83-89 ◽  
Author(s):  
Masanori Baba ◽  
Masaaki Toyama ◽  
Norikazu Sakakibara ◽  
Mika Okamoto ◽  
Naomichi Arima ◽  
...  
Keyword(s):  
Antiviral Agents ◽  
Vero Cells ◽  
Assay System ◽  
Viral Rna ◽  
University Hospital ◽  
Selective Inhibitors ◽  
Reverse Transcription Pcr ◽  
The Family ◽  
Severe Fever

Aims Severe fever with thrombocytopenia syndrome (SFTS) is an emerging tick-borne infectious disease. SFTS is epidemic in Asia, and its fatality rate is around 30% in Japan. The causative virus severe fever with thrombocytopenia syndrome virus (SFTSV) is a phlebovirus of the family Phenuiviridae (the order Bunyavirales). Although effective treatments are required, there are no antiviral agents currently approved for clinical use. Ribavirin and favipiravir were examined for their anti-SFTSV activity and found to be selective inhibitors of SFTSV replication in vitro. However, their activity was not sufficient. Therefore, it is mandatory to identify novel compounds active against SFTSV. To this end, we have established a safe and rapid assay system for screening selective inhibitors of SFTSV. Methods The virus was isolated from SFTS patients treated in Kagoshima University Hospital. Vero cells were infected with SFTSV and incubated in the presence of various concentrations of test compounds. After three days, the cells were examined for their intracellular viral RNA levels by real-time reverse transcription-PCR without extracting viral RNA. The cytotoxicity of test compounds was determined by a tetrazolium dye method. Results Among the test compounds, the antimalarial agent amodiaquine was identified as a selective inhibitor of SFTSV replication. Its 50% effective concentration (EC50) and cytotoxic concentration (CC50) were 19.1 ± 5.1 and >100 µM, respectively. The EC50 value of amodiaquine was comparable to those of ribavirin and favipiravir. Conclusion Amodiaquine is considered to be a promising lead of novel anti-SFTSV agents, and evaluating the anti-SFTSV activity of its derivatives is in progress.

scholarly journals High-throughput human primary cell-based airway model for evaluating influenza, coronavirus, or other respiratory viruses in vitro

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. L. Gard ◽  
R. J. Luu ◽  
C. R. Miller ◽  
R. Maloney ◽  
B. P. Cain ◽  
...  
Keyword(s):  
Influenza A ◽  
Rapid Assessment ◽  
Antiviral Agents ◽  
Antiviral Agent ◽  
Respiratory Viruses ◽  
Airway Epithelial Cells ◽  
Host Cells ◽  
Preclinical Model ◽  
Airway Epithelial

AbstractInfluenza and other respiratory viruses present a significant threat to public health, national security, and the world economy, and can lead to the emergence of global pandemics such as from COVID-19. A barrier to the development of effective therapeutics is the absence of a robust and predictive preclinical model, with most studies relying on a combination of in vitro screening with immortalized cell lines and low-throughput animal models. Here, we integrate human primary airway epithelial cells into a custom-engineered 96-device platform (PREDICT96-ALI) in which tissues are cultured in an array of microchannel-based culture chambers at an air–liquid interface, in a configuration compatible with high resolution in-situ imaging and real-time sensing. We apply this platform to influenza A virus and coronavirus infections, evaluating viral infection kinetics and antiviral agent dosing across multiple strains and donor populations of human primary cells. Human coronaviruses HCoV-NL63 and SARS-CoV-2 enter host cells via ACE2 and utilize the protease TMPRSS2 for spike protein priming, and we confirm their expression, demonstrate infection across a range of multiplicities of infection, and evaluate the efficacy of camostat mesylate, a known inhibitor of HCoV-NL63 infection. This new capability can be used to address a major gap in the rapid assessment of therapeutic efficacy of small molecules and antiviral agents against influenza and other respiratory viruses including coronaviruses.

scholarly journals Fast and efficient purification of SARS-CoV-2 RNA dependent RNA polymerase complex expressed in Escherichia coli

PLoS ONE ◽  
2021 ◽  
Vol 16 (4) ◽  
pp. e0250610
Author(s):  
Clément Madru ◽  
Ayten Dizkirici Tekpinar ◽  
Sandrine Rosario ◽  
Dariusz Czernecki ◽  
Sébastien Brûlé ◽  
...  
Keyword(s):  
Rna Polymerase ◽  
Insect Cells ◽  
Antiviral Agents ◽  
Chemical Compounds ◽  
Rna Dependent Rna Polymerase ◽  
Rna Polymerization ◽  
Purification Protocol ◽  
Transcription And Replication

To stop the COVID-19 pandemic due to the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), which caused more than 2.5 million deaths to date, new antiviral molecules are urgently needed. The replication of SARS-CoV-2 requires the RNA-dependent RNA polymerase (RdRp), making RdRp an excellent target for antiviral agents. RdRp is a multi-subunit complex composed of 3 viral proteins named nsp7, nsp8 and nsp12 that ensure the ~30 kb RNA genome’s transcription and replication. The main strategies employed so far for the overproduction of RdRp consist of expressing and purifying the three subunits separately before assembling the complex in vitro. However, nsp12 shows limited solubility in bacterial expression systems and is often produced in insect cells. Here, we describe an alternative strategy to co-express the full SARS-CoV-2 RdRp in E. coli, using a single plasmid. Characterization of the purified recombinant SARS-CoV-2 RdRp shows that it forms a complex with the expected (nsp7)(nsp8)2(nsp12) stoichiometry. RNA polymerization activity was measured using primer-extension assays showing that the purified enzyme is functional. The purification protocol can be achieved in one single day, surpassing in speed all other published protocols. Our construct is ideally suited for screening RdRp and its variants against very large chemical compounds libraries and has been made available to the scientific community through the Addgene plasmid depository (Addgene ID: 165451).

scholarly journals Sterilization of drug-resistant influenza virus through genetic interference: use of unnatural amino acid-engineered virions

2021 ◽  
Author(s):  
Xuesheng Wu ◽  
Zhetao Zheng ◽  
Hongmin Chen ◽  
Haishuang Lin ◽  
Yuelin Yang ◽  
...  
Keyword(s):  
Influenza Virus ◽  
Amino Acid ◽  
Genetic Code ◽  
Unnatural Amino Acids ◽  
Influenza A ◽  
Antiviral Agent ◽  
Unnatural Amino Acid ◽  
Drug Resistant ◽  
Genetic Code Expansion

AbstractThe frequent emergence of drug resistance during the treatment of influenza A virus (IAV) infections highlights a need for effective antiviral countermeasures. Here, we present an antiviral method that utilizes unnatural amino acid-engineered drug-resistant (UAA-DR) virus. The engineered virus is generated through genetic code expansion to combat emerging drug-resistant viruses. The UAA-DR virus has unnatural amino acids incorporated into its drug-resistant protein and its polymerase complex for replication control. The engineered virus can undergo genomic segment reassortment with normal virus and produce sterilized progenies due to artificial amber codons in the viral genome. We validate in vitro that UAA-DR can provide a broad-spectrum antiviral strategy for several H1N1 strains, different DR-IAV strains, multidrug-resistant (MDR) strains, and even antigenically distant influenza strains (e.g., H3N2). Moreover, a minimum dose of neuraminidase (NA) inhibitors for influenza virus can further enhance the sterilizing effect when combating inhibitor-resistant strains, partly due to the promoted superinfection of unnatural amino acid-modified virus in cellular and animal models. We also exploited the engineered virus to achieve adjustable efficacy after external UAA administration, for mitigating DR virus infection on transgenic mice harboring the pair, and to have substantial elements of the genetic code expansion technology, which further demonstrated the safety and feasibility of the strategy. We anticipate that the use of the UAA-engineered DR virion, which is a novel antiviral agent, could be extended to combat emerging drug-resistant influenza virus and other segmented RNA viruses.

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